Re: [PATCH 1/5] gpio: tps68470: Fix tps68470_gpio_get() reading from the wrong register

[Hans de Goede <hdegoede@xxxxxxxxxx>]

Hi,

On 11/29/22 11:22, Andy Shevchenko wrote:
> On Mon, Nov 28, 2022 at 11:44 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>>
>> For the regular GPIO pins the value should be read from TPS68470_REG_GPDI,
>> so that the actual value of the pin is read, rather then the value the pin
> 
> than

Ack.

>> would output when put in output mode.
> 
> I don't see it here and haven't checked the context, but the idea is
> to check the direction and return either input (if pin is in input
> mode) or [cached] output.If it's the case, the patch looks good to me.

No the idea is to always actually use the input register when reading
the pins, independent of the input/output mode. Instead of always
reading the [cached] output register value.

The input buffer will still work when the device is in output mode
and if somehow an external force is pushing the pin low/high against
the output value then the input buffer will correctly reflect this
(assuming the output is current limited and thus the magic smoke
stays inside the chip).

Regards,

Hans



> 
>> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
>> ---
>>  drivers/gpio/gpio-tps68470.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpio/gpio-tps68470.c b/drivers/gpio/gpio-tps68470.c
>> index aaddcabe9b35..778a72cf800c 100644
>> --- a/drivers/gpio/gpio-tps68470.c
>> +++ b/drivers/gpio/gpio-tps68470.c
>> @@ -30,7 +30,7 @@ static int tps68470_gpio_get(struct gpio_chip *gc, unsigned int offset)
>>  {
>>         struct tps68470_gpio_data *tps68470_gpio = gpiochip_get_data(gc);
>>         struct regmap *regmap = tps68470_gpio->tps68470_regmap;
>> -       unsigned int reg = TPS68470_REG_GPDO;
>> +       unsigned int reg = TPS68470_REG_GPDI;
>>         int val, ret;
>>
>>         if (offset >= TPS68470_N_REGULAR_GPIO) {
>> --
>> 2.38.1
>>
> 
>