Re: [PATCH V2] thermal: imx: correct suspend/resume flow

[Shawn Guo <shawn.guo@linaro.org>]

On Tue, Dec 24, 2013 at 09:43:24AM -0500, Anson Huang wrote:
> Fixes regression introduced by:
> 
> commit 37713a1e8e4c1a1067ad4c99296f78d3c82ed9c4
> Author: Philipp Zabel <p.zabel@pengutronix.de>
> Date:   Thu Aug 1 18:33:12 2013 +0200
> 
>     thermal: imx: implement thermal alarm interrupt handling
> 

Generally, when we quote a commit in the log, it's good enough to use
the output of 'git log --oneline' with patch subject in parentheses.

  37713a1 (thermal: imx: implement thermal alarm interrupt handling)

Anyway, Rui and Eduardo may be fine with what you put there, so

Acked-by: Shawn Guo <shawn.guo@linaro.org>

> The commit 37713a1e8e4 makes imx thermal sensor always powered up as alarm
> function is enabled, but the suspend callback of imx thermal returns
> success only if thermal sensor is powered down, so it will always returns
> fail hence break system's suspend, this patch disables imx thermal sensor
> before suspend and re-enable it after resume.
> 
> Signed-off-by: Anson Huang <b20788@freescale.com>
> ---
>  drivers/thermal/imx_thermal.c |   31 +++++++++++++++++--------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index cbb16f3..9a9a6c2 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -510,27 +510,30 @@ static int imx_thermal_suspend(struct device *dev)
>  {
>  	struct imx_thermal_data *data = dev_get_drvdata(dev);
>  	struct regmap *map = data->tempmon;
> -	u32 val;
>  
> -	regmap_read(map, TEMPSENSE0, &val);
> -	if ((val & TEMPSENSE0_POWER_DOWN) == 0) {
> -		/*
> -		 * If a measurement is taking place, wait for a long enough
> -		 * time for it to finish, and then check again.  If it still
> -		 * does not finish, something must go wrong.
> -		 */
> -		udelay(50);
> -		regmap_read(map, TEMPSENSE0, &val);
> -		if ((val & TEMPSENSE0_POWER_DOWN) == 0)
> -			return -ETIMEDOUT;
> -	}
> +	/*
> +	 * Need to disable thermal sensor, otherwise, when thermal core
> +	 * try to get temperature before thermal sensor resume, a wrong
> +	 * temperature will be read as the thermal sensor is powered
> +	 * down.
> +	 */
> +	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
> +	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
> +	data->mode = THERMAL_DEVICE_DISABLED;
>  
>  	return 0;
>  }
>  
>  static int imx_thermal_resume(struct device *dev)
>  {
> -	/* Nothing to do for now */
> +	struct imx_thermal_data *data = dev_get_drvdata(dev);
> +	struct regmap *map = data->tempmon;
> +
> +	/* Enabled thermal sensor after resume */
> +	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
> +	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
> +	data->mode = THERMAL_DEVICE_ENABLED;
> +
>  	return 0;
>  }
>  #endif
> -- 
> 1.7.9.5
> 
>