linux-kernel - Re: [PATCH] hwmon: lm70: simplify with spi_get_device_match

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Date: Fri, 7 Jun 2024 08:53:45 +0200
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Guenter Roeck <linux@...ck-us.net>, Jean Delvare <jdelvare@...e.com>,
 linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] hwmon: lm70: simplify with spi_get_device_match_data()

On 06/06/2024 17:56, Guenter Roeck wrote:
> On 6/6/24 07:25, Krzysztof Kozlowski wrote:
>> Use spi_get_device_match_data() helper to simplify a bit the driver.
>> Also kernel_ulong_t type is preferred for kernel code over uintptr_t
>> (needed for the cast).
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> ---
>>   drivers/hwmon/lm70.c | 6 +-----
>>   1 file changed, 1 insertion(+), 5 deletions(-)
>>
>> diff --git a/drivers/hwmon/lm70.c b/drivers/hwmon/lm70.c
>> index 481e4e1f8f4f..0d5a250cb672 100644
>> --- a/drivers/hwmon/lm70.c
>> +++ b/drivers/hwmon/lm70.c
>> @@ -169,11 +169,7 @@ static int lm70_probe(struct spi_device *spi)
>>   	struct lm70 *p_lm70;
>>   	int chip;
>>   
>> -	if (dev_fwnode(&spi->dev))
>> -		chip = (int)(uintptr_t)device_get_match_data(&spi->dev);
>> -	else
>> -		chip = spi_get_device_id(spi)->driver_data;
>> -
>> +	chip = (kernel_ulong_t)spi_get_device_match_data(spi);
>>   
>>   	/* signaling is SPI_MODE_0 */
>>   	if ((spi->mode & SPI_MODE_X_MASK) != SPI_MODE_0)
> 
> I'll apply this patch, but ...
> 
> I take it that the earlier claims that driver_data must not be
> something like "(void *) LM70_CHIP_LM70", where LM70_CHIP_LM70 is 0,
> was wrong. I'll start reverting all patches which changed starting
> enum values from 0 to 1 based on that wrong claim.

Yeah, they should not be 0. I think Jonathan also brought it some time
ago for iio drivers:

https://lore.kernel.org/linux-iio/20240226192555.14aa178e@jic23-huawei/

but if all the ID tables are complete, the 0 will work fine:

https://lore.kernel.org/all/20240413154511.52576-1-krzysztof.kozlowski@linaro.org/

Best regards,
Krzysztof