[PATCH 0/4] MXS: I2C improvements

[PATCH 0/4] MXS: I2C improvements

[Marek Vasut]

This patchset implements support for adjustment of I2C bus speed via platform
data. Further, it implements support for DMA transfers into the mxs-i2c driver.
Lastly, there is a fix for GCC4.7 warning included.

Marek Vasut (4):
  MXS: Allow passing i2c bus speed via platform data
  MXS: Set I2C timing registers for mxs-i2c
  MXS: Implement DMA support into mxs-i2c
  MXS: Fix GCC4.7 complaint in mxs-i2c

 arch/arm/mach-mxs/devices-mx28.h                |    3 +-
 arch/arm/mach-mxs/devices/platform-mxs-i2c.c    |   14 +-
 arch/arm/mach-mxs/include/mach/devices-common.h |    5 +-
 arch/arm/mach-mxs/mach-apx4devkit.c             |    7 +-
 arch/arm/mach-mxs/mach-m28evk.c                 |    8 +-
 arch/arm/mach-mxs/mach-mx28evk.c                |    7 +-
 arch/arm/mach-mxs/mach-tx28.c                   |    7 +-
 drivers/i2c/busses/i2c-mxs.c                    |  304 +++++++++++++++++++++--
 include/linux/i2c/mxs-i2c.h                     |   22 ++
 9 files changed, 343 insertions(+), 34 deletions(-)
 create mode 100644 include/linux/i2c/mxs-i2c.h

Cc: Detlev Zundel <dzu@denx.de>
CC: Dong Aisheng <b29396@freescale.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
Cc: linux-i2c at vger.kernel.org
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Shawn Guo <shawn.guo@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
CC: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Wolfram Sang <w.sang@pengutronix.de>

-- 
1.7.10

[PATCH 1/4] MXS: Allow passing i2c bus speed via platform data

[Marek Vasut]

Pass the I2C speed via platform data. This patch only adds the necessary
facilities for the passing and fixes the board files to work with them.
The subsequent patch for i2c-mxs.c then implements the speed adjustment.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
CC: Dong Aisheng <b29396@freescale.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
Cc: linux-i2c at vger.kernel.org
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Shawn Guo <shawn.guo@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
CC: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Wolfram Sang <w.sang@pengutronix.de>
---
 arch/arm/mach-mxs/devices-mx28.h                |    3 ++-
 arch/arm/mach-mxs/devices/platform-mxs-i2c.c    |    9 ++++++---
 arch/arm/mach-mxs/include/mach/devices-common.h |    4 +++-
 arch/arm/mach-mxs/mach-apx4devkit.c             |    7 ++++++-
 arch/arm/mach-mxs/mach-m28evk.c                 |    8 ++++++--
 arch/arm/mach-mxs/mach-mx28evk.c                |    7 ++++++-
 arch/arm/mach-mxs/mach-tx28.c                   |    7 ++++++-
 include/linux/i2c/mxs-i2c.h                     |   21 +++++++++++++++++++++
 8 files changed, 56 insertions(+), 10 deletions(-)
 create mode 100644 include/linux/i2c/mxs-i2c.h

diff --git a/arch/arm/mach-mxs/devices-mx28.h b/arch/arm/mach-mxs/devices-mx28.h
index 9dbeae1..8b3e735 100644
--- a/arch/arm/mach-mxs/devices-mx28.h
+++ b/arch/arm/mach-mxs/devices-mx28.h
@@ -39,7 +39,8 @@ extern const struct mxs_gpmi_nand_data mx28_gpmi_nand_data __initconst;
 	mxs_add_gpmi_nand(pdata, &mx28_gpmi_nand_data)
 
 extern const struct mxs_mxs_i2c_data mx28_mxs_i2c_data[] __initconst;
-#define mx28_add_mxs_i2c(id)		mxs_add_mxs_i2c(&mx28_mxs_i2c_data[id])
+#define mx28_add_mxs_i2c(id, pdata)	\
+	mxs_add_mxs_i2c(&mx28_mxs_i2c_data[id], pdata)
 
 extern const struct mxs_mxs_mmc_data mx28_mxs_mmc_data[] __initconst;
 #define mx28_add_mxs_mmc(id, pdata) \
diff --git a/arch/arm/mach-mxs/devices/platform-mxs-i2c.c b/arch/arm/mach-mxs/devices/platform-mxs-i2c.c
index 79222ec..bb325b9 100644
--- a/arch/arm/mach-mxs/devices/platform-mxs-i2c.c
+++ b/arch/arm/mach-mxs/devices/platform-mxs-i2c.c
@@ -9,6 +9,7 @@
 #include <asm/sizes.h>
 #include <mach/mx28.h>
 #include <mach/devices-common.h>
+#include <linux/i2c/mxs-i2c.h>
 
 #define mxs_i2c_data_entry_single(soc, _id)				\
 	{								\
@@ -29,7 +30,8 @@ const struct mxs_mxs_i2c_data mx28_mxs_i2c_data[] __initconst = {
 #endif
 
 struct platform_device *__init mxs_add_mxs_i2c(
-		const struct mxs_mxs_i2c_data *data)
+		const struct mxs_mxs_i2c_data *data,
+		const struct mxs_i2c_platform_data *pdata)
 {
 	struct resource res[] = {
 		{
@@ -47,6 +49,7 @@ struct platform_device *__init mxs_add_mxs_i2c(
 		},
 	};
 
