Re: [hwmon PATCH v3 4/6] hwmon: (adt7470) Fix swapped PWM3 and PWM4 auto mode masks

[Guenter Roeck]

On 7/26/26 20:34, Luiz Angelo Daros de Luca wrote:
> The ADT7470_PWM3_AUTO_MASK and ADT7470_PWM4_AUTO_MASK macros are
> currently defined with swapped bit values.
>
> According to Table 22 of the ADT7470 datasheet, the Fan Control Mode
> Configuration for register 0x69 follows the exact same bit position
> layout as register 0x68:
> - 0x68 Bit[7] corresponds to BHVR1 (PWM1) -> 0x80
> - 0x68 Bit[6] corresponds to BHVR2 (PWM2) -> 0x40
> - 0x69 Bit[7] corresponds to BHVR3 (PWM3) -> 0x80
> - 0x69 Bit[6] corresponds to BHVR4 (PWM4) -> 0x40
>
> Consequently, PWM3 should use mask 0x80 and PWM4 should use 0x40.
>
> This typo did not cause any functional bugs because these specific
> macros are never referenced in the driver code. Instead, the driver
> correctly applies the configuration by relying on the modulo parity of
> the channel index (e.g., `channel % 2`) to selectively apply either
> ADT7470_PWM1_AUTO_MASK (0x80) or ADT7470_PWM2_AUTO_MASK (0x40).
> Since the bit layout is identical between the two configuration
> registers, the hardware is currently configured correctly.
>
> Fix the macro definitions to reflect the datasheet accurately and
> prevent future bugs or confusion during code review and refactoring.
> As this is a purely cosmetic fix with no functional impact, a backport
> to stable kernels is not necessary.

If the masks are unused, how about just dropping the definitions instead
(including the unused ADT7470_REG_PWM12_CFG and ADT7470_REG_PWM34_CFG) ?
That could be done as first patch of the series.

Thanks,
Guenter