[PATCH v4 2/2] leds: lm3697: Introduce the lm3697 driver

Dan Murphy
2018-08-16T17:20:58Z

Introduce the lm3697 LED driver for
backlighting and display.

Datasheet location:
http://www.ti.com/lit/ds/symlink/lm3697.pdf

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

v4 - Made modifications to the control bank routine to accomodate the DT changes
https://lore.kernel.org/patchwork/patch/974811/
v3 - Add code to support led-sources and control bank configuration also fix
other miscellaneous issues reported- https://lore.kernel.org/patchwork/patch/972336/
v2 - Removed unneed 'of' calls in dt_parse, fixed comment, fixed checkpatch
error, and change led registration - https://lore.kernel.org/patchwork/patch/971327/

drivers/leds/Kconfig | 9 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-lm3697.c | 381 +++++++++++++++++++++++++++++++++++++
3 files changed, 391 insertions(+)
create mode 100644 drivers/leds/leds-lm3697.c

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 44097a3e0fcc..784cbe375724 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -151,6 +151,15 @@ config LEDS_LM3642
converter plus 1.5A constant current driver for a high-current
white LED.

+config LEDS_LM3697
+ tristate "LED support for LM3697 Chip"
+ depends on LEDS_CLASS && I2C
+ select REGMAP_I2C
+ help
+ This option enables support for LEDs connected to LM3697.
+ The LM3697 is an 11 bit high performance backlight driver for
+ keypad and display lighting.
+
config LEDS_LM3692X
tristate "LED support for LM3692x Chips"
depends on LEDS_CLASS && I2C && OF
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 420b5d2cfa62..2813f089f3db 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_LEDS_LOCOMO) += leds-locomo.o
obj-$(CONFIG_LEDS_LM3530) += leds-lm3530.o
obj-$(CONFIG_LEDS_LM3533) += leds-lm3533.o
obj-$(CONFIG_LEDS_LM3642) += leds-lm3642.o
+obj-$(CONFIG_LEDS_LM3697) += leds-lm3697.o
obj-$(CONFIG_LEDS_MIKROTIK_RB532) += leds-rb532.o
obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
obj-$(CONFIG_LEDS_NET48XX) += leds-net48xx.o
diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
new file mode 100644
index 000000000000..390c6a928899
--- /dev/null
+++ b/drivers/leds/leds-lm3697.c
@@ -0,0 +1,381 @@
+// SPDX-License-Identifier: GPL-2.0
+// TI LM3697 LED chip family driver
+// Copyright (C) 2018 Texas Instruments Incorporated - http://www.ti.com/
+
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <uapi/linux/uleds.h>
+
+#define LM3697_REV 0x0
+#define LM3697_RESET 0x1
+#define LM3697_OUTPUT_CONFIG 0x10
+#define LM3697_CTRL_A_RAMP 0x11
+#define LM3697_CTRL_B_RAMP 0x12
+#define LM3697_CTRL_A_B_RT_RAMP 0x13
+#define LM3697_CTRL_A_B_RAMP_CFG 0x14
+#define LM3697_CTRL_A_B_BRT_CFG 0x16
+#define LM3697_CTRL_A_FS_CURR_CFG 0x17
+#define LM3697_CTRL_B_FS_CURR_CFG 0x18
+#define LM3697_PWM_CFG 0x1c
+#define LM3697_CTRL_A_BRT_LSB 0x20
+#define LM3697_CTRL_A_BRT_MSB 0x21
+#define LM3697_CTRL_B_BRT_LSB 0x22
+#define LM3697_CTRL_B_BRT_MSB 0x23
+#define LM3697_CTRL_ENABLE 0x24
+
+#define LM3697_SW_RESET BIT(0)
+
+#define LM3697_CTRL_A_EN BIT(0)
+#define LM3697_CTRL_B_EN BIT(1)
+#define LM3697_CTRL_A_B_EN (LM3697_CTRL_A_EN | LM3697_CTRL_B_EN)
+
+#define LM3697_MAX_LED_STRINGS 3
+
+#define LM3697_CONTROL_A 0
+#define LM3697_CONTROL_B 1
+#define LM3697_HVLED 1
+
+/**
+ * struct lm3697_led -
+ * @hvled_strings - Array of LED strings associated with a control bank
+ * @label - LED label
+ * @led_dev - LED class device
+ * @priv - Pointer to the device struct
+ * @control_bank - Control bank the LED is associated to. 0 is control bank A
+ * 1 is control bank B.
+ */
+struct lm3697_led {
+ u32 hvled_strings[LM3697_MAX_LED_STRINGS];
+ char label[LED_MAX_NAME_SIZE];
+ struct led_classdev led_dev;
