linux-kernel - Re: [PATCH v3 2/6] twl-core: add power off implementation for twl603x

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Message-ID: <20231207171155.GG111411@google.com>
Date:   Thu, 7 Dec 2023 17:11:55 +0000
From:   Lee Jones <lee@...nel.org>
To:     Andreas Kemnade <andreas@...nade.info>
Cc:     robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        conor+dt@...nel.org, bcousson@...libre.com, tony@...mide.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org
Subject: Re: [PATCH v3 2/6] twl-core: add power off implementation for twl603x

On Sun, 03 Dec 2023, Andreas Kemnade wrote:

> If the system-power-controller property is there, enable power off.
> Implementation is based on a Linux v3.0 vendor kernel.
> 
> Signed-off-by: Andreas Kemnade <andreas@...nade.info>
> ---
>  drivers/mfd/twl-core.c  | 28 ++++++++++++++++++++++++++++
>  include/linux/mfd/twl.h |  1 +
>  2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/mfd/twl-core.c b/drivers/mfd/twl-core.c
> index 6e384a79e3418..f3982d18008d1 100644
> --- a/drivers/mfd/twl-core.c
> +++ b/drivers/mfd/twl-core.c
> @@ -124,6 +124,11 @@
>  #define TWL6030_BASEADD_RSV		0x0000
>  #define TWL6030_BASEADD_ZERO		0x0000
>  
> +/* some fields in TWL6030_PHOENIX_DEV_ON */

My preference is for proper grammar in comments please.

"Some"

What is TWL6030_PHOENIX_DEV_ON?  A register?

> +#define TWL6030_APP_DEVOFF		BIT(0)
> +#define TWL6030_CON_DEVOFF		BIT(1)
> +#define TWL6030_MOD_DEVOFF		BIT(2)
> +
>  /* Few power values */
>  #define R_CFG_BOOT			0x05
>  
> @@ -687,6 +692,20 @@ static void twl_remove(struct i2c_client *client)
>  	twl_priv->ready = false;
>  }
>  
> +static void twl6030_power_off(void)
> +{
> +	int err;
> +	u8 val;
> +
> +	err = twl_i2c_read_u8(TWL_MODULE_PM_MASTER, &val, TWL6030_PHOENIX_DEV_ON);
> +	if (err)
> +		return;
> +
> +	val |= TWL6030_APP_DEVOFF | TWL6030_CON_DEVOFF | TWL6030_MOD_DEVOFF;
> +	twl_i2c_write_u8(TWL_MODULE_PM_MASTER, val, TWL6030_PHOENIX_DEV_ON);
> +}
> +
> +
>  static struct of_dev_auxdata twl_auxdata_lookup[] = {
>  	OF_DEV_AUXDATA("ti,twl4030-gpio", 0, "twl4030-gpio", NULL),
>  	{ /* sentinel */ },
> @@ -852,6 +871,15 @@ twl_probe(struct i2c_client *client)
>  			goto free;
>  	}
>  
> +	if (twl_class_is_6030()) {

Is this check required?

> +		if (of_device_is_system_power_controller(node)) {

Shouldn't this cover it?

> +			if (!pm_power_off)
> +				pm_power_off = twl6030_power_off;
> +			else
> +				dev_warn(&client->dev, "Poweroff callback already assigned\n");

Can this happen?  Why would anyone care if it did?

> +		}
> +	}
> +
>  	status = of_platform_populate(node, NULL, twl_auxdata_lookup,
>  				      &client->dev);
>  
> diff --git a/include/linux/mfd/twl.h b/include/linux/mfd/twl.h
> index c062d91a67d92..85dc406173dba 100644
> --- a/include/linux/mfd/twl.h
> +++ b/include/linux/mfd/twl.h
> @@ -461,6 +461,7 @@ static inline int twl6030_mmc_card_detect(struct device *dev, int slot)
>  
>  #define TWL4030_PM_MASTER_GLOBAL_TST		0xb6
>  
> +#define TWL6030_PHOENIX_DEV_ON                  0x06
>  /*----------------------------------------------------------------------*/
>  
>  /* Power bus message definitions */
> -- 
> 2.39.2
> 

-- 
Lee Jones [李琼斯]