| Message ID | 20240125203702.4552-4-ansuelsmth@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | net: phy: generic polarity + LED support for qca808x | expand |
Hi Christian, Hi Andrew, On Thu, Jan 25, 2024 at 09:36:59PM +0100, Christian Marangi wrote: > Add support for PHY LEDs polarity modes. Some PHY require LED to be set > to active low to be turned ON. Adds support for this by declaring > active-low property in DT. > > PHY driver needs to declare .led_polarity_set() to configure LED > polarity modes. Function will pass the index with the LED index and a > bitmap with all the required modes to set. > > Current supported modes are: > - active-low with the flag PHY_LED_ACTIVE_LOW. LED is set to active-low > to turn it ON. > - inactive-high-impedance with the flag PHY_LED_INACTIVE_HIGH_IMPEDANCE. > LED is set to high impedance to turn it OFF. Wanting to make use of this I noticed that polarity settings are only applied once in of_phy_led(), which is not sufficient for my use-case: I'm writing a LED driver for Aquantia PHYs and those PHYs reset the polarity mode every time a PHY reset is triggered. I ended up writing the patch below, but I'm not sure if phy_init_hw should take care of this or if the polarity modes should be stored in memory allocated by the PHY driver and re-applied by the driver after reset (eg. in .config_init). Kinda depends on taste and on how common this behavior is in practise, so I thought the best is to reach out to discuss. Let me know what you think. diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 616bd7ba46cb..1624884fd627 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -1251,6 +1251,7 @@ static int phy_poll_reset(struct phy_device *phydev) int phy_init_hw(struct phy_device *phydev) { int ret = 0; + struct phy_led *phyled; /* Deassert the reset signal */ phy_device_reset(phydev, 0); @@ -1285,6 +1286,17 @@ int phy_init_hw(struct phy_device *phydev) return ret; } + if (phydev->drv->led_polarity_set) { + list_for_each_entry(phyled, &phydev->leds, list) { + if (!phyled->polarity_modes) + continue; + + ret = phydev->drv->led_polarity_set(phydev, phyled->index, phyled->polarity_modes); + if (ret) + return ret; + } + } + return 0; } EXPORT_SYMBOL(phy_init_hw); @@ -3316,7 +3328,6 @@ static int of_phy_led(struct phy_device *phydev, struct device *dev = &phydev->mdio.dev; struct led_init_data init_data = {}; struct led_classdev *cdev; - unsigned long modes = 0; struct phy_led *phyled; u32 index; int err; @@ -3335,18 +3346,14 @@ static int of_phy_led(struct phy_device *phydev, return -EINVAL; if (of_property_read_bool(led, "active-low")) - set_bit(PHY_LED_ACTIVE_LOW, &modes); + set_bit(PHY_LED_ACTIVE_LOW, &phyled->polarity_modes); if (of_property_read_bool(led, "inactive-high-impedance")) - set_bit(PHY_LED_INACTIVE_HIGH_IMPEDANCE, &modes); + set_bit(PHY_LED_INACTIVE_HIGH_IMPEDANCE, &phyled->polarity_modes); - if (modes) { + if (phyled->polarity_modes) { /* Return error if asked to set polarity modes but not supported */ if (!phydev->drv->led_polarity_set) return -EINVAL; - - err = phydev->drv->led_polarity_set(phydev, index, modes); - if (err) - return err; } phyled->index = index; diff --git a/include/linux/phy.h b/include/linux/phy.h index 3ddfe7fe781a..7c8bd72e6fee 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -888,6 +888,7 @@ struct phy_led { struct list_head list; struct phy_device *phydev; struct led_classdev led_cdev; + unsigned long polarity_modes; u8 index; };
> Wanting to make use of this I noticed that polarity settings are only > applied once in of_phy_led(), which is not sufficient for my use-case: > > I'm writing a LED driver for Aquantia PHYs and those PHYs reset the > polarity mode every time a PHY reset is triggered. > > I ended up writing the patch below, but I'm not sure if phy_init_hw > should take care of this or if the polarity modes should be stored in > memory allocated by the PHY driver and re-applied by the driver after > reset (eg. in .config_init). Kinda depends on taste and on how common > this behavior is in practise, so I thought the best is to reach out to > discuss. There was a similar discussion recently about WoL settings getting lost. The conclusion about that was the PHY should keep track of WoL setting. So i would say the same applies there. Please store it in a local priv structure. Andrew
