[PATCH v2] power: reset: use restart_notifier mechanism for msm-poweroff

[PATCH v2] power: reset: use restart_notifier mechanism for msm-poweroff

[Pramod Gurav]

This change replaces use of arm_pm_restart with recently introduced
reset mechanism in Linux kernel called restart_notifier.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Josh Cartwright <joshc@codeaurora.org>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-pm@vger.kernel.org

Signed-off-by: Pramod Gurav <pramod.gurav@smartplayin.com>
---
Tested on Dragonboard APQ8074

Changes since v1:
- Initialized restart_nb with its declaration
- Removed return check for register_restart_handler as it always
  returns 0 as per Guenter's suggestion to Josh's similar patch.
  This takes care of Guenter's comments on error logs and NULL
  initialization of restart_nb.notifier_call.

 drivers/power/reset/msm-poweroff.c |   17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/power/reset/msm-poweroff.c b/drivers/power/reset/msm-poweroff.c
index 774f9a3..db73238 100644
--- a/drivers/power/reset/msm-poweroff.c
+++ b/drivers/power/reset/msm-poweroff.c
@@ -24,17 +24,24 @@
 #include <asm/system_misc.h>
 
 static void __iomem *msm_ps_hold;
-
-static void do_msm_restart(enum reboot_mode reboot_mode, const char *cmd)
+static int do_msm_restart(struct notifier_block *nb, unsigned long action,
+			   void *data)
 {
 	writel(0, msm_ps_hold);
 	mdelay(10000);
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block restart_nb = {
+	.notifier_call = do_msm_restart,
+	.priority = 128,
+};
+
 static void do_msm_poweroff(void)
 {
 	/* TODO: Add poweroff capability */
-	do_msm_restart(REBOOT_HARD, NULL);
+	do_msm_restart(&restart_nb, 0, NULL);
 }
 
 static int msm_restart_probe(struct platform_device *pdev)
@@ -47,8 +54,10 @@ static int msm_restart_probe(struct platform_device *pdev)
 	if (IS_ERR(msm_ps_hold))
 		return PTR_ERR(msm_ps_hold);
 
+	register_restart_handler(&restart_nb);
+
 	pm_power_off = do_msm_poweroff;
-	arm_pm_restart = do_msm_restart;
+
 	return 0;
 }
 
-- 
1.7.9.5

Re: [PATCH v2] power: reset: use restart_notifier mechanism for msm-poweroff

[Guenter Roeck]

On Mon, Sep 22, 2014 at 01:12:54PM +0530, Pramod Gurav wrote:
> This change replaces use of arm_pm_restart with recently introduced
> reset mechanism in Linux kernel called restart_notifier.
> 
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Josh Cartwright <joshc@codeaurora.org>
> Cc: Sebastian Reichel <sre@kernel.org>
> Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Stephen Boyd <sboyd@codeaurora.org>
> Cc: linux-pm@vger.kernel.org
> 
> Signed-off-by: Pramod Gurav <pramod.gurav@smartplayin.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Re: [PATCH v2] power: reset: use restart_notifier mechanism for msm-poweroff

[Stephen Boyd]

On 09/22, Pramod Gurav wrote:
> diff --git a/drivers/power/reset/msm-poweroff.c b/drivers/power/reset/msm-poweroff.c
> index 774f9a3..db73238 100644
> --- a/drivers/power/reset/msm-poweroff.c
> +++ b/drivers/power/reset/msm-poweroff.c
> @@ -24,17 +24,24 @@
>  #include <asm/system_misc.h>

We can remove this include now too?

>  
>  static void __iomem *msm_ps_hold;
> -
[...]
> @@ -47,8 +54,10 @@ static int msm_restart_probe(struct platform_device *pdev)
>  	if (IS_ERR(msm_ps_hold))
>  		return PTR_ERR(msm_ps_hold);
>  
> +	register_restart_handler(&restart_nb);
> +
>  	pm_power_off = do_msm_poweroff;
> -	arm_pm_restart = do_msm_restart;
> +

And it looks like we should be including <linux/pm.h> for the
pm_power_off hook?

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