Re: [net-next PATCH v4 02/14] net: dsa: qca8k: add LEDs basic support

[Michal Kubiak <michal.kubiak@intel.com>]

On Fri, Mar 17, 2023 at 03:31:13AM +0100, Christian Marangi wrote:
> Add LEDs basic support for qca8k Switch Family by adding basic
> brightness_set() support.
> 
> Since these LEDs refelect port status, the default label is set to
> ":port". DT binding should describe the color, function and number of
> the leds using standard LEDs api.
> 
> These LEDs supports only blocking variant of the brightness_set()
> function since they can sleep during access of the switch leds to set
> the brightness.
> 
> While at it add to the qca8k header file each mode defined by the Switch
> Documentation for future use.
> 
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>

Hi Christian,

Please find my comments inline.

Thanks,
Michal

> ---
>  drivers/net/dsa/qca/Kconfig      |   8 ++
>  drivers/net/dsa/qca/Makefile     |   3 +
>  drivers/net/dsa/qca/qca8k-8xxx.c |   5 +
>  drivers/net/dsa/qca/qca8k-leds.c | 192 +++++++++++++++++++++++++++++++
>  drivers/net/dsa/qca/qca8k.h      |  59 ++++++++++
>  drivers/net/dsa/qca/qca8k_leds.h |  16 +++
>  6 files changed, 283 insertions(+)
>  create mode 100644 drivers/net/dsa/qca/qca8k-leds.c
>  create mode 100644 drivers/net/dsa/qca/qca8k_leds.h
> 
> diff --git a/drivers/net/dsa/qca/Kconfig b/drivers/net/dsa/qca/Kconfig
> index ba339747362c..7a86d6d6a246 100644
> --- a/drivers/net/dsa/qca/Kconfig
> +++ b/drivers/net/dsa/qca/Kconfig
> @@ -15,3 +15,11 @@ config NET_DSA_QCA8K
>  	help
>  	  This enables support for the Qualcomm Atheros QCA8K Ethernet
>  	  switch chips.
> +
> +config NET_DSA_QCA8K_LEDS_SUPPORT
> +	bool "Qualcomm Atheros QCA8K Ethernet switch family LEDs support"
> +	depends on NET_DSA_QCA8K
> +	depends on LEDS_CLASS
> +	help
> +	  This enabled support for LEDs present on the Qualcomm Atheros
> +	  QCA8K Ethernet switch chips.
> diff --git a/drivers/net/dsa/qca/Makefile b/drivers/net/dsa/qca/Makefile
> index 701f1d199e93..ce66b1984e5f 100644
> --- a/drivers/net/dsa/qca/Makefile
> +++ b/drivers/net/dsa/qca/Makefile
> @@ -2,3 +2,6 @@
>  obj-$(CONFIG_NET_DSA_AR9331)	+= ar9331.o
>  obj-$(CONFIG_NET_DSA_QCA8K)	+= qca8k.o
>  qca8k-y 			+= qca8k-common.o qca8k-8xxx.o
> +ifdef CONFIG_NET_DSA_QCA8K_LEDS_SUPPORT
> +qca8k-y				+= qca8k-leds.o
> +endif
> diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
> index 8dfc5db84700..5decf6fe3832 100644
> --- a/drivers/net/dsa/qca/qca8k-8xxx.c
> +++ b/drivers/net/dsa/qca/qca8k-8xxx.c
> @@ -22,6 +22,7 @@
>  #include <linux/dsa/tag_qca.h>
>  
>  #include "qca8k.h"
> +#include "qca8k_leds.h"
>  
>  static void
>  qca8k_split_addr(u32 regaddr, u16 *r1, u16 *r2, u16 *page)
> @@ -1727,6 +1728,10 @@ qca8k_setup(struct dsa_switch *ds)
>  	if (ret)
>  		return ret;
>  
> +	ret = qca8k_setup_led_ctrl(priv);
> +	if (ret)
> +		return ret;
> +
>  	qca8k_setup_pcs(priv, &priv->pcs_port_0, 0);
>  	qca8k_setup_pcs(priv, &priv->pcs_port_6, 6);
>  
> diff --git a/drivers/net/dsa/qca/qca8k-leds.c b/drivers/net/dsa/qca/qca8k-leds.c
> new file mode 100644
> index 000000000000..adbe7f6e2994
> --- /dev/null
> +++ b/drivers/net/dsa/qca/qca8k-leds.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/regmap.h>
> +#include <net/dsa.h>
> +
> +#include "qca8k.h"
> +#include "qca8k_leds.h"
> +
> +static int
> +qca8k_get_enable_led_reg(int port_num, int led_num, struct qca8k_led_pattern_en *reg_info)
> +{
> +	switch (port_num) {
> +	case 0:
> +		reg_info->reg = QCA8K_LED_CTRL_REG(led_num);
> +		reg_info->shift = QCA8K_LED_PHY0123_CONTROL_RULE_SHIFT;
> +		break;
> +	case 1:
> +	case 2:
> +	case 3:
> +		/* Port 123 are controlled on a different reg */
> +		reg_info->reg = QCA8K_LED_CTRL_REG(3);
> +		reg_info->shift = QCA8K_LED_PHY123_PATTERN_EN_SHIFT(port_num, led_num);
> +		break;
> +	case 4:
> +		reg_info->reg = QCA8K_LED_CTRL_REG(led_num);
> +		reg_info->shift = QCA8K_LED_PHY4_CONTROL_RULE_SHIFT;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int
> +qca8k_led_brightness_set(struct qca8k_led *led,
> +			 enum led_brightness brightness)
> +{
> +	struct qca8k_led_pattern_en reg_info;
> +	struct qca8k_priv *priv = led->priv;
> +	u32 mask, val = QCA8K_LED_ALWAYS_OFF;

