tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Backlight driver for Marvell Semiconductor 88PM8606
3 *
4 * Copyright (C) 2009 Marvell International Ltd.
5 * Haojian Zhuang <haojian.zhuang@marvell.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/slab.h>
17#include <linux/fb.h>
18#include <linux/i2c.h>
19#include <linux/backlight.h>
20#include <linux/mfd/88pm860x.h>
21#include <linux/module.h>
22
23#define MAX_BRIGHTNESS (0xFF)
24#define MIN_BRIGHTNESS (0)
25
26#define CURRENT_BITMASK (0x1F << 1)
27
28struct pm860x_backlight_data {
29 struct pm860x_chip *chip;
30 struct i2c_client *i2c;
31 int current_brightness;
32 int port;
33 int pwm;
34 int iset;
35 int reg_duty_cycle;
36 int reg_always_on;
37 int reg_current;
38};
39
40static int backlight_power_set(struct pm860x_chip *chip, int port,
41 int on)
42{
43 int ret = -EINVAL;
44
45 switch (port) {
46 case 0:
47 ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) :
48 pm8606_osc_disable(chip, WLED1_DUTY);
49 break;
50 case 1:
51 ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) :
52 pm8606_osc_disable(chip, WLED2_DUTY);
53 break;
54 case 2:
55 ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) :
56 pm8606_osc_disable(chip, WLED3_DUTY);
57 break;
58 }
59 return ret;
60}
61
62static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
63{
64 struct pm860x_backlight_data *data = bl_get_data(bl);
65 struct pm860x_chip *chip = data->chip;
66 unsigned char value;
67 int ret;
68
69 if (brightness > MAX_BRIGHTNESS)
70 value = MAX_BRIGHTNESS;
71 else
72 value = brightness;
73
74 if (brightness)
75 backlight_power_set(chip, data->port, 1);
76
77 ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value);
78 if (ret < 0)
79 goto out;
80
81 if ((data->current_brightness == 0) && brightness) {
82 if (data->iset) {
83 ret = pm860x_set_bits(data->i2c, data->reg_current,
84 CURRENT_BITMASK, data->iset);
85 if (ret < 0)
86 goto out;
87 }
88 if (data->pwm) {
89 ret = pm860x_set_bits(data->i2c, PM8606_PWM,
90 PM8606_PWM_FREQ_MASK, data->pwm);
91 if (ret < 0)
92 goto out;
93 }
94 if (brightness == MAX_BRIGHTNESS) {
95 /* set WLED_ON bit as 100% */
96 ret = pm860x_set_bits(data->i2c, data->reg_always_on,
97 PM8606_WLED_ON, PM8606_WLED_ON);
98 }
99 } else {
100 if (brightness == MAX_BRIGHTNESS) {
101 /* set WLED_ON bit as 100% */
102 ret = pm860x_set_bits(data->i2c, data->reg_always_on,
103 PM8606_WLED_ON, PM8606_WLED_ON);
104 } else {
105 /* clear WLED_ON bit since it's not 100% */
106 ret = pm860x_set_bits(data->i2c, data->reg_always_on,
107 PM8606_WLED_ON, 0);
108 }
109 }
110 if (ret < 0)
111 goto out;
112
113 if (brightness == 0)
114 backlight_power_set(chip, data->port, 0);
115
116 dev_dbg(chip->dev, "set brightness %d\n", value);
117 data->current_brightness = value;
118 return 0;
119out:
120 dev_dbg(chip->dev, "set brightness %d failure with return value: %d\n",
121 value, ret);
122 return ret;
123}
124
125static int pm860x_backlight_update_status(struct backlight_device *bl)
126{
127 int brightness = bl->props.brightness;
128
129 if (bl->props.power != FB_BLANK_UNBLANK)
130 brightness = 0;
131
132 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
133 brightness = 0;
134
135 if (bl->props.state & BL_CORE_SUSPENDED)
136 brightness = 0;
137
138 return pm860x_backlight_set(bl, brightness);
139}
140
141static int pm860x_backlight_get_brightness(struct backlight_device *bl)
142{
143 struct pm860x_backlight_data *data = bl_get_data(bl);
144 struct pm860x_chip *chip = data->chip;
145 int ret;
146
147 ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle);
148 if (ret < 0)
149 goto out;
150 data->current_brightness = ret;
151 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
