[PATCH 0/7] I2C GPIO to use gpiolibs open drain

[PATCH 0/7] I2C GPIO to use gpiolibs open drain

[Linus Walleij]

This augments the I2C GPIO driver to use open drain emulation
or hardware support for open drain from the GPIO driver.

This version layers Geert Uytterhoeven's idea to use explicit
sda-gpios and scl-gpios for the GPIO lines, and strongly
encourage the (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) flags to be
used in all device trees.

We have collected ACKs from the ARM SoC maintainers and the
MFD maintainer and are looking for testers to try this out.

Geert Uytterhoeven (1):
  dt-bindings: i2c: i2c-gpio: Add support for named gpios

Linus Walleij (6):
  i2c: gpio: Convert to use descriptors
  gpio: Make it possible for consumers to enforce open drain
  i2c: gpio: Enforce open drain through gpiolib
  i2c: gpio: Augment all boardfiles to use open drain
  i2c: gpio: Local vars in probe
  i2c: gpio: Add support for named gpios in DT

 Documentation/devicetree/bindings/i2c/i2c-gpio.txt |  32 +++-
 arch/arm/mach-ep93xx/core.c                        |  41 ++--
 arch/arm/mach-ep93xx/edb93xx.c                     |  15 +-
 arch/arm/mach-ep93xx/include/mach/platform.h       |   4 +-
 arch/arm/mach-ep93xx/simone.c                      |  12 +-
 arch/arm/mach-ep93xx/snappercl15.c                 |  12 +-
 arch/arm/mach-ep93xx/vision_ep9307.c               |   7 +-
 arch/arm/mach-ixp4xx/avila-setup.c                 |  17 +-
 arch/arm/mach-ixp4xx/dsmg600-setup.c               |  16 +-
 arch/arm/mach-ixp4xx/fsg-setup.c                   |  16 +-
 arch/arm/mach-ixp4xx/goramo_mlr.c                  |  24 +--
 arch/arm/mach-ixp4xx/ixdp425-setup.c               |  16 +-
 arch/arm/mach-ixp4xx/nas100d-setup.c               |  16 +-
 arch/arm/mach-ixp4xx/nslu2-setup.c                 |  16 +-
 arch/arm/mach-ks8695/board-acs5k.c                 |  15 +-
 arch/arm/mach-pxa/palmz72.c                        |  14 +-
 arch/arm/mach-pxa/viper.c                          |  27 ++-
 arch/arm/mach-sa1100/simpad.c                      |  14 +-
 arch/blackfin/mach-bf533/boards/blackstamp.c       |  19 +-
 arch/blackfin/mach-bf533/boards/ezkit.c            |  18 +-
 arch/blackfin/mach-bf533/boards/stamp.c            |  18 +-
 arch/blackfin/mach-bf561/boards/ezkit.c            |  18 +-
 arch/mips/alchemy/board-gpr.c                      |  23 ++-
 arch/mips/ath79/mach-pb44.c                        |  16 +-
 drivers/gpio/gpiolib.c                             |  13 ++
 drivers/i2c/busses/i2c-gpio.c                      | 213 ++++++++++-----------
 drivers/mfd/sm501.c                                |  49 ++---
 include/linux/gpio/consumer.h                      |   6 +
 include/linux/i2c-gpio.h                           |   4 -
 29 files changed, 423 insertions(+), 288 deletions(-)

-- 
2.13.5

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Linus Walleij]

This converts the GPIO-based I2C-driver to using GPIO
descriptors instead of the old global numberspace-based
GPIO interface. We:

- Convert the driver to unconditionally grab two GPIOs
  from the device by index 0 (SDA) and 1 (SCL) which
  will work fine with device tree and descriptor tables.
  The existing device trees will continue to work just
  like before, but without any roundtrip through the
  global numberspace.

- Brutally convert all boardfiles still passing global
  GPIOs by registering descriptor tables associated with
  the devices instead so this driver does not need to keep
  supporting passing any GPIO numbers as platform data.

There is no stepwise approach as elegant as this, I
strongly prefer this big hammer over any antsteps for this
conversion. This way the old GPIO numbers go away and
NEVER COME BACK.

Special conversion for the different boards utilizing
I2C-GPIO:

- EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
  all boards were using the same two GPIO lines, just define
  these two in a lookup table for "i2c-gpio" and register
  these along with the device. None of them define any
  other platform data so just pass NULL as platform data.
  This platform selects GPIOLIB so all should be smooth.
  The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
  and 0 (SCL).

- IXP4 (arch/arm/mach-ixp4): descriptor tables have to
  be registered for each board separately. They all use
  "IXP4XX_GPIO_CHIP" so it is pretty straight forward.
  Most board define no other platform data than SCL/SDA
  so they can drop the #include of <linux/i2c-gpio.h> and
  assign NULL to platform data.

  The "goramo_mlr" (Goramo Multilink Router) board is a bit
  worrisome: it implements its own I2C bit-banging in the
  board file, and optionally registers an I2C serial port,
  but claims the same GPIO lines for itself in the board file.
  This is not going to work: there will be competition for the
  GPIO lines, so delete the optional extra I2C bus instead, no
  I2C devices are registered on it anyway, there are just hints
  that it may contain an EEPROM that may be accessed from
  userspace. This needs to be fixed up properly by the serial
  clock using I2C emulation so drop a note in the code.

- KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
  has some platform data in addition to the pins so it needs to
  be kept around sans GPIO lines. Its GPIO chip is named
  "KS8695" and the arch selects GPIOLIB.

- PXA boards (arch/arm/mach-pxa/*) use some of the platform
  data so it needs to be preserved here. The viper board even
  registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
  the arch selects GPIOLIB.

- SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
  I2C bus, and the arch selects GPIOLIB.

- Blackfin boards (arch/blackfin/bf533 etc) for these I assume
  their I2C GPIOs refer to the local gpiochip defined in
  arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
  The arch selects GPIOLIB. The boards get spiked with
  IF_ENABLED(I2C_GPIO) but that is a side effect of it
  being like that already (I would just have Kconfig select
  I2C_GPIO and get rid of them all.) I also delete any
  platform data set to 0 as it will get that value anyway
  from static declartions of platform data.

- The MIPS selects GPIOLIB and the Alchemy machine is using
  two local GPIO chips, one of them has a GPIO I2C. We need
  to adjust the local offset from the global number space here.
  The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
  and AFAICT the chip is named "ath79-gpio" and the PB44
  PCF857x expander spawns from this on GPIO 1 and 0. The latter
  board only use the platform data to specify pins so it can be
  cut altogether after this.

- The MFD Silicon Motion SM501 is a special case. It dynamically
  spawns an I2C bus off the MFD using sm501_create_subdev().
  We use an approach to dynamically create a machine descriptor
  table and attach this to the "SM501-LOW" or "SM501-HIGH"
  gpiochip. We use chip-local offsets to grab the right lines.
  We can get rid of two local static inline helpers as part
  of this refactoring.

Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Ville Syrj?l? <ville.syrjala@linux.intel.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Heiko Schocher <hs@denx.de>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v1->v2:
- Fix a minor typo in error path (scl was sda from copy-paste)
- Collected Olof's ACK

Steven (Blackfin): requesting ACK for Wolfram to take this patch.
Ralf (MIPS): requesting ACK for Wolfram to take this patch.
Lee: requesting ACK for Wolfram to take this patch.
SM501 users: requesting Tested-by on this patch.
---
 arch/arm/mach-ep93xx/core.c                  |  39 ++++----
 arch/arm/mach-ep93xx/edb93xx.c               |  15 +--
 arch/arm/mach-ep93xx/include/mach/platform.h |   4 +-
 arch/arm/mach-ep93xx/simone.c                |  12 +--
 arch/arm/mach-ep93xx/snappercl15.c           |  12 +--
 arch/arm/mach-ep93xx/vision_ep9307.c         |   7 +-
 arch/arm/mach-ixp4xx/avila-setup.c           |  17 +++-
 arch/arm/mach-ixp4xx/dsmg600-setup.c         |  16 +++-
 arch/arm/mach-ixp4xx/fsg-setup.c             |  16 +++-
 arch/arm/mach-ixp4xx/goramo_mlr.c            |  24 ++---
 arch/arm/mach-ixp4xx/ixdp425-setup.c         |  16 +++-
 arch/arm/mach-ixp4xx/nas100d-setup.c         |  16 +++-
 arch/arm/mach-ixp4xx/nslu2-setup.c           |  16 +++-
 arch/arm/mach-ks8695/board-acs5k.c           |  13 ++-
 arch/arm/mach-pxa/palmz72.c                  |  12 ++-
 arch/arm/mach-pxa/viper.c                    |  27 +++++-
 arch/arm/mach-sa1100/simpad.c                |  12 ++-
 arch/blackfin/mach-bf533/boards/blackstamp.c |  19 +++-
 arch/blackfin/mach-bf533/boards/ezkit.c      |  18 +++-
 arch/blackfin/mach-bf533/boards/stamp.c      |  18 +++-
 arch/blackfin/mach-bf561/boards/ezkit.c      |  18 +++-
 arch/mips/alchemy/board-gpr.c                |  19 +++-
 arch/mips/ath79/mach-pb44.c                  |  16 +++-
 drivers/i2c/busses/i2c-gpio.c                | 134 +++++++++++++--------------
 drivers/mfd/sm501.c                          |  49 +++++-----
 include/linux/i2c-gpio.h                     |   4 -
 26 files changed, 327 insertions(+), 242 deletions(-)

diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c
index c393b1b0310d..6b4754ecaffc 100644
--- a/arch/arm/mach-ep93xx/core.c
+++ b/arch/arm/mach-ep93xx/core.c
@@ -31,7 +31,7 @@
 #include <linux/amba/serial.h>
 #include <linux/mtd/physmap.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/spi/spi.h>
 #include <linux/export.h>
 #include <linux/irqchip/arm-vic.h>
@@ -320,42 +320,45 @@ void __init ep93xx_register_eth(struct ep93xx_eth_data *data, int copy_addr)
 /*************************************************************************
  * EP93xx i2c peripheral handling
  *************************************************************************/
-static struct i2c_gpio_platform_data ep93xx_i2c_data;
+
+/* All EP93xx devices use the same two GPIO pins for I2C bit-banging */
+static struct gpiod_lookup_table ep93xx_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		/* Use local offsets on gpiochip/port "G" */
+		GPIO_LOOKUP_IDX("G", 1, NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("G", 0, NULL, 1, GPIO_ACTIVE_HIGH),
+	},
+};
 
 static struct platform_device ep93xx_i2c_device = {
 	.name		= "i2c-gpio",
 	.id		= 0,
 	.dev		= {
-		.platform_data	= &ep93xx_i2c_data,
+		.platform_data	= NULL,
 	},
 };
 
 /**
  * ep93xx_register_i2c - Register the i2c platform device.
- * @data:	platform specific i2c-gpio configuration (__initdata)
  * @devices:	platform specific i2c bus device information (__initdata)
  * @num:	the number of devices on the i2c bus
  */
-void __init ep93xx_register_i2c(struct i2c_gpio_platform_data *data,
-				struct i2c_board_info *devices, int num)
+void __init ep93xx_register_i2c(struct i2c_board_info *devices, int num)
 {
 	/*
-	 * Set the EEPROM interface pin drive type control.
-	 * Defines the driver type for the EECLK and EEDAT pins as either
-	 * open drain, which will require an external pull-up, or a normal
-	 * CMOS driver.
+	 * FIXME: this just sets the two pins as non-opendrain, as no
+	 * platforms tries to do that anyway. Flag the applicable lines
+	 * as open drain in the GPIO_LOOKUP above and the driver or
+	 * gpiolib will handle open drain/open drain emulation as need
+	 * be. Right now i2c-gpio emulates open drain which is not
+	 * optimal.
 	 */
-	if (data->sda_is_open_drain && data->sda_pin != EP93XX_GPIO_LINE_EEDAT)
-		pr_warning("sda != EEDAT, open drain has no effect\n");
-	if (data->scl_is_open_drain && data->scl_pin != EP93XX_GPIO_LINE_EECLK)
-		pr_warning("scl != EECLK, open drain has no effect\n");
-
-	__raw_writel((data->sda_is_open_drain << 1) |
-		     (data->scl_is_open_drain << 0),
+	__raw_writel((0 << 1) | (0 << 0),
 		     EP93XX_GPIO_EEDRIVE);
 
-	ep93xx_i2c_data = *data;
 	i2c_register_board_info(0, devices, num);
+	gpiod_add_lookup_table(&ep93xx_i2c_gpiod_table);
 	platform_device_register(&ep93xx_i2c_device);
 }
 
diff --git a/arch/arm/mach-ep93xx/edb93xx.c b/arch/arm/mach-ep93xx/edb93xx.c
index 0ac176386789..7e8f6f580fc3 100644
--- a/arch/arm/mach-ep93xx/edb93xx.c
+++ b/arch/arm/mach-ep93xx/edb93xx.c
@@ -28,7 +28,6 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
 #include <linux/spi/spi.h>
 
 #include <sound/cs4271.h>
@@ -61,14 +60,6 @@ static struct ep93xx_eth_data __initdata edb93xx_eth_data = {
 /*************************************************************************
  * EDB93xx i2c peripheral handling
  *************************************************************************/
-static struct i2c_gpio_platform_data __initdata edb93xx_i2c_gpio_data = {
-	.sda_pin		= EP93XX_GPIO_LINE_EEDAT,
-	.sda_is_open_drain	= 0,
-	.scl_pin		= EP93XX_GPIO_LINE_EECLK,
-	.scl_is_open_drain	= 0,
-	.udelay			= 0,	/* default to 100 kHz */
-	.timeout		= 0,	/* default to 100 ms */
-};
 
 static struct i2c_board_info __initdata edb93xxa_i2c_board_info[] = {
 	{
@@ -86,13 +77,11 @@ static void __init edb93xx_register_i2c(void)
 {
 	if (machine_is_edb9302a() || machine_is_edb9307a() ||
 	    machine_is_edb9315a()) {
-		ep93xx_register_i2c(&edb93xx_i2c_gpio_data,
-				    edb93xxa_i2c_board_info,
+		ep93xx_register_i2c(edb93xxa_i2c_board_info,
 				    ARRAY_SIZE(edb93xxa_i2c_board_info));
 	} else if (machine_is_edb9302() || machine_is_edb9307()
 		|| machine_is_edb9312() || machine_is_edb9315()) {
-		ep93xx_register_i2c(&edb93xx_i2c_gpio_data,
-				    edb93xx_i2c_board_info,
+		ep93xx_register_i2c(edb93xx_i2c_board_info,
 				    ARRAY_SIZE(edb93xx_i2c_board_info));
 	}
 }
diff --git a/arch/arm/mach-ep93xx/include/mach/platform.h b/arch/arm/mach-ep93xx/include/mach/platform.h
index 4c0bbd97f741..df2928aacf7c 100644
--- a/arch/arm/mach-ep93xx/include/mach/platform.h
+++ b/arch/arm/mach-ep93xx/include/mach/platform.h
@@ -7,7 +7,6 @@
 #include <linux/reboot.h>
 
 struct device;
-struct i2c_gpio_platform_data;
 struct i2c_board_info;
 struct spi_board_info;
 struct platform_device;
@@ -36,8 +35,7 @@ void ep93xx_register_flash(unsigned int width,
 			   resource_size_t start, resource_size_t size);
 
 void ep93xx_register_eth(struct ep93xx_eth_data *data, int copy_addr);
-void ep93xx_register_i2c(struct i2c_gpio_platform_data *data,
-			 struct i2c_board_info *devices, int num);
+void ep93xx_register_i2c(struct i2c_board_info *devices, int num);
 void ep93xx_register_spi(struct ep93xx_spi_info *info,
 			 struct spi_board_info *devices, int num);
 void ep93xx_register_fb(struct ep93xxfb_mach_info *data);
diff --git a/arch/arm/mach-ep93xx/simone.c b/arch/arm/mach-ep93xx/simone.c
index c7a40f245892..e61f3dee24c2 100644
--- a/arch/arm/mach-ep93xx/simone.c
+++ b/arch/arm/mach-ep93xx/simone.c
@@ -19,7 +19,6 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
 #include <linux/mmc/host.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/mmc_spi.h>
@@ -129,15 +128,6 @@ static struct ep93xx_spi_info simone_spi_info __initdata = {
 	.use_dma = 1,
 };
 