On Sat, May 11, 2024 at 01:58:13AM +0200, Andrew Lunn wrote: > > Wanting to make use of this I noticed that polarity settings are only > > applied once in of_phy_led(), which is not sufficient for my use-case: > > > > I'm writing a LED driver for Aquantia PHYs and those PHYs reset the > > polarity mode every time a PHY reset is triggered. What sort of reset? There are hard resets that set the registers back to default, and soft resets that don't. I think you are referring to a hard reset, but please be clear. > > I ended up writing the patch below, but I'm not sure if phy_init_hw > > should take care of this or if the polarity modes should be stored in > > memory allocated by the PHY driver and re-applied by the driver after > > reset (eg. in .config_init). Kinda depends on taste and on how common > > this behavior is in practise, so I thought the best is to reach out to > > discuss. > > There was a similar discussion recently about WoL settings getting > lost. The conclusion about that was the PHY should keep track of WoL > setting. So i would say the same applies there. Please store it in a > local priv structure. Agreed. If it turns out that it's something that many PHYs need to do, that would be the tiem to move it into the core phylib code. If it only affects a minority of drivers, then it's something drivers should do. The reasoning here is: if its only a problem for a small amount of PHY drivers, then we don't need to penalise everyone with additional overhead. If it's the majority of drivers, then it makes sense to remove this burden from drivers. Also note that this is one of the reasons I don't particularly like the kernel's approach to PHY hardware resets - if a platform firmware decides to describe the PHy hardware reset to the kernel, then we end up with the hardware reset being used at various points which will clear all the registers back to the reset defaults including clearing WoL settings and the like. That's fine for AN state which will get reloaded, but other state does not, so describing the hardware reset can make things much more complicated and introduce differing behaviours compared to platforms that don't describe it. A lot of platforms choose not to describe the PHY hardware reset, but some people see that there's a way to describe it, so they do whether or not there's a reason for the kernel to be manipulating that reset signal. What I'm saying is there's several issues here that all interact...
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 3611ea64875e..dd778c7fde1d 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -3097,6 +3097,7 @@ static int of_phy_led(struct phy_device *phydev, struct device *dev = &phydev->mdio.dev; struct led_init_data init_data = {}; struct led_classdev *cdev; + unsigned long modes = 0; struct phy_led *phyled; u32 index; int err; @@ -3114,6 +3115,21 @@ static int of_phy_led(struct phy_device *phydev, if (index > U8_MAX) return -EINVAL; + if (of_property_read_bool(led, "active-low")) + set_bit(PHY_LED_ACTIVE_LOW, &modes); + if (of_property_read_bool(led, "inactive-high-impedance")) + set_bit(PHY_LED_INACTIVE_HIGH_IMPEDANCE, &modes); + + if (modes) { + /* Return error if asked to set polarity modes but not supported */ + if (!phydev->drv->led_polarity_set) + return -EINVAL; + + err = phydev->drv->led_polarity_set(phydev, index, modes); + if (err) + return err; + } + phyled->index = index; if (phydev->drv->led_brightness_set) cdev->brightness_set_blocking = phy_led_set_brightness; diff --git a/include/linux/phy.h b/include/linux/phy.h index 684efaeca07c..c9994a59ca2e 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -852,6 +852,15 @@ struct phy_plca_status { bool pst; }; +/* Modes for PHY LED configuration */ +enum phy_led_modes { + PHY_LED_ACTIVE_LOW = 0, + PHY_LED_INACTIVE_HIGH_IMPEDANCE = 1, + + /* keep it last */ + __PHY_LED_MODES_NUM, +}; + /** * struct phy_led: An LED driven by the PHY * @@ -1145,6 +1154,19 @@ struct phy_driver { int (*led_hw_control_get)(struct phy_device *dev, u8 index, unsigned long *rules); + /** + * @led_polarity_set: Set the LED polarity modes + * @dev: PHY device which has the LED + * @index: Which LED of the PHY device + * @modes: bitmap of LED polarity modes + * + * Configure LED with all the required polarity modes in @modes + * to make it correctly turn ON or OFF. + * + * Returns 0, or an error code. + */ + int (*led_polarity_set)(struct phy_device *dev, int index, + unsigned long modes); }; #define to_phy_driver(d) container_of(to_mdio_common_driver(d), \ struct phy_driver, mdiodrv)