[PATCH 1/4 v4] of_spi: add generic binding support to specify cs gpio

[PATCH 1/4 v4] of_spi: add generic binding support to specify cs gpio

[Jean-Christophe PLAGNIOL-VILLARD]

This will allow to use gpio for chip select with no modification in the
driver binding

When use the cs-gpios, the gpio number will be passed via the cs_gpio field
and the number of chip select will automatically increased.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: devicetree-discuss at lists.ozlabs.org
Cc: spi-devel-general at lists.sourceforge.net
---
v4:
	use cs_gpio to pass the gpio number

Best Regards,
J.
 Documentation/devicetree/bindings/spi/spi-bus.txt |    6 ++
 drivers/spi/spi.c                                 |   57 +++++++++++++++++++-
 include/linux/spi/spi.h                           |    6 ++
 3 files changed, 66 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
index e782add..c253379 100644
--- a/Documentation/devicetree/bindings/spi/spi-bus.txt
+++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
@@ -12,6 +12,7 @@ The SPI master node requires the following properties:
 - #size-cells     - should be zero.
 - compatible      - name of SPI bus controller following generic names
     		recommended practice.
+- cs-gpios	  - (optional) gpios chip select.
 No other properties are required in the SPI bus node.  It is assumed
 that a driver for an SPI bus device will understand that it is an SPI bus.
 However, the binding does not attempt to define the specific method for
@@ -21,6 +22,8 @@ assumption that board specific platform code will be used to manage
 chip selects.  Individual drivers can define additional properties to
 support describing the chip select layout.
 
+If cs-gpios is used the number of chip select will automatically increased.
+
 SPI slave nodes must be children of the SPI master node and can
 contain the following properties.
 - reg             - (required) chip select address of device.
@@ -34,6 +37,9 @@ contain the following properties.
 - spi-cs-high     - (optional) Empty property indicating device requires
     		chip select active high
 
+If a gpio chipselect is used for the SPI slave the gpio number will be passed
+via the controller_data
+
 SPI example for an MPC5200 SPI bus:
 	spi at f00 {
 		#address-cells = <1>;
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index b2ccdea..c1d0955 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -28,6 +28,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/spi/spi.h>
 #include <linux/of_spi.h>
+#include <linux/of_gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/export.h>
 
@@ -322,6 +323,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
 	spi->dev.parent = &master->dev;
 	spi->dev.bus = &spi_bus_type;
 	spi->dev.release = spidev_release;
+	spi->cs_gpio = -EINVAL;
 	device_initialize(&spi->dev);
 	return spi;
 }
@@ -339,15 +341,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
 int spi_add_device(struct spi_device *spi)
 {
 	static DEFINE_MUTEX(spi_add_lock);
-	struct device *dev = spi->master->dev.parent;
+	struct spi_master *master = spi->master;
+	struct device *dev = master->dev.parent;
 	struct device *d;
 	int status;
 
 	/* Chipselects are numbered 0..max; validate. */
-	if (spi->chip_select >= spi->master->num_chipselect) {
+	if (spi->chip_select >= master->num_chipselect) {
 		dev_err(dev, "cs%d >= max %d\n",
 			spi->chip_select,
-			spi->master->num_chipselect);
+			master->num_chipselect);
 		return -EINVAL;
 	}
 
@@ -371,6 +374,13 @@ int spi_add_device(struct spi_device *spi)
 		goto done;
 	}
 
+	if (master->num_gpio_cs &&
+	    spi->chip_select >= master->first_gpio_cs) {
+		int num = spi->chip_select - master->first_gpio_cs;
+
+		spi->cs_gpio = master->cs_gpios[num];
+	}
+
 	/* Drivers may modify this initial i/o setup, but will
 	 * normally rely on the device being setup.  Devices
 	 * using SPI_CS_HIGH can't coexist well otherwise...
@@ -561,6 +571,43 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
 }
 EXPORT_SYMBOL_GPL(spi_alloc_master);
 
