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Subject[PATCH v7 2/2] leds: lm3692x: Introduce LM3692x dual string driver
Date
Introducing the LM3692x Dual-String white LED driver.

Data sheet is located
http://www.ti.com/lit/ds/snvsa29/snvsa29.pdf

Signed-off-by: Dan Murphy <dmurphy@ti.com>
---

v7 - Reverted back to creating the LED label within the driver -
https://patchwork.kernel.org/patch/10087473/

v6 - Use new LED API to compose LED label as opposed to creating it. -
https://patchwork.kernel.org/patch/10085565/
v5 - Added OF dependency in Kconfig, added extra fault flag read to ensure that
if a fault exists and it is not a artifact, fixed LED class label to be derived
from either the DT child "label" node or create a label based on
parent_node_name:led color:trigger, removed ifdef for CONFIG_OF and removed
of_match_ptr - https://patchwork.kernel.org/patch/10081073/
v4 - Converted to devm led class register, changed MODULE_LICENSE to GPL v2,
set the led name based on child node name or label entry, removed fault and
returned read_buf for fault checking, added mutex_destroy to remove function,
and removed LED_FULL - https://patchwork.kernel.org/patch/10060109/
v3 - Add missing Makefile and Kconfig from v1 and v2 - https://patchwork.kernel.org/patch/10060075/
v2 - Added data sheet link, fixed linuxdoc format, returned on failure in init
routine, return on fault_check failure, updated brightness calculation and
fixed capitalization issue - https://patchwork.kernel.org/patch/10056675/

drivers/leds/Kconfig | 7 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-lm3692x.c | 393 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 401 insertions(+)
create mode 100644 drivers/leds/leds-lm3692x.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 318a28fd58fe..1d215b39cefd 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -137,6 +137,13 @@ config LEDS_LM3642
converter plus 1.5A constant current driver for a high-current
white LED.

+config LEDS_LM3692X
+ tristate "LED support for LM3692x Chips"
+ depends on LEDS_CLASS && I2C && OF
+ select REGMAP_I2C
+ help
+ This option enables support for the TI LM3692x family
+ of white LED string drivers used for backlighting.

config LEDS_LOCOMO
tristate "LED Support for Locomo device"
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index a2a6b5a4f86d..987884a5b9a5 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -74,6 +74,7 @@ obj-$(CONFIG_LEDS_PM8058) += leds-pm8058.o
obj-$(CONFIG_LEDS_MLXCPLD) += leds-mlxcpld.o
obj-$(CONFIG_LEDS_NIC78BX) += leds-nic78bx.o
obj-$(CONFIG_LEDS_MT6323) += leds-mt6323.o
+obj-$(CONFIG_LEDS_LM3692X) += leds-lm3692x.o

