xref: /openbmc/linux/drivers/leds/leds-cpcap.c (revision 3192f141)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (c) 2017 Sebastian Reichel <sre@kernel.org>
4  */
5 
6 #include <linux/leds.h>
7 #include <linux/mfd/motorola-cpcap.h>
8 #include <linux/module.h>
9 #include <linux/mutex.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 #include <linux/regulator/consumer.h>
14 
15 #define CPCAP_LED_NO_CURRENT 0x0001
16 
17 struct cpcap_led_info {
18 	u16 reg;
19 	u16 mask;
20 	u16 limit;
21 	u16 init_mask;
22 	u16 init_val;
23 };
24 
25 static const struct cpcap_led_info cpcap_led_red = {
26 	.reg	= CPCAP_REG_REDC,
27 	.mask	= 0x03FF,
28 	.limit	= 31,
29 };
30 
31 static const struct cpcap_led_info cpcap_led_green = {
32 	.reg	= CPCAP_REG_GREENC,
33 	.mask	= 0x03FF,
34 	.limit	= 31,
35 };
36 
37 static const struct cpcap_led_info cpcap_led_blue = {
38 	.reg	= CPCAP_REG_BLUEC,
39 	.mask	= 0x03FF,
40 	.limit	= 31,
41 };
42 
43 /* aux display light */
44 static const struct cpcap_led_info cpcap_led_adl = {
45 	.reg		= CPCAP_REG_ADLC,
46 	.mask		= 0x000F,
47 	.limit		= 1,
48 	.init_mask	= 0x7FFF,
49 	.init_val	= 0x5FF0,
50 };
51 
52 /* camera privacy led */
53 static const struct cpcap_led_info cpcap_led_cp = {
54 	.reg		= CPCAP_REG_CLEDC,
55 	.mask		= 0x0007,
56 	.limit		= 1,
57 	.init_mask	= 0x03FF,
58 	.init_val	= 0x0008,
59 };
60 
61 struct cpcap_led {
62 	struct led_classdev led;
63 	const struct cpcap_led_info *info;
64 	struct device *dev;
65 	struct regmap *regmap;
66 	struct mutex update_lock;
67 	struct regulator *vdd;
68 	bool powered;
69 
70 	u32 current_limit;
71 };
72 
cpcap_led_val(u8 current_limit,u8 duty_cycle)73 static u16 cpcap_led_val(u8 current_limit, u8 duty_cycle)
74 {
75 	current_limit &= 0x1f; /* 5 bit */
76 	duty_cycle &= 0x0f; /* 4 bit */
77 
78 	return current_limit << 4 | duty_cycle;
79 }
80 
cpcap_led_set_power(struct cpcap_led * led,bool status)81 static int cpcap_led_set_power(struct cpcap_led *led, bool status)
82 {
83 	int err;
84 
85 	if (status == led->powered)
86 		return 0;
87 
88 	if (status)
89 		err = regulator_enable(led->vdd);
90 	else
91 		err = regulator_disable(led->vdd);
92 
93 	if (err) {
94 		dev_err(led->dev, "regulator failure: %d", err);
95 		return err;
96 	}
97 
98 	led->powered = status;
99 
100 	return 0;
101 }
102 
cpcap_led_set(struct led_classdev * ledc,enum led_brightness value)103 static int cpcap_led_set(struct led_classdev *ledc, enum led_brightness value)
104 {
105 	struct cpcap_led *led = container_of(ledc, struct cpcap_led, led);
106 	int brightness;
107 	int err;
108 
109 	mutex_lock(&led->update_lock);
110 
111 	if (value > LED_OFF) {
112 		err = cpcap_led_set_power(led, true);
113 		if (err)
114 			goto exit;
115 	}
116 
117 	if (value == LED_OFF) {
118 		/* Avoid HW issue by turning off current before duty cycle */
119 		err = regmap_update_bits(led->regmap,
120 			led->info->reg, led->info->mask, CPCAP_LED_NO_CURRENT);
121 		if (err) {
122 			dev_err(led->dev, "regmap failed: %d", err);