+#ifdef CONFIG_OF
+static int of_spi_register_master(struct spi_master *master)
+{
+	int nb, i;
+	int *cs;
+	struct device_node *np = master->dev.of_node;
+
+	if (!np)
+		return 0;
+
+	nb = of_gpio_named_count(np, "cs-gpios");
+
+	if (nb < 1)
+		return 0;
+
+	cs = devm_kzalloc(&master->dev, sizeof(int) * nb, GFP_KERNEL);
+	master->cs_gpios = cs;
+
+	if (!master->cs_gpios)
+		return -ENOMEM;
+
+	master->first_gpio_cs = master->num_chipselect;
+	master->num_chipselect += nb;
+	master->num_gpio_cs = nb;
+
+	for (i = 0; i < nb; i++)
+		cs[i] = of_get_named_gpio(np, "cs-gpios", i);
+
+	return 0;
+}
+#else
+static int of_spi_register_master(struct spi_master *master)
+{
+	return 0;
+}
+#endif
+
 /**
  * spi_register_master - register SPI master controller
  * @master: initialized master, originally from spi_alloc_master()
@@ -592,6 +639,10 @@ int spi_register_master(struct spi_master *master)
 	if (!dev)
 		return -ENODEV;
 
+	status = of_spi_register_master(master);
+	if (status)
+		return status;
+
 	/* even if it's just one always-selected device, there must
 	 * be@least one chipselect
 	 */
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 176fce9..7dcf031 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -89,6 +89,7 @@ struct spi_device {
 	void			*controller_state;
 	void			*controller_data;
 	char			modalias[SPI_NAME_SIZE];
+	int			cs_gpio;	/* chip select gpio */
 
 	/*
 	 * likely need more hooks for more protocol options affecting how
@@ -318,6 +319,11 @@ struct spi_master {
 
 	/* called on release() to free memory provided by spi_master */
 	void			(*cleanup)(struct spi_device *spi);
+
+	/* gpio chip select */
+	int			*cs_gpios;
+	int			first_gpio_cs;
+	int			num_gpio_cs;
 };
 
 static inline void *spi_master_get_devdata(struct spi_master *master)
-- 
1.7.7

[PATCH 2/4 v4] spi/atmel: add DT support

[Jean-Christophe PLAGNIOL-VILLARD]

The atmel_spi use only gpio for chip select.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: devicetree-discuss at lists.ozlabs.org
Cc: spi-devel-general at lists.sourceforge.net
---
 .../devicetree/bindings/spi/spi_atmel.txt          |    6 +++++
 drivers/spi/spi-atmel.c                            |   21 ++++++++++++++++---
 2 files changed, 23 insertions(+), 4 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/spi_atmel.txt

diff --git a/Documentation/devicetree/bindings/spi/spi_atmel.txt b/Documentation/devicetree/bindings/spi/spi_atmel.txt
new file mode 100644
index 0000000..7ec3d8d
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi_atmel.txt
@@ -0,0 +1,6 @@
+Atmel SPI device
+
+Required properties:
+- compatible : should be "atmel,at91rm9200-spi".
+- reg: Address and length of the register set for the device
+- interrupts: Should contain macb interrupt
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 16d6a83..efbc5f8 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -19,6 +19,7 @@
 #include <linux/interrupt.h>
 #include <linux/spi/spi.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 #include <asm/io.h>
 #include <mach/board.h>
@@ -695,7 +696,7 @@ static int atmel_spi_setup(struct spi_device *spi)
 	u32			scbr, csr;
 	unsigned int		bits = spi->bits_per_word;
 	unsigned long		bus_hz;
-	unsigned int		npcs_pin;
+	int			npcs_pin;
 	int			ret;
 
 	as = spi_master_get_devdata(spi->master);
@@ -767,7 +768,9 @@ static int atmel_spi_setup(struct spi_device *spi)
 	csr |= SPI_BF(DLYBCT, 0);
 
