[PATCH 1/2] net: mdio: Handle bus level GPIO Reset

[Roger Quadros]

On 22/02/2024 08:59, Ravi Gunasekaran wrote:
> 
> 
> On 2/19/24 9:03 PM, Roger Quadros wrote:
>> Some platforms have bus level Reset controlled
>> by a GPIO line. If available then handle bus reset
>> via GPIO.
>>
>> Signed-off-by: Roger Quadros <rogerq at kernel.org>
>> ---
>>  include/phy.h     |  7 +++++++
>>  net/mdio-uclass.c | 37 ++++++++++++++++++++++++++++++++++++-
>>  2 files changed, 43 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/phy.h b/include/phy.h
>> index e02cbdb58c..90a595cae4 100644
>> --- a/include/phy.h
>> +++ b/include/phy.h
>> @@ -9,6 +9,7 @@
>>  #ifndef _PHY_H
>>  #define _PHY_H
>>  
>> +#include <asm/gpio.h>
>>  #include <log.h>
>>  #include <phy_interface.h>
>>  #include <dm/ofnode.h>
>> @@ -76,6 +77,12 @@ struct mii_dev {
>>  	int (*reset)(struct mii_dev *bus);
>>  	struct phy_device *phymap[PHY_MAX_ADDR];
>>  	u32 phy_mask;
>> +	/** @reset_delay_us: Bus GPIO reset pulse width in microseconds */
>> +	int reset_delay_us;
>> +	/** @reset_post_delay_us: Bus GPIO reset deassert delay in microseconds */
>> +	int reset_post_delay_us;
>> +	/** @reset_gpiod: Bus Reset GPIO descriptor pointer */
>> +	struct gpio_desc reset_gpiod;
>>  };
>>  
>>  /* struct phy_driver: a structure which defines PHY behavior
>> diff --git a/net/mdio-uclass.c b/net/mdio-uclass.c
>> index e758cc66d7..4500c50430 100644
>> --- a/net/mdio-uclass.c
>> +++ b/net/mdio-uclass.c
>> @@ -14,6 +14,9 @@
>>  #include <dm/of_extra.h>
>>  #include <dm/uclass-internal.h>
>>  #include <linux/compat.h>
>> +#include <linux/delay.h>
>> +
>> +#define DEFAULT_GPIO_RESET_DELAY	10	/* in microseconds */
>>  
>>  void dm_mdio_probe_devices(void)
>>  {
>> @@ -80,6 +83,16 @@ int dm_mdio_write(struct udevice *mdio_dev, int addr, int devad, int reg,
>>  int dm_mdio_reset(struct udevice *mdio_dev)
>>  {
>>  	struct mdio_ops *ops = mdio_get_ops(mdio_dev);
>> +	struct mdio_perdev_priv *pdata = dev_get_uclass_priv(mdio_dev);
>> +	struct mii_dev *mii_bus = pdata->mii_bus;
>> +
>> +	if (dm_gpio_is_valid(&mii_bus->reset_gpiod)) {
>> +		dm_gpio_set_value(&mii_bus->reset_gpiod, 1);
> 
> undefined reference to `dm_gpio_set_value'
> Build fails for configs that don't have CONFIG_DM_GPIO defined.
> 
> We can have this under "if (IS_ENABLED(CONFIG_DM_GPIO))"

Thanks. I'll check this.

> 
>> +		udelay(mii_bus->reset_delay_us);
>> +		dm_gpio_set_value(&mii_bus->reset_gpiod, 0);
>> +		if (mii_bus->reset_post_delay_us > 0)
>> +			udelay(mii_bus->reset_post_delay_us);
>> +	}
>>  
>>  	if (!ops->reset)
>>  		return 0;
>> @@ -111,14 +124,36 @@ static int mdio_reset(struct mii_dev *mii_bus)
>>  static int dm_mdio_post_probe(struct udevice *dev)
>>  {
>>  	struct mdio_perdev_priv *pdata = dev_get_uclass_priv(dev);
>> +	struct mii_dev *mii_bus;
>> +	int ret;
>>  
>> -	pdata->mii_bus = mdio_alloc();
>> +	mii_bus = mdio_alloc();
>> +	if (!mii_bus) {
>> +		dev_err(dev, "couldn't allocate mii_bus\n");
>> +		return -ENOMEM;
>> +	}
>> +	pdata->mii_bus = mii_bus;
>>  	pdata->mii_bus->read = mdio_read;
>>  	pdata->mii_bus->write = mdio_write;
>>  	pdata->mii_bus->reset = mdio_reset;
>>  	pdata->mii_bus->priv = dev;
>>  	strlcpy(pdata->mii_bus->name, dev->name, MDIO_NAME_LEN);
>>  
>> +	if (IS_ENABLED(CONFIG_DM_GPIO)) {
>> +		/* Get bus level PHY reset GPIO details */
>> +		mii_bus->reset_delay_us = dev_read_u32_default(dev, "reset-delay-us",
>> +							       DEFAULT_GPIO_RESET_DELAY);
>> +		mii_bus->reset_post_delay_us = dev_read_u32_default(dev,
>> +								    "reset-post-delay-us",
>> +								    0);
>> +		ret = gpio_request_by_name(dev, "reset-gpios", 0, &mii_bus->reset_gpiod,
>> +					   GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE);
>> +		if (ret && ret != -ENOENT) {
>> +			dev_err(dev, "couldn't get reset-gpios: %d\n", ret);
>> +			return ret;
>> +		}
>> +	}
>> +
>>  	return mdio_register(pdata->mii_bus);
>>  }
>>  
>>
> 

-- 
cheers,
-roger