On Fri, Feb 15, 2013 at 2:17 AM, Bastian Hecht <hechtb@xxxxxxxxx> wrote:
> Currently we provoke i2c timeouts by allowing transfers when
> suspending. This patch adds awareness to suspending and fixes these
> issues.
> The patch follows the style used in i2c-tegra.c - thanks.
>
> Signed-off-by: Bastian Hecht <hechtb+renesas@xxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-sh_mobile.c | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
> index b6e7a83..da28164 100644
> --- a/drivers/i2c/busses/i2c-sh_mobile.c
> +++ b/drivers/i2c/busses/i2c-sh_mobile.c
> @@ -132,6 +132,7 @@ struct sh_mobile_i2c_data {
> struct i2c_msg *msg;
> int pos;
> int sr;
> + bool is_suspended;
> };
>
> #define IIC_FLAG_HAS_ICIC67 (1 << 0)
> @@ -511,6 +512,9 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
> u_int8_t val;
> int i, k, retry_count;
>
> + if (pd->is_suspended)
> + return -EBUSY;
> +
> activate_ch(pd);
>
> /* Process all messages */
> @@ -753,9 +757,33 @@ static int sh_mobile_i2c_runtime_nop(struct device *dev)
> return 0;
> }
>
> +static int sh_mobile_i2c_suspend(struct device *dev)
> +{
> + struct sh_mobile_i2c_data *pd = dev_get_drvdata(dev);
> +
> + i2c_lock_adapter(&pd->adap);
> + pd->is_suspended = true;
> + i2c_unlock_adapter(&pd->adap);
> +
> + return 0;
> +}
> +
> +static int sh_mobile_i2c_resume(struct device *dev)
> +{
> + struct sh_mobile_i2c_data *pd = dev_get_drvdata(dev);
> +
> + i2c_lock_adapter(&pd->adap);
> + pd->is_suspended = false;
> + i2c_unlock_adapter(&pd->adap);
> +
> + return 0;
> +}
> +
> static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
> .runtime_suspend = sh_mobile_i2c_runtime_nop,
> .runtime_resume = sh_mobile_i2c_runtime_nop,
> + .suspend = sh_mobile_i2c_suspend,
> + .resume = sh_mobile_i2c_resume,
> };
>
> static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
> --
Hi Bastian,
Thanks for your work on this. Can you tell us a bit more about where
and when this fix is needed? I am guessing here, but perhaps it only
triggers on SMP hardware with CONFIG_SMP enabled?
Also, do you know the reason why this isn't handled in the i2c layer
by default? I ask because your comment mentions that i2c-tegra.c does
the same thing and I can't see anything in this patch that is actually
related to our I2C hardware.
Thanks,
/ magnus
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