1 /*
2 * sky81452-backlight.c SKY81452 backlight driver
3 *
4 * Copyright 2014 Skyworks Solutions Inc.
5 * Author : Gyungoh Yoo <jack.yoo@skyworksinc.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2
9 * as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License along
17 * with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19
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 /* registers */
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 /* bit mask */
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
sky81452_bl_update_status(struct backlight_device * bd)58 static 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
78 static const struct backlight_ops sky81452_bl_ops = {
79 .update_status = sky81452_bl_update_status,
80 };
81
sky81452_bl_store_enable(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)82 static 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
sky81452_bl_show_open_short(struct device * dev,struct device_attribute * attr,char * buf)101 static 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
sky81452_bl_show_fault(struct device * dev,struct device_attribute * attr,char * buf)131 static 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
154 static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
155 static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
156 static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
157 static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
158
159 static 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
167 static const struct attribute_group sky81452_bl_attr_group = {
168 .attrs = sky81452_bl_attribute,
169 };
170
171 #ifdef CONFIG_OF
sky81452_bl_parse_dt(struct device * dev)172 static 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 of_node_put(np);
211 return ERR_PTR(-EINVAL);
212 }
213
214 pdata->enable = 0;
215 while (--num_entry)
216 pdata->enable |= (1 << sources[num_entry]);
217 }
218
219 ret = of_property_read_u32(np,
220 "skyworks,short-detection-threshold-volt",
221 &pdata->short_detection_threshold);
222 if (ret < 0)
223 pdata->short_detection_threshold = 7;
224
225 ret = of_property_read_u32(np, "skyworks,current-limit-mA",
226 &pdata->boost_current_limit);
227 if (ret < 0)
228 pdata->boost_current_limit = 2750;
229
230 of_node_put(np);
231 return pdata;
232 }
233 #else
sky81452_bl_parse_dt(struct device * dev)234 static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
235 struct device *dev)
236 {
237 return ERR_PTR(-EINVAL);
238 }
239 #endif
240
sky81452_bl_init_device(struct regmap * regmap,struct sky81452_bl_platform_data * pdata)241 static int sky81452_bl_init_device(struct regmap *regmap,
242 struct sky81452_bl_platform_data *pdata)
243 {
244 unsigned int value;
245
246 value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
247 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
248 value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
249
250 if (pdata->boost_current_limit == 2300)
251 value |= SKY81452_ILIM;
252 else if (pdata->boost_current_limit != 2750)
253 return -EINVAL;
254
255 if (pdata->short_detection_threshold < 4 ||
256 pdata->short_detection_threshold > 7)
257 return -EINVAL;
258 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
259
260 return regmap_write(regmap, SKY81452_REG2, value);
261 }
262
sky81452_bl_probe(struct platform_device * pdev)263 static int sky81452_bl_probe(struct platform_device *pdev)
264 {
265 struct device *dev = &pdev->dev;
266 struct regmap *regmap = dev_get_drvdata(dev->parent);
267 struct sky81452_bl_platform_data *pdata = dev_get_platdata(dev);
268 struct backlight_device *bd;
269 struct backlight_properties props;
270 const char *name;
271 int ret;
272
273 if (!pdata) {
274 pdata = sky81452_bl_parse_dt(dev);
275 if (IS_ERR(pdata))
276 return PTR_ERR(pdata);
277 }
278
279 if (gpio_is_valid(pdata->gpio_enable)) {
280 ret = devm_gpio_request_one(dev, pdata->gpio_enable,
281 GPIOF_OUT_INIT_HIGH, "sky81452-en");
282 if (ret < 0) {
283 dev_err(dev, "failed to request GPIO. err=%d\n", ret);
284 return ret;
285 }
286 }
287
288 ret = sky81452_bl_init_device(regmap, pdata);
289 if (ret < 0) {
290 dev_err(dev, "failed to initialize. err=%d\n", ret);
291 return ret;
292 }
293
294 memset(&props, 0, sizeof(props));
295 props.max_brightness = SKY81452_MAX_BRIGHTNESS,
296 name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
297 bd = devm_backlight_device_register(dev, name, dev, regmap,
298 &sky81452_bl_ops, &props);
299 if (IS_ERR(bd)) {
300 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
301 return PTR_ERR(bd);
302 }
303
304 platform_set_drvdata(pdev, bd);
305
306 ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
307 if (ret < 0) {
308 dev_err(dev, "failed to create attribute. err=%d\n", ret);
309 return ret;
310 }
311
312 return ret;
313 }
314
sky81452_bl_remove(struct platform_device * pdev)315 static int sky81452_bl_remove(struct platform_device *pdev)
316 {
317 const struct sky81452_bl_platform_data *pdata =
318 dev_get_platdata(&pdev->dev);
319 struct backlight_device *bd = platform_get_drvdata(pdev);
320
321 sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
322
323 bd->props.power = FB_BLANK_UNBLANK;
324 bd->props.brightness = 0;
325 backlight_update_status(bd);
326
327 if (gpio_is_valid(pdata->gpio_enable))
328 gpio_set_value_cansleep(pdata->gpio_enable, 0);
329
330 return 0;
331 }
332
333 #ifdef CONFIG_OF
334 static const struct of_device_id sky81452_bl_of_match[] = {
335 { .compatible = "skyworks,sky81452-backlight", },
336 { }
337 };
338 MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
339 #endif
340
341 static struct platform_driver sky81452_bl_driver = {
342 .driver = {
343 .name = "sky81452-backlight",
344 .of_match_table = of_match_ptr(sky81452_bl_of_match),
345 },
346 .probe = sky81452_bl_probe,
347 .remove = sky81452_bl_remove,
348 };
349
350 module_platform_driver(sky81452_bl_driver);
351
352 MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
353 MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
354 MODULE_LICENSE("GPL v2");
355