+ struct lm3697 *priv;
+ int control_bank;
+};
+
+/**
+ * struct lm3697 -
+ * @enable_gpio - Hardware enable gpio
+ * @regulator - LED supply regulator pointer
+ * @client - Pointer to the I2C client
+ * @regmap - Devices register map
+ * @dev - Pointer to the devices device struct
+ * @lock - Lock for reading/writing the device
+ * @leds - Array of LED strings.
+ */
+struct lm3697 {
+ struct gpio_desc *enable_gpio;
+ struct regulator *regulator;
+ struct i2c_client *client;
+ struct regmap *regmap;
+ struct device *dev;
+ struct mutex lock;
+ struct lm3697_led leds[];
+};
+
+static const struct reg_default lm3697_reg_defs[] = {
+ {LM3697_OUTPUT_CONFIG, 0x6},
+ {LM3697_CTRL_A_RAMP, 0x0},
+ {LM3697_CTRL_B_RAMP, 0x0},
+ {LM3697_CTRL_A_B_RT_RAMP, 0x0},
+ {LM3697_CTRL_A_B_RAMP_CFG, 0x0},
+ {LM3697_CTRL_A_B_BRT_CFG, 0x0},
+ {LM3697_CTRL_A_FS_CURR_CFG, 0x13},
+ {LM3697_CTRL_B_FS_CURR_CFG, 0x13},
+ {LM3697_PWM_CFG, 0xc},
+ {LM3697_CTRL_A_BRT_LSB, 0x0},
+ {LM3697_CTRL_A_BRT_MSB, 0x0},
+ {LM3697_CTRL_B_BRT_LSB, 0x0},
+ {LM3697_CTRL_B_BRT_MSB, 0x0},
+ {LM3697_CTRL_ENABLE, 0x0},
+};
+
+static const struct regmap_config lm3697_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+
+ .max_register = LM3697_CTRL_ENABLE,
+ .reg_defaults = lm3697_reg_defs,
+ .num_reg_defaults = ARRAY_SIZE(lm3697_reg_defs),
+ .cache_type = REGCACHE_FLAT,
+};
+
+static int lm3697_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brt_val)
+{
+ struct lm3697_led *led = container_of(led_cdev, struct lm3697_led,
+ led_dev);
+ int brt_msb_reg, brt_lsb_reg, ctrl_en_val;
+ int led_brightness_lsb = (brt_val >> 5);
+ int ret;
+
+ mutex_lock(&led->priv->lock);
+
+ if (led->control_bank == LM3697_CONTROL_A) {
+ brt_msb_reg = LM3697_CTRL_A_BRT_MSB;
+ brt_lsb_reg = LM3697_CTRL_A_BRT_LSB;
+ ctrl_en_val = LM3697_CTRL_A_EN;
+ } else {
+ brt_msb_reg = LM3697_CTRL_B_BRT_MSB;
+ brt_lsb_reg = LM3697_CTRL_B_BRT_LSB;
+ ctrl_en_val = LM3697_CTRL_B_EN;
+ }
+
+ if (brt_val == LED_OFF)
+ ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
+ ctrl_en_val, ~ctrl_en_val);
+ else
+ ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
+ ctrl_en_val, ctrl_en_val);
+
+ if (ret) {
+ dev_err(&led->priv->client->dev, "Cannot write CTRL enable\n");
+ goto out;
+ }
+
+ ret = regmap_write(led->priv->regmap, brt_lsb_reg, led_brightness_lsb);
+ if (ret) {
+ dev_err(&led->priv->client->dev, "Cannot write LSB\n");
+ goto out;
+ }
+
+ ret = regmap_write(led->priv->regmap, brt_msb_reg, brt_val);
+ if (ret) {
+ dev_err(&led->priv->client->dev, "Cannot write MSB\n");
+ goto out;
+ }
+out:
+ mutex_unlock(&led->priv->lock);
+ return ret;
+}
+
+static int lm3697_set_control_bank(struct lm3697 *priv)
+{
+ u8 control_bank_config = 0;
+ struct lm3697_led *led;
+ int ret, i;
+
+ led = &priv->leds[0];
+ if (led->control_bank == LM3697_CONTROL_A)
+ led = &priv->leds[1];
+
+ for (i = 0; i < LM3697_MAX_LED_STRINGS; i++) {
+ if (led->hvled_strings[i] == LM3697_HVLED)
+ control_bank_config |= 1 << i;
+ }
+
+ ret = regmap_write(priv->regmap, LM3697_OUTPUT_CONFIG,
+ control_bank_config);
+ if (ret)
+ dev_err(&priv->client->dev, "Cannot write OUTPUT config\n");
+
+ return ret;
+}
+
+static int lm3697_init(struct lm3697 *priv)
+{
+ int ret;
+
+ if (priv->enable_gpio) {
+ gpiod_direction_output(priv->enable_gpio, 1);
+ } else {
+ ret = regmap_write(priv->regmap, LM3697_RESET, LM3697_SW_RESET);
+ if (ret) {
+ dev_err(&priv->client->dev, "Cannot reset the device\n");
+ goto out;
+ }
+ }
+
+ ret = regmap_write(priv->regmap, LM3697_CTRL_ENABLE, 0x0);
+ if (ret) {
+ dev_err(&priv->client->dev, "Cannot write ctrl enable\n");
+ goto out;
+ }
+
+ ret = lm3697_set_control_bank(priv);
+ if (ret)
+ dev_err(&priv->client->dev, "Setting the CRTL bank failed\n");