-	return mxs_add_platform_device("mxs-i2c", data->id, res,
-					ARRAY_SIZE(res), NULL, 0);
+	return mxs_add_platform_device("mxs-i2c", data->id,
+					res, ARRAY_SIZE(res),
+					pdata, sizeof(*pdata));
 }
diff --git a/arch/arm/mach-mxs/include/mach/devices-common.h b/arch/arm/mach-mxs/include/mach/devices-common.h
index f2e3839..7bf2894 100644
--- a/arch/arm/mach-mxs/include/mach/devices-common.h
+++ b/arch/arm/mach-mxs/include/mach/devices-common.h
@@ -77,6 +77,7 @@ mxs_add_gpmi_nand(const struct gpmi_nand_platform_data *pdata,
 		const struct mxs_gpmi_nand_data *data);
 
 /* i2c */
+#include <linux/i2c/mxs-i2c.h>
 struct mxs_mxs_i2c_data {
 	int id;
 	resource_size_t iobase;
@@ -84,7 +85,8 @@ struct mxs_mxs_i2c_data {
 	resource_size_t dmairq;
 };
 struct platform_device * __init mxs_add_mxs_i2c(
-		const struct mxs_mxs_i2c_data *data);
+		const struct mxs_mxs_i2c_data *data,
+		const struct mxs_i2c_platform_data *pdata);
 
 /* mmc */
 #include <mach/mmc.h>
diff --git a/arch/arm/mach-mxs/mach-apx4devkit.c b/arch/arm/mach-mxs/mach-apx4devkit.c
index 48a7fab..cfa5390 100644
--- a/arch/arm/mach-mxs/mach-apx4devkit.c
+++ b/arch/arm/mach-mxs/mach-apx4devkit.c
@@ -26,6 +26,7 @@
 #include <linux/regulator/machine.h>
 #include <linux/regulator/fixed.h>
 #include <linux/micrel_phy.h>
+#include <linux/i2c/mxs-i2c.h>
 
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
@@ -146,6 +147,10 @@ static const struct i2c_board_info apx4devkit_i2c_boardinfo[] __initconst = {
 	{ I2C_BOARD_INFO("pcf8563", 0x51) }, /* RTC */
 };
 
+static struct mxs_i2c_platform_data apx4devkit_i2c_pdata = {
+	.speed_khz = 100,
+};
+
 #if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || \
 		defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
 static struct regulator_consumer_supply apx4devkit_audio_consumer_supplies[] = {
@@ -235,7 +240,7 @@ static void __init apx4devkit_init(void)
 
 	apx4devkit_add_regulators();
 
-	mx28_add_mxs_i2c(0);
+	mx28_add_mxs_i2c(0, &apx4devkit_i2c_pdata);
 	i2c_register_board_info(0, apx4devkit_i2c_boardinfo,
 			ARRAY_SIZE(apx4devkit_i2c_boardinfo));
 
diff --git a/arch/arm/mach-mxs/mach-m28evk.c b/arch/arm/mach-mxs/mach-m28evk.c
index 06d7996..f8eb2b9 100644
--- a/arch/arm/mach-mxs/mach-m28evk.c
+++ b/arch/arm/mach-mxs/mach-m28evk.c
@@ -24,7 +24,7 @@
 #include <linux/clk.h>
 #include <linux/i2c.h>
 #include <linux/i2c/at24.h>
-
+#include <linux/i2c/mxs-i2c.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
 #include <asm/mach/time.h>
@@ -305,6 +305,10 @@ static struct i2c_board_info m28_stk5v3_i2c_boardinfo[] __initdata = {
 	},
 };
 
+static struct mxs_i2c_platform_data m28_i2c_pdata = {
+	.speed_khz	= 400,
+};
+
 static struct mxs_mmc_platform_data m28evk_mmc_pdata[] __initdata = {
 	{
 		/* mmc0 */
@@ -341,7 +345,7 @@ static void __init m28evk_init(void)
 	gpio_led_register_device(0, &m28evk_led_data);
 
 	/* I2C */
-	mx28_add_mxs_i2c(0);
+	mx28_add_mxs_i2c(0, &m28_i2c_pdata);
 	i2c_register_board_info(0, m28_stk5v3_i2c_boardinfo,
 			ARRAY_SIZE(m28_stk5v3_i2c_boardinfo));
 }
diff --git a/arch/arm/mach-mxs/mach-mx28evk.c b/arch/arm/mach-mxs/mach-mx28evk.c
index e386c14..a2792cf 100644
--- a/arch/arm/mach-mxs/mach-mx28evk.c
+++ b/arch/arm/mach-mxs/mach-mx28evk.c
@@ -20,6 +20,7 @@
 #include <linux/i2c.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/fixed.h>
+#include <linux/i2c/mxs-i2c.h>
 
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
@@ -349,6 +350,10 @@ static struct i2c_board_info mxs_i2c0_board_info[] __initdata = {
 	},
 };
 
+static struct mxs_i2c_platform_data mxs_i2c_pdata = {
+	.speed_khz = 100,
+};
+
 #if defined(CONFIG_REGULATOR_FIXED_VOLTAGE) || defined(CONFIG_REGULATOR_FIXED_VOLTAGE_MODULE)
 static struct regulator_consumer_supply mx28evk_audio_consumer_supplies[] = {
 	REGULATOR_SUPPLY("VDDA", "0-000a"),
@@ -439,7 +444,7 @@ static void __init mx28evk_init(void)
 	mx28_add_saif(0, &mx28evk_mxs_saif_pdata[0]);
 	mx28_add_saif(1, &mx28evk_mxs_saif_pdata[1]);
 
-	mx28_add_mxs_i2c(0);
+	mx28_add_mxs_i2c(0, &mxs_i2c_pdata);
 	i2c_register_board_info(0, mxs_i2c0_board_info,
 				ARRAY_SIZE(mxs_i2c0_board_info));
 
diff --git a/arch/arm/mach-mxs/mach-tx28.c b/arch/arm/mach-mxs/mach-tx28.c
index 2c0862e..9c85376 100644
--- a/arch/arm/mach-mxs/mach-tx28.c
+++ b/arch/arm/mach-mxs/mach-tx28.c
@@ -15,6 +15,7 @@
 #include <linux/spi/spi.h>
 #include <linux/spi/spi_gpio.h>
 #include <linux/i2c.h>
+#include <linux/i2c/mxs-i2c.h>
 
