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

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Message-ID: <f89d63ca-1db2-47fa-8d66-943fc7454643@gmail.com>
Date: Thu, 11 Apr 2024 15:14:42 +0300
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Lee Jones <lee@...nel.org>, Andreas Kemnade <andreas@...nade.info>
Cc: robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
 conor+dt@...nel.org, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] mfd: rohm-bd71828: Add power off functionality

On 4/11/24 14:50, Lee Jones wrote:
> 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?

Don't blame me, blame git... Errm... :)
[mvaittin@...ora linux]$ git blame include/linux/mfd/rohm-bd71828.h 
|grep \/\/
1c743ad523bb2 (Matti Vaittinen 2020-01-20 15:43:28 +0200  44) //#define 
BD71828_REG_SWRESET		0x06
1c743ad523bb2 (Matti Vaittinen 2020-01-20 15:43:28 +0200 136) //#define 
BD71828_REG_LDO6_VOLT		0x4

I can send a clean-up patch unless you want to do it while applying 
other stuff...

Yours,
	Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~