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20#include <linux/backlight.h>
21#include <linux/err.h>
22#include <linux/gpio.h>
23#include <linux/init.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26#include <linux/of.h>
27#include <linux/of_gpio.h>
28#include <linux/platform_device.h>
29#include <linux/regmap.h>
30#include <linux/platform_data/sky81452-backlight.h>
31#include <linux/slab.h>
32
33
34#define SKY81452_REG0 0x00
35#define SKY81452_REG1 0x01
36#define SKY81452_REG2 0x02
37#define SKY81452_REG4 0x04
38#define SKY81452_REG5 0x05
39
40
41#define SKY81452_CS 0xFF
42#define SKY81452_EN 0x3F
43#define SKY81452_IGPW 0x20
44#define SKY81452_PWMMD 0x10
45#define SKY81452_PHASE 0x08
46#define SKY81452_ILIM 0x04
47#define SKY81452_VSHRT 0x03
48#define SKY81452_OCP 0x80
49#define SKY81452_OTMP 0x40
50#define SKY81452_SHRT 0x3F
51#define SKY81452_OPN 0x3F
52
53#define SKY81452_DEFAULT_NAME "lcd-backlight"
54#define SKY81452_MAX_BRIGHTNESS (SKY81452_CS + 1)
55
56#define CTZ(b) __builtin_ctz(b)
57
58static int sky81452_bl_update_status(struct backlight_device *bd)
59{
60 const struct sky81452_bl_platform_data *pdata =
61 dev_get_platdata(bd->dev.parent);
62 const unsigned int brightness = (unsigned int)bd->props.brightness;
63 struct regmap *regmap = bl_get_data(bd);
64 int ret;
65
66 if (brightness > 0) {
67 ret = regmap_write(regmap, SKY81452_REG0, brightness - 1);
68 if (ret < 0)
69 return ret;
70
71 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
72 pdata->enable << CTZ(SKY81452_EN));
73 }
74
75 return regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN, 0);
76}
77
78static const struct backlight_ops sky81452_bl_ops = {
79 .update_status = sky81452_bl_update_status,
80};
81
82static ssize_t sky81452_bl_store_enable(struct device *dev,
83 struct device_attribute *attr, const char *buf, size_t count)
84{
85 struct regmap *regmap = bl_get_data(to_backlight_device(dev));
86 unsigned long value;
87 int ret;
88
89 ret = kstrtoul(buf, 16, &value);
90 if (ret < 0)
91 return ret;
92
93 ret = regmap_update_bits(regmap, SKY81452_REG1, SKY81452_EN,
94 value << CTZ(SKY81452_EN));
95 if (ret < 0)
96 return ret;
97
98 return count;
99}
100
101static ssize_t sky81452_bl_show_open_short(struct device *dev,
102 struct device_attribute *attr, char *buf)
103{
104 struct regmap *regmap = bl_get_data(to_backlight_device(dev));
105 unsigned int reg, value = 0;
106 char tmp[3];
107 int i, ret;
108
109 reg = !strcmp(attr->attr.name, "open") ? SKY81452_REG5 : SKY81452_REG4;
110 ret = regmap_read(regmap, reg, &value);
111 if (ret < 0)
112 return ret;
113
114 if (value & SKY81452_SHRT) {
115 *buf = 0;
116 for (i = 0; i < 6; i++) {
117 if (value & 0x01) {
118 sprintf(tmp, "%d ", i + 1);
119 strcat(buf, tmp);
120 }
121 value >>= 1;
122 }
123 strcat(buf, "\n");
124 } else {
125 strcpy(buf, "none\n");
126 }
127
128 return strlen(buf);
129}
130
131static ssize_t sky81452_bl_show_fault(struct device *dev,
132 struct device_attribute *attr, char *buf)
133{
134 struct regmap *regmap = bl_get_data(to_backlight_device(dev));
135 unsigned int value = 0;
136 int ret;
137
138 ret = regmap_read(regmap, SKY81452_REG4, &value);
139 if (ret < 0)
140 return ret;
141
142 *buf = 0;
143
144 if (value & SKY81452_OCP)
145 strcat(buf, "over-current ");
146
147 if (value & SKY81452_OTMP)
148 strcat(buf, "over-temperature");
149
150 strcat(buf, "\n");
151 return strlen(buf);
152}
153
154static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
155static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
156static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
157static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
158
159static struct attribute *sky81452_bl_attribute[] = {
160 &dev_attr_enable.attr,
161 &dev_attr_open.attr,
162 &dev_attr_short.attr,
163 &dev_attr_fault.attr,
164 NULL
165};
166
167static const struct attribute_group sky81452_bl_attr_group = {
168 .attrs = sky81452_bl_attribute,
169};
170
171#ifdef CONFIG_OF
172static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
173 struct device *dev)
174{
175 struct device_node *np = of_node_get(dev->of_node);
176 struct sky81452_bl_platform_data *pdata;
177 int num_entry;
178 unsigned int sources[6];
179 int ret;
180
181 if (!np) {
182 dev_err(dev, "backlight node not found.\n");
183 return ERR_PTR(-ENODATA);
184 }
185
186 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
187 if (!pdata) {
188 of_node_put(np);
189 return ERR_PTR(-ENOMEM);
190 }
191
192 of_property_read_string(np, "name", &pdata->name);
193 pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");