-static struct i2c_gpio_platform_data __initdata simone_i2c_gpio_data = {
-	.sda_pin		= EP93XX_GPIO_LINE_EEDAT,
-	.sda_is_open_drain	= 0,
-	.scl_pin		= EP93XX_GPIO_LINE_EECLK,
-	.scl_is_open_drain	= 0,
-	.udelay			= 0,
-	.timeout		= 0,
-};
-
 static struct i2c_board_info __initdata simone_i2c_board_info[] = {
 	{
 		I2C_BOARD_INFO("ds1337", 0x68),
@@ -161,7 +151,7 @@ static void __init simone_init_machine(void)
 	ep93xx_register_flash(2, EP93XX_CS6_PHYS_BASE, SZ_8M);
 	ep93xx_register_eth(&simone_eth_data, 1);
 	ep93xx_register_fb(&simone_fb_info);
-	ep93xx_register_i2c(&simone_i2c_gpio_data, simone_i2c_board_info,
+	ep93xx_register_i2c(simone_i2c_board_info,
 			    ARRAY_SIZE(simone_i2c_board_info));
 	ep93xx_register_spi(&simone_spi_info, simone_spi_devices,
 			    ARRAY_SIZE(simone_spi_devices));
diff --git a/arch/arm/mach-ep93xx/snappercl15.c b/arch/arm/mach-ep93xx/snappercl15.c
index b2db791b3b38..eeab863b60ca 100644
--- a/arch/arm/mach-ep93xx/snappercl15.c
+++ b/arch/arm/mach-ep93xx/snappercl15.c
@@ -21,7 +21,6 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
 #include <linux/fb.h>
 
 #include <linux/mtd/partitions.h>
@@ -127,15 +126,6 @@ static struct ep93xx_eth_data __initdata snappercl15_eth_data = {
 	.phy_id			= 1,
 };
 
-static struct i2c_gpio_platform_data __initdata snappercl15_i2c_gpio_data = {
-	.sda_pin		= EP93XX_GPIO_LINE_EEDAT,
-	.sda_is_open_drain	= 0,
-	.scl_pin		= EP93XX_GPIO_LINE_EECLK,
-	.scl_is_open_drain	= 0,
-	.udelay			= 0,
-	.timeout		= 0,
-};
-
 static struct i2c_board_info __initdata snappercl15_i2c_data[] = {
 	{
 		/* Audio codec */
@@ -161,7 +151,7 @@ static void __init snappercl15_init_machine(void)
 {
 	ep93xx_init_devices();
 	ep93xx_register_eth(&snappercl15_eth_data, 1);
-	ep93xx_register_i2c(&snappercl15_i2c_gpio_data, snappercl15_i2c_data,
+	ep93xx_register_i2c(snappercl15_i2c_data,
 			    ARRAY_SIZE(snappercl15_i2c_data));
 	ep93xx_register_fb(&snappercl15_fb_info);
 	snappercl15_register_audio();
diff --git a/arch/arm/mach-ep93xx/vision_ep9307.c b/arch/arm/mach-ep93xx/vision_ep9307.c
index 1daf9441058c..5a0b6187990a 100644
--- a/arch/arm/mach-ep93xx/vision_ep9307.c
+++ b/arch/arm/mach-ep93xx/vision_ep9307.c
@@ -22,7 +22,6 @@
 #include <linux/io.h>
 #include <linux/mtd/partitions.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
 #include <linux/platform_data/pca953x.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/flash.h>
@@ -144,10 +143,6 @@ static struct pca953x_platform_data pca953x_77_gpio_data = {
 /*************************************************************************
  * I2C Bus
  *************************************************************************/
-static struct i2c_gpio_platform_data vision_i2c_gpio_data __initdata = {
-	.sda_pin		= EP93XX_GPIO_LINE_EEDAT,
-	.scl_pin		= EP93XX_GPIO_LINE_EECLK,
-};
 
 static struct i2c_board_info vision_i2c_info[] __initdata = {
 	{
@@ -289,7 +284,7 @@ static void __init vision_init_machine(void)
 
 	vision_i2c_info[1].irq = gpio_to_irq(EP93XX_GPIO_LINE_F(7));
 
-	ep93xx_register_i2c(&vision_i2c_gpio_data, vision_i2c_info,
+	ep93xx_register_i2c(vision_i2c_info,
 				ARRAY_SIZE(vision_i2c_info));
 	ep93xx_register_spi(&vision_spi_master, vision_spi_board_info,
 				ARRAY_SIZE(vision_spi_board_info));
diff --git a/arch/arm/mach-ixp4xx/avila-setup.c b/arch/arm/mach-ixp4xx/avila-setup.c
index 6beec150c060..72122b5e7f28 100644
--- a/arch/arm/mach-ixp4xx/avila-setup.c
+++ b/arch/arm/mach-ixp4xx/avila-setup.c
@@ -17,7 +17,7 @@
 #include <linux/serial.h>
 #include <linux/tty.h>
 #include <linux/serial_8250.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <asm/types.h>
 #include <asm/setup.h>
 #include <asm/memory.h>
@@ -49,16 +49,21 @@ static struct platform_device avila_flash = {
 	.resource	= &avila_flash_resource,
 };
 
-static struct i2c_gpio_platform_data avila_i2c_gpio_data = {
-	.sda_pin	= AVILA_SDA_PIN,
-	.scl_pin	= AVILA_SCL_PIN,
+static struct gpiod_lookup_table avila_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", AVILA_SDA_PIN,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", AVILA_SCL_PIN,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct platform_device avila_i2c_gpio = {
 	.name		= "i2c-gpio",
 	.id		= 0,
 	.dev	 = {
-		.platform_data	= &avila_i2c_gpio_data,
+		.platform_data	= NULL,
 	},
 };
 
@@ -147,6 +152,8 @@ static void __init avila_init(void)
 	avila_flash_resource.end =
 		IXP4XX_EXP_BUS_BASE(0) + ixp4xx_exp_bus_size - 1;
 
+	gpiod_add_lookup_table(&avila_i2c_gpiod_table);
+
 	platform_add_devices(avila_devices, ARRAY_SIZE(avila_devices));
 
 	avila_pata_resources[0].start = IXP4XX_EXP_BUS_BASE(1);
diff --git a/arch/arm/mach-ixp4xx/dsmg600-setup.c b/arch/arm/mach-ixp4xx/dsmg600-setup.c
index b3bd0e137f6d..68ccd669051b 100644
--- a/arch/arm/mach-ixp4xx/dsmg600-setup.c
+++ b/arch/arm/mach-ixp4xx/dsmg600-setup.c
@@ -25,7 +25,7 @@
 #include <linux/leds.h>
 #include <linux/reboot.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 
 #include <mach/hardware.h>
 
@@ -68,16 +68,21 @@ static struct platform_device dsmg600_flash = {
 	.resource		= &dsmg600_flash_resource,
 };
 
-static struct i2c_gpio_platform_data dsmg600_i2c_gpio_data = {
-	.sda_pin		= DSMG600_SDA_PIN,
-	.scl_pin		= DSMG600_SCL_PIN,
+static struct gpiod_lookup_table dsmg600_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", DSMG600_SDA_PIN,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", DSMG600_SCL_PIN,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct platform_device dsmg600_i2c_gpio = {
 	.name			= "i2c-gpio",
 	.id			= 0,
 	.dev	 = {
-		.platform_data	= &dsmg600_i2c_gpio_data,
+		.platform_data	= NULL,
 	},
 };
 
@@ -269,6 +274,7 @@ static void __init dsmg600_init(void)
 	dsmg600_flash_resource.end =
 		IXP4XX_EXP_BUS_BASE(0) + ixp4xx_exp_bus_size - 1;
 
+	gpiod_add_lookup_table(&dsmg600_i2c_gpiod_table);
 	i2c_register_board_info(0, dsmg600_i2c_board_info,
 				ARRAY_SIZE(dsmg600_i2c_board_info));
 
diff --git a/arch/arm/mach-ixp4xx/fsg-setup.c b/arch/arm/mach-ixp4xx/fsg-setup.c
index 5c4b0c4a1b37..a0350ad15175 100644
--- a/arch/arm/mach-ixp4xx/fsg-setup.c
+++ b/arch/arm/mach-ixp4xx/fsg-setup.c
@@ -22,7 +22,7 @@
 #include <linux/leds.h>
 #include <linux/reboot.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/io.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
@@ -54,16 +54,21 @@ static struct platform_device fsg_flash = {
 	.resource		= &fsg_flash_resource,
 };
 
-static struct i2c_gpio_platform_data fsg_i2c_gpio_data = {
-	.sda_pin		= FSG_SDA_PIN,
-	.scl_pin		= FSG_SCL_PIN,
+static struct gpiod_lookup_table fsg_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", FSG_SDA_PIN,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", FSG_SCL_PIN,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct platform_device fsg_i2c_gpio = {
 	.name			= "i2c-gpio",
 	.id			= 0,
 	.dev = {
-		.platform_data	= &fsg_i2c_gpio_data,
+		.platform_data	= NULL,
 	},
 };
 
@@ -196,6 +201,7 @@ static void __init fsg_init(void)
 	/* Configure CS2 for operation, 8bit and writable */
 	*IXP4XX_EXP_CS2 = 0xbfff0002;
 
+	gpiod_add_lookup_table(&fsg_i2c_gpiod_table);
 	i2c_register_board_info(0, fsg_i2c_board_info,
 				ARRAY_SIZE(fsg_i2c_board_info));
 
diff --git a/arch/arm/mach-ixp4xx/goramo_mlr.c b/arch/arm/mach-ixp4xx/goramo_mlr.c
index 80bd9d6d04de..f1529aa3f8e2 100644
--- a/arch/arm/mach-ixp4xx/goramo_mlr.c
+++ b/arch/arm/mach-ixp4xx/goramo_mlr.c
@@ -6,7 +6,6 @@
 #include <linux/delay.h>
 #include <linux/gpio.h>
 #include <linux/hdlc.h>
-#include <linux/i2c-gpio.h>
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
@@ -78,6 +77,12 @@
 static u32 hw_bits = 0xFFFFFFFD;    /* assume all hardware present */;
 static u8 control_value;
 
+/*
+ * FIXME: this is reimplementing I2C bit-bangining. Move this
+ * over to using driver/i2c/busses/i2c-gpio.c like all other boards
+ * and register proper I2C device(s) on the bus for this. (See
+ * other IXP4xx boards for examples.)
+ */
 static void set_scl(u8 value)
 {
 	gpio_set_value(GPIO_SCL, !!value);
@@ -216,20 +221,6 @@ static struct platform_device device_flash = {
 	.resource	= &flash_resource,
 };
 
-
-/* I^2C interface */
-static struct i2c_gpio_platform_data i2c_data = {
-	.sda_pin	= GPIO_SDA,
-	.scl_pin	= GPIO_SCL,
-};
-
-static struct platform_device device_i2c = {
-	.name		= "i2c-gpio",
-	.id		= 0,
-	.dev		= { .platform_data = &i2c_data },
-};
-
-
 /* IXP425 2 UART ports */
 static struct resource uart_resources[] = {
 	{
@@ -411,9 +402,6 @@ static void __init gmlr_init(void)
 	if (hw_bits & CFG_HW_HAS_HSS1)
 		device_tab[devices++] = &device_hss_tab[1]; /* max index 5 */
 
-	if (hw_bits & CFG_HW_HAS_EEPROM)
-		device_tab[devices++] = &device_i2c; /* max index 6 */
-
 	gpio_request(GPIO_SCL, "SCL/clock");
 	gpio_request(GPIO_SDA, "SDA/data");
 	gpio_request(GPIO_STR, "strobe");
diff --git a/arch/arm/mach-ixp4xx/ixdp425-setup.c b/arch/arm/mach-ixp4xx/ixdp425-setup.c
index 508c2d7786e2..fd32ccde20c5 100644
--- a/arch/arm/mach-ixp4xx/ixdp425-setup.c
+++ b/arch/arm/mach-ixp4xx/ixdp425-setup.c
@@ -14,7 +14,7 @@
 #include <linux/serial.h>
 #include <linux/tty.h>
 #include <linux/serial_8250.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/io.h>
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/nand.h>
@@ -122,16 +122,21 @@ static struct platform_device ixdp425_flash_nand = {
 };
 #endif	/* CONFIG_MTD_NAND_PLATFORM */
 
-static struct i2c_gpio_platform_data ixdp425_i2c_gpio_data = {
-	.sda_pin	= IXDP425_SDA_PIN,
-	.scl_pin	= IXDP425_SCL_PIN,
+static struct gpiod_lookup_table ixdp425_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", IXDP425_SDA_PIN,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", IXDP425_SCL_PIN,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct platform_device ixdp425_i2c_gpio = {
 	.name		= "i2c-gpio",
 	.id		= 0,
 	.dev	 = {
-		.platform_data	= &ixdp425_i2c_gpio_data,
+		.platform_data	= NULL,
 	},
 };
 
@@ -245,6 +250,7 @@ static void __init ixdp425_init(void)
 		ixdp425_uart_data[1].flags = 0;
 	}
 
+	gpiod_add_lookup_table(&ixdp425_i2c_gpiod_table);
 	platform_add_devices(ixdp425_devices, ARRAY_SIZE(ixdp425_devices));
 }
 
diff --git a/arch/arm/mach-ixp4xx/nas100d-setup.c b/arch/arm/mach-ixp4xx/nas100d-setup.c
index 4e0f762bc651..612ec8c63456 100644
--- a/arch/arm/mach-ixp4xx/nas100d-setup.c
+++ b/arch/arm/mach-ixp4xx/nas100d-setup.c
@@ -27,7 +27,7 @@
 #include <linux/leds.h>
 #include <linux/reboot.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/io.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
@@ -100,16 +100,21 @@ static struct platform_device nas100d_leds = {
 	.dev.platform_data	= &nas100d_led_data,
 };
 
-static struct i2c_gpio_platform_data nas100d_i2c_gpio_data = {
-	.sda_pin		= NAS100D_SDA_PIN,
-	.scl_pin		= NAS100D_SCL_PIN,
+static struct gpiod_lookup_table nas100d_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NAS100D_SDA_PIN,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NAS100D_SCL_PIN,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct platform_device nas100d_i2c_gpio = {
 	.name			= "i2c-gpio",
 	.id			= 0,
 	.dev	 = {
-		.platform_data	= &nas100d_i2c_gpio_data,
+		.platform_data	= NULL,
 	},
 };
 
@@ -280,6 +285,7 @@ static void __init nas100d_init(void)
 	nas100d_flash_resource.end =
 		IXP4XX_EXP_BUS_BASE(0) + ixp4xx_exp_bus_size - 1;
 
+	gpiod_add_lookup_table(&nas100d_i2c_gpiod_table);
 	i2c_register_board_info(0, nas100d_i2c_board_info,
 				ARRAY_SIZE(nas100d_i2c_board_info));
 
diff --git a/arch/arm/mach-ixp4xx/nslu2-setup.c b/arch/arm/mach-ixp4xx/nslu2-setup.c
index 88c025f52d8d..13afb03b50fa 100644
--- a/arch/arm/mach-ixp4xx/nslu2-setup.c
+++ b/arch/arm/mach-ixp4xx/nslu2-setup.c
@@ -24,7 +24,7 @@
 #include <linux/leds.h>
 #include <linux/reboot.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/io.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
@@ -68,9 +68,14 @@ static struct platform_device nslu2_flash = {
 	.resource		= &nslu2_flash_resource,
 };
 