 	/* chipselect must have been muxed as GPIO (e.g. in board setup) */
-	npcs_pin = (unsigned int)spi->controller_data;
+	if (!gpio_is_valid(spi->cs_gpio))
+		spi->cs_gpio = (int)spi->controller_data;
+	npcs_pin = spi->cs_gpio;
 	asd = spi->controller_state;
 	if (!asd) {
 		asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
@@ -887,7 +890,7 @@ static void atmel_spi_cleanup(struct spi_device *spi)
 {
 	struct atmel_spi	*as = spi_master_get_devdata(spi->master);
 	struct atmel_spi_device	*asd = spi->controller_state;
-	unsigned		gpio = (unsigned) spi->controller_data;
+	unsigned		gpio = spi->cs_gpio;
 	unsigned long		flags;
 
 	if (!asd)
@@ -938,7 +941,8 @@ static int __devinit atmel_spi_probe(struct platform_device *pdev)
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 
 	master->bus_num = pdev->id;
-	master->num_chipselect = 4;
+	master->dev.of_node = pdev->dev.of_node;
+	master->num_chipselect = master->dev.of_node ? 0 : 4;
 	master->setup = atmel_spi_setup;
 	master->transfer = atmel_spi_transfer;
 	master->cleanup = atmel_spi_cleanup;
@@ -1064,11 +1068,20 @@ static int atmel_spi_resume(struct platform_device *pdev)
 #define	atmel_spi_resume	NULL
 #endif
 
+#if defined(CONFIG_OF)
+static const struct of_device_id atmel_spi_dt_ids[] = {
+	{ .compatible = "atmel,at91rm9200-spi" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
+#endif
 
 static struct platform_driver atmel_spi_driver = {
 	.driver		= {
 		.name	= "atmel_spi",
 		.owner	= THIS_MODULE,
+		.of_match_table	= of_match_ptr(atmel_spi_dt_ids),
 	},
 	.suspend	= atmel_spi_suspend,
 	.resume		= atmel_spi_resume,
-- 
1.7.7

[PATCH 3/4 v4] ARM: at91: sam9g20 add spi DT support

[Jean-Christophe PLAGNIOL-VILLARD]

usb_a9g20:
	add mmc spi support

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
---
 arch/arm/boot/dts/at91sam9g20.dtsi |   18 ++++++++++++++++++
 arch/arm/boot/dts/usb_a9g20.dts    |   13 +++++++++++++
 arch/arm/mach-at91/at91sam9260.c   |    2 ++
 3 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/arch/arm/boot/dts/at91sam9g20.dtsi b/arch/arm/boot/dts/at91sam9g20.dtsi
index 3cb4226..aef3d5be 100644
--- a/arch/arm/boot/dts/at91sam9g20.dtsi
+++ b/arch/arm/boot/dts/at91sam9g20.dtsi
@@ -203,6 +203,24 @@
 				interrupts = <10 4>;
 				status = "disabled";
 			};
+
+			spi0: spi at fffc8000 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				compatible = "atmel,at91rm9200-spi";
+				reg = <0xfffc8000 0x4000>;
+				interrupts = <12 4>;
+				status = "disabled";
+			};
+
+			spi1: spi at fffcc000 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				compatible = "atmel,at91rm9200-spi";
+				reg = <0xfffcc000 0x4000>;
+				interrupts = <13 4>;
+				status = "disabled";
+			};
 		};
 
