tjh.dev
Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Backlight driver for Marvell Semiconductor 88PM8606
4 *
5 * Copyright (C) 2009 Marvell International Ltd.
6 * Haojian Zhuang <haojian.zhuang@marvell.com>
7 */
8
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/of.h>
12#include <linux/platform_device.h>
13#include <linux/slab.h>
14#include <linux/fb.h>
15#include <linux/i2c.h>
16#include <linux/backlight.h>
17#include <linux/mfd/88pm860x.h>
18#include <linux/module.h>
19
20#define MAX_BRIGHTNESS (0xFF)
21#define MIN_BRIGHTNESS (0)
22
23#define CURRENT_BITMASK (0x1F << 1)
24
25struct pm860x_backlight_data {
26 struct pm860x_chip *chip;
27 struct i2c_client *i2c;
28 int current_brightness;
29 int port;
30 int pwm;
31 int iset;
32 int reg_duty_cycle;
33 int reg_always_on;
34 int reg_current;
35};
36
37static int backlight_power_set(struct pm860x_chip *chip, int port,
38 int on)
39{
40 int ret = -EINVAL;
41
42 switch (port) {
43 case 0:
44 ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) :
45 pm8606_osc_disable(chip, WLED1_DUTY);
46 break;
47 case 1:
48 ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) :
49 pm8606_osc_disable(chip, WLED2_DUTY);
50 break;
51 case 2:
52 ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) :
53 pm8606_osc_disable(chip, WLED3_DUTY);
54 break;
55 }
56 return ret;
57}
58
59static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
60{
61 struct pm860x_backlight_data *data = bl_get_data(bl);
62 struct pm860x_chip *chip = data->chip;
63 unsigned char value;
64 int ret;
65
66 if (brightness > MAX_BRIGHTNESS)
67 value = MAX_BRIGHTNESS;
68 else
69 value = brightness;
70
71 if (brightness)
72 backlight_power_set(chip, data->port, 1);
73
74 ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value);
75 if (ret < 0)
76 goto out;
77
78 if ((data->current_brightness == 0) && brightness) {
79 if (data->iset) {
80 ret = pm860x_set_bits(data->i2c, data->reg_current,
81 CURRENT_BITMASK, data->iset);
82 if (ret < 0)
83 goto out;
84 }
85 if (data->pwm) {
86 ret = pm860x_set_bits(data->i2c, PM8606_PWM,
87 PM8606_PWM_FREQ_MASK, data->pwm);
88 if (ret < 0)
89 goto out;
90 }
91 if (brightness == MAX_BRIGHTNESS) {
92 /* set WLED_ON bit as 100% */
93 ret = pm860x_set_bits(data->i2c, data->reg_always_on,
94 PM8606_WLED_ON, PM8606_WLED_ON);
95 }
96 } else {
97 if (brightness == MAX_BRIGHTNESS) {
98 /* set WLED_ON bit as 100% */
99 ret = pm860x_set_bits(data->i2c, data->reg_always_on,
100 PM8606_WLED_ON, PM8606_WLED_ON);
101 } else {
102 /* clear WLED_ON bit since it's not 100% */
103 ret = pm860x_set_bits(data->i2c, data->reg_always_on,
104 PM8606_WLED_ON, 0);
105 }
106 }
107 if (ret < 0)
108 goto out;
109
110 if (brightness == 0)
111 backlight_power_set(chip, data->port, 0);
112
113 dev_dbg(chip->dev, "set brightness %d\n", value);
114 data->current_brightness = value;
115 return 0;
116out:
117 dev_dbg(chip->dev, "set brightness %d failure with return value: %d\n",
118 value, ret);
119 return ret;
120}
121
122static int pm860x_backlight_update_status(struct backlight_device *bl)
123{
124 return pm860x_backlight_set(bl, backlight_get_brightness(bl));
125}
126
127static int pm860x_backlight_get_brightness(struct backlight_device *bl)
128{
129 struct pm860x_backlight_data *data = bl_get_data(bl);
130 struct pm860x_chip *chip = data->chip;
131 int ret;
132
133 ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle);
134 if (ret < 0)
135 goto out;
136 data->current_brightness = ret;
137 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
138 return data->current_brightness;
139out:
