Re: [PATCH 1/2] thermal: ti-soc-thermal: Enable addition power management

[Adam Ford <aford173@gmail.com>]

On Fri, Sep 11, 2020 at 7:32 AM Adam Ford <aford173@gmail.com> wrote:
>
> The bandgap sensor can be idled when the processor is too, but it
> isn't currently being done, so the power consumption of OMAP3
> boards can elevated if the bangap sensor is enabled.
>
> This patch attempts to use some additional power management
> to idle the clock to the bandgap when not needed.
>
> Signed-off-by: Adam Ford <aford173@gmail.com>
> Reported-by: kernel test robot <lkp@intel.com>
> Tested-by: Andreas Kemnade <andreas@kemnade.info> # GTA04
> ---
> V3:  bandgap_omap_cpu_notifier is only defined when CONFIG_PM_SLEEP
>      is enabled, so make all references to it also depend on
>      CONFIG_PM_SLEEP as well
>

Gentle nudge on this one.  It was in the queue for a while, and got
lost, then resurrected again.

thanks

adam

> V2: Fix issue where variable stating the suspend mode isn't being
>     properly set and cleared.
>
> diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.c b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
> index ab19ceff6e2a..5e596168ba73 100644
> --- a/drivers/thermal/ti-soc-thermal/ti-bandgap.c
> +++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.c
> @@ -25,10 +25,20 @@
>  #include <linux/of_platform.h>
>  #include <linux/of_irq.h>
>  #include <linux/io.h>
> +#include <linux/cpu_pm.h>
> +#include <linux/device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/pm.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>
>  #include "ti-bandgap.h"
>
>  static int ti_bandgap_force_single_read(struct ti_bandgap *bgp, int id);
> +#ifdef CONFIG_PM_SLEEP
> +static int bandgap_omap_cpu_notifier(struct notifier_block *nb,
> +                                 unsigned long cmd, void *v);
> +#endif
>
>  /***   Helper functions to access registers and their bitfields   ***/
>
> @@ -1008,6 +1018,11 @@ int ti_bandgap_probe(struct platform_device *pdev)
>                 }
>         }
>
> +#ifdef CONFIG_PM_SLEEP
> +       bgp->nb.notifier_call = bandgap_omap_cpu_notifier;
> +       cpu_pm_register_notifier(&bgp->nb);
> +#endif
> +
>         return 0;
>
>  remove_last_cooling:
> @@ -1041,7 +1056,9 @@ int ti_bandgap_remove(struct platform_device *pdev)
>         struct ti_bandgap *bgp = platform_get_drvdata(pdev);
>         int i;
>
> -       /* First thing is to remove sensor interfaces */
> +       cpu_pm_unregister_notifier(&bgp->nb);
> +
> +       /* Remove sensor interfaces */
>         for (i = 0; i < bgp->conf->sensor_count; i++) {
>                 if (bgp->conf->sensors[i].unregister_cooling)
>                         bgp->conf->sensors[i].unregister_cooling(bgp, i);
> @@ -1150,9 +1167,43 @@ static int ti_bandgap_suspend(struct device *dev)
>         if (TI_BANDGAP_HAS(bgp, CLK_CTRL))
>                 clk_disable_unprepare(bgp->fclock);
>
> +       bgp->is_suspended = true;
> +
>         return err;
>  }
>
> +static int bandgap_omap_cpu_notifier(struct notifier_block *nb,
> +                                 unsigned long cmd, void *v)
> +{
> +       struct ti_bandgap *bgp;
> +
> +       bgp = container_of(nb, struct ti_bandgap, nb);
> +
> +       spin_lock(&bgp->lock);
> +       switch (cmd) {
> +       case CPU_CLUSTER_PM_ENTER:
> +               if (bgp->is_suspended)
> +                       break;
> +               ti_bandgap_save_ctxt(bgp);
> +               ti_bandgap_power(bgp, false);
> +               if (TI_BANDGAP_HAS(bgp, CLK_CTRL))
> +                       clk_disable(bgp->fclock);
> +               break;
> +       case CPU_CLUSTER_PM_ENTER_FAILED:
> +       case CPU_CLUSTER_PM_EXIT:
> +               if (bgp->is_suspended)
> +                       break;
> +               if (TI_BANDGAP_HAS(bgp, CLK_CTRL))
> +                       clk_enable(bgp->fclock);
> +               ti_bandgap_power(bgp, true);
> +               ti_bandgap_restore_ctxt(bgp);
> +               break;
> +       }
> +       spin_unlock(&bgp->lock);
> +
> +       return NOTIFY_OK;
> +}
> +
>  static int ti_bandgap_resume(struct device *dev)
>  {
>         struct ti_bandgap *bgp = dev_get_drvdata(dev);
> @@ -1161,6 +1212,7 @@ static int ti_bandgap_resume(struct device *dev)
>                 clk_prepare_enable(bgp->fclock);
>
>         ti_bandgap_power(bgp, true);
> +       bgp->is_suspended = false;
>
>         return ti_bandgap_restore_ctxt(bgp);
>  }
> diff --git a/drivers/thermal/ti-soc-thermal/ti-bandgap.h b/drivers/thermal/ti-soc-thermal/ti-bandgap.h
> index fce4657e9486..ed0ea4b17b25 100644
> --- a/drivers/thermal/ti-soc-thermal/ti-bandgap.h
> +++ b/drivers/thermal/ti-soc-thermal/ti-bandgap.h
> @@ -12,6 +12,10 @@
>  #include <linux/spinlock.h>
>  #include <linux/types.h>
>  #include <linux/err.h>
> +#include <linux/cpu_pm.h>
> +#include <linux/device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/pm.h>
>
>  struct gpio_desc;
>
> @@ -203,6 +207,8 @@ struct ti_bandgap {
>         int                             irq;
>         struct gpio_desc                *tshut_gpiod;
>         u32                             clk_rate;
> +       struct notifier_block           nb;
> +       unsigned int is_suspended:1;
>  };
>
>  /**
> --
> 2.25.1
>