[PATCH v2 3/3] leds: add aw2013 driver

From: nikitos . tr
Date: Mon May 11 2020 - 07:12:43 EST

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From: Nikita Travkin <nikitos.tr@xxxxxxxxx>

This commit adds support for AWINIC AW2013 3-channel LED driver.
The chip supports 3 PWM channels and is controlled with I2C.

Signed-off-by: Nikita Travkin <nikitos.tr@xxxxxxxxx>
---
Changes in v2:
- Handling of situations where one of delays for brightness_set()
was zero is fixed.
- probe() is reworked to do led registration at the time of
dt parsing. Support for "default-state" property was removed:
Keeping the old state properly appers to be tricky and
doesn't worth the effort. For other state "default-on" trigger
can be used.
---
drivers/leds/Kconfig | 10 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-aw2013.c | 436 +++++++++++++++++++++++++++++++++++++
3 files changed, 447 insertions(+)
create mode 100644 drivers/leds/leds-aw2013.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 9cdc4cfc5d11..ed943140e1fd 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -103,6 +103,16 @@ config LEDS_AS3645A
controller. V4L2 flash API is provided as well if
CONFIG_V4L2_FLASH_API is enabled.

+config LEDS_AW2013
+ tristate "LED support for Awinic AW2013"
+ depends on LEDS_CLASS && I2C && OF
+ help
+ This option enables support for the AW2013 3-channel
+ LED driver.
+
+ To compile this driver as a module, choose M here: the module
+ will be called leds-aw2013.
+
config LEDS_BCM6328
tristate "LED Support for Broadcom BCM6328"
depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index d0dff504f108..d6b8a792c936 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_LEDS_APU) += leds-apu.o
obj-$(CONFIG_LEDS_ARIEL) += leds-ariel.o
obj-$(CONFIG_LEDS_AS3645A) += leds-as3645a.o
obj-$(CONFIG_LEDS_ASIC3) += leds-asic3.o
+obj-$(CONFIG_LEDS_AW2013) += leds-aw2013.o
obj-$(CONFIG_LEDS_BCM6328) += leds-bcm6328.o
obj-$(CONFIG_LEDS_BCM6358) += leds-bcm6358.o
obj-$(CONFIG_LEDS_BD2802) += leds-bd2802.o
diff --git a/drivers/leds/leds-aw2013.c b/drivers/leds/leds-aw2013.c
new file mode 100644
index 000000000000..d709cc1f949e
--- /dev/null
+++ b/drivers/leds/leds-aw2013.c
@@ -0,0 +1,436 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Driver for Awinic AW2013 3-channel LED driver
+
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define AW2013_MAX_LEDS 3
+
+/* Reset and ID register */
+#define AW2013_RSTR 0x00
+#define AW2013_RSTR_RESET 0x55
+#define AW2013_RSTR_CHIP_ID 0x33
+
+/* Global control register */
+#define AW2013_GCR 0x01
+#define AW2013_GCR_ENABLE BIT(0)
+
+/* LED channel enable register */
+#define AW2013_LCTR 0x30
+#define AW2013_LCTR_LE(x) BIT((x))
+
+/* LED channel control registers */
+#define AW2013_LCFG(x) (0x31 + (x))
+#define AW2013_LCFG_IMAX_MASK (BIT(0) | BIT(1)) // Should be 0-3
+#define AW2013_LCFG_MD BIT(4)
+#define AW2013_LCFG_FI BIT(5)
+#define AW2013_LCFG_FO BIT(6)
+
+/* LED channel PWM registers */
+#define AW2013_REG_PWM(x) (0x34 + (x))
