On Mon, Dec 23, 2013 at 03:49:22PM -0500, Anson Huang wrote:
> Thermal sensor needs pll3_usb_otg when measuring temperature,
> otherwise the temperature read will be incorrect, so need to
> enable this clk before sensor working, for alarm function,
> as hardware will take measurement periodically, so we should
> keep this clk always on once alarm function is enabled.
>
> Signed-off-by: Anson Huang <b20...@freescale.com>
Acked-by: Shawn Guo <shawn....@linaro.org>
> ---
> .../devicetree/bindings/thermal/imx-thermal.txt | 4 ++++
> drivers/thermal/imx_thermal.c | 20
> ++++++++++++++++++++
> 2 files changed, 24 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/thermal/imx-thermal.txt
> b/Documentation/devicetree/bindings/thermal/imx-thermal.txt
> index 541c25e..1f0f672 100644
> --- a/Documentation/devicetree/bindings/thermal/imx-thermal.txt
> +++ b/Documentation/devicetree/bindings/thermal/imx-thermal.txt
> @@ -8,10 +8,14 @@ Required properties:
> calibration data, e.g. OCOTP on imx6q. The details about calibration data
> can be found in SoC Reference Manual.
>
> +Optional properties:
> +- clocks : thermal sensor's clock source.
> +
> Example:
>
> tempmon {
> compatible = "fsl,imx6q-tempmon";
> fsl,tempmon = <&anatop>;
> fsl,tempmon-data = <&ocotp>;
> + clocks = <&clks 172>;
> };
> diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
> index 1d6c801..cbb16f3 100644
> --- a/drivers/thermal/imx_thermal.c
> +++ b/drivers/thermal/imx_thermal.c
> @@ -7,6 +7,7 @@
> *
> */
>
> +#include <linux/clk.h>
> #include <linux/cpu_cooling.h>
> #include <linux/cpufreq.h>
> #include <linux/delay.h>
> @@ -73,6 +74,7 @@ struct imx_thermal_data {
> unsigned long last_temp;
> bool irq_enabled;
> int irq;
> + struct clk *thermal_clk;
> };
>
> static void imx_set_alarm_temp(struct imx_thermal_data *data,
> @@ -457,6 +459,22 @@ static int imx_thermal_probe(struct platform_device
> *pdev)
> return ret;
> }
>
> + data->thermal_clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(data->thermal_clk)) {
> + dev_warn(&pdev->dev, "failed to get thermal clk!\n");
> + } else {
> + /*
> + * Thermal sensor needs clk on to get correct value, normally
> + * we should enable its clk before taking measurement and
> disable
> + * clk after measurement is done, but if alarm function is
> enabled,
> + * hardware will auto measure the temperature periodically, so
> we
> + * need to keep the clk always on for alarm function.
> + */
> + ret = clk_prepare_enable(data->thermal_clk);
> + if (ret)
> + dev_warn(&pdev->dev, "failed to enable thermal clk:
> %d\n", ret);
> + }
> +
> /* Enable measurements at ~ 10 Hz */
> regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
> measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
> @@ -478,6 +496,8 @@ static int imx_thermal_remove(struct platform_device
> *pdev)
>
> /* Disable measurements */
> regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
> + if (!IS_ERR(data->thermal_clk))
> + clk_disable_unprepare(data->thermal_clk);
>
> thermal_zone_device_unregister(data->tz);
> cpufreq_cooling_unregister(data->cdev);
> --
> 1.7.9.5
>
>
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