 #include <asm/mach/arch.h>
 #include <asm/mach/time.h>
@@ -139,6 +140,10 @@ static struct i2c_board_info tx28_stk5v3_i2c_boardinfo[] __initdata = {
 	},
 };
 
+static struct mxs_i2c_platform_data tx28_i2c_pdata = {
+	.speed_khz = 100,
+};
+
 static struct mxs_mmc_platform_data tx28_mmc0_pdata __initdata = {
        .wp_gpio = -EINVAL,
        .flags = SLOTF_4_BIT_CAPABLE,
@@ -157,7 +162,7 @@ static void __init tx28_stk5v3_init(void)
 	spi_register_board_info(tx28_spi_board_info,
 			ARRAY_SIZE(tx28_spi_board_info));
 	gpio_led_register_device(0, &tx28_stk5v3_led_data);
-	mx28_add_mxs_i2c(0);
+	mx28_add_mxs_i2c(0, &tx28_i2c_pdata);
 	i2c_register_board_info(0, tx28_stk5v3_i2c_boardinfo,
 			ARRAY_SIZE(tx28_stk5v3_i2c_boardinfo));
 	mx28_add_mxs_mmc(0, &tx28_mmc0_pdata);
diff --git a/include/linux/i2c/mxs-i2c.h b/include/linux/i2c/mxs-i2c.h
new file mode 100644
index 0000000..781b080
--- /dev/null
+++ b/include/linux/i2c/mxs-i2c.h
@@ -0,0 +1,21 @@
+/*
+ * Freescale MXS I2C bus driver shared data
+ *
+ * Copyright (C) 2012
+ * Marek Vasut, DENX Software Engineering, <marex@denx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#ifndef __INCLUDE_LINUX_I2C_MXS_I2C_H__
+#define __INCLUDE_LINUX_I2C_MXS_I2C_H__
+
+struct mxs_i2c_platform_data {
+	uint16_t	speed_khz;
+};
+
+#endif	/* __INCLUDE_LINUX_I2C_MXS_I2C_H__ */
-- 
1.7.10

[PATCH 2/4] MXS: Set I2C timing registers for mxs-i2c

[Marek Vasut]

This patch configures the I2C bus timing registers according
to information passed via platform data. Currently, 100kHz and
400kHz modes are supported.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
CC: Dong Aisheng <b29396@freescale.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
Cc: linux-i2c at vger.kernel.org
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Shawn Guo <shawn.guo@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
CC: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Wolfram Sang <w.sang@pengutronix.de>
---
 drivers/i2c/busses/i2c-mxs.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 3d471d5..717b7f9 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -20,6 +20,7 @@
 #include <linux/device.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
+#include <linux/i2c/mxs-i2c.h>
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/completion.h>
@@ -43,6 +44,10 @@
 #define MXS_I2C_CTRL0_DIRECTION			0x00010000
 #define MXS_I2C_CTRL0_XFER_COUNT(v)		((v) & 0x0000FFFF)
 
+#define MXS_I2C_TIMING0		(0x10)
+#define MXS_I2C_TIMING1		(0x20)
+#define MXS_I2C_TIMING2		(0x30)
+
 #define MXS_I2C_CTRL1		(0x40)
 #define MXS_I2C_CTRL1_SET	(0x44)
 #define MXS_I2C_CTRL1_CLR	(0x48)
@@ -94,6 +99,25 @@
 #define MXS_CMD_I2C_READ	(MXS_I2C_CTRL0_SEND_NAK_ON_LAST | \
 				 MXS_I2C_CTRL0_MASTER_MODE)
 
+
+struct mxs_i2c_speed_config {
+	uint32_t	timing0;
+	uint32_t	timing1;
+	uint32_t	timing2;
+};
+
+const struct mxs_i2c_speed_config mxs_i2c_95kHz_config = {
+	.timing0	= 0x00780030,
+	.timing1	= 0x00800030,
+	.timing2	= 0x0015000d,
+};
+
+const struct mxs_i2c_speed_config mxs_i2c_400kHz_config = {
+	.timing0	= 0x000f0007,
+	.timing1	= 0x001f000f,
+	.timing2	= 0x0015000d,
+};
+
 /**
  * struct mxs_i2c_dev - per device, private MXS-I2C data
  *
@@ -109,6 +133,7 @@ struct mxs_i2c_dev {
 	struct completion cmd_complete;
 	u32 cmd_err;
 	struct i2c_adapter adapter;
+	const struct mxs_i2c_speed_config *speed;
 };
 
 /*
@@ -118,6 +143,11 @@ struct mxs_i2c_dev {
 static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
 {
 	mxs_reset_block(i2c->regs);
+
+	writel(i2c->speed->timing0, i2c->regs + MXS_I2C_TIMING0);
+	writel(i2c->speed->timing1, i2c->regs + MXS_I2C_TIMING1);
+	writel(i2c->speed->timing2, i2c->regs + MXS_I2C_TIMING2);
+
 	writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
 	writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
 			i2c->regs + MXS_I2C_QUEUECTRL_SET);
@@ -321,12 +351,16 @@ static const struct i2c_algorithm mxs_i2c_algo = {
 static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct mxs_i2c_platform_data *pdata = pdev->dev.platform_data;
 	struct mxs_i2c_dev *i2c;
 	struct i2c_adapter *adap;
 	struct resource *res;
 	resource_size_t res_size;
 	int err, irq;
 