+
+/* LED channel timing registers */
+#define AW2013_LEDT0(x) (0x37 + (x) * 3)
+#define AW2013_LEDT0_T1(x) ((x) << 4) // Should be 0-7
+#define AW2013_LEDT0_T2(x) (x) // Should be 0-5
+
+#define AW2013_LEDT1(x) (0x38 + (x) * 3)
+#define AW2013_LEDT1_T3(x) ((x) << 4) // Should be 0-7
+#define AW2013_LEDT1_T4(x) (x) // Should be 0-7
+
+#define AW2013_LEDT2(x) (0x39 + (x) * 3)
+#define AW2013_LEDT2_T0(x) ((x) << 4) // Should be 0-8
+#define AW2013_LEDT2_REPEAT(x) (x) // Should be 0-15
+
+#define AW2013_REG_MAX 0x77
+
+#define AW2013_TIME_STEP 130 /* ms */
+
+struct aw2013;
+
+struct aw2013_led {
+ struct aw2013 *chip;
+ struct led_classdev cdev;
+ u32 num;
+ unsigned int imax;
+};
+
+struct aw2013 {
+ struct mutex mutex; /* held when writing to registers */
+ struct regulator *vcc_regulator;
+ struct i2c_client *client;
+ struct aw2013_led leds[AW2013_MAX_LEDS];
+ struct regmap *regmap;
+ int num_leds;
+ bool enabled;
+};
+
+static int aw2013_chip_init(struct aw2013 *chip)
+{
+ int i, ret;
+
+ ret = regmap_write(chip->regmap, AW2013_GCR, AW2013_GCR_ENABLE);
+ if (ret) {
+ dev_err(&chip->client->dev, "Failed to enable the chip: %d\n",
+ ret);
+ return ret;
+ }
+
+ for (i = 0; i < chip->num_leds; i++) {
+ ret = regmap_update_bits(chip->regmap,
+ AW2013_LCFG(chip->leds[i].num),
+ AW2013_LCFG_IMAX_MASK,
+ chip->leds[i].imax);
+ if (ret) {
+ dev_err(&chip->client->dev,
+ "Failed to set maximum current for led %d: %d\n",
+ chip->leds[i].num, ret);
+ return ret;
+ }
+ }
+
+ return ret;
+}
+
+static void aw2013_chip_disable(struct aw2013 *chip)
+{
+ int ret;
+
+ if (!chip->enabled)
+ return;
+
+ regmap_write(chip->regmap, AW2013_GCR, 0);
+
+ ret = regulator_disable(chip->vcc_regulator);
+ if (ret) {
+ dev_err(&chip->client->dev,
+ "Failed to disable regulator: %d\n", ret);
+ return;
+ }
+
+ chip->enabled = false;
+}
+
+static int aw2013_chip_enable(struct aw2013 *chip)
+{
+ int ret;
+
+ if (chip->enabled)
+ return 0;
+
+ ret = regulator_enable(chip->vcc_regulator);
+ if (ret) {
+ dev_err(&chip->client->dev,
+ "Failed to enable regulator: %d\n", ret);
+ return ret;
+ }
+ chip->enabled = true;
+
+ ret = aw2013_chip_init(chip);
+ if (ret)
+ aw2013_chip_disable(chip);
+
+ return ret;
+}
+
+static bool aw2013_chip_in_use(struct aw2013 *chip)
+{
+ int i;
+
+ for (i = 0; i < chip->num_leds; i++)
+ if (chip->leds[i].cdev.brightness)
+ return true;
+
+ return false;
+}
+
+static int aw2013_brightness_set(struct led_classdev *cdev,
+ enum led_brightness brightness)
+{
+ struct aw2013_led *led = container_of(cdev, struct aw2013_led, cdev);
+ int ret, num;
+
+ mutex_lock(&led->chip->mutex);
+
+ if (aw2013_chip_in_use(led->chip)) {
+ ret = aw2013_chip_enable(led->chip);
+ if (ret)
+ goto error;
+ }
+
+ num = led->num;
+
+ ret = regmap_write(led->chip->regmap, AW2013_REG_PWM(num), brightness);
+ if (ret)
+ goto error;
+
+ if (brightness) {
+ ret = regmap_update_bits(led->chip->regmap, AW2013_LCTR,
+ AW2013_LCTR_LE(num), 0xFF);
+ } else {