140 return -EINVAL;
141}
142
143static const struct backlight_ops pm860x_backlight_ops = {
144 .options = BL_CORE_SUSPENDRESUME,
145 .update_status = pm860x_backlight_update_status,
146 .get_brightness = pm860x_backlight_get_brightness,
147};
148
149#ifdef CONFIG_OF
150static int pm860x_backlight_dt_init(struct platform_device *pdev,
151 struct pm860x_backlight_data *data,
152 char *name)
153{
154 struct device_node *nproot;
155 int iset = 0;
156
157 nproot = of_get_child_by_name(pdev->dev.parent->of_node, "backlights");
158 if (!nproot) {
159 dev_err(&pdev->dev, "failed to find backlights node\n");
160 return -ENODEV;
161 }
162 for_each_child_of_node_scoped(nproot, np) {
163 if (of_node_name_eq(np, name)) {
164 of_property_read_u32(np, "marvell,88pm860x-iset",
165 &iset);
166 data->iset = PM8606_WLED_CURRENT(iset);
167 of_property_read_u32(np, "marvell,88pm860x-pwm",
168 &data->pwm);
169 break;
170 }
171 }
172 of_node_put(nproot);
173 return 0;
174}
175#else
176#define pm860x_backlight_dt_init(x, y, z) (-1)
177#endif
178
179static int pm860x_backlight_probe(struct platform_device *pdev)
180{
181 struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
182 struct pm860x_backlight_pdata *pdata = dev_get_platdata(&pdev->dev);
183 struct pm860x_backlight_data *data;
184 struct backlight_device *bl;
185 struct resource *res;
186 struct backlight_properties props;
187 char name[MFD_NAME_SIZE];
188 int ret = 0;
189
190 data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data),
191 GFP_KERNEL);
192 if (data == NULL)
193 return -ENOMEM;
194 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle");
195 if (!res) {
196 dev_err(&pdev->dev, "No REG resource for duty cycle\n");
197 return -ENXIO;
198 }
199 data->reg_duty_cycle = res->start;
200 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on");
201 if (!res) {
202 dev_err(&pdev->dev, "No REG resource for always on\n");
203 return -ENXIO;
204 }
205 data->reg_always_on = res->start;
206 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current");
207 if (!res) {
208 dev_err(&pdev->dev, "No REG resource for current\n");
209 return -ENXIO;
210 }
211 data->reg_current = res->start;
212
213 memset(name, 0, MFD_NAME_SIZE);
214 sprintf(name, "backlight-%d", pdev->id);
215 data->port = pdev->id;
216 data->chip = chip;
217 data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion;
218 data->current_brightness = MAX_BRIGHTNESS;
219 if (pm860x_backlight_dt_init(pdev, data, name)) {
220 if (pdata) {
221 data->pwm = pdata->pwm;
222 data->iset = pdata->iset;
223 }
224 }
225
226 memset(&props, 0, sizeof(struct backlight_properties));
227 props.type = BACKLIGHT_RAW;
228 props.max_brightness = MAX_BRIGHTNESS;
229 bl = devm_backlight_device_register(&pdev->dev, name, &pdev->dev, data,
230 &pm860x_backlight_ops, &props);
231 if (IS_ERR(bl)) {
232 dev_err(&pdev->dev, "failed to register backlight\n");
233 return PTR_ERR(bl);
234 }
235 bl->props.brightness = MAX_BRIGHTNESS;
236
237 platform_set_drvdata(pdev, bl);
238
239 /* read current backlight */
240 ret = pm860x_backlight_get_brightness(bl);
241 if (ret < 0)
242 return ret;
243
244 backlight_update_status(bl);
245 return 0;
246}
247
248static struct platform_driver pm860x_backlight_driver = {
249 .driver = {
250 .name = "88pm860x-backlight",
251 },
252 .probe = pm860x_backlight_probe,
253};
254
255module_platform_driver(pm860x_backlight_driver);
256
257MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
258MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
259MODULE_LICENSE("GPL");
260MODULE_ALIAS("platform:88pm860x-backlight");