-static struct i2c_gpio_platform_data nslu2_i2c_gpio_data = {
-	.sda_pin		= NSLU2_SDA_PIN,
-	.scl_pin		= NSLU2_SCL_PIN,
+static struct gpiod_lookup_table nslu2_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NSLU2_SDA_PIN,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NSLU2_SCL_PIN,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct i2c_board_info __initdata nslu2_i2c_board_info [] = {
@@ -115,7 +120,7 @@ static struct platform_device nslu2_i2c_gpio = {
 	.name			= "i2c-gpio",
 	.id			= 0,
 	.dev	 = {
-		.platform_data	= &nslu2_i2c_gpio_data,
+		.platform_data	= NULL,
 	},
 };
 
@@ -250,6 +255,7 @@ static void __init nslu2_init(void)
 	nslu2_flash_resource.end =
 		IXP4XX_EXP_BUS_BASE(0) + ixp4xx_exp_bus_size - 1;
 
+	gpiod_add_lookup_table(&nslu2_i2c_gpiod_table);
 	i2c_register_board_info(0, nslu2_i2c_board_info,
 				ARRAY_SIZE(nslu2_i2c_board_info));
 
diff --git a/arch/arm/mach-ks8695/board-acs5k.c b/arch/arm/mach-ks8695/board-acs5k.c
index e4d709c8ed32..f034724e01e1 100644
--- a/arch/arm/mach-ks8695/board-acs5k.c
+++ b/arch/arm/mach-ks8695/board-acs5k.c
@@ -16,7 +16,7 @@
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/platform_device.h>
-
+#include <linux/gpio/machine.h>
 #include <linux/i2c.h>
 #include <linux/i2c-algo-bit.h>
 #include <linux/i2c-gpio.h>
@@ -38,9 +38,15 @@
 
 #include "generic.h"
 
+static struct gpiod_lookup_table acs5k_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("KS8695", 4, NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("KS8695", 5, NULL, 1, GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data acs5k_i2c_device_platdata = {
-	.sda_pin	= 4,
-	.scl_pin	= 5,
 	.udelay		= 10,
 };
 
@@ -95,6 +101,7 @@ static struct i2c_board_info acs5k_i2c_devs[] __initdata = {
 static void acs5k_i2c_init(void)
 {
 	/* The gpio interface */
+	gpiod_add_lookup_table(&acs5k_i2c_gpiod_table);
 	platform_device_register(&acs5k_i2c_device);
 	/* I2C devices */
 	i2c_register_board_info(0, acs5k_i2c_devs,
diff --git a/arch/arm/mach-pxa/palmz72.c b/arch/arm/mach-pxa/palmz72.c
index 29630061e700..94f75632c007 100644
--- a/arch/arm/mach-pxa/palmz72.c
+++ b/arch/arm/mach-pxa/palmz72.c
@@ -31,6 +31,7 @@
 #include <linux/power_supply.h>
 #include <linux/usb/gpio_vbus.h>
 #include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 
 #include <asm/mach-types.h>
 #include <asm/suspend.h>
@@ -320,9 +321,15 @@ static struct soc_camera_link palmz72_iclink = {
 	.flags		= SOCAM_DATAWIDTH_8,
 };
 
+static struct gpiod_lookup_table palmz72_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("gpio-pxa", 118, NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("gpio-pxa", 117, NULL, 1, GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data palmz72_i2c_bus_data = {
-	.sda_pin	= 118,
-	.scl_pin	= 117,
 	.udelay		= 10,
 	.timeout	= 100,
 };
@@ -369,6 +376,7 @@ static void __init palmz72_camera_init(void)
 {
 	palmz72_cam_gpio_init();
 	pxa_set_camera_info(&palmz72_pxacamera_platform_data);
+	gpiod_add_lookup_table(&palmz72_i2c_gpiod_table);
 	platform_device_register(&palmz72_i2c_bus_device);
 	platform_device_register(&palmz72_camera);
 }
diff --git a/arch/arm/mach-pxa/viper.c b/arch/arm/mach-pxa/viper.c
index 8e89d91b206b..a680742bee2b 100644
--- a/arch/arm/mach-pxa/viper.c
+++ b/arch/arm/mach-pxa/viper.c
@@ -36,6 +36,7 @@
 #include <linux/gpio.h>
 #include <linux/jiffies.h>
 #include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/i2c/pxa-i2c.h>
 #include <linux/serial_8250.h>
 #include <linux/smc91x.h>
@@ -458,9 +459,17 @@ static struct platform_device smc91x_device = {
 };
 
 /* i2c */
+static struct gpiod_lookup_table viper_i2c_gpiod_table = {
+	.dev_id		= "i2c-gpio",
+	.table		= {
+		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_RTC_I2C_SDA_GPIO,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_RTC_I2C_SCL_GPIO,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data i2c_bus_data = {
-	.sda_pin = VIPER_RTC_I2C_SDA_GPIO,
-	.scl_pin = VIPER_RTC_I2C_SCL_GPIO,
 	.udelay  = 10,
 	.timeout = HZ,
 };
@@ -779,12 +788,20 @@ static int __init viper_tpm_setup(char *str)
 
 __setup("tpm=", viper_tpm_setup);
 
+struct gpiod_lookup_table viper_tpm_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_TPM_I2C_SDA_GPIO,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_TPM_I2C_SCL_GPIO,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
+};
+
 static void __init viper_tpm_init(void)
 {
 	struct platform_device *tpm_device;
 	struct i2c_gpio_platform_data i2c_tpm_data = {
-		.sda_pin = VIPER_TPM_I2C_SDA_GPIO,
-		.scl_pin = VIPER_TPM_I2C_SCL_GPIO,
 		.udelay  = 10,
 		.timeout = HZ,
 	};
@@ -794,6 +811,7 @@ static void __init viper_tpm_init(void)
 	if (!viper_tpm)
 		return;
 
+	gpiod_add_lookup_table(&viper_tpm_i2c_gpiod_table);
 	tpm_device = platform_device_alloc("i2c-gpio", 2);
 	if (tpm_device) {
 		if (!platform_device_add_data(tpm_device,
@@ -943,6 +961,7 @@ static void __init viper_init(void)
 		smc91x_device.num_resources--;
 
 	pxa_set_i2c_info(NULL);
+	gpiod_add_lookup_table(&viper_i2c_gpiod_table);
 	pwm_add_table(viper_pwm_lookup, ARRAY_SIZE(viper_pwm_lookup));
 	platform_add_devices(viper_devs, ARRAY_SIZE(viper_devs));
 
diff --git a/arch/arm/mach-sa1100/simpad.c b/arch/arm/mach-sa1100/simpad.c
index bb3ca9c763de..c6e7e6d8733a 100644
--- a/arch/arm/mach-sa1100/simpad.c
+++ b/arch/arm/mach-sa1100/simpad.c
@@ -16,6 +16,7 @@
 #include <linux/mtd/partitions.h>
 #include <linux/io.h>
 #include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
 
 #include <mach/hardware.h>
 #include <asm/setup.h>
@@ -323,9 +324,15 @@ static struct platform_device simpad_gpio_leds = {
 /*
  * i2c
  */
+static struct gpiod_lookup_table simpad_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("gpio", GPIO_GPIO21, NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("gpio", GPIO_GPIO25, NULL, 1, GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data simpad_i2c_data = {
-	.sda_pin = GPIO_GPIO21,
-	.scl_pin = GPIO_GPIO25,
 	.udelay = 10,
 	.timeout = HZ,
 };
@@ -380,6 +387,7 @@ static int __init simpad_init(void)
 			      ARRAY_SIZE(simpad_flash_resources));
 	sa11x0_register_mcp(&simpad_mcp_data);
 
+	gpiod_add_lookup_table(&simpad_i2c_gpiod_table);
 	ret = platform_add_devices(devices, ARRAY_SIZE(devices));
 	if(ret)
 		printk(KERN_WARNING "simpad: Unable to register mq200 framebuffer device");
diff --git a/arch/blackfin/mach-bf533/boards/blackstamp.c b/arch/blackfin/mach-bf533/boards/blackstamp.c
index 0ccf0cf4daaf..d801ca5ca6c4 100644
--- a/arch/blackfin/mach-bf533/boards/blackstamp.c
+++ b/arch/blackfin/mach-bf533/boards/blackstamp.c
@@ -22,6 +22,7 @@
 #include <linux/irq.h>
 #include <linux/gpio.h>
 #include <linux/i2c.h>
+#include <linux/gpio/machine.h>
 #include <asm/dma.h>
 #include <asm/bfin5xx_spi.h>
 #include <asm/portmux.h>
@@ -362,11 +363,17 @@ static struct platform_device bfin_device_gpiokeys = {
 #if IS_ENABLED(CONFIG_I2C_GPIO)
 #include <linux/i2c-gpio.h>
 
+static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF8, NULL, 0,
+				GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF9, NULL, 1,
+				GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data i2c_gpio_data = {
-	.sda_pin		= GPIO_PF8,
-	.scl_pin		= GPIO_PF9,
-	.sda_is_open_drain	= 0,
-	.scl_is_open_drain	= 0,
 	.udelay			= 40,
 }; /* This hasn't actually been used these pins
     * are (currently) free pins on the expansion connector */
@@ -462,7 +469,9 @@ static int __init blackstamp_init(void)
 	int ret;
 
 	printk(KERN_INFO "%s(): registering device resources\n", __func__);
-
+#if IS_ENABLED(CONFIG_I2C_GPIO)
+	gpiod_add_lookup_table(&bfin_i2c_gpiod_table);
+#endif
 	i2c_register_board_info(0, bfin_i2c_board_info,
 				ARRAY_SIZE(bfin_i2c_board_info));
 
diff --git a/arch/blackfin/mach-bf533/boards/ezkit.c b/arch/blackfin/mach-bf533/boards/ezkit.c
index 3625e9eaa8a8..463a72358b0e 100644
--- a/arch/blackfin/mach-bf533/boards/ezkit.c
+++ b/arch/blackfin/mach-bf533/boards/ezkit.c
@@ -19,6 +19,7 @@
 #endif
 #include <linux/irq.h>
 #include <linux/i2c.h>
+#include <linux/gpio/machine.h>
 #include <asm/dma.h>
 #include <asm/bfin5xx_spi.h>
 #include <asm/portmux.h>
@@ -390,11 +391,17 @@ static struct platform_device bfin_device_gpiokeys = {
 #if IS_ENABLED(CONFIG_I2C_GPIO)
 #include <linux/i2c-gpio.h>
 
+static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF1, NULL, 0,
+				GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF0, NULL, 1,
+				GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data i2c_gpio_data = {
-	.sda_pin		= GPIO_PF1,
-	.scl_pin		= GPIO_PF0,
-	.sda_is_open_drain	= 0,
-	.scl_is_open_drain	= 0,
 	.udelay			= 40,
 };
 
@@ -516,6 +523,9 @@ static struct platform_device *ezkit_devices[] __initdata = {
 static int __init ezkit_init(void)
 {
 	printk(KERN_INFO "%s(): registering device resources\n", __func__);
+#if IS_ENABLED(CONFIG_I2C_GPIO)
+	gpiod_add_lookup_table(&bfin_i2c_gpiod_table);
+#endif
 	platform_add_devices(ezkit_devices, ARRAY_SIZE(ezkit_devices));
 	spi_register_board_info(bfin_spi_board_info, ARRAY_SIZE(bfin_spi_board_info));
 	i2c_register_board_info(0, bfin_i2c_board_info,
diff --git a/arch/blackfin/mach-bf533/boards/stamp.c b/arch/blackfin/mach-bf533/boards/stamp.c
index 23eada79439c..d2479359adb7 100644
--- a/arch/blackfin/mach-bf533/boards/stamp.c
+++ b/arch/blackfin/mach-bf533/boards/stamp.c
@@ -21,6 +21,7 @@
 #include <linux/gpio.h>
 #include <linux/irq.h>
 #include <linux/i2c.h>
+#include <linux/gpio/machine.h>
 #include <asm/dma.h>
 #include <asm/bfin5xx_spi.h>
 #include <asm/reboot.h>
@@ -512,11 +513,17 @@ static struct platform_device bfin_device_gpiokeys = {
 #if IS_ENABLED(CONFIG_I2C_GPIO)
 #include <linux/i2c-gpio.h>
 
+static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF2, NULL, 0,
+				GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF3, NULL, 1,
+				GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data i2c_gpio_data = {
-	.sda_pin		= GPIO_PF2,
-	.scl_pin		= GPIO_PF3,
-	.sda_is_open_drain	= 0,
-	.scl_is_open_drain	= 0,
 	.udelay			= 10,
 };
 
@@ -848,6 +855,9 @@ static int __init stamp_init(void)
 
 	printk(KERN_INFO "%s(): registering device resources\n", __func__);
 
+#if IS_ENABLED(CONFIG_I2C_GPIO)
+	gpiod_add_lookup_table(&bfin_i2c_gpiod_table);
+#endif
 	i2c_register_board_info(0, bfin_i2c_board_info,
 				ARRAY_SIZE(bfin_i2c_board_info));
 
diff --git a/arch/blackfin/mach-bf561/boards/ezkit.c b/arch/blackfin/mach-bf561/boards/ezkit.c
index 57d1c43726d9..72f757ebaa84 100644
--- a/arch/blackfin/mach-bf561/boards/ezkit.c
+++ b/arch/blackfin/mach-bf561/boards/ezkit.c
@@ -16,6 +16,7 @@
 #include <linux/interrupt.h>
 #include <linux/gpio.h>
 #include <linux/delay.h>
+#include <linux/gpio/machine.h>
 #include <asm/dma.h>
 #include <asm/bfin5xx_spi.h>
 #include <asm/portmux.h>
@@ -379,11 +380,17 @@ static struct platform_device bfin_device_gpiokeys = {
 #if IS_ENABLED(CONFIG_I2C_GPIO)
 #include <linux/i2c-gpio.h>
 
+static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF1, NULL, 0,
+				GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF0, NULL, 1,
+				GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data i2c_gpio_data = {
-	.sda_pin		= GPIO_PF1,
-	.scl_pin		= GPIO_PF0,
-	.sda_is_open_drain	= 0,
-	.scl_is_open_drain	= 0,
 	.udelay			= 10,
 };
 
@@ -633,6 +640,9 @@ static int __init ezkit_init(void)
 
 	printk(KERN_INFO "%s(): registering device resources\n", __func__);
 
+#if IS_ENABLED(CONFIG_I2C_GPIO)
+	gpiod_add_lookup_table(&bfin_i2c_gpiod_table);
+#endif
 	ret = platform_add_devices(ezkit_devices, ARRAY_SIZE(ezkit_devices));
 	if (ret < 0)
 		return ret;
diff --git a/arch/mips/alchemy/board-gpr.c b/arch/mips/alchemy/board-gpr.c
index 6fb6b3faa158..daebc36e5ecb 100644
--- a/arch/mips/alchemy/board-gpr.c
+++ b/arch/mips/alchemy/board-gpr.c
@@ -30,6 +30,7 @@
 #include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <asm/bootinfo.h>
 #include <asm/idle.h>
 #include <asm/reboot.h>
@@ -218,10 +219,23 @@ static struct platform_device gpr_led_devices = {
 /*
  * I2C
  */
+static struct gpiod_lookup_table gpr_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		/*
+		 * This should be on "GPIO2" which has base at 200 so
+		 * the global numbers 209 and 210 should correspond to
+		 * local offsets 9 and 10.
+		 */
+		GPIO_LOOKUP_IDX("alchemy-gpio2", 9, NULL, 0,
+				GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("alchemy-gpio2", 10, NULL, 1,
+				GPIO_ACTIVE_HIGH),
+	},
+};
+
 static struct i2c_gpio_platform_data gpr_i2c_data = {
-	.sda_pin		= 209,
 	.sda_is_open_drain	= 1,
-	.scl_pin		= 210,
 	.scl_is_open_drain	= 1,
 	.udelay			= 2,		/* ~100 kHz */
 	.timeout		= HZ,
@@ -295,6 +309,7 @@ arch_initcall(gpr_pci_init);
 
 static int __init gpr_dev_init(void)
 {
+	gpiod_add_lookup_table(&gpr_i2c_gpiod_table);
 	i2c_register_board_info(0, gpr_i2c_info, ARRAY_SIZE(gpr_i2c_info));
 
 	return platform_add_devices(gpr_devices, ARRAY_SIZE(gpr_devices));
diff --git a/arch/mips/ath79/mach-pb44.c b/arch/mips/ath79/mach-pb44.c
index be78298dffb4..a95409063847 100644
--- a/arch/mips/ath79/mach-pb44.c
+++ b/arch/mips/ath79/mach-pb44.c
@@ -11,7 +11,7 @@
 #include <linux/init.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
-#include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/platform_data/pcf857x.h>
 
