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OMAP: I2C: Reset support

PATCH Superseded Shubhrajyoti D 2 participants 7 messages Aug 5, 2011 – Aug 29, 2011

Subsystems (6)
Arm (32-bit) Arm sub-architectures I2C subsystem host drivers OMAP2+ support +2 more subsystems

v6 of 9 Superseded Latest is v9 →

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Shubhrajyoti D

author
#0 lore raw

PATCH v6 1/3 OMAP: I2C: Reset support

Under some error conditions the i2c driver may do a reset. Adding a reset field and support in the device-specific code.

Signed-off-by Shubhrajyoti D <[email protected]>
---
 arch/arm/plat-omap/i2c.c |   18 ++++++++++++++++++
 include/linux/i2c-omap.h |    1 +
 2 files changed, 19 insertions(+), 0 deletions(-)
arch/arm/plat-omap/i2c.c +18 -0
index 2388b8e..be36cac 100644
@@ -146,6 +146,22 @@ static struct omap_device_pm_latency omap_i2c_latency[] = {
 		.flags			= OMAP_DEVICE_LATENCY_AUTO_ADJUST,
 	},
 };
+/**
+ * omap2_i2c_reset - reset the omap i2c module.
+ * @dev: struct device*
+ */
+
+static int omap2_i2c_reset(struct device *dev)
+{
+	int r = 0;
+	struct platform_device *pdev = to_platform_device(dev);
+	struct omap_device *odev = to_omap_device(pdev);
+	struct omap_hwmod *oh;
+
+	oh = odev->hwmods[0];
+	r = omap_hwmod_reset(oh);
+	return r;
+}
 
 static inline int omap2_i2c_add_bus(int bus_id)
 {

@@ -187,6 +203,8 @@ static inline int omap2_i2c_add_bus(int bus_id)
 	 */
 	if (cpu_is_omap34xx())
 		pdata->set_mpu_wkup_lat = omap_pm_set_max_mpu_wakeup_lat_compat;
+
+	pdata->device_reset = omap2_i2c_reset;
 	od = omap_device_build(name, bus_id, oh, pdata,
 			sizeof(struct omap_i2c_bus_platform_data),
 			omap_i2c_latency, ARRAY_SIZE(omap_i2c_latency), 0);
include/linux/i2c-omap.h +1 -0
index 98ae49b..8aa91b6 100644
@@ -38,6 +38,7 @@ struct omap_i2c_bus_platform_data {
 	int		(*device_enable) (struct platform_device *pdev);
 	int		(*device_shutdown) (struct platform_device *pdev);
 	int		(*device_idle) (struct platform_device *pdev);
+	int		(*device_reset) (struct device *dev);
 };
 
 #endif
Signature · 1 line
1.7.1
author
#1 lore raw

PATCH v6 2/3 OMAP: I2C: Remove the reset in the init path

- The reset in the driver at init is not needed anymore as the hwmod framework takes care of reseting it.
- Reset is removed from omap_i2c_init, which was called not only during probe, but also after time out and error handling. device_reset were added in those places to effect the reset.
- Earlier the hwmod SYSC settings were over-written in the driver. Removing the same and letting the hwmod take care of the settings.

-  Clean up the SYSS_RESETDONE_MASK macro as it is no longer needed.
-  Clean up the SYSCONFIG SYSC bit defination macros.
-  Fix the typos in wakeup.
Signed-off-by Shubhrajyoti D <[email protected]>
---
 drivers/i2c/busses/i2c-omap.c |   83 +++++++++++------------------------------
 1 files changed, 22 insertions(+), 61 deletions(-)
drivers/i2c/busses/i2c-omap.c +22 -61
index 4e3256f..d8f4470 100644
@@ -155,19 +155,6 @@ enum {
 #define OMAP_I2C_SYSTEST_SDA_O		(1 << 0)	/* SDA line drive out */
 #endif
 
