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