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

From: Christian Marangi <[email-masked]>
Date: Sat, 18 Mar 2023 19:54:03 +0100

On Fri, Mar 17, 2023 at 07:05:57PM +0100, Michal Kubiak wrote:
> On Fri, Mar 17, 2023 at 03:01:28PM +0100, Christian Marangi wrote:
> > On Fri, Mar 17, 2023 at 12:24:23PM +0100, Michal Kubiak wrote:
> > > 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 <[email-masked]>
> > > 
> > > 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.
> > >
> > 
> > Think I should rework the comments and make them more direct/simple.
> > 
> > qca8k switch have a max of 5 port.
> > 
> > each port CAN have a max of 3 leds connected.
> > 
> > It's really a limitation of pin on the switch chip and hw regs so the
> > situation can't happen.
> 
> OK, so it looks like a misunderstanding.
> I interpreted the sentence:
> 	"each port can have AT LEAST 3 leds"
> as
> 	"each port can a MIN of 3 leds connected".
> 
> Most likely it is just a typo and it is a matter of changing "at
> least" to "at most" in the comment :-).
>

Yep just that. Thanks a lot for poiting this out.

> > 
> > > > +
> > > > +		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.
> > > 
> > 
> > This variable it's really to make it easier to reference the led in the
> > priv struct. If asked I can rework this to an array of array (one per
> > port and each port out of 3 possigle LED).
> 
> I wasn't probably clear. I just wanted to ask if you can use the constant
> "QCA8K_LED_PORT_COUNT" instead of a raw number "3".
> 
> BTW, I agree that "array of array" option seems too complex solution for
> a simple thing :-).
> 

Decided to move the index calculation in the header.

> > 
> > > > +
> > > > +		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?
> > > 
> > 
> > As said above, they are unique index that comes from port and LED of the
> > port. Really something to represent the code easier internally.
> 
> Got it. I was just sharing my impression of the name "port_index" itself.
> Maybe, "led_index" would be better because it actually indexes leds, not
> ports?
> 

Funny enough I just started working on this and I just decided the same
name and then I read your suggestion. Anyway yep correct port_index
was very confusing.

> > 
> > > > +		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?
> > > 
> > 
> > Ok will add more info in the port and led that failed to init.
> 
> Thanks, but it's just my suggestion.
> 
> > 
> > > > +	}
> > > > +
> > > > +	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.
> 
> "at least" -> "at most"
> 
> > > > +		 * 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).
> > > 
> > 
> > IMHO for this, we can ignore handling this corner case. The hw doesn't
> > supports leds for port0 and port6 (the 2 CPU port) so the case won't
> > ever apply. But if asked I can add the case, not that it will cause any
> > problem in how the regs and shift are referenced in the code.
> 
> OK, got it. So, as I understand, the previous call in this loop
> "fwnode_property_read_u32()" will never return port_num == 0 (or we fall
> into "continue")?
> 

On a second check I got what you mean with this and I added a check to
skip LED init for port 0 and port 6. Thanks!

> > 
> > > > +		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
> > > > 
> > 
> > -- 
> > 	Ansuel
> 
> 
> Thanks,
> Michal

-- 
	Ansuel