 		nand0: nand at 40000000 {
diff --git a/arch/arm/boot/dts/usb_a9g20.dts b/arch/arm/boot/dts/usb_a9g20.dts
index 390c481..9efaff3 100644
--- a/arch/arm/boot/dts/usb_a9g20.dts
+++ b/arch/arm/boot/dts/usb_a9g20.dts
@@ -46,6 +46,19 @@
 				atmel,vbus-gpio = <&pioC 5 0>;
 				status = "okay";
 			};
+
+			spi1: spi at fffcc000 {
+				cs-gpios = <&pioB 3 0>;
+				status = "okay";
+				mmc-slot at 0 {
+					compatible = "mmc-spi-slot";
+					reg = <0>;
+					gpios = <&pioC 4 0   /* CD */
+						>;
+					voltage-ranges = <3200 3400>;
+					spi-max-frequency = <20000000>;
+				};
+			};
 		};
 
 		nand0: nand at 40000000 {
diff --git a/arch/arm/mach-at91/at91sam9260.c b/arch/arm/mach-at91/at91sam9260.c
index d1e5750..c6e5d0f 100644
--- a/arch/arm/mach-at91/at91sam9260.c
+++ b/arch/arm/mach-at91/at91sam9260.c
@@ -217,6 +217,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID("t1_clk", "fffdc000.timer", &tc4_clk),
 	CLKDEV_CON_DEV_ID("t2_clk", "fffdc000.timer", &tc5_clk),
 	CLKDEV_CON_DEV_ID("hclk", "500000.ohci", &ohci_clk),
+	CLKDEV_CON_DEV_ID("spi_clk", "fffc8000.spi", &spi0_clk),
+	CLKDEV_CON_DEV_ID("spi_clk", "fffcc000.spi", &spi1_clk),
 	/* fake hclk clock */
 	CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &ohci_clk),
 	CLKDEV_CON_ID("pioA", &pioA_clk),
-- 
1.7.7

[PATCH 4/4 v4] ARM: at91: sam9g45 add spi DT support

[Jean-Christophe PLAGNIOL-VILLARD]

at91sam9m10g45ek:
	add dataflash support

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
---
 arch/arm/boot/dts/at91sam9g45.dtsi     |   18 ++++++++++++++++++
 arch/arm/boot/dts/at91sam9m10g45ek.dts |   23 +++++++++++++++++++++++
 arch/arm/mach-at91/at91sam9g45.c       |    2 ++
 3 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/arch/arm/boot/dts/at91sam9g45.dtsi b/arch/arm/boot/dts/at91sam9g45.dtsi
index 7a685f9..8a11530 100644
--- a/arch/arm/boot/dts/at91sam9g45.dtsi
+++ b/arch/arm/boot/dts/at91sam9g45.dtsi
@@ -271,6 +271,24 @@
 					atmel,can-isoc = <1>;
 				};
 			};
+
+			spi0: spi at fffa4000 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				compatible = "atmel,at91rm9200-spi";
+				reg = <0xfffa4000 0x4000>;
+				interrupts = <14 4>;
+				status = "disabled";
+			};
+
+			spi1: spi at fffa8000 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				compatible = "atmel,at91rm9200-spi";
+				reg = <0xfffa8000 0x4000>;
+				interrupts = <15 4>;
+				status = "disabled";
+			};
 		};
 
 		nand0: nand at 40000000 {
diff --git a/arch/arm/boot/dts/at91sam9m10g45ek.dts b/arch/arm/boot/dts/at91sam9m10g45ek.dts
index b9382e3..2b96ab2 100644
--- a/arch/arm/boot/dts/at91sam9m10g45ek.dts
+++ b/arch/arm/boot/dts/at91sam9m10g45ek.dts
@@ -51,6 +51,29 @@
 				atmel,vbus-gpio = <&pioB 19 0>;
 				status = "okay";
 			};
+
+			spi0: spi at fffa4000 {
+				cs-gpios = <&pioB 3 0>;
+				status = "okay";
+				flash: at45db321d at 0 {
+					compatible = "atmel,at45db321d", "atmel,at45", "atmel,dataflash";
+					reg = <0>;
+					spi-max-frequency = <15000000>;
+					#address-cells = <1>;
+					#size-cells = <1>;
+
+					partition at 0 {
+						label = "U-Boot";
+						reg = <0x0 0x40110>;
+						read-only;
+					};
+
+					partition at 40110 {
+						label = "Kernel";
+						reg = <0x40110 0x3dfef0>;
+					};
+				};
+			};
 		};
 
