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 */
55struct 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
68static int sky81452_bl_update_status(struct backlight_device *bd)
69{
70 const struct sky81452_bl_platform_data *pdata =
71 dev_get_platdata(dev: bd->dev.parent);
72 const unsigned int brightness = (unsigned int)bd->props.brightness;
73 struct regmap *regmap = bl_get_data(bl_dev: bd);
74 int ret;
75
76 if (brightness > 0) {
77 ret = regmap_write(map: regmap, SKY81452_REG0, val: brightness - 1);
78 if (ret < 0)
79 return ret;
80
81 return regmap_update_bits(map: regmap, SKY81452_REG1, SKY81452_EN,
82 val: pdata->enable << CTZ(SKY81452_EN));
83 }
84
85 return regmap_update_bits(map: regmap, SKY81452_REG1, SKY81452_EN, val: 0);
86}
87
88static const struct backlight_ops sky81452_bl_ops = {
89 .update_status = sky81452_bl_update_status,
90};
91
92static 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(s: buf, base: 16, res: &value);
100 if (ret < 0)
101 return ret;
102
103 ret = regmap_update_bits(map: regmap, SKY81452_REG1, SKY81452_EN,
104 val: value << CTZ(SKY81452_EN));
105 if (ret < 0)
106 return ret;
107
108 return count;
109}
110
111static 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(map: regmap, reg, val: &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(buf: tmp, fmt: "%d ", i + 1);
129 strcat(p: buf, q: tmp);
130 }
131 value >>= 1;
132 }
133 strcat(p: buf, q: "\n");
134 } else {
135 strcpy(p: buf, q: "none\n");
136 }
137
138 return strlen(buf);
139}
140
141static 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(map: regmap, SKY81452_REG4, val: &value);
149 if (ret < 0)
150 return ret;
151
152 *buf = 0;
153
154 if (value & SKY81452_OCP)
155 strcat(p: buf, q: "over-current ");
156
157 if (value & SKY81452_OTMP)
158 strcat(p: buf, q: "over-temperature");
159
160 strcat(p: buf, q: "\n");
161 return strlen(buf);
162}
163
164static DEVICE_ATTR(enable, S_IWGRP | S_IWUSR, NULL, sky81452_bl_store_enable);
165static DEVICE_ATTR(open, S_IRUGO, sky81452_bl_show_open_short, NULL);
166static DEVICE_ATTR(short, S_IRUGO, sky81452_bl_show_open_short, NULL);
167static DEVICE_ATTR(fault, S_IRUGO, sky81452_bl_show_fault, NULL);
168
169static 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
177static const struct attribute_group sky81452_bl_attr_group = {
178 .attrs = sky81452_bl_attribute,
179};
180
181#ifdef CONFIG_OF
182static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
183 struct device *dev)
184{
185 struct device_node *np = of_node_get(node: 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(error: -ENODATA);
194 }
195
196 pdata = devm_kzalloc(dev, size: sizeof(*pdata), GFP_KERNEL);
197 if (!pdata) {
198 of_node_put(node: np);
199 return ERR_PTR(error: -ENOMEM);
200 }
201
202 of_property_read_string(np, propname: "name", out_string: &pdata->name);
203 pdata->ignore_pwm = of_property_read_bool(np, propname: "skyworks,ignore-pwm");
204 pdata->dpwm_mode = of_property_read_bool(np, propname: "skyworks,dpwm-mode");
205 pdata->phase_shift = of_property_read_bool(np, propname: "skyworks,phase-shift");
206 pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, flags: GPIOD_OUT_HIGH);
207
208 ret = of_property_count_u32_elems(np, propname: "led-sources");
209 if (ret < 0) {
210 pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
211 } else {
212 num_entry = ret;
213 if (num_entry > 6)
214 num_entry = 6;
215
216 ret = of_property_read_u32_array(np, propname: "led-sources", out_values: sources,
217 sz: num_entry);
218 if (ret < 0) {
219 dev_err(dev, "led-sources node is invalid.\n");
220 of_node_put(node: np);
221 return ERR_PTR(error: -EINVAL);
222 }
223
224 pdata->enable = 0;
225 while (--num_entry)
226 pdata->enable |= (1 << sources[num_entry]);
227 }
228
229 ret = of_property_read_u32(np,
230 propname: "skyworks,short-detection-threshold-volt",
231 out_value: &pdata->short_detection_threshold);
232 if (ret < 0)
233 pdata->short_detection_threshold = 7;
234
235 ret = of_property_read_u32(np, propname: "skyworks,current-limit-mA",
236 out_value: &pdata->boost_current_limit);
237 if (ret < 0)
238 pdata->boost_current_limit = 2750;
239
240 of_node_put(node: np);
241 return pdata;
242}
243#else
244static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
245 struct device *dev)
246{
247 return ERR_PTR(-EINVAL);
248}
249#endif
250
251static int sky81452_bl_init_device(struct regmap *regmap,
252 struct sky81452_bl_platform_data *pdata)
253{
254 unsigned int value;
255
256 value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
257 value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
258 value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
259
260 if (pdata->boost_current_limit == 2300)
261 value |= SKY81452_ILIM;
262 else if (pdata->boost_current_limit != 2750)
263 return -EINVAL;
264
265 if (pdata->short_detection_threshold < 4 ||
266 pdata->short_detection_threshold > 7)
267 return -EINVAL;
268 value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
269
270 return regmap_write(map: regmap, SKY81452_REG2, val: value);
271}
272
273static int sky81452_bl_probe(struct platform_device *pdev)
274{
275 struct device *dev = &pdev->dev;
276 struct regmap *regmap = dev_get_drvdata(dev: dev->parent);
277 struct sky81452_bl_platform_data *pdata;
278 struct backlight_device *bd;
279 struct backlight_properties props;
280 const char *name;
281 int ret;
282
283 pdata = sky81452_bl_parse_dt(dev);
284 if (IS_ERR(ptr: pdata))
285 return PTR_ERR(ptr: pdata);
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, parent: dev, devdata: regmap,
297 ops: &sky81452_bl_ops, props: &props);
298 if (IS_ERR(ptr: bd)) {
299 dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
300 return PTR_ERR(ptr: bd);
301 }
302
303 platform_set_drvdata(pdev, data: bd);
304
305 ret = sysfs_create_group(kobj: &bd->dev.kobj, grp: &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 void sky81452_bl_remove(struct platform_device *pdev)
315{
316 const struct sky81452_bl_platform_data *pdata =
317 dev_get_platdata(dev: &pdev->dev);
318 struct backlight_device *bd = platform_get_drvdata(pdev);
319
320 sysfs_remove_group(kobj: &bd->dev.kobj, grp: &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 (pdata->gpiod_enable)
327 gpiod_set_value_cansleep(desc: pdata->gpiod_enable, value: 0);
328}
329
330#ifdef CONFIG_OF
331static const struct of_device_id sky81452_bl_of_match[] = {
332 { .compatible = "skyworks,sky81452-backlight", },
333 { }
334};
335MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
336#endif
337
338static struct platform_driver sky81452_bl_driver = {
339 .driver = {
340 .name = "sky81452-backlight",
341 .of_match_table = of_match_ptr(sky81452_bl_of_match),
342 },
343 .probe = sky81452_bl_probe,
344 .remove_new = sky81452_bl_remove,
345};
346
347module_platform_driver(sky81452_bl_driver);
348
349MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
350MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
351MODULE_LICENSE("GPL v2");
352

source code of linux/drivers/video/backlight/sky81452-backlight.c