leds: pca995x: Add support for PCA995X chips

The PCA995x chips are I2C controlled LED drivers. Each chip has
up to 16 outputs, each one with an individual 8-bit resolution
PWM for brightness control.

Signed-off-by: Isai Gaspar <[e-mail]>
Signed-off-by: Marek Vasut <[e-mail]> # Basically rewrite the driver
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lee Jones <[e-mail]>

drivers/leds/Kconfig

···
 	  LED driver chip accessed via the I2C bus. Supported
 	  devices include PCA9633 and PCA9634
 
+config LEDS_PCA995X
+	tristate "LED Support for PCA995x I2C chips"
+	depends on LEDS_CLASS
+	depends on I2C
+	help
+	  This option enables support for LEDs connected to PCA995x
+	  LED driver chips accessed via the I2C bus. Supported
+	  devices include PCA9955BTW, PCA9952TW and PCA9955TW.
+
 config LEDS_WM831X_STATUS
 	tristate "LED support for status LEDs on WM831x PMICs"
 	depends on LEDS_CLASS

drivers/leds/Makefile

···
 obj-$(CONFIG_LEDS_PCA9532)		+= leds-pca9532.o
 obj-$(CONFIG_LEDS_PCA955X)		+= leds-pca955x.o
 obj-$(CONFIG_LEDS_PCA963X)		+= leds-pca963x.o
+obj-$(CONFIG_LEDS_PCA995X)		+= leds-pca995x.o
 obj-$(CONFIG_LEDS_PM8058)		+= leds-pm8058.o
 obj-$(CONFIG_LEDS_POWERNV)		+= leds-powernv.o
 obj-$(CONFIG_LEDS_PWM)			+= leds-pwm.o