 		nand0: nand at 40000000 {
diff --git a/arch/arm/mach-at91/at91sam9g45.c b/arch/arm/mach-at91/at91sam9g45.c
index da80f0c..06547bf 100644
--- a/arch/arm/mach-at91/at91sam9g45.c
+++ b/arch/arm/mach-at91/at91sam9g45.c
@@ -236,6 +236,8 @@ static struct clk_lookup periph_clocks_lookups[] = {
 	CLKDEV_CON_DEV_ID("ehci_clk", "800000.ehci", &uhphs_clk),
 	CLKDEV_CON_DEV_ID("hclk", "600000.gadget", &utmi_clk),
 	CLKDEV_CON_DEV_ID("pclk", "600000.gadget", &udphs_clk),
+	CLKDEV_CON_DEV_ID("spi_clk", "fffa4000.spi", &spi0_clk),
+	CLKDEV_CON_DEV_ID("spi_clk", "fffa8000.spi", &spi1_clk),
 	/* fake hclk clock */
 	CLKDEV_CON_DEV_ID("hclk", "at91_ohci", &uhphs_clk),
 	CLKDEV_CON_ID("pioA", &pioA_clk),
-- 
1.7.7

[PATCH 1/4 v4] of_spi: add generic binding support to specify cs gpio

[Grant Likely]

On Wed,  7 Mar 2012 13:23:06 +0100, Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> wrote:
> This will allow to use gpio for chip select with no modification in the
> driver binding
> 
> When use the cs-gpios, the gpio number will be passed via the cs_gpio field
> and the number of chip select will automatically increased.
> 
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> Cc: devicetree-discuss at lists.ozlabs.org
> Cc: spi-devel-general at lists.sourceforge.net
> ---
> v4:
> 	use cs_gpio to pass the gpio number
> 
> Best Regards,
> J.
>  Documentation/devicetree/bindings/spi/spi-bus.txt |    6 ++
>  drivers/spi/spi.c                                 |   57 +++++++++++++++++++-
>  include/linux/spi/spi.h                           |    6 ++
>  3 files changed, 66 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
> index e782add..c253379 100644
> --- a/Documentation/devicetree/bindings/spi/spi-bus.txt
> +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
> @@ -12,6 +12,7 @@ The SPI master node requires the following properties:
>  - #size-cells     - should be zero.
>  - compatible      - name of SPI bus controller following generic names
>      		recommended practice.
> +- cs-gpios	  - (optional) gpios chip select.
>  No other properties are required in the SPI bus node.  It is assumed
>  that a driver for an SPI bus device will understand that it is an SPI bus.
>  However, the binding does not attempt to define the specific method for
> @@ -21,6 +22,8 @@ assumption that board specific platform code will be used to manage
>  chip selects.  Individual drivers can define additional properties to
>  support describing the chip select layout.
>  
> +If cs-gpios is used the number of chip select will automatically increased.
> +
>  SPI slave nodes must be children of the SPI master node and can
>  contain the following properties.
>  - reg             - (required) chip select address of device.
> @@ -34,6 +37,9 @@ contain the following properties.
>  - spi-cs-high     - (optional) Empty property indicating device requires
>      		chip select active high
>  
> +If a gpio chipselect is used for the SPI slave the gpio number will be passed
> +via the controller_data
> +
>  SPI example for an MPC5200 SPI bus:
>  	spi at f00 {
>  		#address-cells = <1>;
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index b2ccdea..c1d0955 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -28,6 +28,7 @@
>  #include <linux/mod_devicetable.h>
>  #include <linux/spi/spi.h>
>  #include <linux/of_spi.h>
> +#include <linux/of_gpio.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/export.h>
>  
> @@ -322,6 +323,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
>  	spi->dev.parent = &master->dev;
>  	spi->dev.bus = &spi_bus_type;
>  	spi->dev.release = spidev_release;
> +	spi->cs_gpio = -EINVAL;
>  	device_initialize(&spi->dev);
>  	return spi;
>  }
> @@ -339,15 +341,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
>  int spi_add_device(struct spi_device *spi)
>  {
>  	static DEFINE_MUTEX(spi_add_lock);
> -	struct device *dev = spi->master->dev.parent;
> +	struct spi_master *master = spi->master;
> +	struct device *dev = master->dev.parent;
>  	struct device *d;
>  	int status;
>  
>  	/* Chipselects are numbered 0..max; validate. */
> -	if (spi->chip_select >= spi->master->num_chipselect) {
> +	if (spi->chip_select >= master->num_chipselect) {
>  		dev_err(dev, "cs%d >= max %d\n",
>  			spi->chip_select,
> -			spi->master->num_chipselect);
> +			master->num_chipselect);
>  		return -EINVAL;
>  	}
>  
> @@ -371,6 +374,13 @@ int spi_add_device(struct spi_device *spi)
>  		goto done;
>  	}
>  
> +	if (master->num_gpio_cs &&
> +	    spi->chip_select >= master->first_gpio_cs) {
> +		int num = spi->chip_select - master->first_gpio_cs;
> +
> +		spi->cs_gpio = master->cs_gpios[num];

