| Message ID | 1523873525-23718-2-git-send-email-b.zolnierkie@samsung.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Eduardo Valentin |
| Headers | show |
On 16/04/2018 12:11, Bartlomiej Zolnierkiewicz wrote: > From: Marek Szyprowski <m.szyprowski@samsung.com> > > When thermal sensor is not yet enabled, reading temperature might return > random value. This might even result in stopping system booting when such > temperature is higher than the critical value. Fix this by checking if TMU > has been actually enabled before reading the temperature. > > This change fixes booting of Exynos4210-based board with TMU enabled (for > example Samsung Trats board), which was broken since v4.4 kernel release. Why not move the thermal_zone_of_sensor_register *after* initializing the sensor ? > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > Fixes: 9e4249b40340 ("thermal: exynos: Fix first temperature read after registering sensor") > CC: stable@vger.kernel.org # v4.6+ > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
On Monday, April 16, 2018 02:06:41 PM Daniel Lezcano wrote: > On 16/04/2018 12:11, Bartlomiej Zolnierkiewicz wrote: > > From: Marek Szyprowski <m.szyprowski@samsung.com> > > > > When thermal sensor is not yet enabled, reading temperature might return > > random value. This might even result in stopping system booting when such > > temperature is higher than the critical value. Fix this by checking if TMU > > has been actually enabled before reading the temperature. > > > > This change fixes booting of Exynos4210-based board with TMU enabled (for > > example Samsung Trats board), which was broken since v4.4 kernel release. > > Why not move the thermal_zone_of_sensor_register *after* initializing > the sensor ? For initializing the sensor we need data obtained from therm_zone_of_sensor_register() so it cannot be easily done (especially since we also want the fix to be ported to -stable kernels). For more detailed description please see: https://lkml.org/lkml/2018/4/10/376 > > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> > > Fixes: 9e4249b40340 ("thermal: exynos: Fix first temperature read after registering sensor") > > CC: stable@vger.kernel.org # v4.6+ > > Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
On 16/04/2018 14:17, Bartlomiej Zolnierkiewicz wrote: > On Monday, April 16, 2018 02:06:41 PM Daniel Lezcano wrote: >> On 16/04/2018 12:11, Bartlomiej Zolnierkiewicz wrote: >>> From: Marek Szyprowski <m.szyprowski@samsung.com> >>> >>> When thermal sensor is not yet enabled, reading temperature might return >>> random value. This might even result in stopping system booting when such >>> temperature is higher than the critical value. Fix this by checking if TMU >>> has been actually enabled before reading the temperature. >>> >>> This change fixes booting of Exynos4210-based board with TMU enabled (for >>> example Samsung Trats board), which was broken since v4.4 kernel release. >> >> Why not move the thermal_zone_of_sensor_register *after* initializing >> the sensor ? > > For initializing the sensor we need data obtained from > therm_zone_of_sensor_register() so it cannot be easily > done (especially since we also want the fix to be > ported to -stable kernels). For more detailed description > please see: > > https://lkml.org/lkml/2018/4/10/376 I see, a chicken egg problem :/ Thanks for the pointer.
diff --git a/drivers/thermal/samsung/exynos_tmu.c b/drivers/thermal/samsung/exynos_tmu.c index ed805c7..986cbd0 100644 --- a/drivers/thermal/samsung/exynos_tmu.c +++ b/drivers/thermal/samsung/exynos_tmu.c @@ -185,6 +185,7 @@ * @regulator: pointer to the TMU regulator structure. * @reg_conf: pointer to structure to register with core thermal. * @ntrip: number of supported trip points. + * @enabled: current status of TMU device * @tmu_initialize: SoC specific TMU initialization method * @tmu_control: SoC specific TMU control method * @tmu_read: SoC specific TMU temperature read method @@ -205,6 +206,7 @@ struct exynos_tmu_data { struct regulator *regulator; struct thermal_zone_device *tzd; unsigned int ntrip; + bool enabled; int (*tmu_initialize)(struct platform_device *pdev); void (*tmu_control)(struct platform_device *pdev, bool on); @@ -398,6 +400,7 @@ static void exynos_tmu_control(struct platform_device *pdev, bool on) mutex_lock(&data->lock); clk_enable(data->clk); data->tmu_control(pdev, on); + data->enabled = on; clk_disable(data->clk); mutex_unlock(&data->lock); } @@ -890,7 +893,7 @@ static int exynos_get_temp(void *p, int *temp) { struct exynos_tmu_data *data = p; - if (!data || !data->tmu_read) + if (!data || !data->tmu_read || !data->enabled) return -EINVAL; mutex_lock(&data->lock);