 #include "machtypes.h"
@@ -33,16 +33,21 @@
 #define PB44_KEYS_POLL_INTERVAL		20	/* msecs */
 #define PB44_KEYS_DEBOUNCE_INTERVAL	(3 * PB44_KEYS_POLL_INTERVAL)
 
-static struct i2c_gpio_platform_data pb44_i2c_gpio_data = {
-	.sda_pin	= PB44_GPIO_I2C_SDA,
-	.scl_pin	= PB44_GPIO_I2C_SCL,
+static struct gpiod_lookup_table pb44_i2c_gpiod_table = {
+	.dev_id = "i2c-gpio",
+	.table = {
+		GPIO_LOOKUP_IDX("ath79-gpio", PB44_GPIO_I2C_SDA,
+				NULL, 0, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("ath79-gpio", PB44_GPIO_I2C_SCL,
+				NULL, 1, GPIO_ACTIVE_HIGH),
+	},
 };
 
 static struct platform_device pb44_i2c_gpio_device = {
 	.name		= "i2c-gpio",
 	.id		= 0,
 	.dev = {
-		.platform_data	= &pb44_i2c_gpio_data,
+		.platform_data	= NULL,
 	}
 };
 
@@ -103,6 +108,7 @@ static struct ath79_spi_platform_data pb44_spi_data = {
 
 static void __init pb44_init(void)
 {
+	gpiod_add_lookup_table(&pb44_i2c_gpiod_table);
 	i2c_register_board_info(0, pb44_i2c_board_info,
 				ARRAY_SIZE(pb44_i2c_board_info));
 	platform_device_register(&pb44_i2c_gpio_device);
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index 34cfc0ebdcb9..b4664037eded 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -14,11 +14,12 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/of.h>
-#include <linux/of_gpio.h>
 
 struct i2c_gpio_private_data {
+	struct gpio_desc *sda;
+	struct gpio_desc *scl;
 	struct i2c_adapter adap;
 	struct i2c_algo_bit_data bit_data;
 	struct i2c_gpio_platform_data pdata;
@@ -27,12 +28,18 @@ struct i2c_gpio_private_data {
 /* Toggle SDA by changing the direction of the pin */
 static void i2c_gpio_setsda_dir(void *data, int state)
 {
-	struct i2c_gpio_platform_data *pdata = data;
-
+	struct i2c_gpio_private_data *priv = data;
+
+	/*
+	 * This is a way of saying "do not drive
+	 * me actively high" which means emulating open drain.
+	 * The right way to do this is for gpiolib to
+	 * handle this, by the function below.
+	 */
 	if (state)
-		gpio_direction_input(pdata->sda_pin);
+		gpiod_direction_input(priv->sda);
 	else
-		gpio_direction_output(pdata->sda_pin, 0);
+		gpiod_direction_output(priv->sda, 0);
 }
 
 /*
@@ -42,20 +49,20 @@ static void i2c_gpio_setsda_dir(void *data, int state)
  */
 static void i2c_gpio_setsda_val(void *data, int state)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	gpio_set_value(pdata->sda_pin, state);
+	gpiod_set_value(priv->sda, state);
 }
 
 /* Toggle SCL by changing the direction of the pin. */
 static void i2c_gpio_setscl_dir(void *data, int state)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
 	if (state)
-		gpio_direction_input(pdata->scl_pin);
+		gpiod_direction_input(priv->scl);
 	else
-		gpio_direction_output(pdata->scl_pin, 0);
+		gpiod_direction_output(priv->scl, 0);
 }
 
 /*
@@ -66,44 +73,23 @@ static void i2c_gpio_setscl_dir(void *data, int state)
  */
 static void i2c_gpio_setscl_val(void *data, int state)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	gpio_set_value(pdata->scl_pin, state);
+	gpiod_set_value(priv->scl, state);
 }
 
 static int i2c_gpio_getsda(void *data)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	return gpio_get_value(pdata->sda_pin);
+	return gpiod_get_value(priv->sda);
 }
 
 static int i2c_gpio_getscl(void *data)
 {
-	struct i2c_gpio_platform_data *pdata = data;
+	struct i2c_gpio_private_data *priv = data;
 
-	return gpio_get_value(pdata->scl_pin);
-}
-
-static int of_i2c_gpio_get_pins(struct device_node *np,
-				unsigned int *sda_pin, unsigned int *scl_pin)
-{
-	if (of_gpio_count(np) < 2)
-		return -ENODEV;
-
-	*sda_pin = of_get_gpio(np, 0);
-	*scl_pin = of_get_gpio(np, 1);
-
-	if (*sda_pin == -EPROBE_DEFER || *scl_pin == -EPROBE_DEFER)
-		return -EPROBE_DEFER;
-
-	if (!gpio_is_valid(*sda_pin) || !gpio_is_valid(*scl_pin)) {
-		pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
-		       np->full_name, *sda_pin, *scl_pin);
-		return -ENODEV;
-	}
-
-	return 0;
+	return gpiod_get_value(priv->scl);
 }
 
 static void of_i2c_gpio_get_props(struct device_node *np,
@@ -130,64 +116,65 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	struct i2c_gpio_platform_data *pdata;
 	struct i2c_algo_bit_data *bit_data;
 	struct i2c_adapter *adap;
-	unsigned int sda_pin, scl_pin;
 	int ret;
 
-	/* First get the GPIO pins; if it fails, we'll defer the probe. */
-	if (pdev->dev.of_node) {
-		ret = of_i2c_gpio_get_pins(pdev->dev.of_node,
-					   &sda_pin, &scl_pin);
-		if (ret)
-			return ret;
-	} else {
-		if (!dev_get_platdata(&pdev->dev))
-			return -ENXIO;
-		pdata = dev_get_platdata(&pdev->dev);
-		sda_pin = pdata->sda_pin;
-		scl_pin = pdata->scl_pin;
-	}
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
 
-	ret = devm_gpio_request(&pdev->dev, sda_pin, "sda");
-	if (ret) {
+	/* First get the GPIO pins; if it fails, we'll defer the probe. */
+	priv->sda = devm_gpiod_get_index(&pdev->dev, NULL, 0, GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->sda)) {
+		ret = PTR_ERR(priv->sda);
+		/* FIXME: hack in the old code, is this really necessary? */
 		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;	/* Try again later */
+			ret = -EPROBE_DEFER;
 		return ret;
 	}
-	ret = devm_gpio_request(&pdev->dev, scl_pin, "scl");
-	if (ret) {
+	priv->scl = devm_gpiod_get_index(&pdev->dev, NULL, 1, GPIOD_OUT_LOW);
+	if (IS_ERR(priv->scl)) {
+		ret = PTR_ERR(priv->scl);
+		/* FIXME: hack in the old code, is this really necessary? */
 		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;	/* Try again later */
+			ret = -EPROBE_DEFER;
 		return ret;
 	}
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
-	if (!priv)
-		return -ENOMEM;
 	adap = &priv->adap;
 	bit_data = &priv->bit_data;
 	pdata = &priv->pdata;
 
 	if (pdev->dev.of_node) {
-		pdata->sda_pin = sda_pin;
-		pdata->scl_pin = scl_pin;
 		of_i2c_gpio_get_props(pdev->dev.of_node, pdata);
 	} else {
-		memcpy(pdata, dev_get_platdata(&pdev->dev), sizeof(*pdata));
+		/*
+		 * If all platform data settings are zero it is OK
+		 * to not provide any platform data from the board.
+		 */
+		if (dev_get_platdata(&pdev->dev))
+			memcpy(pdata, dev_get_platdata(&pdev->dev),
+			       sizeof(*pdata));
 	}
 
+	/*
+	 * FIXME: this is a hack emulating the open drain emulation
+	 * that gpiolib can already do for us. Make all clients properly
+	 * flag their lines as open drain and get rid of this property
+	 * and the special callback.
+	 */
 	if (pdata->sda_is_open_drain) {
-		gpio_direction_output(pdata->sda_pin, 1);
+		gpiod_direction_output(priv->sda, 1);
 		bit_data->setsda = i2c_gpio_setsda_val;
 	} else {
-		gpio_direction_input(pdata->sda_pin);
+		gpiod_direction_input(priv->sda);
 		bit_data->setsda = i2c_gpio_setsda_dir;
 	}
 
 	if (pdata->scl_is_open_drain || pdata->scl_is_output_only) {
-		gpio_direction_output(pdata->scl_pin, 1);
+		gpiod_direction_output(priv->scl, 1);
 		bit_data->setscl = i2c_gpio_setscl_val;
 	} else {
-		gpio_direction_input(pdata->scl_pin);
+		gpiod_direction_input(priv->scl);
 		bit_data->setscl = i2c_gpio_setscl_dir;
 	}
 
@@ -207,7 +194,7 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	else
 		bit_data->timeout = HZ / 10;		/* 100 ms */
 
-	bit_data->data = pdata;
+	bit_data->data = priv;
 
 	adap->owner = THIS_MODULE;
 	if (pdev->dev.of_node)
@@ -227,8 +214,13 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
-	dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
-		 pdata->sda_pin, pdata->scl_pin,
+	/*
+	 * FIXME: using global GPIO numbers is not helpful. If/when we
+	 * get accessors to get the actual name of the GPIO line,
+	 * from the descriptor, then provide that instead.
+	 */
+	dev_info(&pdev->dev, "using lines %u (SDA) and %u (SCL%s)\n",
+		 desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
 		 pdata->scl_is_output_only
 		 ? ", no clock stretching" : "");
 
diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
index 40534352e574..4d40d013a412 100644
--- a/drivers/mfd/sm501.c
+++ b/drivers/mfd/sm501.c
@@ -20,6 +20,7 @@
 #include <linux/platform_device.h>
 #include <linux/pci.h>
 #include <linux/i2c-gpio.h>
+#include <linux/gpio/machine.h>
 #include <linux/slab.h>
 
 #include <linux/sm501.h>
@@ -1107,14 +1108,6 @@ static void sm501_gpio_remove(struct sm501_devdata *sm)
 	kfree(gpio->regs_res);
 }
 
-static inline int sm501_gpio_pin2nr(struct sm501_devdata *sm, unsigned int pin)
-{
-	struct sm501_gpio *gpio = &sm->gpio;
-	int base = (pin < 32) ? gpio->low.gpio.base : gpio->high.gpio.base;
-
-	return (pin % 32) + base;
-}
-
 static inline int sm501_gpio_isregistered(struct sm501_devdata *sm)
 {
 	return sm->gpio.registered;
@@ -1129,11 +1122,6 @@ static inline void sm501_gpio_remove(struct sm501_devdata *sm)
 {
 }
 
-static inline int sm501_gpio_pin2nr(struct sm501_devdata *sm, unsigned int pin)
-{
-	return -1;
-}
-
 static inline int sm501_gpio_isregistered(struct sm501_devdata *sm)
 {
 	return 0;
@@ -1145,20 +1133,37 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
 {
 	struct i2c_gpio_platform_data *icd;
 	struct platform_device *pdev;
+	struct gpiod_lookup_table *lookup;
 
 	pdev = sm501_create_subdev(sm, "i2c-gpio", 0,
 				   sizeof(struct i2c_gpio_platform_data));
 	if (!pdev)
 		return -ENOMEM;
 
-	icd = dev_get_platdata(&pdev->dev);
-
-	/* We keep the pin_sda and pin_scl fields relative in case the
-	 * same platform data is passed to >1 SM501.
-	 */
+	/* Create a gpiod lookup using gpiochip-local offsets */
+	lookup = devm_kzalloc(&pdev->dev,
+			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
+			      GFP_KERNEL);
+	lookup->dev_id = "i2c-gpio";
+	if (iic->pin_sda < 32)
+		lookup->table[0].chip_label = "SM501-LOW";
+	else
+		lookup->table[0].chip_label = "SM501-HIGH";
+	lookup->table[0].chip_hwnum = iic->pin_sda % 32;
+	lookup->table[0].con_id = NULL;
+	lookup->table[0].idx = 0;
+	lookup->table[0].flags = GPIO_ACTIVE_HIGH;
+	if (iic->pin_scl < 32)
+		lookup->table[1].chip_label = "SM501-LOW";
+	else
+		lookup->table[1].chip_label = "SM501-HIGH";
+	lookup->table[1].chip_hwnum = iic->pin_scl % 32;
+	lookup->table[1].con_id = NULL;
+	lookup->table[1].idx = 1;
+	lookup->table[1].flags = GPIO_ACTIVE_HIGH;
+	gpiod_add_lookup_table(lookup);
 
-	icd->sda_pin = sm501_gpio_pin2nr(sm, iic->pin_sda);
-	icd->scl_pin = sm501_gpio_pin2nr(sm, iic->pin_scl);
+	icd = dev_get_platdata(&pdev->dev);
 	icd->timeout = iic->timeout;
 	icd->udelay = iic->udelay;
 
@@ -1170,9 +1175,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
 
 	pdev->id = iic->bus_num;
 
-	dev_info(sm->dev, "registering i2c-%d: sda=%d (%d), scl=%d (%d)\n",
+	dev_info(sm->dev, "registering i2c-%d: sda=%d, scl=%d\n",
 		 iic->bus_num,
-		 icd->sda_pin, iic->pin_sda, icd->scl_pin, iic->pin_scl);
+		 iic->pin_sda, iic->pin_scl);
 
 	return sm501_register_device(sm, pdev);
 }
diff --git a/include/linux/i2c-gpio.h b/include/linux/i2c-gpio.h
index c1bcb1f1d73b..352c1426fd4d 100644
--- a/include/linux/i2c-gpio.h
+++ b/include/linux/i2c-gpio.h
@@ -12,8 +12,6 @@
 
 /**
  * struct i2c_gpio_platform_data - Platform-dependent data for i2c-gpio
- * @sda_pin: GPIO pin ID to use for SDA
- * @scl_pin: GPIO pin ID to use for SCL
  * @udelay: signal toggle delay. SCL frequency is (500 / udelay) kHz
  * @timeout: clock stretching timeout in jiffies. If the slave keeps
  *	SCL low for longer than this, the transfer will time out.
@@ -26,8 +24,6 @@
  * @scl_is_output_only: SCL output drivers cannot be turned off.
  */
 struct i2c_gpio_platform_data {
-	unsigned int	sda_pin;
-	unsigned int	scl_pin;
 	int		udelay;
 	int		timeout;
 	unsigned int	sda_is_open_drain:1;
-- 
2.13.5

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Lee Jones]

On Sun, 17 Sep 2017, Linus Walleij wrote:

> This converts the GPIO-based I2C-driver to using GPIO
> descriptors instead of the old global numberspace-based
> GPIO interface. We:

[STUFF]

> - The MFD Silicon Motion SM501 is a special case. It dynamically
>   spawns an I2C bus off the MFD using sm501_create_subdev().
>   We use an approach to dynamically create a machine descriptor
>   table and attach this to the "SM501-LOW" or "SM501-HIGH"
>   gpiochip. We use chip-local offsets to grab the right lines.
>   We can get rid of two local static inline helpers as part
>   of this refactoring.
> 
> Cc: Steven Miao <realmz6@gmail.com>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Ville Syrj?l? <ville.syrjala@linux.intel.com>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Cc: Ben Dooks <ben.dooks@codethink.co.uk>
> Cc: Heiko Schocher <hs@denx.de>
> Acked-by: Olof Johansson <olof@lixom.net>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Fix a minor typo in error path (scl was sda from copy-paste)
> - Collected Olof's ACK
> 
> Steven (Blackfin): requesting ACK for Wolfram to take this patch.
> Ralf (MIPS): requesting ACK for Wolfram to take this patch.
> Lee: requesting ACK for Wolfram to take this patch.

