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 <b20788@xxxxxxxxxxxxx> Acked-by: Shawn Guo <shawn.guo@xxxxxxxxxx> > --- > .../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 > > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html