-/* OCP_SYSSTATUS bit definitions */
-#define SYSS_RESETDONE_MASK		(1 << 0)
-
-/* OCP_SYSCONFIG bit definitions */
-#define SYSC_CLOCKACTIVITY_MASK		(0x3 << 8)
-#define SYSC_SIDLEMODE_MASK		(0x3 << 3)
-#define SYSC_ENAWAKEUP_MASK		(1 << 2)
-#define SYSC_SOFTRESET_MASK		(1 << 1)
-#define SYSC_AUTOIDLE_MASK		(1 << 0)
-
-#define SYSC_IDLEMODE_SMART		0x2
-#define SYSC_CLOCKACTIVITY_FCLK		0x2
-
 /* Errata definitions */
 #define I2C_OMAP_ERRATA_I207		(1 << 0)
 #define I2C_OMAP3_1P153			(1 << 1)

@@ -182,6 +169,7 @@ struct omap_i2c_dev {
 	u32			latency;	/* maximum mpu wkup latency */
 	void			(*set_mpu_wkup_lat)(struct device *dev,
 						    long latency);
+	int			(*device_reset)(struct device *dev);
 	u32			speed;		/* Speed of bus in Khz */
 	u16			cmd_err;
 	u8			*buf;

@@ -317,60 +305,22 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
 	u16 psc = 0, scll = 0, sclh = 0, buf = 0;
 	u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
 	unsigned long fclk_rate = 12000000;
-	unsigned long timeout;
 	unsigned long internal_clk = 0;
 	struct clk *fclk;
 	struct omap_i2c_bus_platform_data *pdata;
 
 	pdata = dev->dev->platform_data;
 
-	if (dev->rev >= OMAP_I2C_OMAP1_REV_2) {
-		/* Disable I2C controller before soft reset */
-		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
-			omap_i2c_read_reg(dev, OMAP_I2C_CON_REG) &
-				~(OMAP_I2C_CON_EN));
-
-		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
-		/* For some reason we need to set the EN bit before the
-		 * reset done bit gets set. */
-		timeout = jiffies + OMAP_I2C_TIMEOUT;
-		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
-		while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
-			 SYSS_RESETDONE_MASK)) {
-			if (time_after(jiffies, timeout)) {
-				dev_warn(dev->dev, "timeout waiting "
-						"for controller reset\n");
-				return -ETIMEDOUT;
-			}
-			msleep(1);
-		}
-
-		/* SYSC register is cleared by the reset; rewrite it */
-		if (dev->rev == OMAP_I2C_REV_ON_2430) {
-
-			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
-					   SYSC_AUTOIDLE_MASK);
-
-		} else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
-			dev->syscstate = SYSC_AUTOIDLE_MASK;
-			dev->syscstate |= SYSC_ENAWAKEUP_MASK;
-			dev->syscstate |= (SYSC_IDLEMODE_SMART <<
-			      __ffs(SYSC_SIDLEMODE_MASK));
-			dev->syscstate |= (SYSC_CLOCKACTIVITY_FCLK <<
-			      __ffs(SYSC_CLOCKACTIVITY_MASK));
-
-			omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
-							dev->syscstate);
-			/*
-			 * Enabling all wakup sources to stop I2C freezing on
-			 * WFI instruction.
-			 * REVISIT: Some wkup sources might not be needed.
-			 */
-			dev->westate = OMAP_I2C_WE_ALL;
-			if (dev->rev < OMAP_I2C_REV_ON_3530_4430)
-				omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
-								dev->westate);
-		}
+	if (dev->rev >= OMAP_I2C_REV_ON_3430) {
+		/*
+		 * Enabling all wakeup sources to stop I2C freezing on
+		 * WFI instruction.
+		 * REVISIT: Some wakeup sources might not be needed.
+		 */
+		dev->westate = OMAP_I2C_WE_ALL;
+		if (dev->rev < OMAP_I2C_REV_ON_3530_4430)
+			omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
+							dev->westate);
 	}
 	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 

@@ -595,6 +545,11 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 		return r;
 	if (r == 0) {
 		dev_err(dev->dev, "controller timed out\n");
+		if (dev->device_reset) {
+			r = dev->device_reset(dev->dev);
+			if (r < 0)
+				dev_err(dev->dev, "reset failed\n");
+		}
 		omap_i2c_init(dev);
 		return -ETIMEDOUT;
 	}