This ...

> SM501 users: requesting Tested-by on this patch.

... loosely depends on this (until it doesn't).

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Linus Walleij]

On Mon, Sep 18, 2017 at 10:36 AM, Lee Jones <lee.jones@linaro.org> wrote:
> On Sun, 17 Sep 2017, Linus Walleij wrote:

>> Lee: requesting ACK for Wolfram to take this patch.
>
> This ...
>
>> SM501 users: requesting Tested-by on this patch.
>
> ... loosely depends on this (until it doesn't).

Yeah I did my best to scout around the commit logs
to figure out who's been contributing to the SM501 and
using it, I hope someone will step up and test it.

Linus

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Ben Dooks]

On 18/09/17 20:00, Linus Walleij wrote:
> On Mon, Sep 18, 2017 at 10:36 AM, Lee Jones <lee.jones@linaro.org> wrote:
>> On Sun, 17 Sep 2017, Linus Walleij wrote:
> 
>>> Lee: requesting ACK for Wolfram to take this patch.
>>
>> This ...
>>
>>> SM501 users: requesting Tested-by on this patch.
>>
>> ... loosely depends on this (until it doesn't).
> 
> Yeah I did my best to scout around the commit logs
> to figure out who's been contributing to the SM501 and
> using it, I hope someone will step up and test it.

I don't know if anything I have available working has an
SM501 on it. We did a couple of boards with S3C2440 and
an SM501 connected via external IO. However these have
not been supported in years (since Simtec)

I don't even think I have the PCI SM501 kit, that may have
ended up either at Simtec or one of the other engineers.

-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Linus Walleij]

On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:

> - The MFD Silicon Motion SM501 is a special case. It dynamically
>   spawns an I2C bus off the MFD using sm501_create_subdev().
>   We use an approach to dynamically create a machine descriptor
>   table and attach this to the "SM501-LOW" or "SM501-HIGH"
>   gpiochip. We use chip-local offsets to grab the right lines.
>   We can get rid of two local static inline helpers as part
>   of this refactoring.
(...)
> SM501 users: requesting Tested-by on this patch.

Paging Simtec (if it reaches anyone), Vincent Sanders,
Teddy Wang at Silicon Motion:

Does any of you have an "Anubis" board so you can test GPIO
on this board before/after this patch and see if it checks out right?

I guess it's this board:
http://www.simtec.co.uk/products/BBD20EUROA/

Does anyone know of a commercially obtainable product using
SM501 with reasonable mainline Linux support so I can test it myself?

Getting a bit desperate...

Yours,
Linus Walleij

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Ben Dooks]

On 02/10/17 02:05, Linus Walleij wrote:
> On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
> <linus.walleij@linaro.org> wrote:
> 
>> - The MFD Silicon Motion SM501 is a special case. It dynamically
>>    spawns an I2C bus off the MFD using sm501_create_subdev().
>>    We use an approach to dynamically create a machine descriptor
>>    table and attach this to the "SM501-LOW" or "SM501-HIGH"
>>    gpiochip. We use chip-local offsets to grab the right lines.
>>    We can get rid of two local static inline helpers as part
>>    of this refactoring.
> (...)
>> SM501 users: requesting Tested-by on this patch.
> 
> Paging Simtec (if it reaches anyone), Vincent Sanders,
> Teddy Wang at Silicon Motion:

I'm fairly sure Simtec is not currently active. See below.
I have no idea if the SM501 is even available for current designs.

> Does any of you have an "Anubis" board so you can test GPIO
> on this board before/after this patch and see if it checks out right?
> 
> I guess it's this board:
> http://www.simtec.co.uk/products/BBD20EUROA/

I think that's fairly close.
We did have a couple of other designs done for clients, but they may
not have been available to the general public.

> 
> Does anyone know of a commercially obtainable product using
> SM501 with reasonable mainline Linux support so I can test it myself?
> 
> Getting a bit desperate...

At the moment I have no time to go through the boxes of ex-Simtec stuff
that I still have... quite a lot of my old Simtec stuff has already been
recycled as it has been over five years since leaving.

> Yours,
> Linus Walleij
> 


-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Lee Jones]

On Sun, 17 Sep 2017, Linus Walleij wrote:

> This converts the GPIO-based I2C-driver to using GPIO
> descriptors instead of the old global numberspace-based
> GPIO interface. We:
> 
> - Convert the driver to unconditionally grab two GPIOs
>   from the device by index 0 (SDA) and 1 (SCL) which
>   will work fine with device tree and descriptor tables.
>   The existing device trees will continue to work just
>   like before, but without any roundtrip through the
>   global numberspace.
> 
> - Brutally convert all boardfiles still passing global
>   GPIOs by registering descriptor tables associated with
>   the devices instead so this driver does not need to keep
>   supporting passing any GPIO numbers as platform data.
> 
> There is no stepwise approach as elegant as this, I
> strongly prefer this big hammer over any antsteps for this
> conversion. This way the old GPIO numbers go away and
> NEVER COME BACK.
> 
> Special conversion for the different boards utilizing
> I2C-GPIO:
> 
> - EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
>   all boards were using the same two GPIO lines, just define
>   these two in a lookup table for "i2c-gpio" and register
>   these along with the device. None of them define any
>   other platform data so just pass NULL as platform data.
>   This platform selects GPIOLIB so all should be smooth.
>   The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
>   and 0 (SCL).
> 
> - IXP4 (arch/arm/mach-ixp4): descriptor tables have to
>   be registered for each board separately. They all use
>   "IXP4XX_GPIO_CHIP" so it is pretty straight forward.
>   Most board define no other platform data than SCL/SDA
>   so they can drop the #include of <linux/i2c-gpio.h> and
>   assign NULL to platform data.
> 
>   The "goramo_mlr" (Goramo Multilink Router) board is a bit
>   worrisome: it implements its own I2C bit-banging in the
>   board file, and optionally registers an I2C serial port,
>   but claims the same GPIO lines for itself in the board file.
>   This is not going to work: there will be competition for the
>   GPIO lines, so delete the optional extra I2C bus instead, no
>   I2C devices are registered on it anyway, there are just hints
>   that it may contain an EEPROM that may be accessed from
>   userspace. This needs to be fixed up properly by the serial
>   clock using I2C emulation so drop a note in the code.
> 
> - KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
>   has some platform data in addition to the pins so it needs to
>   be kept around sans GPIO lines. Its GPIO chip is named
>   "KS8695" and the arch selects GPIOLIB.
> 
> - PXA boards (arch/arm/mach-pxa/*) use some of the platform
>   data so it needs to be preserved here. The viper board even
>   registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
>   the arch selects GPIOLIB.
> 
> - SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
>   I2C bus, and the arch selects GPIOLIB.
> 
> - Blackfin boards (arch/blackfin/bf533 etc) for these I assume
>   their I2C GPIOs refer to the local gpiochip defined in
>   arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
>   The arch selects GPIOLIB. The boards get spiked with
>   IF_ENABLED(I2C_GPIO) but that is a side effect of it
>   being like that already (I would just have Kconfig select
>   I2C_GPIO and get rid of them all.) I also delete any
>   platform data set to 0 as it will get that value anyway
>   from static declartions of platform data.
> 
> - The MIPS selects GPIOLIB and the Alchemy machine is using
>   two local GPIO chips, one of them has a GPIO I2C. We need
>   to adjust the local offset from the global number space here.
>   The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
>   and AFAICT the chip is named "ath79-gpio" and the PB44
>   PCF857x expander spawns from this on GPIO 1 and 0. The latter
>   board only use the platform data to specify pins so it can be
>   cut altogether after this.
> 
> - The MFD Silicon Motion SM501 is a special case. It dynamically
>   spawns an I2C bus off the MFD using sm501_create_subdev().
>   We use an approach to dynamically create a machine descriptor
>   table and attach this to the "SM501-LOW" or "SM501-HIGH"
>   gpiochip. We use chip-local offsets to grab the right lines.
>   We can get rid of two local static inline helpers as part
>   of this refactoring.
> 
> Cc: Steven Miao <realmz6@gmail.com>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Ville Syrj?l? <ville.syrjala@linux.intel.com>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Cc: Ben Dooks <ben.dooks@codethink.co.uk>
> Cc: Heiko Schocher <hs@denx.de>
> Acked-by: Olof Johansson <olof@lixom.net>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Fix a minor typo in error path (scl was sda from copy-paste)
> - Collected Olof's ACK
> 
> Steven (Blackfin): requesting ACK for Wolfram to take this patch.
> Ralf (MIPS): requesting ACK for Wolfram to take this patch.
> Lee: requesting ACK for Wolfram to take this patch.
> SM501 users: requesting Tested-by on this patch.
> ---
>  arch/arm/mach-ep93xx/core.c                  |  39 ++++----
>  arch/arm/mach-ep93xx/edb93xx.c               |  15 +--
>  arch/arm/mach-ep93xx/include/mach/platform.h |   4 +-
>  arch/arm/mach-ep93xx/simone.c                |  12 +--
>  arch/arm/mach-ep93xx/snappercl15.c           |  12 +--
>  arch/arm/mach-ep93xx/vision_ep9307.c         |   7 +-
>  arch/arm/mach-ixp4xx/avila-setup.c           |  17 +++-
>  arch/arm/mach-ixp4xx/dsmg600-setup.c         |  16 +++-
>  arch/arm/mach-ixp4xx/fsg-setup.c             |  16 +++-
>  arch/arm/mach-ixp4xx/goramo_mlr.c            |  24 ++---
>  arch/arm/mach-ixp4xx/ixdp425-setup.c         |  16 +++-
>  arch/arm/mach-ixp4xx/nas100d-setup.c         |  16 +++-
>  arch/arm/mach-ixp4xx/nslu2-setup.c           |  16 +++-
>  arch/arm/mach-ks8695/board-acs5k.c           |  13 ++-
>  arch/arm/mach-pxa/palmz72.c                  |  12 ++-
>  arch/arm/mach-pxa/viper.c                    |  27 +++++-
>  arch/arm/mach-sa1100/simpad.c                |  12 ++-
>  arch/blackfin/mach-bf533/boards/blackstamp.c |  19 +++-
>  arch/blackfin/mach-bf533/boards/ezkit.c      |  18 +++-
>  arch/blackfin/mach-bf533/boards/stamp.c      |  18 +++-
>  arch/blackfin/mach-bf561/boards/ezkit.c      |  18 +++-
>  arch/mips/alchemy/board-gpr.c                |  19 +++-
>  arch/mips/ath79/mach-pb44.c                  |  16 +++-
>  drivers/i2c/busses/i2c-gpio.c                | 134 +++++++++++++--------------
>  drivers/mfd/sm501.c                          |  49 +++++-----

Acked-by: Lee Jones <lee.jones@linaro.org>

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

[PATCH 1/7] i2c: gpio: Convert to use descriptors

[Ralf Baechle]

On Sun, Sep 17, 2017 at 11:39:00AM +0200, Linus Walleij wrote:

> This converts the GPIO-based I2C-driver to using GPIO
> descriptors instead of the old global numberspace-based
> GPIO interface. We:
> 
> - Convert the driver to unconditionally grab two GPIOs
>   from the device by index 0 (SDA) and 1 (SCL) which
>   will work fine with device tree and descriptor tables.
>   The existing device trees will continue to work just
>   like before, but without any roundtrip through the
>   global numberspace.
> 
> - Brutally convert all boardfiles still passing global
>   GPIOs by registering descriptor tables associated with
>   the devices instead so this driver does not need to keep
>   supporting passing any GPIO numbers as platform data.
> 
> There is no stepwise approach as elegant as this, I
> strongly prefer this big hammer over any antsteps for this
> conversion. This way the old GPIO numbers go away and
> NEVER COME BACK.
> 
> Special conversion for the different boards utilizing
> I2C-GPIO:
> 
> - EP93xx (arch/arm/mach-ep93xx): pretty straight forward as
>   all boards were using the same two GPIO lines, just define
>   these two in a lookup table for "i2c-gpio" and register
>   these along with the device. None of them define any
>   other platform data so just pass NULL as platform data.
>   This platform selects GPIOLIB so all should be smooth.
>   The pins appear on a gpiochip for bank "G" as pins 1 (SDA)
>   and 0 (SCL).
> 
> - IXP4 (arch/arm/mach-ixp4): descriptor tables have to
>   be registered for each board separately. They all use
>   "IXP4XX_GPIO_CHIP" so it is pretty straight forward.
>   Most board define no other platform data than SCL/SDA
>   so they can drop the #include of <linux/i2c-gpio.h> and
>   assign NULL to platform data.
> 
>   The "goramo_mlr" (Goramo Multilink Router) board is a bit
>   worrisome: it implements its own I2C bit-banging in the
>   board file, and optionally registers an I2C serial port,
>   but claims the same GPIO lines for itself in the board file.
>   This is not going to work: there will be competition for the
>   GPIO lines, so delete the optional extra I2C bus instead, no
>   I2C devices are registered on it anyway, there are just hints
>   that it may contain an EEPROM that may be accessed from
>   userspace. This needs to be fixed up properly by the serial
>   clock using I2C emulation so drop a note in the code.
> 
> - KS8695 board acs5k (arch/arm/mach-ks8695/board-acs5.c)
>   has some platform data in addition to the pins so it needs to
>   be kept around sans GPIO lines. Its GPIO chip is named
>   "KS8695" and the arch selects GPIOLIB.
> 
> - PXA boards (arch/arm/mach-pxa/*) use some of the platform
>   data so it needs to be preserved here. The viper board even
>   registers two GPIO I2Cs. The gpiochip is named "gpio-pxa" and
>   the arch selects GPIOLIB.
> 
> - SA1100 Simpad (arch/arm/mach-sa1100/simpad.c) defines a GPIO
>   I2C bus, and the arch selects GPIOLIB.
> 
> - Blackfin boards (arch/blackfin/bf533 etc) for these I assume
>   their I2C GPIOs refer to the local gpiochip defined in
>   arch/blackfin/kernel/bfin_gpio.c names "BFIN-GPIO".
>   The arch selects GPIOLIB. The boards get spiked with
>   IF_ENABLED(I2C_GPIO) but that is a side effect of it
>   being like that already (I would just have Kconfig select
>   I2C_GPIO and get rid of them all.) I also delete any
>   platform data set to 0 as it will get that value anyway
>   from static declartions of platform data.
> 
> - The MIPS selects GPIOLIB and the Alchemy machine is using
>   two local GPIO chips, one of them has a GPIO I2C. We need
>   to adjust the local offset from the global number space here.
>   The ATH79 has a proper GPIO driver in drivers/gpio/gpio-ath79.c
>   and AFAICT the chip is named "ath79-gpio" and the PB44
>   PCF857x expander spawns from this on GPIO 1 and 0. The latter
>   board only use the platform data to specify pins so it can be
>   cut altogether after this.
> 
> - The MFD Silicon Motion SM501 is a special case. It dynamically
>   spawns an I2C bus off the MFD using sm501_create_subdev().
>   We use an approach to dynamically create a machine descriptor
>   table and attach this to the "SM501-LOW" or "SM501-HIGH"
>   gpiochip. We use chip-local offsets to grab the right lines.
>   We can get rid of two local static inline helpers as part
>   of this refactoring.
> 
> Cc: Steven Miao <realmz6@gmail.com>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Ville Syrj?l? <ville.syrjala@linux.intel.com>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Cc: Ben Dooks <ben.dooks@codethink.co.uk>
> Cc: Heiko Schocher <hs@denx.de>
> Acked-by: Olof Johansson <olof@lixom.net>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Fix a minor typo in error path (scl was sda from copy-paste)
> - Collected Olof's ACK
> 
> Steven (Blackfin): requesting ACK for Wolfram to take this patch.
> Ralf (MIPS): requesting ACK for Wolfram to take this patch.
> Lee: requesting ACK for Wolfram to take this patch.
> SM501 users: requesting Tested-by on this patch.
> ---
>  arch/arm/mach-ep93xx/core.c                  |  39 ++++----
>  arch/arm/mach-ep93xx/edb93xx.c               |  15 +--
>  arch/arm/mach-ep93xx/include/mach/platform.h |   4 +-
>  arch/arm/mach-ep93xx/simone.c                |  12 +--
>  arch/arm/mach-ep93xx/snappercl15.c           |  12 +--
>  arch/arm/mach-ep93xx/vision_ep9307.c         |   7 +-
>  arch/arm/mach-ixp4xx/avila-setup.c           |  17 +++-
>  arch/arm/mach-ixp4xx/dsmg600-setup.c         |  16 +++-
>  arch/arm/mach-ixp4xx/fsg-setup.c             |  16 +++-
>  arch/arm/mach-ixp4xx/goramo_mlr.c            |  24 ++---
>  arch/arm/mach-ixp4xx/ixdp425-setup.c         |  16 +++-
>  arch/arm/mach-ixp4xx/nas100d-setup.c         |  16 +++-
>  arch/arm/mach-ixp4xx/nslu2-setup.c           |  16 +++-
>  arch/arm/mach-ks8695/board-acs5k.c           |  13 ++-
>  arch/arm/mach-pxa/palmz72.c                  |  12 ++-
>  arch/arm/mach-pxa/viper.c                    |  27 +++++-
>  arch/arm/mach-sa1100/simpad.c                |  12 ++-
>  arch/blackfin/mach-bf533/boards/blackstamp.c |  19 +++-
>  arch/blackfin/mach-bf533/boards/ezkit.c      |  18 +++-
>  arch/blackfin/mach-bf533/boards/stamp.c      |  18 +++-
>  arch/blackfin/mach-bf561/boards/ezkit.c      |  18 +++-
>  arch/mips/alchemy/board-gpr.c                |  19 +++-
>  arch/mips/ath79/mach-pb44.c                  |  16 +++-

