xref: /openbmc/linux/drivers/leds/leds-lm36274.c (revision e90abb95)
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