spi->cs_gpio isn't used anywhere.

> +	}
> +
>  	/* Drivers may modify this initial i/o setup, but will
>  	 * normally rely on the device being setup.  Devices
>  	 * using SPI_CS_HIGH can't coexist well otherwise...
> @@ -561,6 +571,43 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
>  }
>  EXPORT_SYMBOL_GPL(spi_alloc_master);
>  
> +#ifdef CONFIG_OF
> +static int of_spi_register_master(struct spi_master *master)
> +{
> +	int nb, i;
> +	int *cs;
> +	struct device_node *np = master->dev.of_node;
> +
> +	if (!np)
> +		return 0;
> +
> +	nb = of_gpio_named_count(np, "cs-gpios");
> +
> +	if (nb < 1)
> +		return 0;
> +
> +	cs = devm_kzalloc(&master->dev, sizeof(int) * nb, GFP_KERNEL);
> +	master->cs_gpios = cs;
> +
> +	if (!master->cs_gpios)
> +		return -ENOMEM;
> +
> +	master->first_gpio_cs = master->num_chipselect;
> +	master->num_chipselect += nb;
> +	master->num_gpio_cs = nb;

I think this can be simplified.  Rather than trying to optimize by having
a set of integrated cs lines followed by a gpio set, I think it would be
better to have a single cs_gpios table that covers the whole range of
num_chipselect; even if they overlap natural cs lines.  That will make for
an easier to use binding since users won't need to remember how many natural
cs lines are on the device when filling the cs-gpios property.  It will
also make the code simpler because first_gpio_cs and num_gpio_cs can both
be eliminated.  It also means the core can have exact knowledge about which
gpio is associated with which cs number.

