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

From: Jacek Anaszewski
Date: Thu Nov 30 2017 - 16:40:03 EST

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In reply to: Dan Murphy: "[PATCH v5 2/2] leds: lm3692x: Introduce LM3692x dual string driver"
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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)

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");
>

--
Best regards,
Jacek Anaszewski

Next message: Nguyen Phan Quang Minh: "[PATCH] staging: pi433: pi433_if.c Fix SET_CHECKED style issues"
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In reply to: Dan Murphy: "[PATCH v5 2/2] leds: lm3692x: Introduce LM3692x dual string driver"
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