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

[Dan Murphy <dmurphy@ti.com>]

Jacek

On 08/16/2018 02:58 PM, Jacek Anaszewski wrote:
> Dan,
> 
> Thank you for the patch.
> 
> I didn't review DT parsing details in v3, but now I've produced
> diff between v3 and v4 to check what has changed.
> 
> I'm quite surprised realizing that you're not validating
> HVLED and control banks assignment, having in mind earlier
> discussions and your concerns about numerous DT configurations
> to check.
> 
> Is it on purpose?
> 

Yes.  It was on purpose.  After sleeping on it and going through the overall
control to HVLED assignments I realized the user will know quite quickly
that their configuration is messed up.

The suggestions actually simplified the code quite nicely which I am happier to have


> Regardless of that - please find two nits below.
> 
> On 08/16/2018 07:20 PM, Dan Murphy wrote:
>> 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
> 
> s/LM3697_HVLED/LM3697_HVLED_ASSIGNED/
> 
> It will be more informative in this form.

Ack

> 
>> +
>> +/**
>> + * 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);
> 
> Let's simplify it:
> 
> return lm3697_init(led);

ACK

> 
>> +
>> +	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");
>>
> 


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