@@ -605,6 +560,11 @@ static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 	/* We have an error */
 	if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
 			    OMAP_I2C_STAT_XUDF)) {
+		if (dev->device_reset) {
+			r = dev->device_reset(dev->dev);
+			if (r < 0)
+				dev_err(dev->dev, "reset failed\n");
+		}
 		omap_i2c_init(dev);
 		return -EIO;
 	}

@@ -1005,6 +965,7 @@ omap_i2c_probe(struct platform_device *pdev)
 	if (pdata != NULL) {
 		speed = pdata->clkrate;
 		dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat;
+		dev->device_reset = pdata->device_reset;
 	} else {
 		speed = 100;	/* Default speed */
 		dev->set_mpu_wkup_lat = NULL;
Signature · 1 line
1.7.1
#2 lore raw

PATCH v6 2/3 OMAP: I2C: Remove the reset in the init path

Quoted 11 lines · Shubhrajyoti D
(quoted diff) +0 -6
-  The reset in the driver at init is not needed anymore as the
   hwmod framework takes care of reseting it.
-  Reset is removed from omap_i2c_init, which was called
   not only during probe, but also after time out and error handling.
   device_reset were added in those places to effect the reset.
-  Earlier the hwmod SYSC settings were over-written in the driver.
   Removing the same and letting the hwmod take care of the settings.
-  Clean up the SYSS_RESETDONE_MASK macro as it is no longer needed.
-  Clean up the SYSCONFIG SYSC bit defination macros.
-  Fix the typos in wakeup.
Quoted 1 line
Signed-off-by Shubhrajyoti D <[email protected]>

I asked this in an earlier version, but here it is again.

Are you sure a full IP reset is needed on the timeout and error conditions and not just the module-level one done by:

	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
        
        [ and later... ]

	/* Take the I2C module out of reset: */
	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);

I kind of suspect that the IP rese was done because the omap_i2c_init() function was callled under the timeout/error conditions, but that a full IP SW reset is a bit heavy handed.

Kevin

author
#3 lore raw

PATCH v6 2/3 OMAP: I2C: Remove the reset in the init path

Quoted 26 lines · Kevin Hilman
Quoted 11 lines · Shubhrajyoti D
(quoted diff) +0 -6
-  The reset in the driver at init is not needed anymore as the
    hwmod framework takes care of reseting it.
-  Reset is removed from omap_i2c_init, which was called
    not only during probe, but also after time out and error handling.
    device_reset were added in those places to effect the reset.
-  Earlier the hwmod SYSC settings were over-written in the driver.
    Removing the same and letting the hwmod take care of the settings.
-  Clean up the SYSS_RESETDONE_MASK macro as it is no longer needed.
-  Clean up the SYSCONFIG SYSC bit defination macros.
-  Fix the typos in wakeup.
Quoted 1 line
Signed-off-by Shubhrajyoti D<[email protected]>

I asked this in an earlier version, but here it is again.

Are you sure a full IP reset is needed on the timeout and error conditions and not just the module-level one done by:

	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);

         [ and later... ]

	/* Take the I2C module out of reset: */
	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
Quoted 3 lines

I kind of suspect that the IP rese was done because the omap_i2c_init() function was callled under the timeout/error conditions, but that a full IP SW reset is a bit heavy handed.

My idea is that case of lockup in error path it could be helpful.

We internally had a discussion on this
https://gforge01.dal.design.ti.com/gf/project/opbu_mail_arcv/mailman/?action=ListThreads&mailman_id=218&_forum_action=ForumMessageBrowse&thread_id=12483

Quoted 1 line

Kevin

author
#4 lore raw

PATCH v6 3/3 OMAP: I2C: Remove the SYSC register definition

In reply to Shubhrajyoti D

The SYSC register should not accessed in the driver removing the define from the driver.
Also clean up the syscstate from the omap_i2c_dev struct.

