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    SubjectRe: [PATCH 2/2] leds: lm3692x: Introduce LM3692x dual string driver
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    On 11/13/2017 02:50 PM, Dan Murphy wrote:
    > 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>
    > ---
    > drivers/leds/leds-lm3692x.c | 380 ++++++++++++++++++++++++++++++++++++++++++++
    > 1 file changed, 380 insertions(+)
    > create mode 100644 drivers/leds/leds-lm3692x.c
    >
    > diff --git a/drivers/leds/leds-lm3692x.c b/drivers/leds/leds-lm3692x.c
    > new file mode 100644
    > index 000000000000..beb753abc7b0
    > --- /dev/null
    > +++ b/drivers/leds/leds-lm3692x.c
    > @@ -0,0 +1,380 @@
    > +/*
    > + * 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.
    > + *
    > + */
    > +
    > +#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>
    > +
    > +#define LM3692X_LED_NAME "lm3692x_led"
    > +
    > +#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;
    > + const char *label;
    > +};
    > +
    > +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, fault;
    > + unsigned int read_buf;
    > +
    > + ret = regmap_read(led->regmap, LM3692X_FAULT_FLAGS, &read_buf);
    > + if (ret)
    > + goto out;
    > +
    > + fault = read_buf;
    > +
    > + if (fault)
    > + dev_err(&led->client->dev, "Detected a fault 0x%X\n",
    > + fault);
    > +out:
    > + return ret;
    > +}
    > +
    > +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 led_brightness = (brt_val << 4) + 7;

    After a peer review with the hardware team it was determined that the brightness value
    calculation always sets the LSB to a value of 7. Therefore this will be changed in patch
    v2 so that the MSB will contain the brt_val and the LSB will contain the 3 MSB bits of the
    brt_val.

    So the values will look something like this:

    Code 0x00 thru code 0x1f --> LSB = 0
    Code 0x20 thru code 0x3f --> LSB = 1, 0x101 up to 0x1f9
    Code 0x40 thru code 0x5f --> LSB = 2, 0x202 up to 0x2fa
    Code 0x60 thru code 0x7f --> LSB = 3, 0x303 thru 0x3fb
    Code 0x80 thru code 0x9f --> LSB = 4, 0x404 thru 0x4fc
    .
    .
    Code 0xe0 thru code 0xff --> LSB = 7, 0x707 thru 0x7ff

    > + int ret;
    > +
    > + if (brt_val == LED_OFF)
    > + led_brightness = 0;
    > +
    > + 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,
    > + (led_brightness & 0xff0) >> 4);
    > + if (ret) {
    > + dev_err(&led->client->dev, "Cannot write MSB\n");
    > + goto out;
    > + }
    > +
    > + ret = regmap_write(led->regmap, LM3692X_BRT_LSB,
    > + led_brightness & 0x07);
    > + 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");
    > + }
    > +
    > + 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)
    > + dev_err(&led->client->dev, "Fail writing BRT CTRL\n");
    > + /*
    > + * 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)
    > + dev_err(&led->client->dev, "Failed programming PWM CTRL\n");
    > +
    > + ret = regmap_write(led->regmap, LM3692X_BOOST_CTRL,
    > + LM3692X_BRHT_MODE_RAMP_MULTI |
    > + LM3692X_BL_ADJ_POL |
    > + LM3692X_RAMP_RATE_250us);
    > + if (ret)
    > + dev_err(&led->client->dev, "Failed programming BOOST CTRL\n");
    > +
    > + ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_HI, 0x00);
    > + if (ret)
    > + dev_err(&led->client->dev, "Failed programming AUTO HI FREQ\n");
    > +
    > + ret = regmap_write(led->regmap, LM3692X_AUTO_FREQ_LO, 0x00);
    > + if (ret)
    > + dev_err(&led->client->dev, "Failed programming AUTO LO FREQ\n");
    > +
    > +
    > + ret = regmap_write(led->regmap, LM3692X_BL_ADJ_THRESH, 0x00);
    > + if (ret)
    > + dev_err(&led->client->dev, "Failed programming BL Threshold\n");
    > +
    > + ret = regmap_write(led->regmap, LM3692X_BRT_CTRL,
    > + LM3692X_BL_ADJ_POL | LM3692X_PWM_HYSTER_4LSB);
    > + if (ret)
    > + dev_err(&led->client->dev, "Failed programming BRT CTRL\n");
    > +
    > + return ret;
    > +out:
    > +
    > + 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;
    > +
    > + led = devm_kzalloc(&client->dev, sizeof(*led), GFP_KERNEL);
    > + if (!led)
    > + return -ENOMEM;
    > +
    > + if (client->dev.of_node) {
    > + ret = of_property_read_string(np, "label", &led->label);
    > + if (ret)
    > + led->label = LM3692X_LED_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.max_brightness = LED_FULL;
    > + 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 = 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;
    > +
    > + led_classdev_unregister(&led->led_dev);
    > +
    > + 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 0;
    > +}
    > +
    > +static const struct i2c_device_id lm3692x_id[] = {
    > + { "lm3692x", 0 },
    > + { }
    > +};
    > +MODULE_DEVICE_TABLE(i2c, lm3692x_id);
    > +
    > +#ifdef CONFIG_OF
    > +static const struct of_device_id of_lm3692x_leds_match[] = {
    > + { .compatible = "ti,lm3692x", },
    > + {},
    > +};
    > +MODULE_DEVICE_TABLE(of, of_lm3692x_leds_match);
    > +#endif
    > +
    > +static struct i2c_driver lm3692x_driver = {
    > + .driver = {
    > + .name = "lm3692x",
    > + .of_match_table = of_match_ptr(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");
    >


    --
    ------------------
    Dan Murphy

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