+ ret = regmap_update_bits(led->chip->regmap, AW2013_LCTR,
+ AW2013_LCTR_LE(num), 0);
+ if (ret)
+ goto error;
+ ret = regmap_update_bits(led->chip->regmap, AW2013_LCFG(num),
+ AW2013_LCFG_MD, 0);
+ }
+ if (ret)
+ goto error;
+
+ if (!aw2013_chip_in_use(led->chip))
+ aw2013_chip_disable(led->chip);
+
+error:
+ mutex_unlock(&led->chip->mutex);
+
+ return ret;
+}
+
+static int aw2013_blink_set(struct led_classdev *cdev,
+ unsigned long *delay_on, unsigned long *delay_off)
+{
+ struct aw2013_led *led = container_of(cdev, struct aw2013_led, cdev);
+ int ret, num = led->num;
+ unsigned long off = 0, on = 0;
+
+ /* If no blink specified, default to 1 Hz. */
+ if (!*delay_off && !*delay_on) {
+ *delay_off = 500;
+ *delay_on = 500;
+ }
+
+ if (!led->cdev.brightness) {
+ led->cdev.brightness = LED_FULL;
+ ret = aw2013_brightness_set(&led->cdev, led->cdev.brightness);
+ if (ret)
+ return ret;
+ }
+
+ /* Never on - just set to off */
+ if (!*delay_on) {
+ led->cdev.brightness = LED_OFF;
+ return aw2013_brightness_set(&led->cdev, LED_OFF);
+ }
+
+ mutex_lock(&led->chip->mutex);
+
+ /* Never off - brightness is already set, disable blinking */
+ if (!*delay_off) {
+ ret = regmap_update_bits(led->chip->regmap, AW2013_LCFG(num),
+ AW2013_LCFG_MD, 0);
+ goto out;
+ }
+
+ /* Convert into values the HW will understand. */
+ off = min(5, ilog2((*delay_off - 1) / AW2013_TIME_STEP) + 1);
+ on = min(7, ilog2((*delay_on - 1) / AW2013_TIME_STEP) + 1);
+
+ *delay_off = BIT(off) * AW2013_TIME_STEP;
+ *delay_on = BIT(on) * AW2013_TIME_STEP;
+
+ /* Set timings */
+ ret = regmap_write(led->chip->regmap,
+ AW2013_LEDT0(num), AW2013_LEDT0_T2(on));
+ if (ret)
+ goto out;
+ ret = regmap_write(led->chip->regmap,
+ AW2013_LEDT1(num), AW2013_LEDT1_T4(off));
+ if (ret)
+ goto out;
+
+ /* Finally, enable the LED */
+ ret = regmap_update_bits(led->chip->regmap, AW2013_LCFG(num),
+ AW2013_LCFG_MD, 0xFF);
+ if (ret)
+ goto out;
+
+ ret = regmap_update_bits(led->chip->regmap, AW2013_LCTR,
+ AW2013_LCTR_LE(num), 0xFF);
+
+out:
+ mutex_unlock(&led->chip->mutex);
+
+ return ret;
+}
+
+static int aw2013_probe_dt(struct aw2013 *chip)
+{
+ struct device_node *np = chip->client->dev.of_node, *child;
+ int count, ret = 0, i = 0;
+ struct aw2013_led *led;
+
+ count = of_get_child_count(np);
+ if (!count || count > AW2013_MAX_LEDS)
+ return -EINVAL;
+
+ regmap_write(chip->regmap, AW2013_RSTR, AW2013_RSTR_RESET);
+
+ for_each_available_child_of_node(np, child) {
+ struct led_init_data init_data = {};
+ u32 source;
+ u32 imax;
+
+ ret = of_property_read_u32(child, "reg", &source);
+ if (ret != 0 || source >= AW2013_MAX_LEDS) {
+ dev_err(&chip->client->dev,
+ "Couldn't read LED address: %d\n", ret);
+ count--;
+ continue;
+ }
+
+ led = &chip->leds[i];
+ led->num = source;
+ led->chip = chip;
+ init_data.fwnode = of_fwnode_handle(child);
+
+ if (!of_property_read_u32(child, "led-max-microamp", &imax)) {
+ led->imax = min_t(u32, imax / 5000, 3);
+ } else {
+ led->imax = 1; // 5mA
