linux-kernel - Re: [v3,5/5] mfd: rn5t618: register restart handler

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Date:	Sun, 26 Jun 2016 08:13:18 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Stefan Agner <stefan@...er.ch>
Cc:	lee.jones@...aro.org, lgirdwood@...il.com, broonie@...nel.org,
	khilman@...libre.com, carlo@...one.org, b.galvani@...il.com,
	max.oss.09@...il.com, marcel@...wiler.com, linux@...linux.org.uk,
	galak@...eaurora.org, ijc+devicetree@...lion.org.uk,
	mark.rutland@....com, pawel.moll@....com, robh+dt@...nel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-amlogic@...ts.infradead.org
Subject: Re: [v3,5/5] mfd: rn5t618: register restart handler

On Sat, Jun 25, 2016 at 06:15:15PM -0700, Stefan Agner wrote:
> Use the PMIC's repower capability for reboots. Register a restart
> handler and use a slightly elevated priority of 192 since the PMIC
> has suprior reset capability (causing a system wide reset).
> 
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> Reviewed-by: Marcel Ziswiler <marcel.ziswiler@...adex.com>
> ---
>  drivers/mfd/rn5t618.c | 42 ++++++++++++++++++++++++++++++++++++------
>  1 file changed, 36 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/rn5t618.c b/drivers/mfd/rn5t618.c
> index 1831740..14f3b5f 100644
> --- a/drivers/mfd/rn5t618.c
> +++ b/drivers/mfd/rn5t618.c
> @@ -12,11 +12,13 @@
>   * along with this program. If not, see <http://www.gnu.org/licenses/>.
>   */
>  
> +#include <linux/delay.h>
>  #include <linux/i2c.h>
>  #include <linux/mfd/core.h>
>  #include <linux/mfd/rn5t618.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
> +#include <linux/reboot.h>
>  #include <linux/regmap.h>
>  
>  static const struct mfd_cell rn5t618_cells[] = {
> @@ -50,17 +52,37 @@ static const struct regmap_config rn5t618_regmap_config = {
>  };
>  
>  static struct rn5t618 *rn5t618_pm_power_off;
> +static struct notifier_block rn5t618_restart_handler;
>  
> -static void rn5t618_power_off(void)
> +static void rn5t618_trigger_poweroff_sequence(bool repower)
>  {
>  	/* disable automatic repower-on */
>  	regmap_update_bits(rn5t618_pm_power_off->regmap, RN5T618_REPCNT,
> -			   RN5T618_REPCNT_REPWRON, 0);
> +			   RN5T618_REPCNT_REPWRON, repower);

This only works because RN5T618_REPCNT_REPWRON happens to be BIT(0).
Better would be

			RN5T618_REPCNT_REPWRON,
			repower ?  RN5T618_REPCNT_REPWRON : 0

Guenter