Re: [PATCHV2 3/5] OMAP: I2C: Remove the reset in the init path

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On 7/21/2011 4:39 PM, Shubhrajyoti D wrote:
The reset in the driver at init is not needed
anymore as the hwmod framework takes care of
reseting it.

Signed-off-by: Shubhrajyoti D<shubhrajyoti@xxxxxx>
---
  drivers/i2c/busses/i2c-omap.c |   73 ++++++++++++----------------------------
  1 files changed, 22 insertions(+), 51 deletions(-)

Excellent cleanup. Some minor coments


diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 8f87a37..8dc54d5 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -155,9 +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)
@@ -182,6 +179,7 @@ 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;
@@ -332,7 +330,6 @@ 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 platform_device *pdev;
@@ -341,53 +338,16 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
  	pdev = to_platform_device(dev->dev);
  	pdata = pdev->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) {
Space please if (dev->rev >= OMAP_I2C_REV_ON_3430) {
+		/*
+		 * Enabling all wakup sources to stop I2C freezing on
+		 * WFI instruction.
+		 * REVISIT: Some wkup sources might not be needed.
+		 */
Surely not related to your patch. But the 'REVISIT:' caught
my attention. Is the comment still valid.

+		dev->westate = OMAP_I2C_WE_ALL;
+		if (dev->rev<  OMAP_I2C_REV_ON_3530_4430)
Space 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);

@@ -612,6 +572,11 @@ 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 != NULL) {
+			r = dev->device_reset(dev->dev);
+			if (r<  0)
ditto
+				dev_err(dev->dev, "reset failed\n");
+		}
  		omap_i2c_init(dev);
  		return -ETIMEDOUT;
  	}
@@ -622,6 +587,11 @@ 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 |
You can fix this one as well.
  			    OMAP_I2C_STAT_XUDF)) {
+		if (dev->device_reset != NULL) {
+			r = dev->device_reset(dev->dev);
+			if (r<  0)
here too.
+				dev_err(dev->dev, "reset failed\n");
+		}
  		omap_i2c_init(dev);
  		return -EIO;
  	}
@@ -1024,6 +994,7 @@ 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;

Regards
Santosh
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