+ dev_info(&chip->client->dev,
+ "DT property led-max-microamp is missing\n");
+ }
+
+ of_property_read_string(child, "linux,default-trigger",
+ &led->cdev.default_trigger);
+
+ led->cdev.brightness_set_blocking = aw2013_brightness_set;
+ led->cdev.blink_set = aw2013_blink_set;
+
+ ret = devm_led_classdev_register_ext(&chip->client->dev,
+ &led->cdev, &init_data);
+ if (ret < 0)
+ return ret;
+
+ i++;
+ }
+
+ if (!count)
+ return -EINVAL;
+
+ chip->num_leds = i;
+
+ return 0;
+}
+
+static const struct regmap_config aw2013_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = AW2013_REG_MAX,
+};
+
+static int aw2013_probe(struct i2c_client *client)
+{
+ struct aw2013 *chip;
+ int ret;
+ unsigned int chipid;
+
+ chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ mutex_init(&chip->mutex);
+ mutex_lock(&chip->mutex);
+
+ chip->client = client;
+ i2c_set_clientdata(client, chip);
+
+ chip->regmap = devm_regmap_init_i2c(client, &aw2013_regmap_config);
+ if (IS_ERR(chip->regmap)) {
+ ret = PTR_ERR(chip->regmap);
+ dev_err(&client->dev, "Failed to allocate register map: %d\n",
+ ret);
+ goto error;
+ }
+
+ chip->vcc_regulator = devm_regulator_get(&client->dev, "vcc");
+ ret = PTR_ERR_OR_ZERO(chip->vcc_regulator);
+ if (ret) {
+ if (ret != -EPROBE_DEFER)
+ dev_err(&client->dev,
+ "Failed to request regulator: %d\n", ret);
+ goto error;
+ }
+
+ ret = regulator_enable(chip->vcc_regulator);
+ if (ret) {
+ dev_err(&client->dev,
+ "Failed to enable regulator: %d\n", ret);
+ goto error;
+ }
+
+ ret = regmap_read(chip->regmap, AW2013_RSTR, &chipid);
+ if (ret) {
+ dev_err(&client->dev, "Failed to read chip ID: %d\n",
+ ret);
+ goto error_reg;
+ }
+
+ if (chipid != AW2013_RSTR_CHIP_ID) {
+ dev_err(&client->dev, "Chip reported wrong ID: %x\n",
+ chipid);
+ ret = -ENODEV;
+ goto error_reg;
+ }
+
+ ret = aw2013_probe_dt(chip);
+ if (ret < 0)
+ goto error_reg;
+
+ ret = regulator_disable(chip->vcc_regulator);
+ if (ret) {
+ dev_err(&client->dev,
+ "Failed to disable regulator: %d\n", ret);
+ goto error;
+ }
+
+ mutex_unlock(&chip->mutex);
+
+ return 0;
+
+error_reg:
+ regulator_disable(chip->vcc_regulator);
+
+error:
+ mutex_destroy(&chip->mutex);
+ return ret;
+}
+
+static int aw2013_remove(struct i2c_client *client)
+{
+ struct aw2013 *chip = i2c_get_clientdata(client);
+
+ aw2013_chip_disable(chip);
+
+ mutex_destroy(&chip->mutex);
+
+ return 0;
+}
+
+static const struct of_device_id aw2013_match_table[] = {
+ { .compatible = "awinic,aw2013", },
+ { /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, aw2013_match_table);
+
+static struct i2c_driver aw2013_driver = {
+ .driver = {
+ .name = "leds-aw2013",
+ .of_match_table = of_match_ptr(aw2013_match_table),
+ },
+ .probe_new = aw2013_probe,
+ .remove = aw2013_remove,
+};
+
+module_i2c_driver(aw2013_driver);
+
+MODULE_AUTHOR("Nikita Travkin <nikitos.tr@xxxxxxxxx>");
+MODULE_DESCRIPTION("AW2013 LED driver");
+MODULE_LICENSE("GPL v2");
--
2.20.1

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