Date:   Tue, 12 Dec 2017 12:03:46 -0600
From:   Dan Murphy <dmurphy@...com>
To:     <robh+dt@...nel.org>, <mark.rutland@....com>, <rpurdie@...ys.net>,
        <jacek.anaszewski@...il.com>, <pavel@....cz>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-leds@...r.kernel.org>
Subject: Re: [PATCH v10 2/2] leds: lm3692x: Introduce LM3692x dual string
 driver

One minor change

On 12/12/2017 11:00 AM, 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@...com>
> ---
> 
> v10 - No changes - https://patchwork.kernel.org/patch/10105651/
> 
> v9 - Change the no DT label case to pull the device name from the i2c_id struct
> so that the device name can be part of the sysfs node - https://patchwork.kernel.org/patch/10093759/
> v8 - No changes
> 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..7077f9459bce
> --- /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@...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);

This needs to be id->name like below

Dan

> +		else
> +		    snprintf(led->label, sizeof(led->label),
> +			     "%s::backlight_cluster", id->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@...com>");
> +MODULE_LICENSE("GPL v2");
> 


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

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