# LED SPI Drivers
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
diff --git a/drivers/leds/leds-lm3692x.c b/drivers/leds/leds-lm3692x.c
new file mode 100644
index 000000000000..e18f12009612
--- /dev/null
+++ b/drivers/leds/leds-lm3692x.c
@@ -0,0 +1,393 @@
+/*
+ * TI lm3692x LED Driver
+ *
+ * Copyright (C) 2017 Texas Instruments
+ *
+ * Author: Dan Murphy <dmurphy@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * Data sheet is located
+ * http://www.ti.com/lit/ds/snvsa29/snvsa29.pdf
+ */
+
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/slab.h>
+#include <uapi/linux/uleds.h>
+
+#define LM3692X_REV 0x0
+#define LM3692X_RESET 0x1
+#define LM3692X_EN 0x10
+#define LM3692X_BRT_CTRL 0x11
+#define LM3692X_PWM_CTRL 0x12
+#define LM3692X_BOOST_CTRL 0x13
+#define LM3692X_AUTO_FREQ_HI 0x15
+#define LM3692X_AUTO_FREQ_LO 0x16
+#define LM3692X_BL_ADJ_THRESH 0x17
+#define LM3692X_BRT_LSB 0x18
+#define LM3692X_BRT_MSB 0x19
+#define LM3692X_FAULT_CTRL 0x1e
+#define LM3692X_FAULT_FLAGS 0x1f
+
+#define LM3692X_SW_RESET BIT(0)
+#define LM3692X_DEVICE_EN BIT(0)
+#define LM3692X_LED1_EN BIT(1)
+#define LM3692X_LED2_EN BIT(2)
+
+/* Brightness Control Bits */
+#define LM3692X_BL_ADJ_POL BIT(0)
+#define LM3692X_RAMP_RATE_125us 0x00
+#define LM3692X_RAMP_RATE_250us BIT(1)
+#define LM3692X_RAMP_RATE_500us BIT(2)
+#define LM3692X_RAMP_RATE_1ms (BIT(1) | BIT(2))
+#define LM3692X_RAMP_RATE_2ms BIT(3)
+#define LM3692X_RAMP_RATE_4ms (BIT(3) | BIT(1))
+#define LM3692X_RAMP_RATE_8ms (BIT(2) | BIT(3))
+#define LM3692X_RAMP_RATE_16ms (BIT(1) | BIT(2) | BIT(3))
+#define LM3692X_RAMP_EN BIT(4)
+#define LM3692X_BRHT_MODE_REG 0x00
+#define LM3692X_BRHT_MODE_PWM BIT(5)
+#define LM3692X_BRHT_MODE_MULTI_RAMP BIT(6)
+#define LM3692X_BRHT_MODE_RAMP_MULTI (BIT(5) | BIT(6))
+#define LM3692X_MAP_MODE_EXP BIT(7)
+
+/* PWM Register Bits */
+#define LM3692X_PWM_FILTER_100 BIT(0)
+#define LM3692X_PWM_FILTER_150 BIT(1)
+#define LM3692X_PWM_FILTER_200 (BIT(0) | BIT(1))
+#define LM3692X_PWM_HYSTER_1LSB BIT(2)
+#define LM3692X_PWM_HYSTER_2LSB BIT(3)
+#define LM3692X_PWM_HYSTER_3LSB (BIT(3) | BIT(2))
+#define LM3692X_PWM_HYSTER_4LSB BIT(4)
+#define LM3692X_PWM_HYSTER_5LSB (BIT(4) | BIT(2))
+#define LM3692X_PWM_HYSTER_6LSB (BIT(4) | BIT(3))
+#define LM3692X_PWM_POLARITY BIT(5)
+#define LM3692X_PWM_SAMP_4MHZ BIT(6)
+#define LM3692X_PWM_SAMP_24MHZ BIT(7)
+
+/* Boost Control Bits */
+#define LM3692X_OCP_PROT_1A BIT(0)
+#define LM3692X_OCP_PROT_1_25A BIT(1)
+#define LM3692X_OCP_PROT_1_5A (BIT(0) | BIT(1))
+#define LM3692X_OVP_21V BIT(2)
+#define LM3692X_OVP_25V BIT(3)
+#define LM3692X_OVP_29V (BIT(2) | BIT(3))
+#define LM3692X_MIN_IND_22UH BIT(4)
+#define LM3692X_BOOST_SW_1MHZ BIT(5)
+#define LM3692X_BOOST_SW_NO_SHIFT BIT(6)
+
+/* Fault Control Bits */
+#define LM3692X_FAULT_CTRL_OVP BIT(0)
+#define LM3692X_FAULT_CTRL_OCP BIT(1)
+#define LM3692X_FAULT_CTRL_TSD BIT(2)
+#define LM3692X_FAULT_CTRL_OPEN BIT(3)
+
+/* Fault Flag Bits */
+#define LM3692X_FAULT_FLAG_OVP BIT(0)
+#define LM3692X_FAULT_FLAG_OCP BIT(1)
+#define LM3692X_FAULT_FLAG_TSD BIT(2)
+#define LM3692X_FAULT_FLAG_SHRT BIT(3)
+#define LM3692X_FAULT_FLAG_OPEN BIT(4)
+
+/**
+ * struct lm3692x_led -
+ * @lock - Lock for reading/writing the device
+ * @client - Pointer to the I2C client
+ * @led_dev - LED class device pointer
+ * @regmap - Devices register map
+ * @enable_gpio - VDDIO/EN gpio to enable communication interface