Nitpick: RCT

> +
> +	qca8k_get_enable_led_reg(led->port_num, led->led_num, &reg_info);
> +
> +	if (brightness)
> +		val = QCA8K_LED_ALWAYS_ON;
> +
> +	if (led->port_num == 0 || led->port_num == 4) {
> +		mask = QCA8K_LED_PATTERN_EN_MASK;
> +		val <<= QCA8K_LED_PATTERN_EN_SHIFT;
> +	} else {
> +		mask = QCA8K_LED_PHY123_PATTERN_EN_MASK;
> +	}
> +
> +	return regmap_update_bits(priv->regmap, reg_info.reg,
> +				  mask << reg_info.shift,
> +				  val << reg_info.shift);
> +}
> +
> +static int
> +qca8k_cled_brightness_set_blocking(struct led_classdev *ldev,
> +				   enum led_brightness brightness)
> +{
> +	struct qca8k_led *led = container_of(ldev, struct qca8k_led, cdev);
> +
> +	return qca8k_led_brightness_set(led, brightness);
> +}
> +
> +static enum led_brightness
> +qca8k_led_brightness_get(struct qca8k_led *led)
> +{
> +	struct qca8k_led_pattern_en reg_info;
> +	struct qca8k_priv *priv = led->priv;
> +	u32 val;
> +	int ret;
> +
> +	qca8k_get_enable_led_reg(led->port_num, led->led_num, &reg_info);
> +
> +	ret = regmap_read(priv->regmap, reg_info.reg, &val);
> +	if (ret)
> +		return 0;
> +
> +	val >>= reg_info.shift;
> +
> +	if (led->port_num == 0 || led->port_num == 4) {
> +		val &= QCA8K_LED_PATTERN_EN_MASK;
> +		val >>= QCA8K_LED_PATTERN_EN_SHIFT;
> +	} else {
> +		val &= QCA8K_LED_PHY123_PATTERN_EN_MASK;
> +	}
> +
> +	/* Assume brightness ON only when the LED is set to always ON */
> +	return val == QCA8K_LED_ALWAYS_ON;
> +}
> +
> +static int
> +qca8k_parse_port_leds(struct qca8k_priv *priv, struct fwnode_handle *port, int port_num)
> +{
> +	struct fwnode_handle *led = NULL, *leds = NULL;
> +	struct led_init_data init_data = { };
> +	enum led_default_state state;
> +	struct qca8k_led *port_led;
> +	int led_num, port_index;
> +	int ret;
> +
> +	leds = fwnode_get_named_child_node(port, "leds");
> +	if (!leds) {
> +		dev_dbg(priv->dev, "No Leds node specified in device tree for port %d!\n",
> +			port_num);
> +		return 0;
> +	}
> +
> +	fwnode_for_each_child_node(leds, led) {
> +		/* Reg represent the led number of the port.
> +		 * Each port can have at least 3 leds attached
> +		 * Commonly:
> +		 * 1. is gigabit led
> +		 * 2. is mbit led
> +		 * 3. additional status led
> +		 */
> +		if (fwnode_property_read_u32(led, "reg", &led_num))
> +			continue;
> +
> +		if (led_num >= QCA8K_LED_PORT_COUNT) {
> +			dev_warn(priv->dev, "Invalid LED reg defined %d", port_num);
> +			continue;
> +		}

In the comment above you say "each port can have AT LEAST 3 leds".
However, now it seems that if the port has more than 3 leds, all the
remaining leds are not initialized.
Is this intentional? If so, maybe it is worth describing in the comment
that for ports with more than 3 leds, only the first 3 leds are
initialized?