drivers/leds/leds-pca995x.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LED driver for PCA995x I2C LED drivers
+ *
+ * Copyright 2011 bct electronic GmbH
+ * Copyright 2013 Qtechnology/AS
+ * Copyright 2022 NXP
+ * Copyright 2023 Marek Vasut
+ */
+
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+/* Register definition */
+#define PCA995X_MODE1			0x00
+#define PCA995X_MODE2			0x01
+#define PCA995X_LEDOUT0			0x02
+#define PCA9955B_PWM0			0x08
+#define PCA9952_PWM0			0x0A
+#define PCA9952_IREFALL			0x43
+#define PCA9955B_IREFALL		0x45
+
+/* Auto-increment disabled. Normal mode */
+#define PCA995X_MODE1_CFG		0x00
+
+/* LED select registers determine the source that drives LED outputs */
+#define PCA995X_LED_OFF			0x0
+#define PCA995X_LED_ON			0x1
+#define PCA995X_LED_PWM_MODE		0x2
+#define PCA995X_LDRX_MASK		0x3
+#define PCA995X_LDRX_BITS		2
+
+#define PCA995X_MAX_OUTPUTS		16
+#define PCA995X_OUTPUTS_PER_REG		4
+
+#define PCA995X_IREFALL_FULL_CFG	0xFF
+#define PCA995X_IREFALL_HALF_CFG	(PCA995X_IREFALL_FULL_CFG / 2)
+
+#define PCA995X_TYPE_NON_B		0
+#define PCA995X_TYPE_B			1
+
+#define ldev_to_led(c)	container_of(c, struct pca995x_led, ldev)
+
+struct pca995x_led {
+	unsigned int led_no;
+	struct led_classdev ldev;
+	struct pca995x_chip *chip;
+};
+
+struct pca995x_chip {
+	struct regmap *regmap;
+	struct pca995x_led leds[PCA995X_MAX_OUTPUTS];
+	int btype;
+};
+
+static int pca995x_brightness_set(struct led_classdev *led_cdev,
+				  enum led_brightness brightness)
+{
+	struct pca995x_led *led = ldev_to_led(led_cdev);
+	struct pca995x_chip *chip = led->chip;
+	u8 ledout_addr, pwmout_addr;
+	int shift, ret;
+
+	pwmout_addr = (chip->btype ? PCA9955B_PWM0 : PCA9952_PWM0) + led->led_no;
+	ledout_addr = PCA995X_LEDOUT0 + (led->led_no / PCA995X_OUTPUTS_PER_REG);
+	shift = PCA995X_LDRX_BITS * (led->led_no % PCA995X_OUTPUTS_PER_REG);
+
+	switch (brightness) {
+	case LED_FULL:
+		return regmap_update_bits(chip->regmap, ledout_addr,
+					  PCA995X_LDRX_MASK << shift,
+					  PCA995X_LED_ON << shift);
+	case LED_OFF:
+		return regmap_update_bits(chip->regmap, ledout_addr,
+					  PCA995X_LDRX_MASK << shift, 0);
+	default:
+		/* Adjust brightness as per user input by changing individual PWM */
+		ret = regmap_write(chip->regmap, pwmout_addr, brightness);
+		if (ret)
+			return ret;
+
+		/*
+		 * Change LDRx configuration to individual brightness via PWM.
+		 * LED will stop blinking if it's doing so.
+		 */
+		return regmap_update_bits(chip->regmap, ledout_addr,
+					  PCA995X_LDRX_MASK << shift,
+					  PCA995X_LED_PWM_MODE << shift);
+	}
+}
+
+static const struct regmap_config pca995x_regmap = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0x49,
+};
+
+static int pca995x_probe(struct i2c_client *client)
+{
+	struct fwnode_handle *led_fwnodes[PCA995X_MAX_OUTPUTS] = { 0 };
+	struct fwnode_handle *np, *child;
+	struct device *dev = &client->dev;
+	struct pca995x_chip *chip;
+	struct pca995x_led *led;
+	int i, btype, reg, ret;
+
+	btype = (unsigned long)device_get_match_data(&client->dev);
+
+	np = dev_fwnode(dev);
+	if (!np)
+		return -ENODEV;
+
+	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->btype = btype;
+	chip->regmap = devm_regmap_init_i2c(client, &pca995x_regmap);
+	if (IS_ERR(chip->regmap))
+		return PTR_ERR(chip->regmap);
+
+	i2c_set_clientdata(client, chip);
+
+	fwnode_for_each_available_child_node(np, child) {
+		ret = fwnode_property_read_u32(child, "reg", &reg);
+		if (ret) {
+			fwnode_handle_put(child);
+			return ret;
+		}
+
+		if (reg < 0 || reg >= PCA995X_MAX_OUTPUTS || led_fwnodes[reg]) {
+			fwnode_handle_put(child);
+			return -EINVAL;
+		}
+
+		led = &chip->leds[reg];
+		led_fwnodes[reg] = child;
+		led->chip = chip;
+		led->led_no = reg;
+		led->ldev.brightness_set_blocking = pca995x_brightness_set;
+		led->ldev.max_brightness = 255;
+	}
+
+	for (i = 0; i < PCA995X_MAX_OUTPUTS; i++) {
+		struct led_init_data init_data = {};
+
+		if (!led_fwnodes[i])
+			continue;
+
+		init_data.fwnode = led_fwnodes[i];
+
+		ret = devm_led_classdev_register_ext(dev,
+						     &chip->leds[i].ldev,
+						     &init_data);
+		if (ret < 0) {
+			fwnode_handle_put(child);
+			return dev_err_probe(dev, ret,
+					     "Could not register LED %s\n",
+					     chip->leds[i].ldev.name);
+		}
+	}
+
+	/* Disable LED all-call address and set normal mode */
+	ret = regmap_write(chip->regmap, PCA995X_MODE1, PCA995X_MODE1_CFG);
+	if (ret)
+		return ret;
+
+	/* IREF Output current value for all LEDn outputs */
+	return regmap_write(chip->regmap,
+			    btype ? PCA9955B_IREFALL : PCA9952_IREFALL,
+			    PCA995X_IREFALL_HALF_CFG);
+}
+
+static const struct i2c_device_id pca995x_id[] = {
+	{ "pca9952", .driver_data = (kernel_ulong_t)PCA995X_TYPE_NON_B },
+	{ "pca9955b", .driver_data = (kernel_ulong_t)PCA995X_TYPE_B },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, pca995x_id);
+
+static const struct of_device_id pca995x_of_match[] = {
+	{ .compatible = "nxp,pca9952",  .data = (void *)PCA995X_TYPE_NON_B },
+	{ .compatible = "nxp,pca9955b", .data = (void *)PCA995X_TYPE_B },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, pca995x_of_match);
+
+static struct i2c_driver pca995x_driver = {
+	.driver = {
+		.name = "leds-pca995x",
+		.of_match_table = pca995x_of_match,
+	},
+	.probe = pca995x_probe,
+	.id_table = pca995x_id,
+};
+module_i2c_driver(pca995x_driver);
+
+MODULE_AUTHOR("Isai Gaspar <[e-mail]>");
+MODULE_DESCRIPTION("PCA995x LED driver");
+MODULE_LICENSE("GPL");