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authorAnson Huang <b20788@freescale.com>2013-12-23 15:49:22 -0500
committerZhang Rui <rui.zhang@intel.com>2014-01-03 22:49:16 +0800
commit329fe7b14d6cef4b8cf8c866ff41057a70224de2 (patch)
tree21a45022a95bf88cf529d61c4cec1a2c5e7161c5 /drivers/thermal
parentbeeb5a1e0ef774d0a3e18c5a0e78c39e3e1a5389 (diff)
thermal: imx: add necessary clk operation
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@freescale.com> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Diffstat (limited to 'drivers/thermal')
-rw-r--r--drivers/thermal/imx_thermal.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
index 77a962f1837..deab7baeeb7 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);