For MIPS:

Acked-by: Ralf Baechle <ralf@linux-mips.org>

  Ralf

[PATCH 2/7] gpio: Make it possible for consumers to enforce open drain

[Linus Walleij]

Some busses, like I2C, strictly need to have the line handled
as open drain, i.e. not actively driven high. For this reason
the i2c-gpio.c bit-banged I2C driver is reimplementing open
drain handling outside of gpiolib.

This is not very optimal. Instead make it possible for a
consumer to explcitly express that the line must be handled
as open drain instead of allowing local hacks papering over
this issue.

The descriptor tables, whether DT, ACPI or board files, should
of course have flagged these lines as open drain. E.g.:
enum gpio_lookup_flags GPIO_OPEN_DRAIN for a board file, or
gpios = <&foo 42 GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN>; in a
device tree using <dt-bindings/gpio/gpio.h>

But more often than not, these descriptors are wrong. So
we need to make it possible for consumers to enforce this
open drain behaviour.

We now have two new enumerated GPIO descriptor config flags:
GPIOD_OUT_LOW_OPEN_DRAIN and GPIOD_OUT_HIGH_OPEN_DRAIN
that will set up the lined enforced as open drain as output
low or high, using open drain (if the driver supports it)
or using open drain emulation (setting the line as input
to drive it high) from the gpiolib core.

Cc: linux-gpio at vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
Obviously I authorize this patch to be applied directly
to the I2C tree as part of the refactorings.
---
 drivers/gpio/gpiolib.c        | 13 +++++++++++++
 include/linux/gpio/consumer.h |  6 ++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index cd003b74512f..cb73a50a5d5d 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3228,8 +3228,21 @@ int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
 
 	if (lflags & GPIO_ACTIVE_LOW)
 		set_bit(FLAG_ACTIVE_LOW, &desc->flags);
+
 	if (lflags & GPIO_OPEN_DRAIN)
 		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
+	else if (dflags & GPIOD_FLAGS_BIT_OPEN_DRAIN) {
+		/*
+		 * This enforces open drain mode from the consumer side.
+		 * This is necessary for some busses like I2C, but the lookup
+		 * should *REALLY* have specified them as open drain in the
+		 * first place, so print a little warning here.
+		 */
+		set_bit(FLAG_OPEN_DRAIN, &desc->flags);
+		gpiod_warn(desc,
+			   "enforced open drain please flag it properly in DT/ACPI DSDT/board file\n");
+	}
+
 	if (lflags & GPIO_OPEN_SOURCE)
 		set_bit(FLAG_OPEN_SOURCE, &desc->flags);
 	if (lflags & GPIO_SLEEP_MAY_LOOSE_VALUE)
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 8f702fcbe485..5f72a49d1aa3 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -28,6 +28,7 @@ struct gpio_descs {
 #define GPIOD_FLAGS_BIT_DIR_SET		BIT(0)
 #define GPIOD_FLAGS_BIT_DIR_OUT		BIT(1)
 #define GPIOD_FLAGS_BIT_DIR_VAL		BIT(2)
+#define GPIOD_FLAGS_BIT_OPEN_DRAIN	BIT(3)
 
 /**
  * Optional flags that can be passed to one of gpiod_* to configure direction
@@ -39,6 +40,11 @@ enum gpiod_flags {
 	GPIOD_OUT_LOW	= GPIOD_FLAGS_BIT_DIR_SET | GPIOD_FLAGS_BIT_DIR_OUT,
 	GPIOD_OUT_HIGH	= GPIOD_FLAGS_BIT_DIR_SET | GPIOD_FLAGS_BIT_DIR_OUT |
 			  GPIOD_FLAGS_BIT_DIR_VAL,
+	GPIOD_OUT_LOW_OPEN_DRAIN = GPIOD_FLAGS_BIT_DIR_SET |
+			  GPIOD_FLAGS_BIT_DIR_OUT | GPIOD_FLAGS_BIT_OPEN_DRAIN,
+	GPIOD_OUT_HIGH_OPEN_DRAIN = GPIOD_FLAGS_BIT_DIR_SET |
+			  GPIOD_FLAGS_BIT_DIR_OUT | GPIOD_FLAGS_BIT_DIR_VAL |
+			  GPIOD_FLAGS_BIT_OPEN_DRAIN,
 };
 
 #ifdef CONFIG_GPIOLIB
-- 
2.13.5

[PATCH 3/7] i2c: gpio: Enforce open drain through gpiolib

[Linus Walleij]

The I2C GPIO bitbang driver currently emulates open drain
behaviour by implementing what the gpiolib already does:
not actively driving the line high, instead setting it to
input.

This makes no sense. Use the new facility in gpiolib to
request the lines enforced into open drain mode, and let
the open drain emulation already present in the gpiolib
kick in and handle this.

As a bonus: if the GPIO driver in the back-end actually
supports open drain in hardware using the .set_config()
callback, it will be utilized. That's correct: we never
used that hardware feature before, instead relying on
emulating open drain even if the GPIO controller could
actually handle this for us.

Users will sometimes get messages like this:
gpio-485 (?): enforced open drain please flag it properly
  in DT/ACPI DSDT/board file
gpio-486 (?): enforced open drain please flag it properly
  in DT/ACPI DSDT/board file
i2c-gpio gpio-i2c: using lines 485 (SDA) and 486 (SCL)

Which is completely proper: since the line is used as
open drain, it should actually be flagged properly with
e.g.

gpios = <&gpio0 5 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>,
        <&gpio0 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;

Or similar facilities in board file descriptor tables
or ACPI DSDT.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v1->v2:
- Fix a minor typo in error path (copy-paste scl was sda)
---
 drivers/i2c/busses/i2c-gpio.c | 102 ++++++++++++++++--------------------------
 1 file changed, 39 insertions(+), 63 deletions(-)

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index b4664037eded..97b9c29e9429 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -25,23 +25,6 @@ struct i2c_gpio_private_data {
 	struct i2c_gpio_platform_data pdata;
 };
 
-/* Toggle SDA by changing the direction of the pin */
-static void i2c_gpio_setsda_dir(void *data, int state)
-{
-	struct i2c_gpio_private_data *priv = data;
-
-	/*
-	 * This is a way of saying "do not drive
-	 * me actively high" which means emulating open drain.
-	 * The right way to do this is for gpiolib to
-	 * handle this, by the function below.
-	 */
-	if (state)
-		gpiod_direction_input(priv->sda);
-	else
-		gpiod_direction_output(priv->sda, 0);
-}
-
 /*
  * Toggle SDA by changing the output value of the pin. This is only
  * valid for pins configured as open drain (i.e. setting the value
@@ -54,17 +37,6 @@ static void i2c_gpio_setsda_val(void *data, int state)
 	gpiod_set_value(priv->sda, state);
 }
 
-/* Toggle SCL by changing the direction of the pin. */
-static void i2c_gpio_setscl_dir(void *data, int state)
-{
-	struct i2c_gpio_private_data *priv = data;
-
-	if (state)
-		gpiod_direction_input(priv->scl);
-	else
-		gpiod_direction_output(priv->scl, 0);
-}
-
 /*
  * Toggle SCL by changing the output value of the pin. This is used
  * for pins that are configured as open drain and for output-only
@@ -116,30 +88,13 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	struct i2c_gpio_platform_data *pdata;
 	struct i2c_algo_bit_data *bit_data;
 	struct i2c_adapter *adap;
+	enum gpiod_flags gflags;
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	/* First get the GPIO pins; if it fails, we'll defer the probe. */
-	priv->sda = devm_gpiod_get_index(&pdev->dev, NULL, 0, GPIOD_OUT_HIGH);
-	if (IS_ERR(priv->sda)) {
-		ret = PTR_ERR(priv->sda);
-		/* FIXME: hack in the old code, is this really necessary? */
-		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;
-		return ret;
-	}
-	priv->scl = devm_gpiod_get_index(&pdev->dev, NULL, 1, GPIOD_OUT_LOW);
-	if (IS_ERR(priv->scl)) {
-		ret = PTR_ERR(priv->scl);
-		/* FIXME: hack in the old code, is this really necessary? */
-		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;
-		return ret;
-	}
-
 	adap = &priv->adap;
 	bit_data = &priv->bit_data;
 	pdata = &priv->pdata;
@@ -157,27 +112,48 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	}
 
 	/*
-	 * FIXME: this is a hack emulating the open drain emulation
-	 * that gpiolib can already do for us. Make all clients properly
-	 * flag their lines as open drain and get rid of this property
-	 * and the special callback.
+	 * First get the GPIO pins; if it fails, we'll defer the probe.
+	 * If the SDA line is marked from platform data or device tree as
+	 * "open drain" it means something outside of our control is making
+	 * this line being handled as open drain, and we should just handle
+	 * it as any other output. Else we enforce open drain as this is
+	 * required for an I2C bus.
 	 */
-	if (pdata->sda_is_open_drain) {
-		gpiod_direction_output(priv->sda, 1);
-		bit_data->setsda = i2c_gpio_setsda_val;
-	} else {
-		gpiod_direction_input(priv->sda);
-		bit_data->setsda = i2c_gpio_setsda_dir;
+	if (pdata->sda_is_open_drain)
+		gflags = GPIOD_OUT_HIGH;
+	else
+		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
+	priv->sda = devm_gpiod_get_index(&pdev->dev, NULL, 0, gflags);
+	if (IS_ERR(priv->sda)) {
+		ret = PTR_ERR(priv->sda);
+		/* FIXME: hack in the old code, is this really necessary? */
+		if (ret == -EINVAL)
+			ret = -EPROBE_DEFER;
+		return ret;
 	}
-
-	if (pdata->scl_is_open_drain || pdata->scl_is_output_only) {
-		gpiod_direction_output(priv->scl, 1);
-		bit_data->setscl = i2c_gpio_setscl_val;
-	} else {
-		gpiod_direction_input(priv->scl);
-		bit_data->setscl = i2c_gpio_setscl_dir;
+	/*
+	 * If the SCL line is marked from platform data or device tree as
+	 * "open drain" it means something outside of our control is making
+	 * this line being handled as open drain, and we should just handle
+	 * it as any other output. Else we enforce open drain as this is
+	 * required for an I2C bus.
+	 */
+	if (pdata->scl_is_open_drain)
+		gflags = GPIOD_OUT_LOW;
+	else
+		gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
+	priv->scl = devm_gpiod_get_index(&pdev->dev, NULL, 1, gflags);
+	if (IS_ERR(priv->scl)) {
+		ret = PTR_ERR(priv->scl);
+		/* FIXME: hack in the old code, is this really necessary? */
+		if (ret == -EINVAL)
+			ret = -EPROBE_DEFER;
+		return ret;
 	}
 
+	bit_data->setsda = i2c_gpio_setsda_val;
+	bit_data->setscl = i2c_gpio_setscl_val;
+
 	if (!pdata->scl_is_output_only)
 		bit_data->getscl = i2c_gpio_getscl;
 	bit_data->getsda = i2c_gpio_getsda;
-- 
2.13.5

[PATCH 4/7] i2c: gpio: Augment all boardfiles to use open drain

[Linus Walleij]

We now handle the open drain mode internally in the I2C GPIO
driver, but we will get warnings from the gpiolib that we
override the default mode of the line so it becomes open
drain.

We can fix all in-kernel users by simply passing the right
flag along in the descriptor table, and we already touched
all of these files in the series so let's just tidy it up.

Cc: Steven Miao <realmz6@gmail.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v1->v2:
- Collected ACKs.