+ * @regulator - LED supply regulator pointer
+ * @label - LED label
+ */
+struct lm3692x_led {
+ struct mutex lock;
+ struct i2c_client *client;
+ struct led_classdev led_dev;
+ struct regmap *regmap;
+ struct gpio_desc *enable_gpio;
+ struct regulator *regulator;
+ char label[LED_MAX_NAME_SIZE];
+};
+
+static const struct reg_default lm3692x_reg_defs[] = {
+ {LM3692X_EN, 0xf},
+ {LM3692X_BRT_CTRL, 0x61},
+ {LM3692X_PWM_CTRL, 0x73},
+ {LM3692X_BOOST_CTRL, 0x6f},
+ {LM3692X_AUTO_FREQ_HI, 0x0},
+ {LM3692X_AUTO_FREQ_LO, 0x0},
+ {LM3692X_BL_ADJ_THRESH, 0x0},
+ {LM3692X_BRT_LSB, 0x7},
+ {LM3692X_BRT_MSB, 0xff},
+ {LM3692X_FAULT_CTRL, 0x7},
+};
+
+static const struct regmap_config lm3692x_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+
+ .max_register = LM3692X_FAULT_FLAGS,
+ .reg_defaults = lm3692x_reg_defs,
+ .num_reg_defaults = ARRAY_SIZE(lm3692x_reg_defs),
+ .cache_type = REGCACHE_RBTREE,
+};
+
+static int lm3692x_fault_check(struct lm3692x_led *led)
+{
+ int ret;
+ unsigned int read_buf;
+
+ ret = regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
+ if (ret)
+ return ret;
+
+ if (read_buf)
+ dev_err(&led->client->dev, "Detected a fault 0x%X\n", read_buf);
+
+ /* The first read may clear the fault. Check again to see if the fault
+ * still exits and return that value.
+ */
+ regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
+ if (read_buf)
+ dev_err(&led->client->dev, "Second read of fault flags 0x%X\n",
+ read_buf);
+
+ return read_buf;
+}
+
+static int lm3692x_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brt_val)
+{
+ struct lm3692x_led *led =
+ container_of(led_cdev, struct lm3692x_led, led_dev);
+ int ret;
+ int led_brightness_lsb = (brt_val >> 5);
+
+ mutex_lock(&led->lock);
+
+ ret = lm3692x_fault_check(led);
+ if (ret) {
+ dev_err(&led->client->dev, "Cannot read/clear faults\n");
+ goto out;
+ }
+
+ ret = regmap_write(led->regmap, LM3692X_BRT_MSB, brt_val);
+ if (ret) {
+ dev_err(&led->client->dev, "Cannot write MSB\n");
+ goto out;
+ }
+
+ ret = regmap_write(led->regmap, LM3692X_BRT_LSB, led_brightness_lsb);
+ if (ret) {
+ dev_err(&led->client->dev, "Cannot write LSB\n");
+ goto out;
+ }
+out:
+ mutex_unlock(&led->lock);
+ return ret;
+}
+
+static int lm3692x_init(struct lm3692x_led *led)
+{
+ int ret;
+
+ if (led->regulator) {
+ ret = regulator_enable(led->regulator);
+ if (ret) {
+ dev_err(&led->client->dev,
+ "Failed to enable regulator\n");
+ return ret;
+ }
+ }
+
+ if (led->enable_gpio)
+ gpiod_direction_output(led->enable_gpio, 1);
+
+ ret = lm3692x_fault_check(led);
+ if (ret) {
+ dev_err(&led->client->dev, "Cannot read/clear faults\n");
+ goto out;
+ }
+
+ ret = regmap_write(led->regmap, LM3692X_BRT_CTRL, 0x00);
+ if (ret)
+ goto out;
+
+ /*
+ * For glitch free operation, the following data should
+ * only be written while device enable bit is 0
+ * per Section 7.5.14 of the data sheet
+ */
+ ret = regmap_write(led->regmap, LM3692X_PWM_CTRL,
+ LM3692X_PWM_FILTER_100 | LM3692X_PWM_SAMP_24MHZ);
+ if (ret)
+ goto out;
+
+ ret = regmap_write(led->regmap, LM3692X_BOOST_CTRL,
+ LM3692X_BRHT_MODE_RAMP_MULTI |
+ LM3692X_BL_ADJ_POL |
+ LM3692X_RAMP_RATE_250us);
+ if (ret)
+ goto out;
+
+ ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_HI, 0x00);
+ if (ret)
+ goto out;
+
+ ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_LO, 0x00);
+ if (ret)
+ goto out;
+
+ ret = regmap_write(led->regmap, LM3692X_BL_ADJ_THRESH, 0x00);
