Re: [PATCH v5 2/2] leds: lm3692x: Introduce LM3692x dual string driver

From: Dan Murphy
Date: Fri Dec 01 2017 - 11:34:59 EST

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Jacek

On 11/30/2017 03:38 PM, Jacek Anaszewski wrote:
> Dan,
>
> Thanks for addressing my remarks. LED class device name
> composition stills needs some tweaking, though.
>
> Please refer below to the piece of code in question.
>
> On 11/30/2017 08:22 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@xxxxxx>
>> ---
>> 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 | 396 ++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 404 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..70c974e06bd7
>> --- /dev/null
>> +++ b/drivers/leds/leds-lm3692x.c
>> @@ -0,0 +1,396 @@
>> +/*
>> + * TI lm3692x LED Driver
>> + *
>> + * Copyright (C) 2017 Texas Instruments
>> + *
>> + * Author: Dan Murphy <dmurphy@xxxxxx>
>> + *
>> + * 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>
>> +
>> +#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[32];
>> +};
>> +
>> +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;
>> + char trigger[32] = ":none";
>> +
>> + 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);
>> +
>> + if (led->led_dev.default_trigger)
>> + snprintf(trigger, sizeof(trigger), ":%s",
>> + led->led_dev.default_trigger);
>
> Let's not use trigger name for the LED function name. Trigger cannot
> define LED function, since LED class device can be assigned any
> other trigger at any time. Please drop above "if" statement.
>
>> +
>> + ret = of_property_read_string(child_node, "label", &name);
>> + if (!ret)
>> + strlcpy(led->label, name, sizeof(led->label));
>> + else
>> + snprintf(led->label, sizeof(led->label), "%s:white%s",
>> + np->name, trigger);
>
> You'll need to change label in your DT bindings example to:
>
> label = "white:backlight_cluster"
>
> and after that the LED class device name should be constructed like
> below. Sorry for not being precise enough.
>
> 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:white:backlight_cluster",
> np->name)
>
> You could even make this a generic LED core function e.g.
>
> void of_led_compose_name(struct device_node *parent,
> struct device_node *child)
>

New LED class API coming your way in v6 along with some other driver changes for examples

Dan

> It's up to you, I'm going to do that anyway when I'll find a moment.
>
>> + };
>> +
>> + 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@xxxxxx>");
>> +MODULE_LICENSE("GPL v2");
>>
>

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

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