Steven (Blackfin): requesting ACK for Wolfram to take this patch.
Ralf (MIPS): requesting ACK for Wolfram to take this patch.
---
 arch/arm/mach-ep93xx/core.c                  | 6 ++++--
 arch/arm/mach-ixp4xx/avila-setup.c           | 4 ++--
 arch/arm/mach-ixp4xx/dsmg600-setup.c         | 4 ++--
 arch/arm/mach-ixp4xx/fsg-setup.c             | 4 ++--
 arch/arm/mach-ixp4xx/ixdp425-setup.c         | 4 ++--
 arch/arm/mach-ixp4xx/nas100d-setup.c         | 4 ++--
 arch/arm/mach-ixp4xx/nslu2-setup.c           | 4 ++--
 arch/arm/mach-ks8695/board-acs5k.c           | 6 ++++--
 arch/arm/mach-pxa/palmz72.c                  | 6 ++++--
 arch/arm/mach-pxa/viper.c                    | 8 ++++----
 arch/arm/mach-sa1100/simpad.c                | 6 ++++--
 arch/blackfin/mach-bf533/boards/blackstamp.c | 4 ++--
 arch/blackfin/mach-bf533/boards/ezkit.c      | 4 ++--
 arch/blackfin/mach-bf533/boards/stamp.c      | 4 ++--
 arch/blackfin/mach-bf561/boards/ezkit.c      | 4 ++--
 arch/mips/alchemy/board-gpr.c                | 4 ++++
 arch/mips/ath79/mach-pb44.c                  | 4 ++--
 drivers/mfd/sm501.c                          | 4 ++--
 18 files changed, 48 insertions(+), 36 deletions(-)

diff --git a/arch/arm/mach-ep93xx/core.c b/arch/arm/mach-ep93xx/core.c
index 6b4754ecaffc..efddea867cbe 100644
--- a/arch/arm/mach-ep93xx/core.c
+++ b/arch/arm/mach-ep93xx/core.c
@@ -326,8 +326,10 @@ static struct gpiod_lookup_table ep93xx_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		/* Use local offsets on gpiochip/port "G" */
-		GPIO_LOOKUP_IDX("G", 1, NULL, 0, GPIO_ACTIVE_HIGH),
-		GPIO_LOOKUP_IDX("G", 0, NULL, 1, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("G", 1, NULL, 0,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
+		GPIO_LOOKUP_IDX("G", 0, NULL, 1,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ixp4xx/avila-setup.c b/arch/arm/mach-ixp4xx/avila-setup.c
index 72122b5e7f28..bb6fbfc9b11a 100644
--- a/arch/arm/mach-ixp4xx/avila-setup.c
+++ b/arch/arm/mach-ixp4xx/avila-setup.c
@@ -53,9 +53,9 @@ static struct gpiod_lookup_table avila_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", AVILA_SDA_PIN,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", AVILA_SCL_PIN,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ixp4xx/dsmg600-setup.c b/arch/arm/mach-ixp4xx/dsmg600-setup.c
index 68ccd669051b..af543dd3da5d 100644
--- a/arch/arm/mach-ixp4xx/dsmg600-setup.c
+++ b/arch/arm/mach-ixp4xx/dsmg600-setup.c
@@ -72,9 +72,9 @@ static struct gpiod_lookup_table dsmg600_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", DSMG600_SDA_PIN,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", DSMG600_SCL_PIN,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ixp4xx/fsg-setup.c b/arch/arm/mach-ixp4xx/fsg-setup.c
index a0350ad15175..8afb3f4db376 100644
--- a/arch/arm/mach-ixp4xx/fsg-setup.c
+++ b/arch/arm/mach-ixp4xx/fsg-setup.c
@@ -58,9 +58,9 @@ static struct gpiod_lookup_table fsg_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", FSG_SDA_PIN,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", FSG_SCL_PIN,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ixp4xx/ixdp425-setup.c b/arch/arm/mach-ixp4xx/ixdp425-setup.c
index fd32ccde20c5..483d48bf252e 100644
--- a/arch/arm/mach-ixp4xx/ixdp425-setup.c
+++ b/arch/arm/mach-ixp4xx/ixdp425-setup.c
@@ -126,9 +126,9 @@ static struct gpiod_lookup_table ixdp425_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", IXDP425_SDA_PIN,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", IXDP425_SCL_PIN,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ixp4xx/nas100d-setup.c b/arch/arm/mach-ixp4xx/nas100d-setup.c
index 612ec8c63456..7e59c59c96a3 100644
--- a/arch/arm/mach-ixp4xx/nas100d-setup.c
+++ b/arch/arm/mach-ixp4xx/nas100d-setup.c
@@ -104,9 +104,9 @@ static struct gpiod_lookup_table nas100d_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NAS100D_SDA_PIN,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NAS100D_SCL_PIN,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ixp4xx/nslu2-setup.c b/arch/arm/mach-ixp4xx/nslu2-setup.c
index 13afb03b50fa..224717eb8ac2 100644
--- a/arch/arm/mach-ixp4xx/nslu2-setup.c
+++ b/arch/arm/mach-ixp4xx/nslu2-setup.c
@@ -72,9 +72,9 @@ static struct gpiod_lookup_table nslu2_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NSLU2_SDA_PIN,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("IXP4XX_GPIO_CHIP", NSLU2_SCL_PIN,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-ks8695/board-acs5k.c b/arch/arm/mach-ks8695/board-acs5k.c
index f034724e01e1..937eb1d47e7b 100644
--- a/arch/arm/mach-ks8695/board-acs5k.c
+++ b/arch/arm/mach-ks8695/board-acs5k.c
@@ -41,8 +41,10 @@
 static struct gpiod_lookup_table acs5k_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
-		GPIO_LOOKUP_IDX("KS8695", 4, NULL, 0, GPIO_ACTIVE_HIGH),
-		GPIO_LOOKUP_IDX("KS8695", 5, NULL, 1, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("KS8695", 4, NULL, 0,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
+		GPIO_LOOKUP_IDX("KS8695", 5, NULL, 1,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-pxa/palmz72.c b/arch/arm/mach-pxa/palmz72.c
index 94f75632c007..5877e547cecd 100644
--- a/arch/arm/mach-pxa/palmz72.c
+++ b/arch/arm/mach-pxa/palmz72.c
@@ -324,8 +324,10 @@ static struct soc_camera_link palmz72_iclink = {
 static struct gpiod_lookup_table palmz72_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
-		GPIO_LOOKUP_IDX("gpio-pxa", 118, NULL, 0, GPIO_ACTIVE_HIGH),
-		GPIO_LOOKUP_IDX("gpio-pxa", 117, NULL, 1, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("gpio-pxa", 118, NULL, 0,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
+		GPIO_LOOKUP_IDX("gpio-pxa", 117, NULL, 1,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-pxa/viper.c b/arch/arm/mach-pxa/viper.c
index a680742bee2b..4185e7ff073f 100644
--- a/arch/arm/mach-pxa/viper.c
+++ b/arch/arm/mach-pxa/viper.c
@@ -463,9 +463,9 @@ static struct gpiod_lookup_table viper_i2c_gpiod_table = {
 	.dev_id		= "i2c-gpio",
 	.table		= {
 		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_RTC_I2C_SDA_GPIO,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_RTC_I2C_SCL_GPIO,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
@@ -792,9 +792,9 @@ struct gpiod_lookup_table viper_tpm_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
 		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_TPM_I2C_SDA_GPIO,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("gpio-pxa", VIPER_TPM_I2C_SCL_GPIO,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/arm/mach-sa1100/simpad.c b/arch/arm/mach-sa1100/simpad.c
index c6e7e6d8733a..91526024964b 100644
--- a/arch/arm/mach-sa1100/simpad.c
+++ b/arch/arm/mach-sa1100/simpad.c
@@ -327,8 +327,10 @@ static struct platform_device simpad_gpio_leds = {
 static struct gpiod_lookup_table simpad_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
-		GPIO_LOOKUP_IDX("gpio", GPIO_GPIO21, NULL, 0, GPIO_ACTIVE_HIGH),
-		GPIO_LOOKUP_IDX("gpio", GPIO_GPIO25, NULL, 1, GPIO_ACTIVE_HIGH),
+		GPIO_LOOKUP_IDX("gpio", GPIO_GPIO21, NULL, 0,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
+		GPIO_LOOKUP_IDX("gpio", GPIO_GPIO25, NULL, 1,
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/blackfin/mach-bf533/boards/blackstamp.c b/arch/blackfin/mach-bf533/boards/blackstamp.c
index d801ca5ca6c4..fab69c736515 100644
--- a/arch/blackfin/mach-bf533/boards/blackstamp.c
+++ b/arch/blackfin/mach-bf533/boards/blackstamp.c
@@ -367,9 +367,9 @@ static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF8, NULL, 0,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF9, NULL, 1,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/blackfin/mach-bf533/boards/ezkit.c b/arch/blackfin/mach-bf533/boards/ezkit.c
index 463a72358b0e..d64d270e9e62 100644
--- a/arch/blackfin/mach-bf533/boards/ezkit.c
+++ b/arch/blackfin/mach-bf533/boards/ezkit.c
@@ -395,9 +395,9 @@ static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF1, NULL, 0,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF0, NULL, 1,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/blackfin/mach-bf533/boards/stamp.c b/arch/blackfin/mach-bf533/boards/stamp.c
index d2479359adb7..27cbf2fa2c62 100644
--- a/arch/blackfin/mach-bf533/boards/stamp.c
+++ b/arch/blackfin/mach-bf533/boards/stamp.c
@@ -517,9 +517,9 @@ static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF2, NULL, 0,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF3, NULL, 1,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/blackfin/mach-bf561/boards/ezkit.c b/arch/blackfin/mach-bf561/boards/ezkit.c
index 72f757ebaa84..acc5363f60c6 100644
--- a/arch/blackfin/mach-bf561/boards/ezkit.c
+++ b/arch/blackfin/mach-bf561/boards/ezkit.c
@@ -384,9 +384,9 @@ static struct gpiod_lookup_table bfin_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF1, NULL, 0,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("BFIN-GPIO", GPIO_PF0, NULL, 1,
-				GPIO_ACTIVE_HIGH),
+				GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/arch/mips/alchemy/board-gpr.c b/arch/mips/alchemy/board-gpr.c
index daebc36e5ecb..328d697e72b4 100644
--- a/arch/mips/alchemy/board-gpr.c
+++ b/arch/mips/alchemy/board-gpr.c
@@ -235,6 +235,10 @@ static struct gpiod_lookup_table gpr_i2c_gpiod_table = {
 };
 
 static struct i2c_gpio_platform_data gpr_i2c_data = {
+	/*
+	 * The open drain mode is hardwired somewhere or an electrical
+	 * property of the alchemy GPIO controller.
+	 */
 	.sda_is_open_drain	= 1,
 	.scl_is_open_drain	= 1,
 	.udelay			= 2,		/* ~100 kHz */
diff --git a/arch/mips/ath79/mach-pb44.c b/arch/mips/ath79/mach-pb44.c
index a95409063847..6b2c6f3baefa 100644
--- a/arch/mips/ath79/mach-pb44.c
+++ b/arch/mips/ath79/mach-pb44.c
@@ -37,9 +37,9 @@ static struct gpiod_lookup_table pb44_i2c_gpiod_table = {
 	.dev_id = "i2c-gpio",
 	.table = {
 		GPIO_LOOKUP_IDX("ath79-gpio", PB44_GPIO_I2C_SDA,
-				NULL, 0, GPIO_ACTIVE_HIGH),
+				NULL, 0, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 		GPIO_LOOKUP_IDX("ath79-gpio", PB44_GPIO_I2C_SCL,
-				NULL, 1, GPIO_ACTIVE_HIGH),
+				NULL, 1, GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN),
 	},
 };
 
diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
index 4d40d013a412..ad774161a22d 100644
--- a/drivers/mfd/sm501.c
+++ b/drivers/mfd/sm501.c
@@ -1152,7 +1152,7 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
 	lookup->table[0].chip_hwnum = iic->pin_sda % 32;
 	lookup->table[0].con_id = NULL;
 	lookup->table[0].idx = 0;
-	lookup->table[0].flags = GPIO_ACTIVE_HIGH;
+	lookup->table[0].flags = GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN;
 	if (iic->pin_scl < 32)
 		lookup->table[1].chip_label = "SM501-LOW";
 	else
@@ -1160,7 +1160,7 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
 	lookup->table[1].chip_hwnum = iic->pin_scl % 32;
 	lookup->table[1].con_id = NULL;
 	lookup->table[1].idx = 1;
-	lookup->table[1].flags = GPIO_ACTIVE_HIGH;
+	lookup->table[1].flags = GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN;
 	gpiod_add_lookup_table(lookup);
 
 	icd = dev_get_platdata(&pdev->dev);
-- 
2.13.5

[PATCH 4/7] i2c: gpio: Augment all boardfiles to use open drain

[Robert Jarzmik]

Linus Walleij <linus.walleij@linaro.org> writes:

> We now handle the open drain mode internally in the I2C GPIO
> driver, but we will get warnings from the gpiolib that we
> override the default mode of the line so it becomes open
> drain.
>
> We can fix all in-kernel users by simply passing the right
> flag along in the descriptor table, and we already touched
> all of these files in the series so let's just tidy it up.
>
> Cc: Steven Miao <realmz6@gmail.com>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Acked-by: Olof Johansson <olof@lixom.net>
> Acked-by: Lee Jones <lee.jones@linaro.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Collected ACKs.
>
> Steven (Blackfin): requesting ACK for Wolfram to take this patch.
> Ralf (MIPS): requesting ACK for Wolfram to take this patch.
For mach-pxa:
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>

Cheers.

--
Robert

[PATCH 4/7] i2c: gpio: Augment all boardfiles to use open drain

[Ralf Baechle]

On Sun, Sep 17, 2017 at 11:39:03AM +0200, Linus Walleij wrote:

> Steven (Blackfin): requesting ACK for Wolfram to take this patch.
> Ralf (MIPS): requesting ACK for Wolfram to take this patch.

Acked-by: Ralf Baechle <ralf@linux-mips.org>

  Ralf

[Adi-buildroot-devel] [PATCH 4/7] i2c: gpio: Augment all boardfiles to use open drain

[Wu, Aaron]

Hi all,

Steven is no longer working on this for ADI. Acked by me if this works. Thanks.

Best regards,
Aaron Wu
Analog Devices Inc.

-----Original Message-----
From: Ralf Baechle [mailto:ralf at linux-mips.org] 
Sent: Monday, October 09, 2017 10:28 PM
To: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-mips at linux-mips.org; Steven Miao <realmz6@gmail.com>; adi-buildroot-devel at lists.sourceforge.net; Geert Uytterhoeven <geert@linux-m68k.org>; linux-i2c at vger.kernel.org; linux-arm-kernel at lists.infradead.org
Subject: Re: [Adi-buildroot-devel] [PATCH 4/7] i2c: gpio: Augment all boardfiles to use open drain

On Sun, Sep 17, 2017 at 11:39:03AM +0200, Linus Walleij wrote:

> Steven (Blackfin): requesting ACK for Wolfram to take this patch.
> Ralf (MIPS): requesting ACK for Wolfram to take this patch.

Acked-by: Ralf Baechle <ralf@linux-mips.org>

  Ralf

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[PATCH 5/7] i2c: gpio: Local vars in probe

[Linus Walleij]

By creating local variables for *dev and *np, the code become
much easier to read, in my opinion.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
I put this at the end of the series because compared to the
rest of the patches it is completely unimportant.
---
 drivers/i2c/busses/i2c-gpio.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index 97b9c29e9429..beb5ce523684 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -88,10 +88,12 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	struct i2c_gpio_platform_data *pdata;
 	struct i2c_algo_bit_data *bit_data;
 	struct i2c_adapter *adap;
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
 	enum gpiod_flags gflags;
 	int ret;
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
@@ -99,15 +101,15 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	bit_data = &priv->bit_data;
 	pdata = &priv->pdata;
 
-	if (pdev->dev.of_node) {
-		of_i2c_gpio_get_props(pdev->dev.of_node, pdata);
+	if (np) {
+		of_i2c_gpio_get_props(np, pdata);
 	} else {
 		/*
 		 * If all platform data settings are zero it is OK
 		 * to not provide any platform data from the board.
 		 */
-		if (dev_get_platdata(&pdev->dev))
-			memcpy(pdata, dev_get_platdata(&pdev->dev),
+		if (dev_get_platdata(dev))
+			memcpy(pdata, dev_get_platdata(dev),
 			       sizeof(*pdata));
 	}
 
