xref: /openbmc/linux/drivers/leds/leds-acer-a500.c (revision 2cf1c348)
1 // SPDX-License-Identifier: GPL-2.0+
2 
3 #include <linux/leds.h>
4 #include <linux/module.h>
5 #include <linux/platform_device.h>
6 #include <linux/regmap.h>
7 
8 #define A500_EC_LED_DELAY_USEC	(100 * 1000)
9 
10 enum {
11 	REG_RESET_LEDS = 0x40,
12 	REG_POWER_LED_ON = 0x42,
13 	REG_CHARGE_LED_ON = 0x43,
14 	REG_ANDROID_LEDS_OFF = 0x5a,
15 };
16 
17 struct a500_led {
18 	struct led_classdev cdev;
19 	const struct reg_sequence *enable_seq;
20 	struct a500_led *other;
21 	struct regmap *rmap;
22 };
23 
24 static const struct reg_sequence a500_ec_leds_reset_seq[] = {
25 	REG_SEQ(REG_RESET_LEDS, 0x0, A500_EC_LED_DELAY_USEC),
26 	REG_SEQ(REG_ANDROID_LEDS_OFF, 0x0, A500_EC_LED_DELAY_USEC),
27 };
28 
29 static const struct reg_sequence a500_ec_white_led_enable_seq[] = {
30 	REG_SEQ(REG_POWER_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
31 };
32 
33 static const struct reg_sequence a500_ec_orange_led_enable_seq[] = {
34 	REG_SEQ(REG_CHARGE_LED_ON, 0x0, A500_EC_LED_DELAY_USEC),
35 };
36 
37 static int a500_ec_led_brightness_set(struct led_classdev *led_cdev,
38 				      enum led_brightness value)
39 {
40 	struct a500_led *led = container_of(led_cdev, struct a500_led, cdev);
41 	struct reg_sequence control_seq[2];
42 	unsigned int num_regs = 1;
43 
44 	if (value) {
45 		control_seq[0] = led->enable_seq[0];
46 	} else {
47 		/*
48 		 * There is no separate controls which can disable LEDs
49 		 * individually, there is only RESET_LEDS command that turns
50 		 * off both LEDs.
51 		 *
52 		 * RESET_LEDS turns off both LEDs, thus restore other LED if
53 		 * it's turned ON.
54 		 */
55 		if (led->other->cdev.brightness)
56 			num_regs = 2;
57 
58 		control_seq[0] = a500_ec_leds_reset_seq[0];
59 		control_seq[1] = led->other->enable_seq[0];
60 	}
61 
62 	return regmap_multi_reg_write(led->rmap, control_seq, num_regs);
63 }
64 
65 static int a500_ec_leds_probe(struct platform_device *pdev)
66 {
67 	struct a500_led *white_led, *orange_led;
68 	struct regmap *rmap;
69 	int err;
70 
71 	rmap = dev_get_regmap(pdev->dev.parent, "KB930");
72 	if (!rmap)
73 		return -EINVAL;
74 
75 	/* reset and turn off LEDs */
76 	regmap_multi_reg_write(rmap, a500_ec_leds_reset_seq, 2);
77 
78 	white_led = devm_kzalloc(&pdev->dev, sizeof(*white_led), GFP_KERNEL);
79 	if (!white_led)
80 		return -ENOMEM;
81 
82 	white_led->cdev.name = "power:white";
83 	white_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
84 	white_led->cdev.flags = LED_CORE_SUSPENDRESUME;
85 	white_led->cdev.max_brightness = 1;
86 	white_led->enable_seq = a500_ec_white_led_enable_seq;
87 	white_led->rmap = rmap;
88 
89 	orange_led = devm_kzalloc(&pdev->dev, sizeof(*orange_led), GFP_KERNEL);
90 	if (!orange_led)
91 		return -ENOMEM;
92 
93 	orange_led->cdev.name = "power:orange";
94 	orange_led->cdev.brightness_set_blocking = a500_ec_led_brightness_set;
95 	orange_led->cdev.flags = LED_CORE_SUSPENDRESUME;
96 	orange_led->cdev.max_brightness = 1;
97 	orange_led->enable_seq = a500_ec_orange_led_enable_seq;
98 	orange_led->rmap = rmap;
99 
100 	white_led->other = orange_led;
101 	orange_led->other = white_led;
102 
103 	err = devm_led_classdev_register(&pdev->dev, &white_led->cdev);
104 	if (err) {
105 		dev_err(&pdev->dev, "failed to register white LED\n");
106 		return err;
107 	}
108 
109 	err = devm_led_classdev_register(&pdev->dev, &orange_led->cdev);
110 	if (err) {
111 		dev_err(&pdev->dev, "failed to register orange LED\n");
112 		return err;
113 	}
114 
115 	return 0;
116 }
117 
118 static struct platform_driver a500_ec_leds_driver = {
119 	.driver = {
120 		.name = "acer-a500-iconia-leds",
121 	},
122 	.probe = a500_ec_leds_probe,
123 };
124 module_platform_driver(a500_ec_leds_driver);
125 
126 MODULE_DESCRIPTION("LED driver for Acer Iconia Tab A500 Power Button");
127 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
128 MODULE_ALIAS("platform:acer-a500-iconia-leds");
129 MODULE_LICENSE("GPL");
130