> +
> +	for (i = 0; i < nb; i++)
> +		cs[i] = of_get_named_gpio(np, "cs-gpios", i);
> +
> +	return 0;
> +}
> +#else
> +static int of_spi_register_master(struct spi_master *master)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /**
>   * spi_register_master - register SPI master controller
>   * @master: initialized master, originally from spi_alloc_master()
> @@ -592,6 +639,10 @@ int spi_register_master(struct spi_master *master)
>  	if (!dev)
>  		return -ENODEV;
>  
> +	status = of_spi_register_master(master);
> +	if (status)
> +		return status;
> +
>  	/* even if it's just one always-selected device, there must
>  	 * be at least one chipselect
>  	 */
> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> index 176fce9..7dcf031 100644
> --- a/include/linux/spi/spi.h
> +++ b/include/linux/spi/spi.h
> @@ -89,6 +89,7 @@ struct spi_device {
>  	void			*controller_state;
>  	void			*controller_data;
>  	char			modalias[SPI_NAME_SIZE];
> +	int			cs_gpio;	/* chip select gpio */
>  
>  	/*
>  	 * likely need more hooks for more protocol options affecting how
> @@ -318,6 +319,11 @@ struct spi_master {
>  
>  	/* called on release() to free memory provided by spi_master */
>  	void			(*cleanup)(struct spi_device *spi);
> +
> +	/* gpio chip select */
> +	int			*cs_gpios;
> +	int			first_gpio_cs;
> +	int			num_gpio_cs;
>  };
>  
>  static inline void *spi_master_get_devdata(struct spi_master *master)
> -- 
> 1.7.7
> 
> _______________________________________________
> devicetree-discuss mailing list
> devicetree-discuss at lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/devicetree-discuss

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies,Ltd.

[PATCH 1/4 v4] of_spi: add generic binding support to specify cs gpio

[Jean-Christophe PLAGNIOL-VILLARD]

On 08:14 Fri 09 Mar     , Grant Likely wrote:
> On Wed,  7 Mar 2012 13:23:06 +0100, Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> wrote:
> > This will allow to use gpio for chip select with no modification in the
> > driver binding
> > 
> > When use the cs-gpios, the gpio number will be passed via the cs_gpio field
> > and the number of chip select will automatically increased.
> > 
> > Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> > Cc: devicetree-discuss at lists.ozlabs.org
> > Cc: spi-devel-general at lists.sourceforge.net
> > ---
> > v4:
> > 	use cs_gpio to pass the gpio number
> > 
> > Best Regards,
> > J.
> >  Documentation/devicetree/bindings/spi/spi-bus.txt |    6 ++
> >  drivers/spi/spi.c                                 |   57 +++++++++++++++++++-
> >  include/linux/spi/spi.h                           |    6 ++
> >  3 files changed, 66 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/spi/spi-bus.txt b/Documentation/devicetree/bindings/spi/spi-bus.txt
> > index e782add..c253379 100644
> > --- a/Documentation/devicetree/bindings/spi/spi-bus.txt
> > +++ b/Documentation/devicetree/bindings/spi/spi-bus.txt
> > @@ -12,6 +12,7 @@ The SPI master node requires the following properties:
> >  - #size-cells     - should be zero.
> >  - compatible      - name of SPI bus controller following generic names
> >      		recommended practice.
> > +- cs-gpios	  - (optional) gpios chip select.
> >  No other properties are required in the SPI bus node.  It is assumed
> >  that a driver for an SPI bus device will understand that it is an SPI bus.
> >  However, the binding does not attempt to define the specific method for
> > @@ -21,6 +22,8 @@ assumption that board specific platform code will be used to manage
> >  chip selects.  Individual drivers can define additional properties to
> >  support describing the chip select layout.
> >  
> > +If cs-gpios is used the number of chip select will automatically increased.
> > +
> >  SPI slave nodes must be children of the SPI master node and can
> >  contain the following properties.
> >  - reg             - (required) chip select address of device.
> > @@ -34,6 +37,9 @@ contain the following properties.
> >  - spi-cs-high     - (optional) Empty property indicating device requires
> >      		chip select active high
> >  
> > +If a gpio chipselect is used for the SPI slave the gpio number will be passed
> > +via the controller_data
> > +
> >  SPI example for an MPC5200 SPI bus:
> >  	spi at f00 {
> >  		#address-cells = <1>;
> > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> > index b2ccdea..c1d0955 100644
> > --- a/drivers/spi/spi.c
> > +++ b/drivers/spi/spi.c
> > @@ -28,6 +28,7 @@
> >  #include <linux/mod_devicetable.h>
> >  #include <linux/spi/spi.h>
> >  #include <linux/of_spi.h>
> > +#include <linux/of_gpio.h>
> >  #include <linux/pm_runtime.h>
> >  #include <linux/export.h>
> >  
> > @@ -322,6 +323,7 @@ struct spi_device *spi_alloc_device(struct spi_master *master)
> >  	spi->dev.parent = &master->dev;
> >  	spi->dev.bus = &spi_bus_type;
> >  	spi->dev.release = spidev_release;
> > +	spi->cs_gpio = -EINVAL;
> >  	device_initialize(&spi->dev);
> >  	return spi;
> >  }
> > @@ -339,15 +341,16 @@ EXPORT_SYMBOL_GPL(spi_alloc_device);
> >  int spi_add_device(struct spi_device *spi)
> >  {
> >  	static DEFINE_MUTEX(spi_add_lock);
> > -	struct device *dev = spi->master->dev.parent;
> > +	struct spi_master *master = spi->master;
> > +	struct device *dev = master->dev.parent;
> >  	struct device *d;
> >  	int status;
> >  
> >  	/* Chipselects are numbered 0..max; validate. */
> > -	if (spi->chip_select >= spi->master->num_chipselect) {
> > +	if (spi->chip_select >= master->num_chipselect) {
> >  		dev_err(dev, "cs%d >= max %d\n",
> >  			spi->chip_select,
> > -			spi->master->num_chipselect);
> > +			master->num_chipselect);
> >  		return -EINVAL;
> >  	}
> >  
> > @@ -371,6 +374,13 @@ int spi_add_device(struct spi_device *spi)
> >  		goto done;
> >  	}
> >  
> > +	if (master->num_gpio_cs &&
> > +	    spi->chip_select >= master->first_gpio_cs) {
> > +		int num = spi->chip_select - master->first_gpio_cs;
> > +
> > +		spi->cs_gpio = master->cs_gpios[num];
> 
> spi->cs_gpio isn't used anywhere.
driver
as example atmel spi

