]> git.sur5r.net Git - u-boot/blob - drivers/video/pwm_backlight.c
Merge git://git.denx.de/u-boot-fdt
[u-boot] / drivers / video / pwm_backlight.c
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;
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 };