On 02/09/2017 06:04, Leo Yan wrote: > On Wed, Aug 30, 2017 at 10:47:37AM +0200, Daniel Lezcano wrote: >> The mutex is used to protect against writes in the configuration register. >> >> That happens at probe time, with no possible race yet. >> >> Then when the module is unloaded and at suspend/resume. >> >> When the module is unloaded, it is an userspace operation, thus via a >> process. >> Suspending the system goes through the freezer to suspend all the tasks >> synchronously before continuing. So it is not possible to hit the suspend ops >> in this driver while we are unloading it. >> >> The resume is the same situation than the probe. >> >> In other words, even if there are several places where we write the >> configuration register, there is no situation where we can write it at the >> same >> time, so far as I can judge > > After applied your previous patches, configuration reigster accessing > only happens in the probe and resume functions. So shouldn't have > chance to access it at the same time. > > BTW, I verified this patch with system suspend/resume, so far it works > well after system resume back.
Great, thanks for testing this. >> Signed-off-by: Daniel Lezcano <[email protected]> > > Reviewed-by: Leo Yan <[email protected]> > Tested-by: Leo Yan <[email protected]> > >> --- >> drivers/thermal/hisi_thermal.c | 6 ------ >> 1 file changed, 6 deletions(-) >> >> diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c >> index b1b086ab..b9e8ee2 100644 >> --- a/drivers/thermal/hisi_thermal.c >> +++ b/drivers/thermal/hisi_thermal.c >> @@ -51,7 +51,6 @@ struct hisi_thermal_sensor { >> }; >> >> struct hisi_thermal_data { >> - struct mutex thermal_lock; /* protects register data */ >> struct platform_device *pdev; >> struct clk *clk; >> struct hisi_thermal_sensor sensor; >> @@ -196,14 +195,10 @@ static inline void hisi_thermal_hdak_set(void __iomem >> *addr, int value) >> >> static void hisi_thermal_disable_sensor(struct hisi_thermal_data *data) >> { >> - mutex_lock(&data->thermal_lock); >> - >> /* disable sensor module */ >> hisi_thermal_enable(data->regs, 0); >> hisi_thermal_alarm_enable(data->regs, 0); >> hisi_thermal_reset_enable(data->regs, 0); >> - >> - mutex_unlock(&data->thermal_lock); >> } >> >> static int hisi_thermal_get_temp(void *__data, int *temp) >> @@ -340,7 +335,6 @@ static int hisi_thermal_probe(struct platform_device >> *pdev) >> if (!data) >> return -ENOMEM; >> >> - mutex_init(&data->thermal_lock); >> data->pdev = pdev; >> >> res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> -- >> 2.7.4 >> -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