123 			goto exit;
124 		}
125 
126 		brightness = cpcap_led_val(value, LED_OFF);
127 	} else {
128 		brightness = cpcap_led_val(value, LED_ON);
129 	}
130 
131 	err = regmap_update_bits(led->regmap, led->info->reg, led->info->mask,
132 		brightness);
133 	if (err) {
134 		dev_err(led->dev, "regmap failed: %d", err);
135 		goto exit;
136 	}
137 
138 	if (value == LED_OFF) {
139 		err = cpcap_led_set_power(led, false);
140 		if (err)
141 			goto exit;
142 	}
143 
144 exit:
145 	mutex_unlock(&led->update_lock);
146 	return err;
147 }
148 
149 static const struct of_device_id cpcap_led_of_match[] = {
150 	{ .compatible = "motorola,cpcap-led-red", .data = &cpcap_led_red },
151 	{ .compatible = "motorola,cpcap-led-green", .data = &cpcap_led_green },
152 	{ .compatible = "motorola,cpcap-led-blue",  .data = &cpcap_led_blue },
153 	{ .compatible = "motorola,cpcap-led-adl", .data = &cpcap_led_adl },
154 	{ .compatible = "motorola,cpcap-led-cp", .data = &cpcap_led_cp },
155 	{},
156 };
157 MODULE_DEVICE_TABLE(of, cpcap_led_of_match);
158 
cpcap_led_probe(struct platform_device * pdev)159 static int cpcap_led_probe(struct platform_device *pdev)
160 {
161 	struct cpcap_led *led;
162 	int err;
163 
164 	led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
165 	if (!led)
166 		return -ENOMEM;
167 	platform_set_drvdata(pdev, led);
168 	led->info = device_get_match_data(&pdev->dev);
169 	led->dev = &pdev->dev;
170 
171 	if (led->info->reg == 0x0000) {
172 		dev_err(led->dev, "Unsupported LED");
173 		return -ENODEV;
174 	}
175 
176 	led->regmap = dev_get_regmap(pdev->dev.parent, NULL);
177 	if (!led->regmap)
178 		return -ENODEV;
179 
180 	led->vdd = devm_regulator_get(&pdev->dev, "vdd");
181 	if (IS_ERR(led->vdd)) {
182 		err = PTR_ERR(led->vdd);
183 		dev_err(led->dev, "Couldn't get regulator: %d", err);
184 		return err;
185 	}
186 
187 	err = device_property_read_string(&pdev->dev, "label", &led->led.name);
188 	if (err) {
189 		dev_err(led->dev, "Couldn't read LED label: %d", err);
190 		return err;
191 	}
192 
193 	if (led->info->init_mask) {
194 		err = regmap_update_bits(led->regmap, led->info->reg,
195 			led->info->init_mask, led->info->init_val);
196 		if (err) {
197 			dev_err(led->dev, "regmap failed: %d", err);
198 			return err;
199 		}
200 	}
201 
202 	mutex_init(&led->update_lock);
203 
204 	led->led.max_brightness = led->info->limit;
205 	led->led.brightness_set_blocking = cpcap_led_set;
206 	err = devm_led_classdev_register(&pdev->dev, &led->led);
207 	if (err) {
208 		dev_err(led->dev, "Couldn't register LED: %d", err);
209 		return err;
210 	}
211 
212 	return 0;
213 }
214 
215 static struct platform_driver cpcap_led_driver = {
216 	.probe = cpcap_led_probe,
217 	.driver = {
218 		.name = "cpcap-led",
219 		.of_match_table = cpcap_led_of_match,
220 	},
221 };
222 module_platform_driver(cpcap_led_driver);
223 
224 MODULE_DESCRIPTION("CPCAP LED driver");
225 MODULE_AUTHOR("Sebastian Reichel <sre@kernel.org>");
226 MODULE_LICENSE("GPL");
227