+	if (!pdata)
+		return -ENODEV;
+
 	i2c = devm_kzalloc(dev, sizeof(struct mxs_i2c_dev), GFP_KERNEL);
 	if (!i2c)
 		return -ENOMEM;
@@ -352,6 +386,14 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 		return err;
 
 	i2c->dev = dev;
+
+	/* Configure the bus speed. */
+	i2c->speed = &mxs_i2c_95kHz_config;
+	if (pdata->speed_khz == 400)
+		i2c->speed = &mxs_i2c_400kHz_config;
+	else if (pdata->speed_khz != 100)
+		dev_err(dev, "Invalid I2C speed selected, using 100kHz\n");
+
 	platform_set_drvdata(pdev, i2c);
 
 	/* Do reset to enforce correct startup after pinmuxing */
-- 
1.7.10

[PATCH 3/4] MXS: Implement DMA support into mxs-i2c

[Marek Vasut]

This patch implements DMA support into mxs-i2c. DMA transfers are now enabled
via platform data. The behaviour of this driver should not change for any of
the current platforms. Though it is recommended to enable DMA operation.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
CC: Dong Aisheng <b29396@freescale.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
Cc: linux-i2c at vger.kernel.org
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Shawn Guo <shawn.guo@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
CC: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Wolfram Sang <w.sang@pengutronix.de>
---
 arch/arm/mach-mxs/devices/platform-mxs-i2c.c    |    5 +
 arch/arm/mach-mxs/include/mach/devices-common.h |    1 +
 drivers/i2c/busses/i2c-mxs.c                    |  260 +++++++++++++++++++++--
 include/linux/i2c/mxs-i2c.h                     |    1 +
 4 files changed, 244 insertions(+), 23 deletions(-)

diff --git a/arch/arm/mach-mxs/devices/platform-mxs-i2c.c b/arch/arm/mach-mxs/devices/platform-mxs-i2c.c
index bb325b9..341aec9 100644
--- a/arch/arm/mach-mxs/devices/platform-mxs-i2c.c
+++ b/arch/arm/mach-mxs/devices/platform-mxs-i2c.c
@@ -15,6 +15,7 @@
 	{								\
 		.id = _id,						\
 		.iobase = soc ## _I2C ## _id ## _BASE_ADDR,		\
+		.dma	= soc ## _DMA_I2C ## _id,			\
 		.errirq = soc ## _INT_I2C ## _id ## _ERROR,		\
 		.dmairq = soc ## _INT_I2C ## _id ## _DMA,		\
 	}
@@ -39,6 +40,10 @@ struct platform_device *__init mxs_add_mxs_i2c(
 			.end = data->iobase + SZ_8K - 1,
 			.flags = IORESOURCE_MEM,
 		}, {
+			.start	= data->dma,
+			.end	= data->dma,
+			.flags	= IORESOURCE_DMA,
+		}, {
 			.start = data->errirq,
 			.end = data->errirq,
 			.flags = IORESOURCE_IRQ,
diff --git a/arch/arm/mach-mxs/include/mach/devices-common.h b/arch/arm/mach-mxs/include/mach/devices-common.h
index 7bf2894..f5d3bf6 100644
--- a/arch/arm/mach-mxs/include/mach/devices-common.h
+++ b/arch/arm/mach-mxs/include/mach/devices-common.h
@@ -81,6 +81,7 @@ mxs_add_gpmi_nand(const struct gpmi_nand_platform_data *pdata,
 struct mxs_mxs_i2c_data {
 	int id;
 	resource_size_t iobase;
+	resource_size_t dma;
 	resource_size_t errirq;
 	resource_size_t dmairq;
 };
diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 717b7f9..7491194 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -7,8 +7,6 @@
  *
  * Copyright (C) 2009-2010 Freescale Semiconductor, Inc. All Rights Reserved.
  *
- * TODO: add dma-support if platform-support for it is available
- *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
@@ -27,6 +25,9 @@
 #include <linux/platform_device.h>
 #include <linux/jiffies.h>
 #include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/fsl/mxs-dma.h>
 
 #include <mach/common.h>
 
@@ -134,6 +135,16 @@ struct mxs_i2c_dev {
 	u32 cmd_err;
 	struct i2c_adapter adapter;
 	const struct mxs_i2c_speed_config *speed;
+
+	/* DMA support components */
+	bool				dma_mode;
+	struct resource			*dmares;
+	struct dma_chan         	*dmach;
+	struct mxs_dma_data		dma_data;
+	uint32_t			pio_data[2];
+	uint32_t			addr_data;
+	struct scatterlist		sg_io[2];
+	bool				dma_read;
 };
 
 /*
@@ -149,7 +160,12 @@ static void mxs_i2c_reset(struct mxs_i2c_dev *i2c)
 	writel(i2c->speed->timing2, i2c->regs + MXS_I2C_TIMING2);
 
 	writel(MXS_I2C_IRQ_MASK << 8, i2c->regs + MXS_I2C_CTRL1_SET);
-	writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
+
+	if (i2c->dma_mode)
+		writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
+			i2c->regs + MXS_I2C_QUEUECTRL_CLR);
+	else
+		writel(MXS_I2C_QUEUECTRL_PIO_QUEUE_MODE,
 			i2c->regs + MXS_I2C_QUEUECTRL_SET);
 }
 
@@ -240,9 +256,155 @@ static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
 	return 0;
 }
 
