linux-kernel - Re: [PATCH] hwmon:max6697: Make sure the OVERT mask is set correctly

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Date:   Wed, 24 Jun 2020 09:38:23 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Chu Lin <linchuyuan@...gle.com>
Cc:     Jean Delvare <jdelvare@...e.com>, linux-hwmon@...r.kernel.org,
        Jason Ling <jasonling@...gle.com>,
        Kais Belgaied <belgaied@...gle.com>,
        Zhongqi Li <zhongqil@...gle.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hwmon:max6697: Make sure the OVERT mask is set correctly

On Tue, Jun 23, 2020 at 10:13:08PM +0000, Chu Lin wrote:
> Per the datasheet for max6697, OVERT mask and ALERT mask is different.
> For example, the 7th bit of OVERT is the local channel but for alert
> mask, the 6th bit is the local channel. Therefore, we can't apply the
> same mask for both reg. In addition to that, max6697 driver is suppose
> to be compatibale with different models. I mannually went over all the
> listed chip and made sure all the chip type has the same layout.
> 
> Testing;
>     mask value of 0x9 should map to 0x44 for ALERT and 0x84 for OVERT.
> I used iotool to read the reg value back to verify. I only tested this
> change on max6581
> 
> Reference:
> https://datasheets.maximintegrated.com/en/ds/MAX6581.pdf
> https://datasheets.maximintegrated.com/en/ds/MAX6697.pdf
> https://datasheets.maximintegrated.com/en/ds/MAX6699.pdf
> 
> Signed-off-by: Chu Lin <linchuyuan@...gle.com>

Nice catch.

Applied, thanks

Guenter

> ---
>  drivers/hwmon/max6697.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/hwmon/max6697.c b/drivers/hwmon/max6697.c
> index 743752a2467a..64122eb38060 100644
> --- a/drivers/hwmon/max6697.c
> +++ b/drivers/hwmon/max6697.c
> @@ -38,8 +38,9 @@ static const u8 MAX6697_REG_CRIT[] = {
>   * Map device tree / platform data register bit map to chip bit map.
>   * Applies to alert register and over-temperature register.
>   */
> -#define MAX6697_MAP_BITS(reg)	((((reg) & 0x7e) >> 1) | \
> +#define MAX6697_ALERT_MAP_BITS(reg)	((((reg) & 0x7e) >> 1) | \
>  				 (((reg) & 0x01) << 6) | ((reg) & 0x80))
> +#define MAX6697_OVERT_MAP_BITS(reg) (((reg) >> 1) | (((reg) & 0x01) << 7))
>  
>  #define MAX6697_REG_STAT(n)		(0x44 + (n))
>  
> @@ -562,12 +563,12 @@ static int max6697_init_chip(struct max6697_data *data,
>  		return ret;
>  
>  	ret = i2c_smbus_write_byte_data(client, MAX6697_REG_ALERT_MASK,
> -					MAX6697_MAP_BITS(pdata->alert_mask));
> +				MAX6697_ALERT_MAP_BITS(pdata->alert_mask));
>  	if (ret < 0)
>  		return ret;
>  
>  	ret = i2c_smbus_write_byte_data(client, MAX6697_REG_OVERT_MASK,
> -				MAX6697_MAP_BITS(pdata->over_temperature_mask));
> +			MAX6697_OVERT_MAP_BITS(pdata->over_temperature_mask));
>  	if (ret < 0)
>  		return ret;
>  
> -- 
> 2.27.0.111.gc72c7da667-goog
>