sky81452-backlight.c

  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 = 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		return ERR_PTR(-ENOMEM);
199
200	of_property_read_string(np, "name", &pdata->name);
201	pdata->ignore_pwm = of_property_read_bool(np, "skyworks,ignore-pwm");
202	pdata->dpwm_mode = of_property_read_bool(np, "skyworks,dpwm-mode");
203	pdata->phase_shift = of_property_read_bool(np, "skyworks,phase-shift");
204	pdata->gpiod_enable = devm_gpiod_get_optional(dev, NULL, GPIOD_OUT_HIGH);
205
206	ret = of_property_count_u32_elems(np, "led-sources");
207	if (ret < 0) {
208		pdata->enable = SKY81452_EN >> CTZ(SKY81452_EN);
209	} else {
210		num_entry = ret;
211		if (num_entry > 6)
212			num_entry = 6;
213
214		ret = of_property_read_u32_array(np, "led-sources", sources,
215					num_entry);
216		if (ret < 0) {
217			dev_err(dev, "led-sources node is invalid.\n");
218			return ERR_PTR(-EINVAL);
219		}
220
221		pdata->enable = 0;
222		while (--num_entry)
223			pdata->enable |= (1 << sources[num_entry]);
224	}
225
226	ret = of_property_read_u32(np,
227			"skyworks,short-detection-threshold-volt",
228			&pdata->short_detection_threshold);
229	if (ret < 0)
230		pdata->short_detection_threshold = 7;
231
232	ret = of_property_read_u32(np, "skyworks,current-limit-mA",
233			&pdata->boost_current_limit);
234	if (ret < 0)
235		pdata->boost_current_limit = 2750;
236
237	return pdata;
238}
239#else
240static struct sky81452_bl_platform_data *sky81452_bl_parse_dt(
241							struct device *dev)
242{
243	return ERR_PTR(-EINVAL);
244}
245#endif
246
247static int sky81452_bl_init_device(struct regmap *regmap,
248		struct sky81452_bl_platform_data *pdata)
249{
250	unsigned int value;
251
252	value = pdata->ignore_pwm ? SKY81452_IGPW : 0;
253	value |= pdata->dpwm_mode ? SKY81452_PWMMD : 0;
254	value |= pdata->phase_shift ? 0 : SKY81452_PHASE;
255
256	if (pdata->boost_current_limit == 2300)
257		value |= SKY81452_ILIM;
258	else if (pdata->boost_current_limit != 2750)
259		return -EINVAL;
260
261	if (pdata->short_detection_threshold < 4 ||
262				pdata->short_detection_threshold > 7)
263		return -EINVAL;
264	value |= (7 - pdata->short_detection_threshold) << CTZ(SKY81452_VSHRT);
265
266	return regmap_write(regmap, SKY81452_REG2, value);
267}
268
269static int sky81452_bl_probe(struct platform_device *pdev)
270{
271	struct device *dev = &pdev->dev;
272	struct regmap *regmap = dev_get_drvdata(dev->parent);
273	struct sky81452_bl_platform_data *pdata;
274	struct backlight_device *bd;
275	struct backlight_properties props;
276	const char *name;
277	int ret;
278
279	pdata = sky81452_bl_parse_dt(dev);
280	if (IS_ERR(pdata))
281		return PTR_ERR(pdata);
282
283	ret = sky81452_bl_init_device(regmap, pdata);
284	if (ret < 0) {
285		dev_err(dev, "failed to initialize. err=%d\n", ret);
286		return ret;
287	}
288
289	memset(&props, 0, sizeof(props));
290	props.max_brightness = SKY81452_MAX_BRIGHTNESS;
291	name = pdata->name ? pdata->name : SKY81452_DEFAULT_NAME;
292	bd = devm_backlight_device_register(dev, name, dev, regmap,
293						&sky81452_bl_ops, &props);
294	if (IS_ERR(bd)) {
295		dev_err(dev, "failed to register. err=%ld\n", PTR_ERR(bd));
296		return PTR_ERR(bd);
297	}
298
299	platform_set_drvdata(pdev, bd);
300
301	ret = sysfs_create_group(&bd->dev.kobj, &sky81452_bl_attr_group);
302	if (ret < 0) {
303		dev_err(dev, "failed to create attribute. err=%d\n", ret);
304		return ret;
305	}
306
307	return ret;
308}
309
310static void sky81452_bl_remove(struct platform_device *pdev)
311{
312	const struct sky81452_bl_platform_data *pdata =
313						dev_get_platdata(&pdev->dev);
314	struct backlight_device *bd = platform_get_drvdata(pdev);
315
316	sysfs_remove_group(&bd->dev.kobj, &sky81452_bl_attr_group);
317
318	bd->props.power = BACKLIGHT_POWER_ON;
319	bd->props.brightness = 0;
320	backlight_update_status(bd);
321
322	if (pdata->gpiod_enable)
323		gpiod_set_value_cansleep(pdata->gpiod_enable, 0);
324}
325
326#ifdef CONFIG_OF
327static const struct of_device_id sky81452_bl_of_match[] = {
328	{ .compatible = "skyworks,sky81452-backlight", },
329	{ }
330};
331MODULE_DEVICE_TABLE(of, sky81452_bl_of_match);
332#endif
333
334static struct platform_driver sky81452_bl_driver = {
335	.driver = {
336		.name = "sky81452-backlight",
337		.of_match_table = of_match_ptr(sky81452_bl_of_match),
338	},
339	.probe = sky81452_bl_probe,
340	.remove = sky81452_bl_remove,
341};
342
343module_platform_driver(sky81452_bl_driver);
344
345MODULE_DESCRIPTION("Skyworks SKY81452 backlight driver");
346MODULE_AUTHOR("Gyungoh Yoo <jack.yoo@skyworksinc.com>");
347MODULE_LICENSE("GPL v2");