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