1 /*
2  * Copyright (c) 2016 Google, Inc
3  * Written by Simon Glass <sjg@chromium.org>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 #include <common.h>
9 #include <dm.h>
10 #include <backlight.h>
11 #include <pwm.h>
12 #include <asm/gpio.h>
13 #include <power/regulator.h>
14 
15 DECLARE_GLOBAL_DATA_PTR;
16 
17 struct pwm_backlight_priv {
18 	struct udevice *reg;
19 	struct gpio_desc enable;
20 	struct udevice *pwm;
21 	uint channel;
22 	uint period_ns;
23 	uint default_level;
24 	uint min_level;
25 	uint max_level;
26 };
27 
28 static int pwm_backlight_enable(struct udevice *dev)
29 {
30 	struct pwm_backlight_priv *priv = dev_get_priv(dev);
31 	uint duty_cycle;
32 	int ret;
33 
34 	debug("%s: Enable '%s', regulator '%s'\n", __func__, dev->name,
35 	      priv->reg->name);
36 	ret = regulator_set_enable(priv->reg, true);
37 	if (ret) {
38 		debug("%s: Cannot enable regulator for PWM '%s'\n", __func__,
39 		      dev->name);
40 		return ret;
41 	}
42 	mdelay(120);
43 
44 	duty_cycle = priv->period_ns * (priv->default_level - priv->min_level) /
45 		(priv->max_level - priv->min_level + 1);
46 	ret = pwm_set_config(priv->pwm, priv->channel, priv->period_ns,
47 			     duty_cycle);
48 	if (ret)
49 		return ret;
50 	ret = pwm_set_enable(priv->pwm, priv->channel, true);
51 	if (ret)
52 		return ret;
53 	mdelay(10);
54 	dm_gpio_set_value(&priv->enable, 1);
55 
56 	return 0;
57 }
58 
59 static int pwm_backlight_ofdata_to_platdata(struct udevice *dev)
60 {
61 	struct pwm_backlight_priv *priv = dev_get_priv(dev);
62 	struct fdtdec_phandle_args args;
63 	const void *blob = gd->fdt_blob;
64 	int node = dev_of_offset(dev);
65 	int index, ret, count, len;
66 	const u32 *cell;
67 
68 	ret = uclass_get_device_by_phandle(UCLASS_REGULATOR, dev,
69 					   "power-supply", &priv->reg);
70 	if (ret) {
71 		debug("%s: Cannot get power supply: ret=%d\n", __func__, ret);
72 		return ret;
73 	}
74 	ret = gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable,
75 				   GPIOD_IS_OUT);
76 	if (ret) {
77 		debug("%s: Warning: cannot get enable GPIO: ret=%d\n",
78 		      __func__, ret);
79 		if (ret != -ENOENT)
80 			return ret;
81 	}
82 	ret = fdtdec_parse_phandle_with_args(blob, node, "pwms", "#pwm-cells",
83 					     0, 0, &args);
84 	if (ret) {
85 		debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret);
86 		return ret;
87 	}
88 
89 	ret = uclass_get_device_by_of_offset(UCLASS_PWM, args.node, &priv->pwm);
90 	if (ret) {
91 		debug("%s: Cannot get PWM: ret=%d\n", __func__, ret);
92 		return ret;
93 	}
94 	priv->channel = args.args[0];
95 	priv->period_ns = args.args[1];
96 
97 	index = fdtdec_get_int(blob, node, "default-brightness-level", 255);
98 	cell = fdt_getprop(blob, node, "brightness-levels", &len);
99 	count = len / sizeof(u32);
100 	if (cell && count > index) {
101 		priv->default_level = fdt32_to_cpu(cell[index]);
102 		priv->max_level = fdt32_to_cpu(cell[count - 1]);
103 	} else {
104 		priv->default_level = index;
105 		priv->max_level = 255;
106 	}
107 
108 
109 	return 0;
110 }
111 
112 static int pwm_backlight_probe(struct udevice *dev)
113 {
114 	return 0;
115 }
116 
117 static const struct backlight_ops pwm_backlight_ops = {
118 	.enable	= pwm_backlight_enable,
119 };
120 
121 static const struct udevice_id pwm_backlight_ids[] = {
122 	{ .compatible = "pwm-backlight" },
123 	{ }
124 };
125 
126 U_BOOT_DRIVER(pwm_backlight) = {
127 	.name	= "pwm_backlight",
128 	.id	= UCLASS_PANEL_BACKLIGHT,
129 	.of_match = pwm_backlight_ids,
130 	.ops	= &pwm_backlight_ops,
131 	.ofdata_to_platdata	= pwm_backlight_ofdata_to_platdata,
132 	.probe		= pwm_backlight_probe,
133 	.priv_auto_alloc_size	= sizeof(struct pwm_backlight_priv),
134 };
135