+static void mxs_i2c_dma_finish(struct mxs_i2c_dev *i2c)
+{
+	if (i2c->dma_read) {
+		dma_unmap_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE);
+		dma_unmap_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE);
+	} else {
+		dma_unmap_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE);
+	}
+}
+
+static void mxs_i2c_dma_irq_callback(void *param)
+{
+	struct mxs_i2c_dev *i2c = param;
+
+	complete(&i2c->cmd_complete);
+	mxs_i2c_dma_finish(i2c);
+}
+
+static int mxs_i2c_dma_setup_xfer(struct i2c_adapter *adap,
+			struct i2c_msg *msg, uint32_t flags)
+{
+	struct dma_async_tx_descriptor *desc;
+	struct mxs_i2c_dev *i2c = i2c_get_adapdata(adap);
+
+	if (msg->flags & I2C_M_RD) {
+		i2c->dma_read = 1;
+		i2c->addr_data = (msg->addr << 1) | I2C_SMBUS_READ;
+
+		/*
+		 * SELECT command.
+		 */
+
+		/* Queue the PIO register write transfer. */
+		i2c->pio_data[0] = MXS_CMD_I2C_SELECT;
+		desc = dmaengine_prep_slave_sg(i2c->dmach,
+					(struct scatterlist *)&i2c->pio_data[0],
+					1, DMA_TRANS_NONE, 0);
+		if (!desc) {
+			dev_err(i2c->dev,
+				"Failed to get PIO reg. write descriptor.\n");
+			goto select_init_pio_fail;
+		}
+
+		/* Queue the DMA data transfer. */
+		sg_init_one(&i2c->sg_io[0], &i2c->addr_data, 1);
+		dma_map_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE);
+		desc = dmaengine_prep_slave_sg(i2c->dmach, &i2c->sg_io[0], 1,
+					DMA_MEM_TO_DEV,
+					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (!desc) {
+			dev_err(i2c->dev,
+				"Failed to get DMA data write descriptor.\n");
+			goto select_init_dma_fail;
+		}
+
+		/*
+		 * READ command.
+		 */
+
+		/* Queue the PIO register write transfer. */
+		i2c->pio_data[1] = flags | MXS_CMD_I2C_READ |
+				MXS_I2C_CTRL0_XFER_COUNT(msg->len);
+		desc = dmaengine_prep_slave_sg(i2c->dmach,
+					(struct scatterlist *)&i2c->pio_data[1],
+					1, DMA_TRANS_NONE, DMA_PREP_INTERRUPT);
+		if (!desc) {
+			dev_err(i2c->dev,
+				"Failed to get PIO reg. write descriptor.\n");
+			goto select_init_dma_fail;
+		}
+
+		/* Queue the DMA data transfer. */
+		sg_init_one(&i2c->sg_io[1], msg->buf, msg->len);
+		dma_map_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE);
+		desc = dmaengine_prep_slave_sg(i2c->dmach, &i2c->sg_io[1], 1,
+					DMA_DEV_TO_MEM,
+					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (!desc) {
+			dev_err(i2c->dev,
+				"Failed to get DMA data write descriptor.\n");
+			goto read_init_dma_fail;
+		}
+	} else {
+		i2c->dma_read = 0;
+		i2c->addr_data = (msg->addr << 1) | I2C_SMBUS_WRITE;
+
+		/*
+		 * WRITE command.
+		 */
+
+		/* Queue the PIO register write transfer. */
+		i2c->pio_data[0] = flags | MXS_CMD_I2C_WRITE |
+				MXS_I2C_CTRL0_XFER_COUNT(msg->len + 1);
+		desc = dmaengine_prep_slave_sg(i2c->dmach,
+					(struct scatterlist *)&i2c->pio_data[0],
+					1, DMA_TRANS_NONE, 0);
+		if (!desc) {
+			dev_err(i2c->dev,
+				"Failed to get PIO reg. write descriptor.\n");
+			goto write_init_pio_fail;
+		}
+
+		/* Queue the DMA data transfer. */
+		sg_init_table(i2c->sg_io, 2);
+		sg_set_buf(&i2c->sg_io[0], &i2c->addr_data, 1);
+		sg_set_buf(&i2c->sg_io[1], msg->buf, msg->len);
+		dma_map_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE);
+		desc = dmaengine_prep_slave_sg(i2c->dmach, i2c->sg_io, 2,
+					DMA_MEM_TO_DEV,
+					DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+		if (!desc) {
+			dev_err(i2c->dev,
+				"Failed to get DMA data write descriptor.\n");
+			goto write_init_dma_fail;
+		}
+	}
+
+	/*
+	 * The last descriptor must have this callback,
+	 * to finish the DMA transaction.
+	 */
+	desc->callback = mxs_i2c_dma_irq_callback;
+	desc->callback_param = i2c;
+
+	/* Start the transfer. */
+	dmaengine_submit(desc);
+	dma_async_issue_pending(i2c->dmach);
+	return 0;
+
+/* Read failpath. */
+read_init_dma_fail:
+	dma_unmap_sg(i2c->dev, &i2c->sg_io[1], 1, DMA_FROM_DEVICE);
+select_init_dma_fail:
+	dma_unmap_sg(i2c->dev, &i2c->sg_io[0], 1, DMA_TO_DEVICE);
+select_init_pio_fail:
+	return 1;
+
+
+/* Write failpath. */
+write_init_dma_fail:
+	dma_unmap_sg(i2c->dev, i2c->sg_io, 2, DMA_TO_DEVICE);
+write_init_pio_fail:
+	return 1;
+}
+
 /*
  * Low level master read/write transaction.
  */
+
 static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
 				int stop)
 {
@@ -250,6 +412,8 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
 	int ret;
 	int flags;
 
+	flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
+
 	dev_dbg(i2c->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
 		msg->addr, msg->len, msg->flags, stop);
 
@@ -258,23 +422,30 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
 
 	init_completion(&i2c->cmd_complete);
 
-	flags = stop ? MXS_I2C_CTRL0_POST_SEND_STOP : 0;
-
-	if (msg->flags & I2C_M_RD)
-		mxs_i2c_pioq_setup_read(i2c, msg->addr, msg->len, flags);
-	else
-		mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf, msg->len,
-					flags);
+	if (i2c->dma_mode) {
+		ret = mxs_i2c_dma_setup_xfer(adap, msg, flags);
+		if (ret)
+			return -EINVAL;
+	} else {
+		if (msg->flags & I2C_M_RD) {
+			mxs_i2c_pioq_setup_read(i2c, msg->addr,
+						msg->len, flags);
+		} else {
+			mxs_i2c_pioq_setup_write(i2c, msg->addr, msg->buf,
+						msg->len, flags);
+		}
 