+ if (ret)
+ goto out;
+
+ ret = regmap_write(led->regmap, LM3692X_BRT_CTRL,
+ LM3692X_BL_ADJ_POL | LM3692X_PWM_HYSTER_4LSB);
+ if (ret)
+ goto out;
+
+ return ret;
+out:
+ dev_err(&led->client->dev, "Fail writing initialization values\n");
+
+ if (led->enable_gpio)
+ gpiod_direction_output(led->enable_gpio, 0);
+
+ if (led->regulator) {
+ ret = regulator_disable(led->regulator);
+ if (ret)
+ dev_err(&led->client->dev,
+ "Failed to disable regulator\n");
+ }
+
+ return ret;
+}
+
+static int lm3692x_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int ret;
+ struct lm3692x_led *led;
+ struct device_node *np = client->dev.of_node;
+ struct device_node *child_node;
+ const char *name;
+
+ led = devm_kzalloc(&client->dev, sizeof(*led), GFP_KERNEL);
+ if (!led)
+ return -ENOMEM;
+
+ for_each_available_child_of_node(np, child_node) {
+ led->led_dev.default_trigger = of_get_property(child_node,
+ "linux,default-trigger",
+ NULL);
+
+ ret = of_property_read_string(child_node, "label", &name);
+ if (!ret)
+ snprintf(led->label, sizeof(led->label), "%s:%s",
+ np->name, name);
+ else
+ snprintf(led->label, sizeof(led->label),
+ "%s::backlight_cluster", np->name);
+ };
+
+ led->enable_gpio = devm_gpiod_get_optional(&client->dev,
+ "enable", GPIOD_OUT_LOW);
+ if (IS_ERR(led->enable_gpio)) {
+ ret = PTR_ERR(led->enable_gpio);
+ dev_err(&client->dev, "Failed to get enable gpio: %d\n", ret);
+ return ret;
+ }
+
+ led->regulator = devm_regulator_get(&client->dev, "vled");
+ if (IS_ERR(led->regulator))
+ led->regulator = NULL;
+
+ led->client = client;
+ led->led_dev.name = led->label;
+ led->led_dev.brightness_set_blocking = lm3692x_brightness_set;
+
+ mutex_init(&led->lock);
+
+ i2c_set_clientdata(client, led);
+
+ led->regmap = devm_regmap_init_i2c(client, &lm3692x_regmap_config);
+ if (IS_ERR(led->regmap)) {
+ ret = PTR_ERR(led->regmap);
+ dev_err(&client->dev, "Failed to allocate register map: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = lm3692x_init(led);
+ if (ret)
+ return ret;
+
+ ret = devm_led_classdev_register(&client->dev, &led->led_dev);
+ if (ret) {
+ dev_err(&client->dev, "led register err: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int lm3692x_remove(struct i2c_client *client)
+{
+ struct lm3692x_led *led = i2c_get_clientdata(client);
+ int ret;
+
+ if (led->enable_gpio)
+ gpiod_direction_output(led->enable_gpio, 0);
+
+ if (led->regulator) {
+ ret = regulator_disable(led->regulator);
+ if (ret)
+ dev_err(&led->client->dev,
+ "Failed to disable regulator\n");
+ }
+
+ mutex_destroy(&led->lock);
+
+ return 0;
+}
+
+static const struct i2c_device_id lm3692x_id[] = {
+ { "lm36922", 0 },
+ { "lm36923", 1 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lm3692x_id);
+
+static const struct of_device_id of_lm3692x_leds_match[] = {
+ { .compatible = "ti,lm36922", },
+ { .compatible = "ti,lm36923", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_lm3692x_leds_match);
+
+static struct i2c_driver lm3692x_driver = {
+ .driver = {
+ .name = "lm3692x",
+ .of_match_table = of_lm3692x_leds_match,
+ },
+ .probe = lm3692x_probe,
+ .remove = lm3692x_remove,
+ .id_table = lm3692x_id,
+};
+module_i2c_driver(lm3692x_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LM3692X LED driver");
+MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
+MODULE_LICENSE("GPL v2");
--
2.15.0.124.g7668cbc60
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