88pm860x_bl.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Backlight driver for Marvell Semiconductor 88PM8606
  4 *
  5 * Copyright (C) 2009 Marvell International Ltd.
  6 *	Haojian Zhuang <haojian.zhuang@marvell.com>
  7 */
  8
  9#include <linux/init.h>
 10#include <linux/kernel.h>
 11#include <linux/of.h>
 12#include <linux/platform_device.h>
 13#include <linux/slab.h>
 14#include <linux/i2c.h>
 15#include <linux/backlight.h>
 16#include <linux/mfd/88pm860x.h>
 17#include <linux/module.h>
 18
 19#define MAX_BRIGHTNESS		(0xFF)
 20#define MIN_BRIGHTNESS		(0)
 21
 22#define CURRENT_BITMASK		(0x1F << 1)
 23
 24struct pm860x_backlight_data {
 25	struct pm860x_chip *chip;
 26	struct i2c_client *i2c;
 27	int	current_brightness;
 28	int	port;
 29	int	pwm;
 30	int	iset;
 31	int	reg_duty_cycle;
 32	int	reg_always_on;
 33	int	reg_current;
 34};
 35
 36static int backlight_power_set(struct pm860x_chip *chip, int port,
 37		int on)
 38{
 39	int ret = -EINVAL;
 40
 41	switch (port) {
 42	case 0:
 43		ret = on ? pm8606_osc_enable(chip, WLED1_DUTY) :
 44			pm8606_osc_disable(chip, WLED1_DUTY);
 45		break;
 46	case 1:
 47		ret = on ? pm8606_osc_enable(chip, WLED2_DUTY) :
 48			pm8606_osc_disable(chip, WLED2_DUTY);
 49		break;
 50	case 2:
 51		ret = on ? pm8606_osc_enable(chip, WLED3_DUTY) :
 52			pm8606_osc_disable(chip, WLED3_DUTY);
 53		break;
 54	}
 55	return ret;
 56}
 57
 58static int pm860x_backlight_set(struct backlight_device *bl, int brightness)
 59{
 60	struct pm860x_backlight_data *data = bl_get_data(bl);
 61	struct pm860x_chip *chip = data->chip;
 62	unsigned char value;
 63	int ret;
 64
 65	if (brightness > MAX_BRIGHTNESS)
 66		value = MAX_BRIGHTNESS;
 67	else
 68		value = brightness;
 69
 70	if (brightness)
 71		backlight_power_set(chip, data->port, 1);
 72
 73	ret = pm860x_reg_write(data->i2c, data->reg_duty_cycle, value);
 74	if (ret < 0)
 75		goto out;
 76
 77	if ((data->current_brightness == 0) && brightness) {
 78		if (data->iset) {
 79			ret = pm860x_set_bits(data->i2c, data->reg_current,
 80					      CURRENT_BITMASK, data->iset);
 81			if (ret < 0)
 82				goto out;
 83		}
 84		if (data->pwm) {
 85			ret = pm860x_set_bits(data->i2c, PM8606_PWM,
 86					      PM8606_PWM_FREQ_MASK, data->pwm);
 87			if (ret < 0)
 88				goto out;
 89		}
 90		if (brightness == MAX_BRIGHTNESS) {
 91			/* set WLED_ON bit as 100% */
 92			ret = pm860x_set_bits(data->i2c, data->reg_always_on,
 93					      PM8606_WLED_ON, PM8606_WLED_ON);
 94		}
 95	} else {
 96		if (brightness == MAX_BRIGHTNESS) {
 97			/* set WLED_ON bit as 100% */
 98			ret = pm860x_set_bits(data->i2c, data->reg_always_on,
 99					      PM8606_WLED_ON, PM8606_WLED_ON);
100		} else {
101			/* clear WLED_ON bit since it's not 100% */
102			ret = pm860x_set_bits(data->i2c, data->reg_always_on,
103					      PM8606_WLED_ON, 0);
104		}
105	}
106	if (ret < 0)
107		goto out;
108
109	if (brightness == 0)
110		backlight_power_set(chip, data->port, 0);
111
112	dev_dbg(chip->dev, "set brightness %d\n", value);
113	data->current_brightness = value;
