Best Regards. Anson huang 黄勇才 Freescale Semiconductor Shanghai 上海浦东新区亮景路192号A座2楼 201203 Tel:021-28937058 >-----Original Message----- >From: Shawn Guo [mailto:shawn.guo@xxxxxxxxxx] >Sent: Thursday, December 19, 2013 5:11 PM >To: Huang Yongcai-B20788 >Cc: kernel@xxxxxxxxxxxxxx; rui.zhang@xxxxxxxxx; eduardo.valentin@xxxxxx; >devicetree@xxxxxxxxxxxxxxx; linux-doc@xxxxxxxxxxxxxxx; linux-arm- >kernel@xxxxxxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx >Subject: Re: [PATCH V2 2/2] thermal: imx: add necessary clk operation > >On Thu, Dec 19, 2013 at 03:53:22PM -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> >> --- >> .../devicetree/bindings/thermal/imx-thermal.txt | 2 ++ >> drivers/thermal/imx_thermal.c | 18 >++++++++++++++++++ >> 2 files changed, 20 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/thermal/imx-thermal.txt >> b/Documentation/devicetree/bindings/thermal/imx-thermal.txt >> index 541c25e..e518c6e 100644 >> --- a/Documentation/devicetree/bindings/thermal/imx-thermal.txt >> +++ b/Documentation/devicetree/bindings/thermal/imx-thermal.txt >> @@ -7,6 +7,7 @@ Required properties: >> - fsl,tempmon-data : phandle pointer to fuse controller that contains >TEMPMON >> calibration data, e.g. OCOTP on imx6q. The details about calibration >data >> can be found in SoC Reference Manual. >> +- clocks : thermal sensor's clock source. > >This should be listed in 'Optional properties:' now. Right, will send a V3 later. > >Shawn > >> >> Example: >> >> @@ -14,4 +15,5 @@ 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..c2b8173 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 */ >> -- >> 1.7.9.5 >> >> ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