-	writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
+		writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
 			i2c->regs + MXS_I2C_QUEUECTRL_SET);
+	}
 
 	ret = wait_for_completion_timeout(&i2c->cmd_complete,
 						msecs_to_jiffies(1000));
+
 	if (ret == 0)
 		goto timeout;
 
-	if ((!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
+	if (!i2c->dma_mode && (!i2c->cmd_err) && (msg->flags & I2C_M_RD)) {
 		ret = mxs_i2c_finish_read(i2c, msg->buf, msg->len);
 		if (ret)
 			goto timeout;
@@ -289,7 +460,9 @@ static int mxs_i2c_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg,
 
 timeout:
 	dev_dbg(i2c->dev, "Timeout!\n");
+	mxs_i2c_dma_finish(i2c);
 	mxs_i2c_reset(i2c);
+
 	return -ETIMEDOUT;
 }
 
@@ -332,11 +505,13 @@ static irqreturn_t mxs_i2c_isr(int this_irq, void *dev_id)
 	else
 		i2c->cmd_err = 0;
 
-	is_last_cmd = (readl(i2c->regs + MXS_I2C_QUEUESTAT) &
-		MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK) == 0;
+	if (!i2c->dma_mode) {
+		is_last_cmd = (readl(i2c->regs + MXS_I2C_QUEUESTAT) &
+			MXS_I2C_QUEUESTAT_WRITE_QUEUE_CNT_MASK) == 0;
 
-	if (is_last_cmd || i2c->cmd_err)
-		complete(&i2c->cmd_complete);
+		if (!i2c->dma_mode && (is_last_cmd || i2c->cmd_err))
+			complete(&i2c->cmd_complete);
+	}
 
 	writel(stat, i2c->regs + MXS_I2C_CTRL1_CLR);
 
@@ -348,15 +523,31 @@ static const struct i2c_algorithm mxs_i2c_algo = {
 	.functionality = mxs_i2c_func,
 };
 
+static bool mxs_i2c_dma_filter(struct dma_chan *chan, void *param)
+{
+	struct mxs_i2c_dev *i2c = param;
+
+	if (!mxs_dma_is_apbx(chan))
+		return false;
+
+	if (chan->chan_id != i2c->dmares->start)
+		return false;
+
+	chan->private = &i2c->dma_data;
+
+	return true;
+}
+
 static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct mxs_i2c_platform_data *pdata = pdev->dev.platform_data;
 	struct mxs_i2c_dev *i2c;
 	struct i2c_adapter *adap;
-	struct resource *res;
+	struct resource *res, *dmares;
 	resource_size_t res_size;
-	int err, irq;
+	int err, irq, dmairq;
+	dma_cap_mask_t mask;
 
 	if (!pdata)
 		return -ENODEV;
@@ -366,7 +557,11 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!res)
+	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+	irq = platform_get_irq(pdev, 0);
+	dmairq = platform_get_irq(pdev, 1);
+
+	if (!res || !dmares || irq < 0 || dmairq < 0)
 		return -ENOENT;
 
 	res_size = resource_size(res);
@@ -377,10 +572,6 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 	if (!i2c->regs)
 		return -EBUSY;
 
-	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
-		return irq;
-
 	err = devm_request_irq(dev, irq, mxs_i2c_isr, 0, dev_name(dev), i2c);
 	if (err)
 		return err;
@@ -394,6 +585,26 @@ static int __devinit mxs_i2c_probe(struct platform_device *pdev)
 	else if (pdata->speed_khz != 100)
 		dev_err(dev, "Invalid I2C speed selected, using 100kHz\n");
 
+	/*
+	 * The MXS I2C DMA mode is prefered and enabled by default.
+	 * The PIO mode is still supported, but should be used only
+	 * for debuging purposes etc.
+	 */
+	i2c->dma_mode = !pdata->use_pioqueue;
+
+	/* Setup the DMA */
+	if (i2c->dma_mode) {
+		i2c->dmares = dmares;
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+		i2c->dma_data.chan_irq = dmairq;
+		i2c->dmach = dma_request_channel(mask, mxs_i2c_dma_filter, i2c);
+		if (!i2c->dmach) {
+			dev_err(dev, "Failed to request dma\n");
+			return -ENODEV;
+		}
+	}
+
 	platform_set_drvdata(pdev, i2c);
 
 	/* Do reset to enforce correct startup after pinmuxing */
@@ -426,6 +637,9 @@ static int __devexit mxs_i2c_remove(struct platform_device *pdev)
 	if (ret)
 		return -EBUSY;
 
+	if (i2c->dmach)
+		dma_release_channel(i2c->dmach);
+
 	writel(MXS_I2C_QUEUECTRL_QUEUE_RUN,
 			i2c->regs + MXS_I2C_QUEUECTRL_CLR);
 	writel(MXS_I2C_CTRL0_SFTRST, i2c->regs + MXS_I2C_CTRL0_SET);
diff --git a/include/linux/i2c/mxs-i2c.h b/include/linux/i2c/mxs-i2c.h
index 781b080..16f23dc 100644
--- a/include/linux/i2c/mxs-i2c.h
+++ b/include/linux/i2c/mxs-i2c.h
@@ -16,6 +16,7 @@
 
 struct mxs_i2c_platform_data {
 	uint16_t	speed_khz;
+	bool		use_pioqueue;
 };
 