152 return data->current_brightness;
153out:
154 return -EINVAL;
155}
156
157static const struct backlight_ops pm860x_backlight_ops = {
158 .options = BL_CORE_SUSPENDRESUME,
159 .update_status = pm860x_backlight_update_status,
160 .get_brightness = pm860x_backlight_get_brightness,
161};
162
163#ifdef CONFIG_OF
164static int pm860x_backlight_dt_init(struct platform_device *pdev,
165 struct pm860x_backlight_data *data,
166 char *name)
167{
168 struct device_node *nproot, *np;
169 int iset = 0;
170
171 nproot = of_node_get(pdev->dev.parent->of_node);
172 if (!nproot)
173 return -ENODEV;
174 nproot = of_find_node_by_name(nproot, "backlights");
175 if (!nproot) {
176 dev_err(&pdev->dev, "failed to find backlights node\n");
177 return -ENODEV;
178 }
179 for_each_child_of_node(nproot, np) {
180 if (!of_node_cmp(np->name, name)) {
181 of_property_read_u32(np, "marvell,88pm860x-iset",
182 &iset);
183 data->iset = PM8606_WLED_CURRENT(iset);
184 of_property_read_u32(np, "marvell,88pm860x-pwm",
185 &data->pwm);
186 break;
187 }
188 }
189 of_node_put(nproot);
190 return 0;
191}
192#else
193#define pm860x_backlight_dt_init(x, y, z) (-1)
194#endif
195
196static int pm860x_backlight_probe(struct platform_device *pdev)
197{
198 struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
199 struct pm860x_backlight_pdata *pdata = dev_get_platdata(&pdev->dev);
200 struct pm860x_backlight_data *data;
201 struct backlight_device *bl;
202 struct resource *res;
203 struct backlight_properties props;
204 char name[MFD_NAME_SIZE];
205 int ret = 0;
206
207 data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data),
208 GFP_KERNEL);
209 if (data == NULL)
210 return -ENOMEM;
211 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle");
212 if (!res) {
213 dev_err(&pdev->dev, "No REG resource for duty cycle\n");
214 return -ENXIO;
215 }
216 data->reg_duty_cycle = res->start;
217 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on");
218 if (!res) {
219 dev_err(&pdev->dev, "No REG resorce for always on\n");
220 return -ENXIO;
221 }
222 data->reg_always_on = res->start;
223 res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current");
224 if (!res) {
225 dev_err(&pdev->dev, "No REG resource for current\n");
226 return -ENXIO;
227 }
228 data->reg_current = res->start;
229
230 memset(name, 0, MFD_NAME_SIZE);
231 sprintf(name, "backlight-%d", pdev->id);
232 data->port = pdev->id;
233 data->chip = chip;
234 data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion;
235 data->current_brightness = MAX_BRIGHTNESS;
236 if (pm860x_backlight_dt_init(pdev, data, name)) {
237 if (pdata) {
238 data->pwm = pdata->pwm;
239 data->iset = pdata->iset;
240 }
241 }
242
243 memset(&props, 0, sizeof(struct backlight_properties));
244 props.type = BACKLIGHT_RAW;
245 props.max_brightness = MAX_BRIGHTNESS;
246 bl = devm_backlight_device_register(&pdev->dev, name, &pdev->dev, data,
247 &pm860x_backlight_ops, &props);
248 if (IS_ERR(bl)) {
249 dev_err(&pdev->dev, "failed to register backlight\n");
250 return PTR_ERR(bl);
251 }
252 bl->props.brightness = MAX_BRIGHTNESS;
253
254 platform_set_drvdata(pdev, bl);
255
256 /* read current backlight */
257 ret = pm860x_backlight_get_brightness(bl);
258 if (ret < 0)
259 return ret;
260
261 backlight_update_status(bl);
262 return 0;
263}
264
265static struct platform_driver pm860x_backlight_driver = {
266 .driver = {
267 .name = "88pm860x-backlight",
268 .owner = THIS_MODULE,
269 },
270 .probe = pm860x_backlight_probe,
271};
272
273module_platform_driver(pm860x_backlight_driver);
274
275MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
276MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
277MODULE_LICENSE("GPL");
278MODULE_ALIAS("platform:88pm860x-backlight");