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

Dan Murphy
2018-08-16T20:44:48Z

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