 #endif	/* __INCLUDE_LINUX_I2C_MXS_I2C_H__ */
-- 
1.7.10

[PATCH 4/4] MXS: Fix GCC4.7 complaint in mxs-i2c

[Marek Vasut]

drivers/i2c/busses/i2c-mxs.c: In function 'mxs_i2c_xfer':
drivers/i2c/busses/i2c-mxs.c:253:8: warning: 'data' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/i2c/busses/i2c-mxs.c:243:6: note: 'data' was declared here

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
CC: Dong Aisheng <b29396@freescale.com>
CC: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
Cc: linux-i2c at vger.kernel.org
CC: Sascha Hauer <s.hauer@pengutronix.de>
CC: Shawn Guo <shawn.guo@linaro.org>
Cc: Stefano Babic <sbabic@denx.de>
CC: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Wolfram Sang <w.sang@pengutronix.de>
---
 drivers/i2c/busses/i2c-mxs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-mxs.c b/drivers/i2c/busses/i2c-mxs.c
index 7491194..89ea19d 100644
--- a/drivers/i2c/busses/i2c-mxs.c
+++ b/drivers/i2c/busses/i2c-mxs.c
@@ -240,7 +240,7 @@ static int mxs_i2c_wait_for_data(struct mxs_i2c_dev *i2c)
 
 static int mxs_i2c_finish_read(struct mxs_i2c_dev *i2c, u8 *buf, int len)
 {
-	u32 data;
+	u32 data = 0;
 	int i;
 
 	for (i = 0; i < len; i++) {
-- 
1.7.10

[PATCH 0/4] MXS: I2C improvements

[Marek Vasut]

> This patchset implements support for adjustment of I2C bus speed via
> platform data. Further, it implements support for DMA transfers into the
> mxs-i2c driver. Lastly, there is a fix for GCC4.7 warning included.

btw. this patchset is also available here:

http://git.kernel.org/?p=linux/kernel/git/marex/linux-2.6.git;a=shortlog;h=refs/heads/mxs-
i2c

> 
> Marek Vasut (4):
>   MXS: Allow passing i2c bus speed via platform data
>   MXS: Set I2C timing registers for mxs-i2c
>   MXS: Implement DMA support into mxs-i2c
>   MXS: Fix GCC4.7 complaint in mxs-i2c
> 
>  arch/arm/mach-mxs/devices-mx28.h                |    3 +-
>  arch/arm/mach-mxs/devices/platform-mxs-i2c.c    |   14 +-
>  arch/arm/mach-mxs/include/mach/devices-common.h |    5 +-
>  arch/arm/mach-mxs/mach-apx4devkit.c             |    7 +-
>  arch/arm/mach-mxs/mach-m28evk.c                 |    8 +-
>  arch/arm/mach-mxs/mach-mx28evk.c                |    7 +-
>  arch/arm/mach-mxs/mach-tx28.c                   |    7 +-
>  drivers/i2c/busses/i2c-mxs.c                    |  304
> +++++++++++++++++++++-- include/linux/i2c/mxs-i2c.h                     | 
>  22 ++
>  9 files changed, 343 insertions(+), 34 deletions(-)
>  create mode 100644 include/linux/i2c/mxs-i2c.h
> 
> Cc: Detlev Zundel <dzu@denx.de>
> CC: Dong Aisheng <b29396@freescale.com>
> CC: Fabio Estevam <fabio.estevam@freescale.com>
> Cc: Linux ARM kernel <linux-arm-kernel@lists.infradead.org>
> Cc: linux-i2c at vger.kernel.org
> CC: Sascha Hauer <s.hauer@pengutronix.de>
> CC: Shawn Guo <shawn.guo@linaro.org>
> Cc: Stefano Babic <sbabic@denx.de>
> CC: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
> Cc: Wolfgang Denk <wd@denx.de>
> Cc: Wolfram Sang <w.sang@pengutronix.de>

Best regards,
Marek Vasut

[PATCH 0/4] MXS: I2C improvements

[Marek Vasut]

> This patchset implements support for adjustment of I2C bus speed via
> platform data. Further, it implements support for DMA transfers into the
> mxs-i2c driver. Lastly, there is a fix for GCC4.7 warning included.
> 
> Marek Vasut (4):
>   MXS: Allow passing i2c bus speed via platform data
>   MXS: Set I2C timing registers for mxs-i2c
>   MXS: Implement DMA support into mxs-i2c
>   MXS: Fix GCC4.7 complaint in mxs-i2c

Bump?

Best regards,
Marek Vasut

[PATCH 0/4] MXS: I2C improvements

[Shawn Guo]

On Wed, May 09, 2012 at 08:33:46PM +0200, Marek Vasut wrote:
> > This patchset implements support for adjustment of I2C bus speed via
> > platform data. Further, it implements support for DMA transfers into the
> > mxs-i2c driver. Lastly, there is a fix for GCC4.7 warning included.
> > 
> > Marek Vasut (4):
> >   MXS: Allow passing i2c bus speed via platform data
> >   MXS: Set I2C timing registers for mxs-i2c
> >   MXS: Implement DMA support into mxs-i2c
> >   MXS: Fix GCC4.7 complaint in mxs-i2c
> 
> Bump?
> 
Sorry, Marek.  Since we are moving over to device tree, I'm not going
to ack the arch/arm/mach-mxs changes, which are introducing more use
of platform data.

-- 
Regards,
Shawn

[PATCH 0/4] MXS: I2C improvements

[Marek Vasut]

Dear Shawn Guo,

> On Wed, May 09, 2012 at 08:33:46PM +0200, Marek Vasut wrote:
> > > This patchset implements support for adjustment of I2C bus speed via
> > > platform data. Further, it implements support for DMA transfers into
> > > the mxs-i2c driver. Lastly, there is a fix for GCC4.7 warning
> > > included.
> > > 
> > > Marek Vasut (4):
> > >   MXS: Allow passing i2c bus speed via platform data
> > >   MXS: Set I2C timing registers for mxs-i2c
> > >   MXS: Implement DMA support into mxs-i2c
> > >   MXS: Fix GCC4.7 complaint in mxs-i2c
> > 
> > Bump?
> 
> Sorry, Marek.  Since we are moving over to device tree, I'm not going
> to ack the arch/arm/mach-mxs changes, which are introducing more use
> of platform data.