Acked-by Santosh Shilimkar <[email protected]>
Signed-off-by Shubhrajyoti D <[email protected]>
---
 drivers/i2c/busses/i2c-omap.c |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)
drivers/i2c/busses/i2c-omap.c +0 -5
index d8f4470..d05efe7 100644
@@ -63,7 +63,6 @@ enum {
 	OMAP_I2C_BUF_REG,
 	OMAP_I2C_CNT_REG,
 	OMAP_I2C_DATA_REG,
-	OMAP_I2C_SYSC_REG,
 	OMAP_I2C_CON_REG,
 	OMAP_I2C_OA_REG,
 	OMAP_I2C_SA_REG,

@@ -187,7 +186,6 @@ struct omap_i2c_dev {
 	u16			scllstate;
 	u16			sclhstate;
 	u16			bufstate;
-	u16			syscstate;
 	u16			westate;
 	u16			errata;
 };

@@ -202,7 +200,6 @@ const static u8 reg_map_ip_v1[] = {
 	[OMAP_I2C_BUF_REG] = 0x05,
 	[OMAP_I2C_CNT_REG] = 0x06,
 	[OMAP_I2C_DATA_REG] = 0x07,
-	[OMAP_I2C_SYSC_REG] = 0x08,
 	[OMAP_I2C_CON_REG] = 0x09,
 	[OMAP_I2C_OA_REG] = 0x0a,
 	[OMAP_I2C_SA_REG] = 0x0b,

@@ -223,7 +220,6 @@ const static u8 reg_map_ip_v2[] = {
 	[OMAP_I2C_BUF_REG] = 0x94,
 	[OMAP_I2C_CNT_REG] = 0x98,
 	[OMAP_I2C_DATA_REG] = 0x9c,
-	[OMAP_I2C_SYSC_REG] = 0x20,
 	[OMAP_I2C_CON_REG] = 0xa4,
 	[OMAP_I2C_OA_REG] = 0xa8,
 	[OMAP_I2C_SA_REG] = 0xac,

@@ -264,7 +260,6 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev)
 		omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
 		omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
 		omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, dev->bufstate);
-		omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, dev->syscstate);
 		omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
 		omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 	}
Signature · 1 line
1.7.1
#5 lore raw

PATCH v6 1/3 OMAP: I2C: Reset support

In reply to Shubhrajyoti D
Quoted 4 lines · Shubhrajyoti D

Under some error conditions the i2c driver may do a reset. Adding a reset field and support in the device-specific code.

Signed-off-by Shubhrajyoti D <[email protected]>

Needs update/rebase to apply against my for_3.2/i2c-cleanup branch...

[...]

include/linux/i2c-omap.h struct omap_i2c_bus_platform_data { · line 40

Quoted 8 lines
include/linux/i2c-omap.h +0 -0
index 98ae49b..8aa91b6 100644
@@ -38,6 +38,7 @@ struct omap_i2c_bus_platform_data {
 	int		(*device_enable) (struct platform_device *pdev);
 	int		(*device_shutdown) (struct platform_device *pdev);
 	int		(*device_idle) (struct platform_device *pdev);

The above functions no longer exist in the platform_data struct.

include/linux/i2c-omap.h struct omap_i2c_bus_platform_data { · line 44

Quoted 4 lines
include/linux/i2c-omap.h +1 -0
+	int		(*device_reset) (struct device *dev);
 };
 
 #endif

Kevin

author
#6 lore raw

PATCH v6 1/3 OMAP: I2C: Reset support

Quoted 9 lines · Kevin Hilman
Quoted 4 lines · Shubhrajyoti D

Under some error conditions the i2c driver may do a reset. Adding a reset field and support in the device-specific code.

Signed-off-by Shubhrajyoti D<[email protected]>

Needs update/rebase to apply against my for_3.2/i2c-cleanup branch...

[...]

Will rebase and send.

Quoted 15 lines

include/linux/i2c-omap.h struct omap_i2c_bus_platform_data { · line 40

Quoted 8 lines
include/linux/i2c-omap.h +0 -0
index 98ae49b..8aa91b6 100644
@@ -38,6 +38,7 @@ struct omap_i2c_bus_platform_data {
  	int		(*device_enable) (struct platform_device *pdev);
  	int		(*device_shutdown) (struct platform_device *pdev);
  	int		(*device_idle) (struct platform_device *pdev);

The above functions no longer exist in the platform_data struct.

include/linux/i2c-omap.h struct omap_i2c_bus_platform_data { · line 44

Quoted 4 lines
include/linux/i2c-omap.h +1 -0
+	int		(*device_reset) (struct device *dev);
  };
 
  #endif

Kevin