linux-kernel - Re: [PATCH v3 2/2] mfd: rohm-bd71828: Add power off functionality

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Message-ID: <20240411115047.GI1980182@google.com>
Date: Thu, 11 Apr 2024 12:50:47 +0100
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, mazziesaccount@...il.com,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] mfd: rohm-bd71828: Add power off functionality

On Tue, 02 Apr 2024, Andreas Kemnade wrote:

> Since the chip can power off the system, add the corresponding
> functionality.
> Based on https://github.com/kobolabs/Kobo-Reader/raw/master/hw/imx6sll-clara2e/kernel.tar.bz2
> 
> Signed-off-by: Andreas Kemnade <andreas@...nade.info>
> Acked-by: Matti Vaittinen <mazziesaccount@...il.com>
> ---
>  drivers/mfd/rohm-bd71828.c       | 36 +++++++++++++++++++++++++++++++-
>  include/linux/mfd/rohm-bd71828.h |  3 +++
>  2 files changed, 38 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/rohm-bd71828.c b/drivers/mfd/rohm-bd71828.c
> index 594718f7e8e1..4a1fa8a0d76a 100644
> --- a/drivers/mfd/rohm-bd71828.c
> +++ b/drivers/mfd/rohm-bd71828.c
> @@ -464,6 +464,27 @@ static int set_clk_mode(struct device *dev, struct regmap *regmap,
>  				  OUT32K_MODE_CMOS);
>  }
>  
> +static struct i2c_client *bd71828_dev;
> +static void bd71828_power_off(void)
> +{
> +	while (true) {
> +		s32 val;
> +
> +		/* We are not allowed to sleep, so do not use regmap involving mutexes here. */
> +		val = i2c_smbus_read_byte_data(bd71828_dev, BD71828_REG_PS_CTRL_1);
> +		if (val >= 0)
> +			i2c_smbus_write_byte_data(bd71828_dev,
> +						  BD71828_REG_PS_CTRL_1,
> +						  BD71828_MASK_STATE_HBNT | (u8)val);
> +		mdelay(500);
> +	}
> +}
> +
> +static void bd71828_remove_poweroff(void *data)
> +{
> +	pm_power_off = NULL;
> +}
> +
>  static int bd71828_i2c_probe(struct i2c_client *i2c)
>  {
>  	struct regmap_irq_chip_data *irq_data;
> @@ -542,7 +563,20 @@ static int bd71828_i2c_probe(struct i2c_client *i2c)
>  	ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO, mfd, cells,
>  				   NULL, 0, regmap_irq_get_domain(irq_data));
>  	if (ret)
> -		dev_err_probe(&i2c->dev, ret, "Failed to create subdevices\n");
> +		return	dev_err_probe(&i2c->dev, ret, "Failed to create subdevices\n");
> +
> +	if (of_device_is_system_power_controller(i2c->dev.of_node) &&
> +	    chip_type == ROHM_CHIP_TYPE_BD71828) {
> +		if (!pm_power_off) {
> +			bd71828_dev = i2c;
> +			pm_power_off = bd71828_power_off;
> +			ret = devm_add_action_or_reset(&i2c->dev,
> +						       bd71828_remove_poweroff,
> +						       NULL);
> +		} else {
> +			dev_warn(&i2c->dev, "Poweroff callback already assigned\n");
> +		}
> +	}
>  
>  	return ret;
>  }
> diff --git a/include/linux/mfd/rohm-bd71828.h b/include/linux/mfd/rohm-bd71828.h
> index 3b5f3a7db4bd..9776fde1262d 100644
> --- a/include/linux/mfd/rohm-bd71828.h
> +++ b/include/linux/mfd/rohm-bd71828.h
> @@ -4,6 +4,7 @@
>  #ifndef __LINUX_MFD_BD71828_H__
>  #define __LINUX_MFD_BD71828_H__
>  
> +#include <linux/bits.h>
>  #include <linux/mfd/rohm-generic.h>
>  #include <linux/mfd/rohm-shared.h>
>  
> @@ -41,6 +42,8 @@ enum {
>  #define BD71828_REG_PS_CTRL_2		0x05
>  #define BD71828_REG_PS_CTRL_3		0x06
>  
> +#define BD71828_MASK_STATE_HBNT		BIT(1)
> +
>  //#define BD71828_REG_SWRESET		0x06

How did this get in here?

>  #define BD71828_MASK_RUN_LVL_CTRL	0x30
>  
> -- 
> 2.39.2
> 

-- 
Lee Jones [李琼斯]