1// SPDX-License-Identifier: GPL-2.0
  2// TI LM36274 LED chip family driver
  3// Copyright (C) 2019 Texas Instruments Incorporated - https://www.ti.com/
  4
  5#include <linux/bitops.h>
  6#include <linux/device.h>
  7#include <linux/err.h>
  8#include <linux/leds.h>
  9#include <linux/leds-ti-lmu-common.h>
 10#include <linux/mod_devicetable.h>
 11#include <linux/module.h>
 12#include <linux/platform_device.h>
 13#include <linux/property.h>
 14
 15#include <linux/mfd/ti-lmu.h>
 16#include <linux/mfd/ti-lmu-register.h>
 17
 18#include <uapi/linux/uleds.h>
 19
 20#define LM36274_MAX_STRINGS	4
 21#define LM36274_BL_EN		BIT(4)
 22
 23/**
 24 * struct lm36274
 25 * @pdev: platform device
 26 * @led_dev: led class device
 27 * @lmu_data: Register and setting values for common code
 28 * @regmap: Devices register map
 29 * @dev: Pointer to the devices device struct
 30 * @led_sources: The LED strings supported in this array
 31 * @num_leds: Number of LED strings are supported in this array
 32 */
 33struct lm36274 {
 34	struct platform_device *pdev;
 35	struct led_classdev led_dev;
 36	struct ti_lmu_bank lmu_data;
 37	struct regmap *regmap;
 38	struct device *dev;
 39
 40	u32 led_sources[LM36274_MAX_STRINGS];
 41	int num_leds;
 42};
 43
 44static int lm36274_brightness_set(struct led_classdev *led_cdev,
 45				  enum led_brightness brt_val)
 46{
 47	struct lm36274 *chip = container_of(led_cdev, struct lm36274, led_dev);
 48
 49	return ti_lmu_common_set_brightness(&chip->lmu_data, brt_val);
 50}
 51
 52static int lm36274_init(struct lm36274 *chip)
 53{
 54	int enable_val = 0;
 55	int i;
 56
 57	for (i = 0; i < chip->num_leds; i++)
 58		enable_val |= (1 << chip->led_sources[i]);
 59
 60	if (!enable_val) {
 61		dev_err(chip->dev, "No LEDs were enabled\n");
 62		return -EINVAL;
 63	}
 64
 65	enable_val |= LM36274_BL_EN;
 66
 67	return regmap_write(chip->regmap, LM36274_REG_BL_EN, enable_val);
 68}
 69
 70static int lm36274_parse_dt(struct lm36274 *chip,
 71			    struct led_init_data *init_data)
 72{
 73	struct device *dev = chip->dev;
 74	struct fwnode_handle *child;
 75	int ret;
 76
 77	/* There should only be 1 node */
 78	if (device_get_child_node_count(dev) != 1)
 79		return -EINVAL;
 80
 81	child = device_get_next_child_node(dev, NULL);
 82
 83	init_data->fwnode = child;
 84	init_data->devicename = chip->pdev->name;
 85	/* for backwards compatibility when `label` property is not present */
 86	init_data->default_label = ":";
 87
 88	chip->num_leds = fwnode_property_count_u32(child, "led-sources");
 89	if (chip->num_leds <= 0) {
 90		ret = -ENODEV;
 91		goto err;
 92	}
 93
 94	ret = fwnode_property_read_u32_array(child, "led-sources",
 95					     chip->led_sources, chip->num_leds);
 96	if (ret) {
 97		dev_err(dev, "led-sources property missing\n");
 98		goto err;
 99	}
100
101	return 0;
102err:
103	fwnode_handle_put(child);
104	return ret;
105}
106
107static int lm36274_probe(struct platform_device *pdev)
108{
109	struct ti_lmu *lmu = dev_get_drvdata(pdev->dev.parent);
110	struct led_init_data init_data = {};
111	struct lm36274 *chip;
112	int ret;
113
114	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
115	if (!chip)
116		return -ENOMEM;
117
118	chip->pdev = pdev;
119	chip->dev = &pdev->dev;
120	chip->regmap = lmu->regmap;
121	platform_set_drvdata(pdev, chip);
122
123	ret = lm36274_parse_dt(chip, &init_data);
124	if (ret) {
125		dev_err(chip->dev, "Failed to parse DT node\n");
126		return ret;
127	}
128
129	ret = lm36274_init(chip);
130	if (ret) {
131		fwnode_handle_put(init_data.fwnode);
132		dev_err(chip->dev, "Failed to init the device\n");
133		return ret;
134	}
135
136	chip->lmu_data.regmap = chip->regmap;
137	chip->lmu_data.max_brightness = MAX_BRIGHTNESS_11BIT;
138	chip->lmu_data.msb_brightness_reg = LM36274_REG_BRT_MSB;
139	chip->lmu_data.lsb_brightness_reg = LM36274_REG_BRT_LSB;
140
141	chip->led_dev.max_brightness = MAX_BRIGHTNESS_11BIT;
142	chip->led_dev.brightness_set_blocking = lm36274_brightness_set;
143
144	ret = devm_led_classdev_register_ext(chip->dev, &chip->led_dev,
145					     &init_data);
146	if (ret)
147		dev_err(chip->dev, "Failed to register LED for node %pfw\n",
148			init_data.fwnode);
149
150	fwnode_handle_put(init_data.fwnode);
151
152	return ret;
153}
154
155static const struct of_device_id of_lm36274_leds_match[] = {
156	{ .compatible = "ti,lm36274-backlight", },
157	{},
158};
159MODULE_DEVICE_TABLE(of, of_lm36274_leds_match);
160
161static struct platform_driver lm36274_driver = {
162	.probe  = lm36274_probe,
163	.driver = {
164		.name = "lm36274-leds",
165		.of_match_table = of_lm36274_leds_match,
166	},
167};
168module_platform_driver(lm36274_driver)
169
170MODULE_DESCRIPTION("Texas Instruments LM36274 LED driver");
171MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
172MODULE_LICENSE("GPL v2");