@@ -123,7 +125,7 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 		gflags = GPIOD_OUT_HIGH;
 	else
 		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
-	priv->sda = devm_gpiod_get_index(&pdev->dev, NULL, 0, gflags);
+	priv->sda = devm_gpiod_get_index(dev, NULL, 0, gflags);
 	if (IS_ERR(priv->sda)) {
 		ret = PTR_ERR(priv->sda);
 		/* FIXME: hack in the old code, is this really necessary? */
@@ -142,7 +144,7 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 		gflags = GPIOD_OUT_LOW;
 	else
 		gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
-	priv->scl = devm_gpiod_get_index(&pdev->dev, NULL, 1, gflags);
+	priv->scl = devm_gpiod_get_index(dev, NULL, 1, gflags);
 	if (IS_ERR(priv->scl)) {
 		ret = PTR_ERR(priv->scl);
 		/* FIXME: hack in the old code, is this really necessary? */
@@ -173,15 +175,15 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	bit_data->data = priv;
 
 	adap->owner = THIS_MODULE;
-	if (pdev->dev.of_node)
-		strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name));
+	if (np)
+		strlcpy(adap->name, dev_name(dev), sizeof(adap->name));
 	else
 		snprintf(adap->name, sizeof(adap->name), "i2c-gpio%d", pdev->id);
 
 	adap->algo_data = bit_data;
 	adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
-	adap->dev.parent = &pdev->dev;
-	adap->dev.of_node = pdev->dev.of_node;
+	adap->dev.parent = dev;
+	adap->dev.of_node = np;
 
 	adap->nr = pdev->id;
 	ret = i2c_bit_add_numbered_bus(adap);
@@ -195,7 +197,7 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 	 * get accessors to get the actual name of the GPIO line,
 	 * from the descriptor, then provide that instead.
 	 */
-	dev_info(&pdev->dev, "using lines %u (SDA) and %u (SCL%s)\n",
+	dev_info(dev, "using lines %u (SDA) and %u (SCL%s)\n",
 		 desc_to_gpio(priv->sda), desc_to_gpio(priv->scl),
 		 pdata->scl_is_output_only
 		 ? ", no clock stretching" : "");
-- 
2.13.5

[PATCH 5/7] i2c: gpio: Local vars in probe

[Geert Uytterhoeven]

Hi Linus,

On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> By creating local variables for *dev and *np, the code become
> much easier to read, in my opinion.
>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> I put this at the end of the series because compared to the
> rest of the patches it is completely unimportant.
> ---
>  drivers/i2c/busses/i2c-gpio.c | 26 ++++++++++++++------------
>  1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> index 97b9c29e9429..beb5ce523684 100644
> --- a/drivers/i2c/busses/i2c-gpio.c
> +++ b/drivers/i2c/busses/i2c-gpio.c

> @@ -99,15 +101,15 @@ static int i2c_gpio_probe(struct platform_device *pdev)
>         bit_data = &priv->bit_data;
>         pdata = &priv->pdata;
>
> -       if (pdev->dev.of_node) {
> -               of_i2c_gpio_get_props(pdev->dev.of_node, pdata);
> +       if (np) {
> +               of_i2c_gpio_get_props(np, pdata);
>         } else {
>                 /*
>                  * If all platform data settings are zero it is OK
>                  * to not provide any platform data from the board.
>                  */
> -               if (dev_get_platdata(&pdev->dev))
> -                       memcpy(pdata, dev_get_platdata(&pdev->dev),
> +               if (dev_get_platdata(dev))
> +                       memcpy(pdata, dev_get_platdata(dev),
>                                sizeof(*pdata));

This fits on one line again (you have to do something to offset the LoC
increase 14 insertions(+), 12 deletions(-) ;-)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH 6/7] dt-bindings: i2c: i2c-gpio: Add support for named gpios

[Linus Walleij]

From: Geert Uytterhoeven <geert+renesas () glider ! be>

The current i2c-gpio DT bindings use a single unnamed "gpios" property
to refer to the SDA and SCL signal lines by index.  This is error-prone
for the casual DT writer and reviewer, as one has to look up the order
in the DT bindings.

Fix this by amending the DT bindings to use two separate named gpios
properties, and deprecate the old unnamed variant.

Take this opportunity to clearly deprecate the "i2c-gpio,sda-open-drain"
and "i2c-gpio,scl-open-drain" flags as well. The commit describes
in detail what these flags actually mean, and why they should not be
used in new device trees.

Cc: devicetree at vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
[Augmented to what I and Rob would like]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v1->v2:
- Create a special section for the deprecated bindings
- Also deprecate the open drain bool properties
- Update the example to use the new style of bindings
---
 Documentation/devicetree/bindings/i2c/i2c-gpio.txt | 32 ++++++++++++++++------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt
index 4f8ec947c6bd..38a05562d1d2 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt
@@ -2,25 +2,39 @@ Device-Tree bindings for i2c gpio driver
 
 Required properties:
 	- compatible = "i2c-gpio";
-	- gpios: sda and scl gpio
-
+	- sda-gpios: gpio used for the sda signal, this should be flagged as
+	  active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)
+	  from <dt-bindings/gpio/gpio.h> since the signal is by definition
+	  open drain.
+	- scl-gpios: gpio used for the scl signal, this should be flagged as
+	  active high using open drain with (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)
+	  from <dt-bindings/gpio/gpio.h> since the signal is by definition
+	  open drain.
 
 Optional properties:
-	- i2c-gpio,sda-open-drain: sda as open drain
-	- i2c-gpio,scl-open-drain: scl as open drain
 	- i2c-gpio,scl-output-only: scl as output only
 	- i2c-gpio,delay-us: delay between GPIO operations (may depend on each platform)
 	- i2c-gpio,timeout-ms: timeout to get data
 
+Deprecated properties, do not use in new device tree sources:
+	- gpios: sda and scl gpio, alternative for {sda,scl}-gpios
+	- i2c-gpio,sda-open-drain: this means that something outside of our
+	  control has put the GPIO line used for SDA into open drain mode, and
+	  that something is not the GPIO chip. It is essentially an
+	  inconsistency flag.
+	- i2c-gpio,scl-open-drain: this means that something outside of our
+	  control has put the GPIO line used for SCL into open drain mode, and
+	  that something is not the GPIO chip. It is essentially an
+	  inconsistency flag.
+
 Example nodes:
 
+#include <dt-bindings/gpio/gpio.h>
+
 i2c at 0 {
 	compatible = "i2c-gpio";
-	gpios = <&pioA 23 0 /* sda */
-		 &pioA 24 0 /* scl */
-		>;
-	i2c-gpio,sda-open-drain;
-	i2c-gpio,scl-open-drain;
+	sda-gpios = <&pioA 23 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+	scl-gpios = <&pioA 24 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
 	i2c-gpio,delay-us = <2>;	/* ~100 kHz */
 	#address-cells = <1>;
 	#size-cells = <0>;
-- 
2.13.5

[PATCH 6/7] dt-bindings: i2c: i2c-gpio: Add support for named gpios

[Rob Herring]

On Sun, Sep 17, 2017 at 11:39:05AM +0200, Linus Walleij wrote:
> From: Geert Uytterhoeven <geert+renesas () glider ! be>
> 
> The current i2c-gpio DT bindings use a single unnamed "gpios" property
> to refer to the SDA and SCL signal lines by index.  This is error-prone
> for the casual DT writer and reviewer, as one has to look up the order
> in the DT bindings.
> 
> Fix this by amending the DT bindings to use two separate named gpios
> properties, and deprecate the old unnamed variant.
> 
> Take this opportunity to clearly deprecate the "i2c-gpio,sda-open-drain"
> and "i2c-gpio,scl-open-drain" flags as well. The commit describes
> in detail what these flags actually mean, and why they should not be
> used in new device trees.
> 
> Cc: devicetree at vger.kernel.org
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> [Augmented to what I and Rob would like]
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Create a special section for the deprecated bindings
> - Also deprecate the open drain bool properties
> - Update the example to use the new style of bindings
> ---
>  Documentation/devicetree/bindings/i2c/i2c-gpio.txt | 32 ++++++++++++++++------
>  1 file changed, 23 insertions(+), 9 deletions(-)

Acked-by: Rob Herring <robh@kernel.org>

[PATCH 7/7] i2c: gpio: Add support for named gpios in DT

[Linus Walleij]

This adds support for using the "sda" and "scl" GPIOs in
device tree instead of anonymously using index 0 and 1 of
the "gpios" property.

We add a helper function to retrieve the GPIO descriptors
and some explicit error handling since the probe may have
to be deferred. At least this happened to me when moving
to using named "sda" and "scl" lines (all of a sudden this
started to probe before the GPIO driver) so we need to
gracefully defer probe when we ge -ENOENT in the error
pointer.

Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
This is pretty much a rewrite of Geerts patch on top of
my own changes to support descriptors.
---
 drivers/i2c/busses/i2c-gpio.c | 59 +++++++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 16 deletions(-)

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index beb5ce523684..2738b851f470 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -82,6 +82,42 @@ static void of_i2c_gpio_get_props(struct device_node *np,
 		of_property_read_bool(np, "i2c-gpio,scl-output-only");
 }
 
+static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
+					   const char *con_id,
+					   unsigned int index,
+					   enum gpiod_flags gflags)
+{
+	struct gpio_desc *retdesc;
+	int ret;
+
+	retdesc = devm_gpiod_get(dev, con_id, gflags);
+	if (!IS_ERR(retdesc)) {
+		dev_dbg(dev, "got GPIO from name %s\n", con_id);
+		return retdesc;
+	}
+
+	retdesc = devm_gpiod_get_index(dev, NULL, index, gflags);
+	if (!IS_ERR(retdesc)) {
+		dev_dbg(dev, "got GPIO from index %u\n", index);
+		return retdesc;
+	}
+
+	ret = PTR_ERR(retdesc);
+
+	/* FIXME: hack in the old code, is this really necessary? */
+	if (ret == -EINVAL)
+		retdesc = ERR_PTR(-EPROBE_DEFER);
+
+	/* This happens if the GPIO driver is not yet probed, let's defer */
+	if (ret == -ENOENT)
+		retdesc = ERR_PTR(-EPROBE_DEFER);
+
+	if (ret != -EPROBE_DEFER)
+		dev_err(dev, "error trying to get descriptor: %ld\n", ret);
+
+	return retdesc;
+}
+
 static int i2c_gpio_probe(struct platform_device *pdev)
 {
 	struct i2c_gpio_private_data *priv;
@@ -125,14 +161,10 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 		gflags = GPIOD_OUT_HIGH;
 	else
 		gflags = GPIOD_OUT_HIGH_OPEN_DRAIN;
-	priv->sda = devm_gpiod_get_index(dev, NULL, 0, gflags);
-	if (IS_ERR(priv->sda)) {
-		ret = PTR_ERR(priv->sda);
-		/* FIXME: hack in the old code, is this really necessary? */
-		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;
-		return ret;
-	}
+	priv->sda = i2c_gpio_get_desc(dev, "sda", 0, gflags);
+	if (IS_ERR(priv->sda))
+		return PTR_ERR(priv->sda);
+
 	/*
 	 * If the SCL line is marked from platform data or device tree as
 	 * "open drain" it means something outside of our control is making
@@ -144,14 +176,9 @@ static int i2c_gpio_probe(struct platform_device *pdev)
 		gflags = GPIOD_OUT_LOW;
 	else
 		gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
-	priv->scl = devm_gpiod_get_index(dev, NULL, 1, gflags);
-	if (IS_ERR(priv->scl)) {
-		ret = PTR_ERR(priv->scl);
-		/* FIXME: hack in the old code, is this really necessary? */
-		if (ret == -EINVAL)
-			ret = -EPROBE_DEFER;
-		return ret;
-	}
+	priv->scl = i2c_gpio_get_desc(dev, "scl", 1, gflags);
+	if (IS_ERR(priv->scl))
+		return PTR_ERR(priv->scl);
 
 	bit_data->setsda = i2c_gpio_setsda_val;
 	bit_data->setscl = i2c_gpio_setscl_val;
-- 
2.13.5

[PATCH 7/7] i2c: gpio: Add support for named gpios in DT

[Geert Uytterhoeven]

On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> This adds support for using the "sda" and "scl" GPIOs in
> device tree instead of anonymously using index 0 and 1 of
> the "gpios" property.
>
> We add a helper function to retrieve the GPIO descriptors
> and some explicit error handling since the probe may have
> to be deferred. At least this happened to me when moving
> to using named "sda" and "scl" lines (all of a sudden this
> started to probe before the GPIO driver) so we need to
> gracefully defer probe when we ge -ENOENT in the error

get

> pointer.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH 7/7] i2c: gpio: Add support for named gpios in DT

[Geert Uytterhoeven]

Hi Linus,

On Sun, Sep 17, 2017 at 11:39 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> This adds support for using the "sda" and "scl" GPIOs in
> device tree instead of anonymously using index 0 and 1 of
> the "gpios" property.
>
> We add a helper function to retrieve the GPIO descriptors
> and some explicit error handling since the probe may have
> to be deferred. At least this happened to me when moving
> to using named "sda" and "scl" lines (all of a sudden this
> started to probe before the GPIO driver) so we need to
> gracefully defer probe when we ge -ENOENT in the error
> pointer.
>
> Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> This is pretty much a rewrite of Geerts patch on top of
> my own changes to support descriptors.
> ---
>  drivers/i2c/busses/i2c-gpio.c | 59 +++++++++++++++++++++++++++++++------------
>  1 file changed, 43 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
> index beb5ce523684..2738b851f470 100644
> --- a/drivers/i2c/busses/i2c-gpio.c
> +++ b/drivers/i2c/busses/i2c-gpio.c
> @@ -82,6 +82,42 @@ static void of_i2c_gpio_get_props(struct device_node *np,
>                 of_property_read_bool(np, "i2c-gpio,scl-output-only");
>  }
>
> +static struct gpio_desc *i2c_gpio_get_desc(struct device *dev,
> +                                          const char *con_id,
> +                                          unsigned int index,
> +                                          enum gpiod_flags gflags)
> +{
> +       struct gpio_desc *retdesc;
> +       int ret;

[...]

> +       if (ret != -EPROBE_DEFER)
> +               dev_err(dev, "error trying to get descriptor: %ld\n", ret);

warning: format '%ld' expects argument of type 'long int', but
argument 3 has type 'int' [-Wformat=]

%d (0day busy?)

> +
> +       return retdesc;
> +}

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH 7/7] i2c: gpio: Add support for named gpios in DT

[Linus Walleij]

On Mon, Sep 18, 2017 at 11:58 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:

>> +       if (ret != -EPROBE_DEFER)
>> +               dev_err(dev, "error trying to get descriptor: %ld\n", ret);
>
> warning: format '%ld' expects argument of type 'long int', but
> argument 3 has type 'int' [-Wformat=]
>
> %d (0day busy?)

Bah haven't pushed it to the 0day builders yet.
I'll do that tonight so I can drown in the build errors.
:-D

Fixing it.

Yours,
Linus Walleij

[PATCH 0/7] I2C GPIO to use gpiolibs open drain

[Geert Uytterhoeven]

Hi Linus,

On Sun, Sep 17, 2017 at 11:38 AM, Linus Walleij
<linus.walleij@linaro.org> wrote:
> This augments the I2C GPIO driver to use open drain emulation
> or hardware support for open drain from the GPIO driver.
>
> This version layers Geert Uytterhoeven's idea to use explicit
> sda-gpios and scl-gpios for the GPIO lines, and strongly
> encourage the (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN) flags to be
> used in all device trees.
>
> We have collected ACKs from the ARM SoC maintainers and the
> MFD maintainer and are looking for testers to try this out.
>
> Geert Uytterhoeven (1):
>   dt-bindings: i2c: i2c-gpio: Add support for named gpios
>
> Linus Walleij (6):
>   i2c: gpio: Convert to use descriptors
>   gpio: Make it possible for consumers to enforce open drain
>   i2c: gpio: Enforce open drain through gpiolib
>   i2c: gpio: Augment all boardfiles to use open drain
>   i2c: gpio: Local vars in probe
>   i2c: gpio: Add support for named gpios in DT

Thanks for doing this, and picking up my patch.

I gave this a try on r8a7740/armadillo800eva.
Without DT changes, the GPIO i2c bus still works fine, but a warning is
printed, as expected:

    gpio-208 (sda): enforced open drain please flag it properly in
DT/ACPI DSDT/board file
    gpio-91 (scl): enforced open drain please flag it properly in
DT/ACPI DSDT/board file

After

    -  sda-gpios = <&pfc 208 GPIO_ACTIVE_HIGH>;
    -  scl-gpios = <&pfc 91 GPIO_ACTIVE_HIGH>;
    + sda-gpios = <&pfc 208 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
    + scl-gpios = <&pfc 91 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;

the warning is gone, and the GPIO i2c bus still works.

Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds