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 */
33 struct 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
lm36274_brightness_set(struct led_classdev * led_cdev,enum led_brightness brt_val)44 static 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
lm36274_init(struct lm36274 * chip)52 static 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
lm36274_parse_dt(struct lm36274 * chip,struct led_init_data * init_data)70 static 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;
102 err:
103 fwnode_handle_put(child);
104 return ret;
105 }
106
lm36274_probe(struct platform_device * pdev)107 static 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
155 static const struct of_device_id of_lm36274_leds_match[] = {
156 { .compatible = "ti,lm36274-backlight", },
157 {},
158 };
159 MODULE_DEVICE_TABLE(of, of_lm36274_leds_match);
160
161 static 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 };
168 module_platform_driver(lm36274_driver)
169
170 MODULE_DESCRIPTION("Texas Instruments LM36274 LED driver");
171 MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
172 MODULE_LICENSE("GPL v2");
173