Subject: Re: [PATCH] net: phy: marvell-88q2xxx: Add support for PHY LEDs on 88q2xxx

From: Dimitri Fedrau <[email-masked]>
Date: Fri, 10 Jan 2025 19:30:58 +0100

Hi Stefan,

Am Fri, Jan 10, 2025 at 06:27:43PM +0100 schrieb Stefan Eichenberger:
> Hi Dimitri ,
> 
> On Fri, Jan 10, 2025 at 04:10:04PM +0100, Dimitri Fedrau wrote:
> > Marvell 88Q2XXX devices support up to two configurable Light Emitting
> > Diode (LED). Add minimal LED controller driver supporting the most common
> > uses with the 'netdev' trigger.
> > 
> > Signed-off-by: Dimitri Fedrau <[email-masked]>
> > ---
> >  drivers/net/phy/marvell-88q2xxx.c | 161 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 161 insertions(+)
> > 
> > diff --git a/drivers/net/phy/marvell-88q2xxx.c b/drivers/net/phy/marvell-88q2xxx.c
> > index 5107f58338aff4ed6cfea4d91e37282d9bb60ba5..bef3357b9d279fca5d1f86ff0eaa0d45a699e3f9 100644
> > --- a/drivers/net/phy/marvell-88q2xxx.c
> > +++ b/drivers/net/phy/marvell-88q2xxx.c
> > @@ -8,6 +8,7 @@
> >   */
> >  #include <linux/ethtool_netlink.h>
> >  #include <linux/marvell_phy.h>
> > +#include <linux/of.h>
> >  #include <linux/phy.h>
> >  #include <linux/hwmon.h>
> >  
> > @@ -27,6 +28,9 @@
> >  #define MDIO_MMD_AN_MV_STAT2_100BT1		0x2000
> >  #define MDIO_MMD_AN_MV_STAT2_1000BT1		0x4000
> >  
> > +#define MDIO_MMD_PCS_MV_RESET_CTRL		32768
> > +#define MDIO_MMD_PCS_MV_RESET_CTRL_TX_DISABLE	0x8
> > +
> >  #define MDIO_MMD_PCS_MV_INT_EN			32784
> >  #define MDIO_MMD_PCS_MV_INT_EN_LINK_UP		0x0040
> >  #define MDIO_MMD_PCS_MV_INT_EN_LINK_DOWN	0x0080
> > @@ -40,6 +44,15 @@
> >  #define MDIO_MMD_PCS_MV_GPIO_INT_CTRL			32787
> >  #define MDIO_MMD_PCS_MV_GPIO_INT_CTRL_TRI_DIS		0x0800
> >  
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL			32790
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_GPIO_MASK		GENMASK(7, 4)
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_TX_EN_MASK	GENMASK(3, 0)
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_LINK		0x0 /* Link established */
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_LINK_RX_TX	0x1 /* Link established, blink for rx or tx activity */
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_RX_TX		0x4 /* Receive or Transmit activity */
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_TX		0x5 /* Transmit activity */
> > +#define MDIO_MMD_PCS_MV_LED_FUNC_CTRL_LINK_1000BT1	0x7 /* 1000BT1 link established */
> > +
> >  #define MDIO_MMD_PCS_MV_TEMP_SENSOR1			32833
> >  #define MDIO_MMD_PCS_MV_TEMP_SENSOR1_RAW_INT		0x0001
> >  #define MDIO_MMD_PCS_MV_TEMP_SENSOR1_INT		0x0040
> > @@ -95,6 +108,9 @@
> >  
> >  #define MDIO_MMD_PCS_MV_TDR_OFF_CUTOFF			65246
> >  
> > +#define MV88Q2XXX_LED_INDEX_TX_ENABLE	0
> > +#define MV88Q2XXX_LED_INDEX_GPIO	1
> 
> Not sure if I understand this. TX_ENABLE would be LED0 and GPIO would be
> LED1? In my datasheet the 88Q222x only has a GPIO pin (which is also
> TX_ENABLE), is this a problem? Would we need a led_count variable per
> chip? 
> 
Yes you understand it correctly.
Looking at the datasheets for 88Q212x, 88Q211x and 88Q222x, they have all
TX_ENABLE and GPIO pin. Registers are also the same. Did I miss anything ?
For which device GPIO pin and TX_ENABLE are the same ?

> In the 88Q2110 I can see that there is a TX_ENABLE (0) and a GPIO (1)
> pin. In the register description they just call it LED [0] Control and
> LED [1] Control. Maybe calling it LED_0 and LED_1 would be easier to
> understand? Same for MDIO_MMD_PCS_MV_LED_FUNC_CTRL_GPIO_MASK and
> MDIO_MMD_PCS_MV_LED_FUNC_CTRL_TX_EN_MASK.
> 
I named them just as the pin. Probably it would be easier to understand,
but the mapping between pin and index would be lost. What do you think ?

> > +
> >  struct mmd_val {
> >  	int devad;
> >  	u32 regnum;
> > @@ -741,8 +757,58 @@ static int mv88q2xxx_hwmon_probe(struct phy_device *phydev)
> >  }
> >  #endif
> >  
> > +#if IS_ENABLED(CONFIG_OF_MDIO)
> > +static int mv88q2xxx_leds_probe(struct phy_device *phydev)
> > +{
> > +	struct device_node *node = phydev->mdio.dev.of_node;
> > +	struct device_node *leds;
> > +	int ret = 0;
> > +	u32 index;
> > +
> > +	if (!node)
> > +		return 0;
> > +
> > +	leds = of_get_child_by_name(node, "leds");
> > +	if (!leds)
> > +		return 0;
> > +
> > +	for_each_available_child_of_node_scoped(leds, led) {
> > +		ret = of_property_read_u32(led, "reg", &index);
> > +		if (ret)
> > +			goto exit;
> > +
> > +		if (index > MV88Q2XXX_LED_INDEX_GPIO) {
> > +			ret = -EINVAL;
> > +			goto exit;
> > +		}
> > +
> > +		if (index == MV88Q2XXX_LED_INDEX_TX_ENABLE)
> > +			ret = phy_clear_bits_mmd(phydev, MDIO_MMD_PCS,
> > +						 MDIO_MMD_PCS_MV_RESET_CTRL,
> > +						 MDIO_MMD_PCS_MV_RESET_CTRL_TX_DISABLE);
> 
> If I understand it correctly, this switches the function of the pin from
> TX_DISABLE to GPIO? Can you maybe add a comment here?
>
You are right, will add the comment.

Best regards,
Dimitri Fedrau