[Linux-stm32] [PATCH] net: stmmac: Support gpio high-level reset for devices requiring it

[lizhe]

Hi, 




Thx !




i conducted an experiment, and no matter whether i configured it as 

GPIO_ACTIVE_LOW or GPIO_ACTIVE_HIGH in the dts, the resulting

GPIO pin state was 0, indicating a low level.







if (delays[2])

    msleep(DIV_ROUND_UP(DELAYS[2], 1000));




+ gpio_state = gpiod_get_value_can_sleep(reset_gpio);

+ pr_info("gpio_state: %d\n", gpio_state);














At 2025-07-09 01:40:06, "Russell King (Oracle)" <linux at armlinux.org.uk> wrote:
>On Tue, Jul 08, 2025 at 09:50:44AM -0700, Lizhe wrote:
>> some devices only reset when the GPIO is at a high level, but the
>> current function lacks support for such devices. add high-level
>> reset functionality to the function to support devices that require
>> high-level triggering for reset
>> 
>> Signed-off-by: Lizhe <sensor1010 at 163.com>
>> ---
>>  drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c | 8 ++++++--
>>  1 file changed, 6 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
>> index 836f2848dfeb..cb989e6d7eac 100644
>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c
>> @@ -458,6 +458,7 @@ int stmmac_mdio_reset(struct mii_bus *bus)
>>  
>>  #ifdef CONFIG_OF
>>  	if (priv->device->of_node) {
>> +		int active_low = 0;
>>  		struct gpio_desc *reset_gpio;
>>  		u32 delays[3] = { 0, 0, 0 };
>>  
>> @@ -467,6 +468,9 @@ int stmmac_mdio_reset(struct mii_bus *bus)
>>  		if (IS_ERR(reset_gpio))
>>  			return PTR_ERR(reset_gpio);
>>  
>> +		if (reset_gpio)
>> +			active_low = gpiod_is_active_low(reset_gpio);
>> +
>>  		device_property_read_u32_array(priv->device,
>>  					       "snps,reset-delays-us",
>>  					       delays, ARRAY_SIZE(delays));
>> @@ -474,11 +478,11 @@ int stmmac_mdio_reset(struct mii_bus *bus)
>>  		if (delays[0])
>>  			msleep(DIV_ROUND_UP(delays[0], 1000));
>>  
>> -		gpiod_set_value_cansleep(reset_gpio, 1);
>> +		gpiod_set_value_cansleep(reset_gpio, active_low ? 1 : 0);
>>  		if (delays[1])
>>  			msleep(DIV_ROUND_UP(delays[1], 1000));
>>  
>> -		gpiod_set_value_cansleep(reset_gpio, 0);
>> +		gpiod_set_value_cansleep(reset_gpio, active_low ? 0 : 1);
>>  		if (delays[2])
>>  			msleep(DIV_ROUND_UP(delays[2], 1000));
>>  	}
>
>NAK. Not required. The GPIO layer can cope with active-high and
>active-low signals declared in firmware without needing driver
>modification. Use the right data in the firmware and you don't
>need to patch.
>
>/* Bit 0 express polarity */
>#define GPIO_ACTIVE_HIGH 0
>#define GPIO_ACTIVE_LOW 1
>
>-- 
>RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
>FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
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