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(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
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(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
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(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
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(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
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(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		of_node_put(np);
199		return ERR_PTR(-ENOMEM);
200	}
201
202	of_property_read_string(np, "name", &pdata->name);
203	pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");
204	pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
205	pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
206	pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);
207
208	ret = of_property_count_u32_elems(np, "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, "led-sources", sources,
217					num_entry);
218		if (ret < 0) {
219			dev_err(dev, "led-sources node is invalid.\n");
220			of_node_put(np);
221			return ERR_PTR(-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			"skyworks,short-detection-threshold-volt",
231			&pdata->short_detection_threshold);
232	if (ret < 0)
233		pdata->short_detection_threshold = 7;
234
235	ret = of_property_read_u32(np, "skyworks,current-limit-mA",
236			&pdata->boost_current_limit);
237	if (ret < 0)
238		pdata->boost_current_limit = 2750;
239
240	of_node_put(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(regmap, SKY81452_REG2, 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->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(pdata))
285		return PTR_ERR(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, 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 void 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 (pdata->gpiod_enable)
327		gpiod_set_value_cansleep(pdata->gpiod_enable, 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