Re: [PATCH 1/2] net: designware: eqos: reset phy

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hello Sascha,

On 07.06.21 16:10, Sascha Hauer wrote:
> The designware eqos DT binding has support for specifying reset GPIOs.
> Add support for them.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/net/designware_eqos.c | 33 +++++++++++++++++++++++++++++++++
>  drivers/of/of_gpio.c          |  7 +++++++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/drivers/net/designware_eqos.c b/drivers/net/designware_eqos.c
> index d2baaeaf63..0321024169 100644
> --- a/drivers/net/designware_eqos.c
> +++ b/drivers/net/designware_eqos.c
> @@ -8,9 +8,11 @@
>  
>  #include <common.h>
>  #include <init.h>
> +#include <gpio.h>
>  #include <dma.h>
>  #include <net.h>
>  #include <of_net.h>
> +#include <of_gpio.h>
>  #include <linux/iopoll.h>
>  #include <linux/time.h>
>  #include <linux/sizes.h>
> @@ -189,6 +191,33 @@ struct eqos_desc {
>  
>  #define MII_BUSY		(1 << 0)
>  
> +static int eqos_phy_reset(struct device_d *dev, struct eqos *eqos)
> +{
> +	int phy_reset;
> +	int ret;
> +	u32 delays[3] = { 0, 0, 0 };
> +
> +	phy_reset = of_get_named_gpio(dev->device_node, "snps,reset-gpio", 0);
> +
> +        if (!gpio_is_valid(phy_reset))
> +		return 0;

Whitespace is wrong.

> +
> +	ret = gpio_request(phy_reset, "phy-reset");
> +	if (ret)
> +		return ret;

Can you use gpiod_get instead? This would reduce the boilerplate here.

> +
> +	of_property_read_u32_array(dev->device_node,
> +				   "snps,reset-delays-us",
> +				   delays, ARRAY_SIZE(delays));
> +

Looks strange to read out a delay and not act on it. I'd prefer
waiting delays[0] here.

> +	gpio_direction_active(phy_reset, 0);

This always sets logical zero, because gpio_request above doesn't
accept a flag telling it otherwise. You'll need of_get_named_gpio_flags
here, at which point, you'll have basically open-coded gpiod_get(), so
you could use that.

> +	udelay(delays[1]);

Linux rounds up to 1 msec granularity here. We should do likewise.

> +	gpio_set_active(phy_reset, 1);

Nitpick: true/false.

> +	udelay(delays[2]);
> +
> +	return 0;
> +}
> +
>  static int eqos_mdio_wait_idle(struct eqos *eqos)
>  {
>  	u32 idle;
> @@ -843,6 +872,10 @@ int eqos_probe(struct device_d *dev, const struct eqos_ops *ops, void *priv)
>  	if (ret)
>  		return ret;
>  
> +	ret = eqos_phy_reset(dev, eqos);
> +	if (ret)
> +		return ret;
> +
>  	ret = mdiobus_register(miibus);
>  	if (ret)
>  		return ret;
> diff --git a/drivers/of/of_gpio.c b/drivers/of/of_gpio.c
> index 7cbeeaf69e..e1cafdc848 100644
> --- a/drivers/of/of_gpio.c
> +++ b/drivers/of/of_gpio.c
> @@ -35,6 +35,13 @@ static void of_gpio_flags_quirks(struct device_node *np,
>  		if (active_low)
>  			*flags |= OF_GPIO_ACTIVE_LOW;
>  	}
> +
> +	/* Legacy handling of stmmac's active-low PHY reset line */
> +	if (IS_ENABLED(CONFIG_DRIVER_NET_DESIGNWARE_EQOS) &&
> +	    !strcmp(propname, "snps,reset-gpio") &&
> +	    of_property_read_bool(np, "snps,reset-active-low"))
> +		*flags |= OF_GPIO_ACTIVE_LOW;
> +
>  }
>  
>  /**
> 

-- 
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