Re: [PATCH] i2c: omap: re-factor omap_i2c_init function

[Felipe Balbi <balbi-l0cyMroinI0@public.gmane.org>]

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Hi,

On Tue, Oct 23, 2012 at 08:57:19PM +0530, Shubhrajyoti D wrote:
> re-factor omap_i2c_init() so that we can re-use it for resume.
> While at it also remove the bufstate variable as we write it
> in omap_i2c_resize_fifo for every transfer.
> 
> Signed-off-by: Shubhrajyoti D <shubhrajyoti-l0cyMroinI0@public.gmane.org>
> ---
> Applies on Felipe's series
> http://www.spinics.net/lists/linux-omap/msg79995.html
> 
> Tested with Terro sys fix + Felipe's stop sched_clock() during suspend
> on omap3636 beagle both idle and suspend.
> 
> Functional testing on omap4sdp.
> 
>  drivers/i2c/busses/i2c-omap.c |   68 +++++++++++++++++------------------------
>  1 files changed, 28 insertions(+), 40 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 5e5cefb..338cee7 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -209,7 +209,6 @@ struct omap_i2c_dev {
>  	u16			pscstate;
>  	u16			scllstate;
>  	u16			sclhstate;
> -	u16			bufstate;
>  	u16			syscstate;
>  	u16			westate;
>  	u16			errata;
> @@ -285,9 +284,26 @@ static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
>  	}
>  }
>  
> +static void __omap_i2c_init(struct omap_i2c_dev *dev)
> +{
> +
> +	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
> +	/* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
> +	omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);
> +
> +	/* SCL low and high time values */
> +	omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
> +	omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
> +	if (dev->rev >= OMAP_I2C_REV_ON_3430_3530)
> +		omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
> +	/* Take the I2C module out of reset: */
> +	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
> +	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
> +
> +}
>  static int omap_i2c_init(struct omap_i2c_dev *dev)
>  {
> -	u16 psc = 0, scll = 0, sclh = 0, buf = 0;
> +	u16 psc = 0, scll = 0, sclh = 0;
>  	u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
>  	unsigned long fclk_rate = 12000000;
>  	unsigned long timeout;
> @@ -337,11 +353,8 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
>  			 * REVISIT: Some wkup sources might not be needed.
>  			 */
>  			dev->westate = OMAP_I2C_WE_ALL;
> -			omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
> -							dev->westate);
>  		}
>  	}
> -	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
>  
>  	if (dev->flags & OMAP_I2C_FLAG_ALWAYS_ARMXOR_CLK) {
>  		/*
> @@ -426,28 +439,18 @@ static int omap_i2c_init(struct omap_i2c_dev *dev)
>  		sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
>  	}
>  
> -	/* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
> -	omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
> -
> -	/* SCL low and high time values */
> -	omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
> -	omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
> -
> -	/* Take the I2C module out of reset: */
> -	omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
> -
>  	/* Enable interrupts */
>  	dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
>  			OMAP_I2C_IE_NACK | OMAP_I2C_IE_AL)  |
>  			((dev->fifo_size) ? (OMAP_I2C_IE_RDR |
>  				OMAP_I2C_IE_XDR) : 0);
> -	omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
> -	if (dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
> -		dev->pscstate = psc;
> -		dev->scllstate = scll;
> -		dev->sclhstate = sclh;
> -		dev->bufstate = buf;
> -	}
> +
> +	dev->pscstate = psc;
> +	dev->scllstate = scll;
> +	dev->sclhstate = sclh;
> +
> +	__omap_i2c_init(dev);
> +
>  	return 0;
>  }
>  
> @@ -1136,7 +1139,7 @@ omap_i2c_probe(struct platform_device *pdev)
>  	if (IS_ERR_VALUE(r))
>  		goto err_free_mem;
>  
> -	dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
> +	dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG)  & 0xff;
>  
>  	dev->errata = 0;
>  
> @@ -1268,23 +1271,8 @@ static int omap_i2c_runtime_resume(struct device *dev)
>  {
>  	struct omap_i2c_dev *_dev = dev_get_drvdata(dev);
>  
> -	if (_dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE) {
> -		omap_i2c_write_reg(_dev, OMAP_I2C_CON_REG, 0);
> -		omap_i2c_write_reg(_dev, OMAP_I2C_PSC_REG, _dev->pscstate);
> -		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);
> -	}
> -
> -	/*
> -	 * Don't write to this register if the IE state is 0 as it can
> -	 * cause deadlock.
> -	 */
> -	if (_dev->iestate)
> -		omap_i2c_write_reg(_dev, OMAP_I2C_IE_REG, _dev->iestate);
> +	if (_dev->flags & OMAP_I2C_FLAG_RESET_REGS_POSTIDLE)
> +		__omap_i2c_init(_dev);
>  
>  	return 0;
>  }

another thing, the few places in omap_i2c_xfer_msg() which are currently
calling omap_i2c_init() should also be converted to call the newly added
__omap_i2c_init(). We don't need to recalculate any of those clock
dividers and whatnot.

-- 
balbi

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