Re: [PATCH 2/2] I2C: OMAP: remove dev->idle, use usage counting provided by runtime PM

Felipe Balbi
2011-08-03T22:36:05Z

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Hi,

On Wed, Aug 03, 2011 at 11:09:20AM -0700, Kevin Hilman wrote:
> Current usage of runtime PM is not quite correct. The actual
> idle/unidle of the I2C hardware should not happen until the runtime PM
> callbacks are called. Therefore, change omap_i2c_[un]idle() functions
> to only be called from the runtime PM callbacks (when usage count
> transitions to/from zero.)
>
> Also, the runtime PM core does usage counting and replaces
> functionality currently managed by the dev->idle flag. Remove usage
> of dev->idle in favor of using runtime PM, and checking status using
> pm_runtime_suspended().
>
> Signed-off-by: Kevin Hilman <khilman-l0cyMroinI0@public.gmane.org>
> ---
> drivers/i2c/busses/i2c-omap.c | 58 ++++++++++++++++++++++++++--------------
> 1 files changed, 38 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 12d0cbc..1b5325b 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -194,7 +194,6 @@ struct omap_i2c_dev {
> */
> u8 rev;
> unsigned b_hw:1; /* bad h/w fixes */
> - unsigned idle:1;
> u16 iestate; /* Saved interrupt register */
> u16 pscstate;
> u16 scllstate;
> @@ -269,12 +268,8 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev)
> {
> struct omap_i2c_bus_platform_data *pdata;
>
> - WARN_ON(!dev->idle);
> -
> pdata = dev->dev->platform_data;
>
> - pm_runtime_get_sync(dev->dev);
> -
> if (pdata->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);
> @@ -285,7 +280,6 @@ static void omap_i2c_unidle(struct omap_i2c_dev *dev)
> omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
> omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
> }
> - dev->idle = 0;
>
> /*
> * Don't write to this register if the IE state is 0 as it can
> @@ -300,8 +294,6 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev)
> struct omap_i2c_bus_platform_data *pdata;
> u16 iv;
>
> - WARN_ON(dev->idle);
> -
> pdata = dev->dev->platform_data;
>
> dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
> @@ -315,12 +307,9 @@ static void omap_i2c_idle(struct omap_i2c_dev *dev)
> } else {
> omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
>
> - /* Flush posted write before the dev->idle store occurs */
> + /* Flush posted write */
> omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
> }
> - dev->idle = 1;
> -
> - pm_runtime_put_sync(dev->dev);
> }
>
> static int omap_i2c_init(struct omap_i2c_dev *dev)
> @@ -644,7 +633,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> int i;
> int r;
>
> - omap_i2c_unidle(dev);
> + pm_runtime_get_sync(dev->dev);
>
> r = omap_i2c_wait_for_bb(dev);
> if (r < 0)
> @@ -667,7 +656,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>
> omap_i2c_wait_for_bb(dev);
> out:
> - omap_i2c_idle(dev);
> + pm_runtime_put_sync(dev->dev);

I wonder if these pm_runtime_put need to be synchronous ? Could we just
call pm_runtime_put() instead ? Ditto to all other.

> @@ -1140,6 +1128,36 @@ omap_i2c_remove(struct platform_device *pdev)
> return 0;
> }
>
> +#ifdef CONFIG_PM_RUNTIME
> +static int omap_i2c_runtime_suspend(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);

what happened to dev_get_drvdata(dev) ??

> + omap_i2c_idle(_dev);
> +
> + return 0;
> +}
> +
> +static int omap_i2c_runtime_resume(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct omap_i2c_dev *_dev = platform_get_drvdata(pdev);

ditto

> + omap_i2c_unidle(_dev);
> +
> + return 0;
> +}
> +
> +static struct dev_pm_ops omap_i2c_pm_ops = {
> + .runtime_suspend = omap_i2c_runtime_suspend,
> + .runtime_resume = omap_i2c_runtime_resume,
> +};
> +#define OMAP_I2C_PM_OPS (&omap_i2c_pm_ops)
> +#else
> +#define OMAP_I2C_PM_OPS NULL
> +#endif

OMAP_I2C_PM_OPS isn't used anywhere ??

--
balbi

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