+
+out:
+ return ret;
+}
+
+static int lm3697_probe_dt(struct lm3697 *priv)
+{
+ struct fwnode_handle *child = NULL;
+ struct lm3697_led *led;
+ const char *name;
+ int control_bank;
+ size_t i = 0;
+ int ret;
+
+ priv->enable_gpio = devm_gpiod_get_optional(&priv->client->dev,
+ "enable", GPIOD_OUT_LOW);
+ if (IS_ERR(priv->enable_gpio)) {
+ ret = PTR_ERR(priv->enable_gpio);
+ dev_err(&priv->client->dev, "Failed to get enable gpio: %d\n",
+ ret);
+ return ret;
+ }
+
+ priv->regulator = devm_regulator_get(&priv->client->dev, "vled");
+ if (IS_ERR(priv->regulator))
+ priv->regulator = NULL;
+
+ device_for_each_child_node(priv->dev, child) {
+ ret = fwnode_property_read_u32(child, "reg", &control_bank);
+ if (ret) {
+ dev_err(&priv->client->dev, "reg property missing\n");
+ fwnode_handle_put(child);
+ goto child_out;
+ }
+
+ if (control_bank > LM3697_CONTROL_B) {
+ dev_err(&priv->client->dev, "reg property is invalid\n");
+ ret = -EINVAL;
+ fwnode_handle_put(child);
+ goto child_out;
+ }
+
+ led = &priv->leds[i];
+ led->control_bank = control_bank;
+ ret = fwnode_property_read_u32_array(child, "led-sources",
+ led->hvled_strings,
+ LM3697_MAX_LED_STRINGS);
+ if (ret) {
+ dev_err(&priv->client->dev, "led-sources property missing\n");
+ fwnode_handle_put(child);
+ goto child_out;
+ }
+
+ fwnode_property_read_string(child, "linux,default-trigger",
+ &led->led_dev.default_trigger);
+
+ ret = fwnode_property_read_string(child, "label", &name);
+ if (ret)
+ snprintf(led->label, sizeof(led->label),
+ "%s::", priv->client->name);
+ else
+ snprintf(led->label, sizeof(led->label),
+ "%s:%s", priv->client->name, name);
+
+ led->priv = priv;
+ led->led_dev.name = led->label;
+ led->led_dev.brightness_set_blocking = lm3697_brightness_set;
+
+ ret = devm_led_classdev_register(priv->dev, &led->led_dev);
+ if (ret) {
+ dev_err(&priv->client->dev, "led register err: %d\n",
+ ret);
+ fwnode_handle_put(child);
+ goto child_out;
+ }
+
+ i++;
+ }
+
+child_out:
+ return ret;
+}
+
+static int lm3697_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct lm3697 *led;
+ int count;
+ int ret;
+
+ count = device_get_child_node_count(&client->dev);
+ if (!count) {
+ dev_err(&client->dev, "LEDs are not defined in device tree!");
+ return -ENODEV;
+ }
+
+ led = devm_kzalloc(&client->dev, struct_size(led, leds, count),
+ GFP_KERNEL);
+ if (!led)
+ return -ENOMEM;
+
+ mutex_init(&led->lock);
+ i2c_set_clientdata(client, led);
+
+ led->client = client;
+ led->dev = &client->dev;
+ led->regmap = devm_regmap_init_i2c(client, &lm3697_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 = lm3697_probe_dt(led);
+ if (ret)
+ return ret;
+
+ ret = lm3697_init(led);
+
+ return ret;
+}
+
+static int lm3697_remove(struct i2c_client *client)
+{
+ struct lm3697 *led = i2c_get_clientdata(client);
+ int ret;
+
+ ret = regmap_update_bits(led->regmap, LM3697_CTRL_ENABLE,
+ LM3697_CTRL_A_B_EN, 0);
+ if (ret) {
+ dev_err(&led->client->dev, "Failed to disable the device\n");
+ return 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 lm3697_id[] = {
+ { "lm3697", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lm3697_id);
+
+static const struct of_device_id of_lm3697_leds_match[] = {
+ { .compatible = "ti,lm3697", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, of_lm3697_leds_match);
+
+static struct i2c_driver lm3697_driver = {
+ .driver = {
+ .name = "lm3697",
+ .of_match_table = of_lm3697_leds_match,
+ },
+ .probe = lm3697_probe,
+ .remove = lm3697_remove,
+ .id_table = lm3697_id,
+};
+module_i2c_driver(lm3697_driver);
+
+MODULE_DESCRIPTION("Texas Instruments LM3697 LED driver");
+MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
+MODULE_LICENSE("GPL v2");
--
2.17.0.582.gccdcbd54c