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Date:   Tue, 4 Aug 2020 14:28:16 -0700
From:   Guenter Roeck <linux@roeck-us.net>
To:     Roy van Doormaal <roy.van.doormaal@prodrive-technologies.com>
Cc:     linux-hwmon@vger.kernel.org, Jean Delvare <jdelvare@suse.com>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] hwmon: (adc128d818) Fix advanced configuration register
 init
Message-ID: <20200804212816.GA218922@roeck-us.net>
References: <20200728151846.231785-1-roy.van.doormaal@prodrive-technologies.com>
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On Tue, Jul 28, 2020 at 05:18:45PM +0200, Roy van Doormaal wrote:
> If the operation mode is non-zero and an external reference voltage is set,
> first the operation mode is written to the advanced configuration register,
> followed by the externel reference enable bit,
> resetting the configuration mode to 0.
> 
> To fix this, first compose the value of the advanced configuration register
> based on the configuration mode and the external reference voltage.
> The advanced configuration register is then written to the device,
> if it is different from the default register value (0x0).
> 
> Signed-off-by: Roy van Doormaal <roy.van.doormaal@prodrive-technologies.com>

Applied.

Thanks,
Guenter

> ---
>  drivers/hwmon/adc128d818.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/hwmon/adc128d818.c b/drivers/hwmon/adc128d818.c
> index f9edec195c35..571d5454c6b2 100644
> --- a/drivers/hwmon/adc128d818.c
> +++ b/drivers/hwmon/adc128d818.c
> @@ -393,6 +393,7 @@ static int adc128_init_client(struct adc128_data *data)
>  {
>  	struct i2c_client *client = data->client;
>  	int err;
> +	u8 regval = 0x0;
>  
>  	/*
>  	 * Reset chip to defaults.
> @@ -403,10 +404,17 @@ static int adc128_init_client(struct adc128_data *data)
>  		return err;
>  
>  	/* Set operation mode, if non-default */
> -	if (data->mode != 0) {
> -		err = i2c_smbus_write_byte_data(client,
> -						ADC128_REG_CONFIG_ADV,
> -						data->mode << 1);
> +	if (data->mode != 0)
> +		regval |= data->mode << 1;
> +
> +	/* If external vref is selected, configure the chip to use it */
> +	if (data->regulator)
> +		regval |= 0x01;
> +
> +	/* Write advanced configuration register */
> +	if (regval != 0x0) {
> +		err = i2c_smbus_write_byte_data(client, ADC128_REG_CONFIG_ADV,
> +						regval);
>  		if (err)
>  			return err;
>  	}
> @@ -416,14 +424,6 @@ static int adc128_init_client(struct adc128_data *data)
>  	if (err)
>  		return err;
>  
> -	/* If external vref is selected, configure the chip to use it */
> -	if (data->regulator) {
> -		err = i2c_smbus_write_byte_data(client,
> -						ADC128_REG_CONFIG_ADV, 0x01);
> -		if (err)
> -			return err;
> -	}
> -
>  	return 0;
>  }
>