linux-kernel - Re: [PATCH v2 2/2] mfd: rk808: Prepare rk805 for poweroff

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 3 Jun 2019 13:44:50 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Stefan Mavrodiev <stefan@...mex.com>
Cc:     Heiko Stuebner <heiko@...ech.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] mfd: rk808: Prepare rk805 for poweroff

On Tue, 21 May 2019, Stefan Mavrodiev wrote:

> RK805 has SLEEP signal, which can put the device into SLEEP or OFF
> mode. The default is SLEEP mode.
> 
> However, when the kernel performs power-off (actually the ATF) the
> device will not go fully off and this will result in higher power
> consumption and inability to wake the device with RTC alarm.
> 
> The solution is to enable pm_power_off_prepare function, which will
> configure SLEEP pin for OFF function.
> 
> Signed-off-by: Stefan Mavrodiev <stefan@...mex.com>
> ---
> Changes for v2:
>  - Move pm_pwroff_prep_fn to header
>  - Check pm_power_off_prepare before make it NULL
> 
>  drivers/mfd/rk808.c       | 29 +++++++++++++++++++++++++++++
>  include/linux/mfd/rk808.h |  1 +
>  2 files changed, 30 insertions(+)
> 
> diff --git a/drivers/mfd/rk808.c b/drivers/mfd/rk808.c
> index c0b179792bbf..fb6cdf900899 100644
> --- a/drivers/mfd/rk808.c
> +++ b/drivers/mfd/rk808.c
> @@ -387,6 +387,24 @@ static void rk805_device_shutdown(void)
>  		dev_err(&rk808_i2c_client->dev, "power off error!\n");
>  }
>  
> +static void rk805_device_shutdown_prepare(void)
> +{
> +	int ret;
> +	struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client);
> +
> +	if (!rk808) {
> +		dev_warn(&rk808_i2c_client->dev,
> +			 "have no rk805, so do nothing here\n");

No need for this message I think.

If it's not available, just return.

> +		return;
> +	}
> +
> +	ret = regmap_update_bits(rk808->regmap,
> +				 RK805_GPIO_IO_POL_REG,
> +				 SLP_SD_MSK, SHUTDOWN_FUN);
> +	if (ret)
> +		dev_err(&rk808_i2c_client->dev, "power off error!\n");
> +}

"Failed to shutdown device"

>  static void rk808_device_shutdown(void)
>  {
>  	int ret;
> @@ -475,6 +493,7 @@ static int rk808_probe(struct i2c_client *client,
>  		cells = rk805s;
>  		nr_cells = ARRAY_SIZE(rk805s);
>  		rk808->pm_pwroff_fn = rk805_device_shutdown;
> +		rk808->pm_pwroff_prep_fn = rk805_device_shutdown_prepare;
>  		break;
>  	case RK808_ID:
>  		rk808->regmap_cfg = &rk808_regmap_config;
> @@ -550,6 +569,12 @@ static int rk808_probe(struct i2c_client *client,
>  		pm_power_off = rk808->pm_pwroff_fn;
>  	}
>  
> +	if (pm_off && !pm_power_off_prepare) {
> +		if (!rk808_i2c_client)
> +			rk808_i2c_client = client;
> +		pm_power_off_prepare = rk808->pm_pwroff_prep_fn;
> +	}
> +
>  	return 0;
>  
>  err_irq:
> @@ -566,6 +591,10 @@ static int rk808_remove(struct i2c_client *client)
>  	if (rk808->pm_pwroff_fn && pm_power_off == rk808->pm_pwroff_fn)
>  		pm_power_off = NULL;
>  
> +	if (rk808->pm_pwroff_prep_fn &&
> +	    pm_power_off_prepare == rk808->pm_pwroff_prep_fn)
> +		pm_power_off_prepare = NULL;

I think this block would benefit from a comment.

>  	return 0;
>  }
>  
> diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h
> index 8b5d68a7bb9c..ec928173e507 100644
> --- a/include/linux/mfd/rk808.h
> +++ b/include/linux/mfd/rk808.h
> @@ -454,5 +454,6 @@ struct rk808 {
>  	const struct regmap_config	*regmap_cfg;
>  	const struct regmap_irq_chip	*regmap_irq_chip;
>  	void				(*pm_pwroff_fn)(void);
> +	void				(*pm_pwroff_prep_fn)(void);
>  };
>  #endif /* __LINUX_REGULATOR_RK808_H */

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog