1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * sky81452-backlight.c SKY81452 backlight driver
4 *
5 * Copyright 2014 Skyworks Solutions Inc.
6 * Author : Gyungoh Yoo <jack.yoo@skyworksinc.com>
7 */
8
9 #include <linux/backlight.h>
10 #include <linux/err.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/regmap.h>
18 #include <linux/slab.h>
19
20 /* registers */
21 #define SKY81452_REG0 0x00
22 #define SKY81452_REG1 0x01
23 #define SKY81452_REG2 0x02
24 #define SKY81452_REG4 0x04
25 #define SKY81452_REG5 0x05
26
27 /* bit mask */
28 #define SKY81452_CS 0xFF
29 #define SKY81452_EN 0x3F
30 #define SKY81452_IGPW 0x20
31 #define SKY81452_PWMMD 0x10
32 #define SKY81452_PHASE 0x08
33 #define SKY81452_ILIM 0x04
34 #define SKY81452_VSHRT 0x03
35 #define SKY81452_OCP 0x80
36 #define SKY81452_OTMP 0x40
37 #define SKY81452_SHRT 0x3F
38 #define SKY81452_OPN 0x3F
39
40 #define SKY81452_DEFAULT_NAME "lcd-backlight"
41 #define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1)
42
43 /**
44 * struct sky81452_bl_platform_data - backlight platform data
45 * @name: backlight driver name.
46 * If it is not defined, default name is lcd-backlight.
47 * @gpiod_enable:GPIO descriptor which control EN pin
48 * @enable: Enable mask for current sink channel 1, 2, 3, 4, 5 and 6.
49 * @ignore_pwm: true if DPWMI should be ignored.
50 * @dpwm_mode: true is DPWM dimming mode, otherwise Analog dimming mode.
51 * @phase_shift:true is phase shift mode.
52 * @short_detection_threshold: It should be one of 4, 5, 6 and 7V.
53 * @boost_current_limit: It should be one of 2300, 2750mA.
54 */
55 struct sky81452_bl_platform_data {
56 const char *name;
57 struct gpio_desc *gpiod_enable;
58 unsigned int enable;
59 bool ignore_pwm;
60 bool dpwm_mode;
61 bool phase_shift;
62 unsigned int short_detection_threshold;
63 unsigned int boost_current_limit;
64 };
65
66 #define CTZ(b) __builtin_ctz(b)
67
sky81452_bl_update_status(struct backlight_device * bd)68 static int sky81452_bl_update_status(struct backlight_device *bd)
69 {
70 const struct sky81452_bl_platform_data *pdata =
71 dev_get_platdata(bd->dev.parent);
72 const unsigned int brightness = (unsigned int)bd->props.brightness;
73 struct regmap *regmap = bl_get_data(bd);
74 int ret;
75
76 if (brightness > 0) {
77 ret = regmap_write(regmap, SKY81452_REG0, brightness - 1);
78 if (ret < 0)
79 return ret;
80
81 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
82 pdata->enable << CTZ(SKY81452_EN));
83 }
84
85 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0);
86 }
87
88 static const struct backlight_ops sky81452_bl_ops = {
89 .update_status = sky81452_bl_update_status,
90 };
91
sky81452_bl_store_enable(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)92 static ssize_t sky81452_bl_store_enable(struct device *dev,
93 struct device_attribute *attr, const char *buf, size_t count)
94 {
95 struct regmap *regmap = bl_get_data(to_backlight_device(dev));
96 unsigned long value;
97 int ret;
98
99 ret = kstrtoul(buf, 16, &value);
100 if (ret < 0)
101 return ret;
102
103 ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
104 value << CTZ(SKY81452_EN));
105 if (ret < 0)
106 return ret;
107
108 return count;
109 }
110
sky81452_bl_show_open_short(struct device * dev,struct device_attribute * attr,char * buf)111 static ssize_t sky81452_bl_show_open_short(struct device *dev,
112 struct device_attribute *attr, char *buf)
113 {
114 struct regmap *regmap = bl_get_data(to_backlight_device(dev));
115 unsigned int reg, value = 0;
116 char tmp[3];
117 int i, ret;
118
119 reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4;
120 ret = regmap_read(regmap, reg, &value);
121 if (ret < 0)
122 return ret;
123
124 if (value & SKY81452_SHRT) {
125 *buf = 0;
126 for (i = 0; i < 6; i++) {
127 if (value & 0x01) {
128 sprintf(tmp, "%d ", i + 1);
129 strcat(buf, tmp);
130 }
131 value >>= 1;
132 }
133 strcat(buf, "\n");
134 } else {
135 strcpy(buf, "none\n");
136 }
137
138 return strlen(buf);
139 }
140
sky81452_bl_show_fault(struct device * dev,struct device_attribute * attr,char * buf)141 static ssize_t sky81452_bl_show_fault(struct device *dev,
142 struct device_attribute *attr, char *buf)
143 {
144 struct regmap *regmap = bl_get_data(to_backlight_device(dev));
145 unsigned int value = 0;
146 int ret;
147
148 ret = regmap_read(regmap, SKY81452_REG4, &value);
149 if (ret < 0)
150 return ret;
151
152 *buf = 0;
153
154 if (value & SKY81452_OCP)
155 strcat(buf, "over-current ");
156
157 if (value & SKY81452_OTMP)
158 strcat(buf, "over-temperature");
159
160 strcat(buf, "\n");
161 return strlen(buf);
162 }
163
164 static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
165 static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
166 static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
167 static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
168
169 static struct attribute *sky81452_bl_attribute[] = {
170 &dev_attr_enable.attr,
171 &dev_attr_open.attr,
172 &dev_attr_short.attr,
173 &dev_attr_fault.attr,
174 NULL
175 };
176
177 static const struct attribute_group sky81452_bl_attr_group = {
178 .attrs = sky81452_bl_attribute,