194 pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
195 pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
196 pdata->gpio_enable = of_get_gpio(np, 0);
197
198 ret = of_property_count_u32_elems(np, "led-sources");
199 if (ret < 0) {
200 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
201 } else {
202 num_entry = ret;
203 if (num_entry > 6)
204 num_entry = 6;
205
206 ret = of_property_read_u32_array(np, "led-sources", sources,
207 num_entry);
208 if (ret < 0) {
209 dev_err(dev, "led-sources node is invalid.\n");
210 return ERR_PTR(-EINVAL);
211 }
212
213 pdata->enable = 0;
214 while (--num_entry)
215 pdata->enable |= (1 << sources[num_entry]);
216 }
217
218 ret = of_property_read_u32(np,
219 "skyworks,short-detection-threshold-volt",
220 &pdata->short_detection_threshold);
221 if (ret < 0)
222 pdata->short_detection_threshold = 7;
223
224 ret = of_property_read_u32(np, "skyworks,current-limit-mA",
225 &pdata->boost_current_limit);
226 if (ret < 0)
227 pdata->boost_current_limit = 2750;
228
229 of_node_put(np);
230 return pdata;
231}
232#else
233static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
234 struct device *dev)
235{
236 return ERR_PTR(-EINVAL);
237}
238#endif
239
240static int sky81452_bl_init_device(struct regmap *regmap,
241 struct sky81452_bl_platform_data *pdata)
242{
243 unsigned int value;
244
245 value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
246 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
247 value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
248
249 if (pdata->boost_current_limit == 2300)
250 value |= SKY81452_ILIM;
251 else if (pdata->boost_current_limit != 2750)
252 return -EINVAL;
253
254 if (pdata->short_detection_threshold < 4 ||
255 pdata->short_detection_threshold > 7)
256 return -EINVAL;
257 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
258
259 return regmap_write(regmap, SKY81452_REG2, value);
260}
261
262static int sky81452_bl_probe(struct platform_device *pdev)
263{
264 struct device *dev = &pdev->dev;
265 struct regmap *regmap = dev_get_drvdata(dev->parent);
266 struct sky81452_bl_platform_data *pdata = dev_get_platdata(dev);
267 struct backlight_device *bd;
268 struct backlight_properties props;
269 const char *name;
270 int ret;
271
272 if (!pdata) {
273 pdata = sky81452_bl_parse_dt(dev);
274 if (IS_ERR(pdata))
275 return PTR_ERR(pdata);
276 }
277
278 if (gpio_is_valid(pdata->gpio_enable)) {
279 ret = devm_gpio_request_one(dev, pdata->gpio_enable,
280 GPIOF_OUT_INIT_HIGH, "sky81452-en");
281 if (ret < 0) {
282 dev_err(dev, "failed to request GPIO. err=%d\n", ret);
283 return ret;
284 }
285 }
286
287 ret = sky81452_bl_init_device(regmap, pdata);
288 if (ret < 0) {
289 dev_err(dev, "failed to initialize. err=%d\n", ret);
290 return ret;
291 }
292
293 memset(&props, 0, sizeof(props));
294 props.max_brightness = SKY81452_MAX_BRIGHTNESS,
295 name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
296 bd = devm_backlight_device_register(dev, name, dev, regmap,
297 &sky81452_bl_ops, &props);
298 if (IS_ERR(bd)) {
299 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
300 return PTR_ERR(bd);
301 }
302
303 platform_set_drvdata(pdev, bd);
304
305 ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
306 if (ret < 0) {
307 dev_err(dev, "failed to create attribute. err=%d\n", ret);
308 return ret;
309 }
310
311 return ret;
312}
313
314static int sky81452_bl_remove(struct platform_device *pdev)
315{
316 const struct sky81452_bl_platform_data *pdata =
317 dev_get_platdata(&pdev->dev);
318 struct backlight_device *bd = platform_get_drvdata(pdev);
319
320 sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
321
322 bd->props.power = FB_BLANK_UNBLANK;
323 bd->props.brightness = 0;
324 backlight_update_status(bd);
325
326 if (gpio_is_valid(pdata->gpio_enable))
327 gpio_set_value_cansleep(pdata->gpio_enable, 0);
328
329 return 0;
330}
331
332#ifdef CONFIG_OF
333static const struct of_device_id sky81452_bl_of_match[] = {
334 { .compatible = "skyworks,sky81452-backlight", },
335 { }
336};
337MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
338#endif
339
340static struct platform_driver sky81452_bl_driver = {
341 .driver = {
342 .name = "sky81452-backlight",
343 .of_match_table = of_match_ptr(sky81452_bl_of_match),
344 },
345 .probe = sky81452_bl_probe,
346 .remove = sky81452_bl_remove,
347};
348
349module_platform_driver(sky81452_bl_driver);
350
351MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
352MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
353MODULE_LICENSE("GPL v2");
354
