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linux/drivers/leds/leds-lm3697.c
Andy Shevchenko d299ae942e leds: lm3697: Make error handling more robust 
It's easy to miss necessary clean up, e.g. firmware node reference counting,
during error path in ->probe(). Make it more robust by moving to a single
point of return.

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Pavel Machek <pavel@ucw.cz>
2021-08-03 23:49:31 +02:00

393 lines
9.6 KiB
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// SPDX-License-Identifier: GPL-2.0
// TI LM3697 LED chip family driver
// Copyright (C) 2018 Texas Instruments Incorporated - https://www.ti.com/
#include <linux/bits.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/types.h>
#include <linux/leds-ti-lmu-common.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_MAX_CONTROL_BANKS 2
/**
* 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
* @lmu_data: Register and setting values for common code
* @control_bank: Control bank the LED is associated to. 0 is control bank A
* 1 is control bank B
* @enabled: LED brightness level (or LED_OFF)
* @num_leds: Number of LEDs available
*/
struct lm3697_led {
u32 hvled_strings[LM3697_MAX_LED_STRINGS];
char label[LED_MAX_NAME_SIZE];
struct led_classdev led_dev;
struct lm3697 *priv;
struct ti_lmu_bank lmu_data;
int control_bank;
int enabled;
int num_leds;
};
/**
* 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
* @bank_cfg: OUTPUT_CONFIG register values
* @num_banks: Number of control banks
*/
struct lm3697 {
struct gpio_desc *enable_gpio;
struct regulator *regulator;
struct i2c_client *client;
struct regmap *regmap;
struct device *dev;
struct mutex lock;
int bank_cfg;
int num_banks;
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 ctrl_en_val = (1 << led->control_bank);
struct device *dev = led->priv->dev;
int ret;
mutex_lock(&led->priv->lock);
if (brt_val == LED_OFF) {
ret = regmap_update_bits(led->priv->regmap, LM3697_CTRL_ENABLE,
ctrl_en_val, ~ctrl_en_val);
if (ret) {
dev_err(dev, "Cannot write ctrl register\n");
goto brightness_out;
}
led->enabled = LED_OFF;
} else {
ret = ti_lmu_common_set_brightness(&led->lmu_data, brt_val);
if (ret) {
dev_err(dev, "Cannot write brightness\n");
goto brightness_out;
}
if (!led->enabled) {
ret = regmap_update_bits(led->priv->regmap,
LM3697_CTRL_ENABLE,
ctrl_en_val, ctrl_en_val);
if (ret) {
dev_err(dev, "Cannot enable the device\n");
goto brightness_out;
}
led->enabled = brt_val;
}
}
brightness_out:
mutex_unlock(&led->priv->lock);
return ret;
}
static int lm3697_init(struct lm3697 *priv)
{
struct device *dev = priv->dev;
struct lm3697_led *led;
int i, 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(dev, "Cannot reset the device\n");
goto out;
}
}
ret = regmap_write(priv->regmap, LM3697_CTRL_ENABLE, 0x0);
if (ret) {
dev_err(dev, "Cannot write ctrl enable\n");
goto out;
}
ret = regmap_write(priv->regmap, LM3697_OUTPUT_CONFIG, priv->bank_cfg);
if (ret)
dev_err(dev, "Cannot write OUTPUT config\n");
for (i = 0; i < priv->num_banks; i++) {
led = &priv->leds[i];
ret = ti_lmu_common_set_ramp(&led->lmu_data);
if (ret)
dev_err(dev, "Setting the ramp rate failed\n");
}
out:
return ret;
}
static int lm3697_probe_dt(struct lm3697 *priv)
{
struct fwnode_handle *child = NULL;
struct device *dev = priv->dev;
struct lm3697_led *led;
int ret = -EINVAL;
int control_bank;
size_t i = 0;
int j;
priv->enable_gpio = devm_gpiod_get_optional(dev, "enable",
GPIOD_OUT_LOW);
if (IS_ERR(priv->enable_gpio))
return dev_err_probe(dev, PTR_ERR(priv->enable_gpio),
"Failed to get enable GPIO\n");
priv->regulator = devm_regulator_get(dev, "vled");
if (IS_ERR(priv->regulator))
priv->regulator = NULL;
device_for_each_child_node(dev, child) {
struct led_init_data init_data = {};
ret = fwnode_property_read_u32(child, "reg", &control_bank);
if (ret) {
dev_err(dev, "reg property missing\n");
goto child_out;
}
if (control_bank > LM3697_CONTROL_B) {
dev_err(dev, "reg property is invalid\n");
ret = -EINVAL;
goto child_out;
}
led = &priv->leds[i];
ret = ti_lmu_common_get_brt_res(dev, child, &led->lmu_data);
if (ret)
dev_warn(dev,
"brightness resolution property missing\n");
led->control_bank = control_bank;
led->lmu_data.regmap = priv->regmap;
led->lmu_data.runtime_ramp_reg = LM3697_CTRL_A_RAMP +
control_bank;
led->lmu_data.msb_brightness_reg = LM3697_CTRL_A_BRT_MSB +
led->control_bank * 2;
led->lmu_data.lsb_brightness_reg = LM3697_CTRL_A_BRT_LSB +
led->control_bank * 2;
led->num_leds = fwnode_property_count_u32(child, "led-sources");
if (led->num_leds > LM3697_MAX_LED_STRINGS) {
dev_err(dev, "Too many LED strings defined\n");
continue;
}
ret = fwnode_property_read_u32_array(child, "led-sources",
led->hvled_strings,
led->num_leds);
if (ret) {
dev_err(dev, "led-sources property missing\n");
goto child_out;
}
for (j = 0; j < led->num_leds; j++)
priv->bank_cfg |=
(led->control_bank << led->hvled_strings[j]);
ret = ti_lmu_common_get_ramp_params(dev, child, &led->lmu_data);
if (ret)
dev_warn(dev, "runtime-ramp properties missing\n");
init_data.fwnode = child;
init_data.devicename = priv->client->name;
/* for backwards compatibility if `label` is not present */
init_data.default_label = ":";
led->priv = priv;
led->led_dev.max_brightness = led->lmu_data.max_brightness;
led->led_dev.brightness_set_blocking = lm3697_brightness_set;
ret = devm_led_classdev_register_ext(dev, &led->led_dev,
&init_data);
if (ret) {
dev_err(dev, "led register err: %d\n", ret);
goto child_out;
}
i++;
}
return ret;
child_out:
fwnode_handle_put(child);
return ret;
}
static int lm3697_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct lm3697 *led;
int count;
int ret;
count = device_get_child_node_count(dev);
if (!count || count > LM3697_MAX_CONTROL_BANKS) {
dev_err(dev, "Strange device tree!");
return -ENODEV;
}
led = devm_kzalloc(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 = dev;
led->num_banks = count;
led->regmap = devm_regmap_init_i2c(client, &lm3697_regmap_config);
if (IS_ERR(led->regmap)) {
ret = PTR_ERR(led->regmap);
dev_err(dev, "Failed to allocate register map: %d\n", ret);
return ret;
}
ret = lm3697_probe_dt(led);
if (ret)
return ret;
return lm3697_init(led);
}
static int lm3697_remove(struct i2c_client *client)
{
struct lm3697 *led = i2c_get_clientdata(client);
struct device *dev = &led->client->dev;
int ret;
ret = regmap_update_bits(led->regmap, LM3697_CTRL_ENABLE,
LM3697_CTRL_A_B_EN, 0);
if (ret) {
dev_err(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(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");
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