179 };
180
181 #ifdef CONFIG_OF
sky81452_bl_parse_dt(struct device * dev)182 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
183 struct device *dev)
184 {
185 struct device_node *np = dev->of_node;
186 struct sky81452_bl_platform_data *pdata;
187 int num_entry;
188 unsigned int sources[6];
189 int ret;
190
191 if (!np) {
192 dev_err(dev, "backlight node not found.\n");
193 return ERR_PTR(-ENODATA);
194 }
195
196 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
197 if (!pdata)
198 return ERR_PTR(-ENOMEM);
199
200 of_property_read_string(np, "name", &pdata->name);
201 pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");
202 pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
203 pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
204 pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);
205
206 ret = of_property_count_u32_elems(np, "led-sources");
207 if (ret < 0) {
208 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
209 } else {
210 num_entry = ret;
211 if (num_entry > 6)
212 num_entry = 6;
213
214 ret = of_property_read_u32_array(np, "led-sources", sources,
215 num_entry);
216 if (ret < 0) {
217 dev_err(dev, "led-sources node is invalid.\n");
218 return ERR_PTR(-EINVAL);
219 }
220
221 pdata->enable = 0;
222 while (--num_entry)
223 pdata->enable |= (1 << sources[num_entry]);
224 }
225
226 ret = of_property_read_u32(np,
227 "skyworks,short-detection-threshold-volt",
228 &pdata->short_detection_threshold);
229 if (ret < 0)
230 pdata->short_detection_threshold = 7;
231
232 ret = of_property_read_u32(np, "skyworks,current-limit-mA",
233 &pdata->boost_current_limit);
234 if (ret < 0)
235 pdata->boost_current_limit = 2750;
236
237 return pdata;
238 }
239 #else
sky81452_bl_parse_dt(struct device * dev)240 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
241 struct device *dev)
242 {
243 return ERR_PTR(-EINVAL);
244 }
245 #endif
246
sky81452_bl_init_device(struct regmap * regmap,struct sky81452_bl_platform_data * pdata)247 static int sky81452_bl_init_device(struct regmap *regmap,
248 struct sky81452_bl_platform_data *pdata)
249 {
250 unsigned int value;
251
252 value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
253 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
254 value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
255
256 if (pdata->boost_current_limit == 2300)
257 value |= SKY81452_ILIM;
258 else if (pdata->boost_current_limit != 2750)
259 return -EINVAL;
260
261 if (pdata->short_detection_threshold < 4 ||
262 pdata->short_detection_threshold > 7)
263 return -EINVAL;
264 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
265
266 return regmap_write(regmap, SKY81452_REG2, value);
267 }
268
sky81452_bl_probe(struct platform_device * pdev)269 static int sky81452_bl_probe(struct platform_device *pdev)
270 {
271 struct device *dev = &pdev->dev;
272 struct regmap *regmap = dev_get_drvdata(dev->parent);
273 struct sky81452_bl_platform_data *pdata;
274 struct backlight_device *bd;
275 struct backlight_properties props;
276 const char *name;
277 int ret;
278
279 pdata = sky81452_bl_parse_dt(dev);
280 if (IS_ERR(pdata))
281 return PTR_ERR(pdata);
282
283 ret = sky81452_bl_init_device(regmap, pdata);
284 if (ret < 0) {
285 dev_err(dev, "failed to initialize. err=%d\n", ret);
286 return ret;
287 }
288
289 memset(&props, 0, sizeof(props));
290 props.max_brightness = SKY81452_MAX_BRIGHTNESS;
291 name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
292 bd = devm_backlight_device_register(dev, name, dev, regmap,
293 &sky81452_bl_ops, &props);
294 if (IS_ERR(bd)) {
295 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
296 return PTR_ERR(bd);
297 }
298
299 platform_set_drvdata(pdev, bd);
300
301 ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
302 if (ret < 0) {
303 dev_err(dev, "failed to create attribute. err=%d\n", ret);
304 return ret;
305 }
306
307 return ret;
308 }
309
sky81452_bl_remove(struct platform_device * pdev)310 static void sky81452_bl_remove(struct platform_device *pdev)
311 {
312 const struct sky81452_bl_platform_data *pdata =
313 dev_get_platdata(&pdev->dev);
314 struct backlight_device *bd = platform_get_drvdata(pdev);
315
316 sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
317
318 bd->props.power = BACKLIGHT_POWER_ON;
319 bd->props.brightness = 0;
320 backlight_update_status(bd);
321
322 if (pdata->gpiod_enable)
323 gpiod_set_value_cansleep(pdata->gpiod_enable, 0);
324 }
325
326 #ifdef CONFIG_OF
327 static const struct of_device_id sky81452_bl_of_match[] = {
328 { .compatible = "skyworks,sky81452-backlight", },
329 { }
330 };
331 MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
332 #endif
333
334 static struct platform_driver sky81452_bl_driver = {
335 .driver = {
336 .name = "sky81452-backlight",
337 .of_match_table = of_match_ptr(sky81452_bl_of_match),
338 },
339 .probe = sky81452_bl_probe,
340 .remove_new = sky81452_bl_remove,
341 };
342
343 module_platform_driver(sky81452_bl_driver);
344
345 MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
346 MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
347 MODULE_LICENSE("GPL v2");
348