I choose to let the driver to manage it as they may need to manange specific
register when using both hw and gpio cs
> 
> > +	}
> > +
> >  	/* Drivers may modify this initial i/o setup, but will
> >  	 * normally rely on the device being setup.  Devices
> >  	 * using SPI_CS_HIGH can't coexist well otherwise...
> > @@ -561,6 +571,43 @@ struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
> >  }
> >  EXPORT_SYMBOL_GPL(spi_alloc_master);
> >  
> > +#ifdef CONFIG_OF
> > +static int of_spi_register_master(struct spi_master *master)
> > +{
> > +	int nb, i;
> > +	int *cs;
> > +	struct device_node *np = master->dev.of_node;
> > +
> > +	if (!np)
> > +		return 0;
> > +
> > +	nb = of_gpio_named_count(np, "cs-gpios");
> > +
> > +	if (nb < 1)
> > +		return 0;
> > +
> > +	cs = devm_kzalloc(&master->dev, sizeof(int) * nb, GFP_KERNEL);
> > +	master->cs_gpios = cs;
> > +
> > +	if (!master->cs_gpios)
> > +		return -ENOMEM;
> > +
> > +	master->first_gpio_cs = master->num_chipselect;
> > +	master->num_chipselect += nb;
> > +	master->num_gpio_cs = nb;
> 
> I think this can be simplified.  Rather than trying to optimize by having
> a set of integrated cs lines followed by a gpio set, I think it would be
> better to have a single cs_gpios table that covers the whole range of
> num_chipselect; even if they overlap natural cs lines.  That will make for
> an easier to use binding since users won't need to remember how many natural
> cs lines are on the device when filling the cs-gpios property.  It will
> also make the code simpler because first_gpio_cs and num_gpio_cs can both
> be eliminated.  It also means the core can have exact knowledge about which
> gpio is associated with which cs number.
ok why not so I feel the array with -EINVAL for hw cs;

Best Regards,
J.