[PATCHv5 2/3] OMAP: I2C: Remove the reset in the init path

[Kevin Hilman]

Shubhrajyoti D <shubhrajyoti at ti.com> writes:

> -  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.

Not specifically related to this patch, as the reset behavior was
already there, but do you know why the reset is needed after timeout and
error handling?

IOW, was the reset truly required in those cases, or was just the
re-init necessary?

To me doing a full reset of the IP in those cases sounds like a hack for
a buggy driver.

> -  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 <shubhrajyoti at ti.com>
> ---
>  drivers/i2c/busses/i2c-omap.c |   83 +++++++++++------------------------------
>  1 files changed, 22 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 4e3256f..d8f4470 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -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 != NULL) {

No need for the '!= NULL'

                if (dev->device_reset)

is more typical.  

And based on my comments in 1/3, this would become device_shutdown.

> +			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 != NULL) {
> +			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;

Kevin