According to the code it looks like the port can have up to 3 leds.

> +
> +		port_index = 3 * port_num + led_num;

Can QCA8K_LED_PORT_COUNT be used instead of "3"? I guess it is the number
of LEDs per port.

> +
> +		port_led = &priv->ports_led[port_index];

Also, the name of the "port_index" variable seems confusing to me. It is
not an index of the port, but rather a unique index of the LED across
all ports, right?

> +		port_led->port_num = port_num;
> +		port_led->led_num = led_num;
> +		port_led->priv = priv;
> +
> +		state = led_init_default_state_get(led);
> +		switch (state) {
> +		case LEDS_DEFSTATE_ON:
> +			port_led->cdev.brightness = 1;
> +			qca8k_led_brightness_set(port_led, 1);
> +			break;
> +		case LEDS_DEFSTATE_KEEP:
> +			port_led->cdev.brightness =
> +					qca8k_led_brightness_get(port_led);
> +			break;
> +		default:
> +			port_led->cdev.brightness = 0;
> +			qca8k_led_brightness_set(port_led, 0);
> +		}
> +
> +		port_led->cdev.max_brightness = 1;
> +		port_led->cdev.brightness_set_blocking = qca8k_cled_brightness_set_blocking;
> +		init_data.default_label = ":port";
> +		init_data.devicename = "qca8k";
> +		init_data.fwnode = led;
> +
> +		ret = devm_led_classdev_register_ext(priv->dev, &port_led->cdev, &init_data);
> +		if (ret)
> +			dev_warn(priv->dev, "Failed to int led");

Typo: "init".
How about adding an index of the LED that could not be initialized?

> +	}
> +
> +	return 0;
> +}
> +
> +int
> +qca8k_setup_led_ctrl(struct qca8k_priv *priv)
> +{
> +	struct fwnode_handle *ports, *port;
> +	int port_num;
> +	int ret;
> +
> +	ports = device_get_named_child_node(priv->dev, "ports");
> +	if (!ports) {
> +		dev_info(priv->dev, "No ports node specified in device tree!\n");
> +		return 0;
> +	}
> +
> +	fwnode_for_each_child_node(ports, port) {
> +		if (fwnode_property_read_u32(port, "reg", &port_num))
> +			continue;
> +
> +		/* Each port can have at least 3 different leds attached.
> +		 * Switch port starts from 0 to 6, but port 0 and 6 are CPU
> +		 * port. The port index needs to be decreased by one to identify
> +		 * the correct port for LED setup.
> +		 */

Again, are there really "at least 3 different leds" per port?
It's confusing a little bit, because  QCA8K_LED_PORT_COUNT == 3, so I
would say it cannot have more than 3.

> +		ret = qca8k_parse_port_leds(priv, port, qca8k_port_to_phy(port_num));

As I checked, the function "qca8k_port_to_phy()" can return all 0xFFs
for port_num == 0. Then, this value is implicitly casted to int (as the
last parameter of "qca8k_parse_port_leds()"). Internally, in
"qca8k_parse_port_leds()" this parameter can be used to do some
computing - that looks dangerous.
In summary, I think a special check for CPU port_num == 0 should be
added.
(I guess the LED configuration i only makes sense for non-CPU ports? It
seems you want to configure up to 15 LEDs in total for 5 ports).

> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> diff --git a/drivers/net/dsa/qca/qca8k.h b/drivers/net/dsa/qca/qca8k.h
> index 4e48e4dd8b0f..3c3c072fa9c2 100644
> --- a/drivers/net/dsa/qca/qca8k.h
> +++ b/drivers/net/dsa/qca/qca8k.h
> @@ -11,6 +11,7 @@
>  #include <linux/delay.h>
>  #include <linux/regmap.h>
>  #include <linux/gpio.h>
> +#include <linux/leds.h>
>  #include <linux/dsa/tag_qca.h>
>  
>  #define QCA8K_ETHERNET_MDIO_PRIORITY			7
> @@ -85,6 +86,50 @@
>  #define   QCA8K_MDIO_MASTER_DATA(x)			FIELD_PREP(QCA8K_MDIO_MASTER_DATA_MASK, x)
>  #define   QCA8K_MDIO_MASTER_MAX_PORTS			5
>  #define   QCA8K_MDIO_MASTER_MAX_REG			32
> +
> +/* LED control register */
> +#define QCA8K_LED_COUNT					15
> +#define QCA8K_LED_PORT_COUNT				3
> +#define QCA8K_LED_RULE_COUNT				6
> +#define QCA8K_LED_RULE_MAX				11
> +
> +#define QCA8K_LED_PHY123_PATTERN_EN_SHIFT(_phy, _led)	((((_phy) - 1) * 6) + 8 + (2 * (_led)))
> +#define QCA8K_LED_PHY123_PATTERN_EN_MASK		GENMASK(1, 0)
> +
> +#define QCA8K_LED_PHY0123_CONTROL_RULE_SHIFT		0
> +#define QCA8K_LED_PHY4_CONTROL_RULE_SHIFT		16
> +
> +#define QCA8K_LED_CTRL_REG(_i)				(0x050 + (_i) * 4)
> +#define QCA8K_LED_CTRL0_REG				0x50
> +#define QCA8K_LED_CTRL1_REG				0x54
> +#define QCA8K_LED_CTRL2_REG				0x58
> +#define QCA8K_LED_CTRL3_REG				0x5C
> +#define   QCA8K_LED_CTRL_SHIFT(_i)			(((_i) % 2) * 16)
> +#define   QCA8K_LED_CTRL_MASK				GENMASK(15, 0)
> +#define QCA8K_LED_RULE_MASK				GENMASK(13, 0)
> +#define QCA8K_LED_BLINK_FREQ_MASK			GENMASK(1, 0)
> +#define QCA8K_LED_BLINK_FREQ_SHITF			0
> +#define   QCA8K_LED_BLINK_2HZ				0
> +#define   QCA8K_LED_BLINK_4HZ				1
> +#define   QCA8K_LED_BLINK_8HZ				2
> +#define   QCA8K_LED_BLINK_AUTO				3
> +#define QCA8K_LED_LINKUP_OVER_MASK			BIT(2)
> +#define QCA8K_LED_TX_BLINK_MASK				BIT(4)
> +#define QCA8K_LED_RX_BLINK_MASK				BIT(5)
> +#define QCA8K_LED_COL_BLINK_MASK			BIT(7)
> +#define QCA8K_LED_LINK_10M_EN_MASK			BIT(8)
> +#define QCA8K_LED_LINK_100M_EN_MASK			BIT(9)
> +#define QCA8K_LED_LINK_1000M_EN_MASK			BIT(10)
> +#define QCA8K_LED_POWER_ON_LIGHT_MASK			BIT(11)
> +#define QCA8K_LED_HALF_DUPLEX_MASK			BIT(12)
> +#define QCA8K_LED_FULL_DUPLEX_MASK			BIT(13)
> +#define QCA8K_LED_PATTERN_EN_MASK			GENMASK(15, 14)
> +#define QCA8K_LED_PATTERN_EN_SHIFT			14
> +#define   QCA8K_LED_ALWAYS_OFF				0
> +#define   QCA8K_LED_ALWAYS_BLINK_4HZ			1
> +#define   QCA8K_LED_ALWAYS_ON				2
> +#define   QCA8K_LED_RULE_CONTROLLED			3
> +
>  #define QCA8K_GOL_MAC_ADDR0				0x60
>  #define QCA8K_GOL_MAC_ADDR1				0x64
>  #define QCA8K_MAX_FRAME_SIZE				0x78
> @@ -383,6 +428,19 @@ struct qca8k_pcs {
>  	int port;
>  };
>  
> +struct qca8k_led_pattern_en {
> +	u32 reg;
> +	u8 shift;
> +};
> +
> +struct qca8k_led {
> +	u8 port_num;
> +	u8 led_num;
> +	u16 old_rule;
> +	struct qca8k_priv *priv;
> +	struct led_classdev cdev;
> +};
> +
>  struct qca8k_priv {
>  	u8 switch_id;
>  	u8 switch_revision;
> @@ -407,6 +465,7 @@ struct qca8k_priv {
>  	struct qca8k_pcs pcs_port_0;
>  	struct qca8k_pcs pcs_port_6;
>  	const struct qca8k_match_data *info;
> +	struct qca8k_led ports_led[QCA8K_LED_COUNT];
>  };
>  
>  struct qca8k_mib_desc {
> diff --git a/drivers/net/dsa/qca/qca8k_leds.h b/drivers/net/dsa/qca/qca8k_leds.h
> new file mode 100644
> index 000000000000..ab367f05b173
> --- /dev/null
> +++ b/drivers/net/dsa/qca/qca8k_leds.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef __QCA8K_LEDS_H
> +#define __QCA8K_LEDS_H
> +
> +/* Leds Support function */
> +#ifdef CONFIG_NET_DSA_QCA8K_LEDS_SUPPORT
> +int qca8k_setup_led_ctrl(struct qca8k_priv *priv);
> +#else
> +static inline int qca8k_setup_led_ctrl(struct qca8k_priv *priv)
> +{
> +	return 0;
> +}
> +#endif
> +
> +#endif /* __QCA8K_LEDS_H */
> -- 
> 2.39.2
>