Can you please tell me what _exactly_ is the formal reason for
NAKing these changes?  As far as I can see, they do not introduce
new aspects of platform data but rather fix the usage in the
current context, so I do not quite understand the reasoning.

I consider your current approach of NAKing these changes very
harmful to MXS. If it wasn't for your NAKing every patch for MXS
that doesn't use device tree, the platform would currently be in
much better shape. By now, you'd already have good SPI driver,
this I2C driver and maybe others. I wonder if others agree with
me on this one?

But now we're waiting for the device tree support, which will
take some more time to fully arrive. Maybe 3.5, but I doubt full
DT support will hit mainline before 3.6. I'd understand you
NAKing patches that don't use DT support if DT support for MXS
was already in place, but there is not a trace of it in mainline.

Finally, consider people who write patches for MXS (remember
fixes for mxs-spi, or this fix for mxs-i2c for example
again). They will easily be demotivated by this approach and give
up on MXS, probably not reposting these changes. What is the plan
on saving all the precious efforts that are currently NAKed by
you?  How do we ensure this work does not get lost?

Thank you.

Best regards,
Marek Vasut

[PATCH 0/4] MXS: I2C improvements

[Shawn Guo]

On Thu, May 10, 2012 at 01:17:25PM +0200, Marek Vasut wrote:
> > Sorry, Marek.  Since we are moving over to device tree, I'm not going
> > to ack the arch/arm/mach-mxs changes, which are introducing more use
> > of platform data.
> 
> Can you please tell me what _exactly_ is the formal reason for
> NAKing these changes?

I said I'm not going to ack the changes, not I'm NAKing the changes.
But since you have put me on that position, ok, I'm now NAKing the
changes.  The reason is obvious, you are adding something we are trying
hard to remove.

> As far as I can see, they do not introduce
> new aspects of platform data but rather fix the usage in the
> current context, so I do not quite understand the reasoning.
> 
The i2c-mxs driver currently does not use platform_data at all, the
first patch creates a new file include/linux/i2c/mxs-i2c.h to introduce
it.

> I consider your current approach of NAKing these changes very
> harmful to MXS.

I take it in the opposite way.  It's helpful for MXS, especially
in the long run.

> If it wasn't for your NAKing every patch for MXS
> that doesn't use device tree, the platform would currently be in
> much better shape. By now, you'd already have good SPI driver,
> this I2C driver and maybe others. I wonder if others agree with
> me on this one?
> 
All the examples you put here are submitted in this development cycle,
how can they make the MXS support much better already without waiting
v3.5-rc1 to hit the mainline?

> But now we're waiting for the device tree support, which will
> take some more time to fully arrive. Maybe 3.5, but I doubt full
> DT support will hit mainline before 3.6. I'd understand you
> NAKing patches that don't use DT support if DT support for MXS
> was already in place, but there is not a trace of it in mainline.
> 
I would expect the support will hit mainline in a few weeks with
v3.5-rc1, so none of the examples you put here, neither SPI driver
nor I2C changes, can really hit the mainline earlier than DT.

> Finally, consider people who write patches for MXS (remember
> fixes for mxs-spi,

This is a new driver.

> or this fix for mxs-i2c for example
> again). They will easily be demotivated by this approach and give
> up on MXS, probably not reposting these changes.

That's a bit unfortunate.  Let me put an interesting story here.
When Huang Shijie adds DT support for gpmi-nand driver, he chooses to
not maintain the compatibility of non-DT support to make the code
a lot clean and simple.  When I asked how he can do this before all
those non-DT board files are converted to DT, I was reminded that
is not a problem because I rejected his board file changes coming along
with the driver, there is no in-tree board files are users of gpmi-nand
driver.  What I put here is it's much easier and cleaner to create a DT
only driver from the beginning than having a non-DT driver and then
converting it to DT.

> What is the plan
> on saving all the precious efforts that are currently NAKed by
> you?  How do we ensure this work does not get lost?
> 
If they do not get reposted to have DT support from the beginning,
I believe other people will do when the need of the patches are seen.

-- 
Regards,
Shawn

[PATCH 0/4] MXS: I2C improvements

[Wolfram Sang]

On Wed, May 09, 2012 at 08:33:46PM +0200, Marek Vasut wrote:
> > This patchset implements support for adjustment of I2C bus speed via
> > platform data. Further, it implements support for DMA transfers into the
> > mxs-i2c driver. Lastly, there is a fix for GCC4.7 warning included.
> > 
> > Marek Vasut (4):
> >   MXS: Allow passing i2c bus speed via platform data
> >   MXS: Set I2C timing registers for mxs-i2c
> >   MXS: Implement DMA support into mxs-i2c
> >   MXS: Fix GCC4.7 complaint in mxs-i2c
> 
> Bump?

Regarding I2C, I think we will have DT support for it already in 3.5.
So, I am with Shawn here to not introduce new features with new
platform_data when there is a more recent alternative. So, drop 1/4 and
refactor 2/4 according to DT (you only need to get and parse the
"clock-frequency" property).

3/4 is the most interesting patch of this series, since it is a major
bugfix. Due to holidays, I won't be able to test it in the next 10 days,
but I am very eager to get it into 3.5. Since it is a bugfix, we could
probably get it in after the merge window, but I'll try to make the
merge window nontheless. If somebody donates Tested or Acked or Reviewed
tags, that would also help.

I already NACKed 4/4, so I wonder why you resent it.

Thanks,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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