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