114	return 0;
115out:
116	dev_dbg(chip->dev, "set brightness %d failure with return value: %d\n",
117		value, ret);
118	return ret;
119}
120
121static int pm860x_backlight_update_status(struct backlight_device *bl)
122{
123	return pm860x_backlight_set(bl, backlight_get_brightness(bl));
124}
125
126static int pm860x_backlight_get_brightness(struct backlight_device *bl)
127{
128	struct pm860x_backlight_data *data = bl_get_data(bl);
129	struct pm860x_chip *chip = data->chip;
130	int ret;
131
132	ret = pm860x_reg_read(data->i2c, data->reg_duty_cycle);
133	if (ret < 0)
134		goto out;
135	data->current_brightness = ret;
136	dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
137	return data->current_brightness;
138out:
139	return -EINVAL;
140}
141
142static const struct backlight_ops pm860x_backlight_ops = {
143	.options	= BL_CORE_SUSPENDRESUME,
144	.update_status	= pm860x_backlight_update_status,
145	.get_brightness	= pm860x_backlight_get_brightness,
146};
147
148#ifdef CONFIG_OF
149static int pm860x_backlight_dt_init(struct platform_device *pdev,
150				    struct pm860x_backlight_data *data,
151				    char *name)
152{
153	struct device_node *nproot;
154	int iset = 0;
155
156	nproot = of_get_child_by_name(pdev->dev.parent->of_node, "backlights");
157	if (!nproot) {
158		dev_err(&pdev->dev, "failed to find backlights node\n");
159		return -ENODEV;
160	}
161	for_each_child_of_node_scoped(nproot, np) {
162		if (of_node_name_eq(np, name)) {
163			of_property_read_u32(np, "marvell,88pm860x-iset",
164					     &iset);
165			data->iset = PM8606_WLED_CURRENT(iset);
166			of_property_read_u32(np, "marvell,88pm860x-pwm",
167					     &data->pwm);
168			break;
169		}
170	}
171	of_node_put(nproot);
172	return 0;
173}
174#else
175#define pm860x_backlight_dt_init(x, y, z)	(-1)
176#endif
177
178static int pm860x_backlight_probe(struct platform_device *pdev)
179{
180	struct pm860x_chip *chip = dev_get_drvdata(pdev->dev.parent);
181	struct pm860x_backlight_pdata *pdata = dev_get_platdata(&pdev->dev);
182	struct pm860x_backlight_data *data;
183	struct backlight_device *bl;
184	struct resource *res;
185	struct backlight_properties props;
186	char name[MFD_NAME_SIZE];
187	int ret = 0;
188
189	data = devm_kzalloc(&pdev->dev, sizeof(struct pm860x_backlight_data),
190			    GFP_KERNEL);
191	if (data == NULL)
192		return -ENOMEM;
193	res = platform_get_resource_byname(pdev, IORESOURCE_REG, "duty cycle");
194	if (!res) {
195		dev_err(&pdev->dev, "No REG resource for duty cycle\n");
196		return -ENXIO;
197	}
198	data->reg_duty_cycle = res->start;
199	res = platform_get_resource_byname(pdev, IORESOURCE_REG, "always on");
200	if (!res) {
201		dev_err(&pdev->dev, "No REG resource for always on\n");
202		return -ENXIO;
203	}
204	data->reg_always_on = res->start;
205	res = platform_get_resource_byname(pdev, IORESOURCE_REG, "current");
206	if (!res) {
207		dev_err(&pdev->dev, "No REG resource for current\n");
208		return -ENXIO;
209	}
210	data->reg_current = res->start;
211
212	memset(name, 0, MFD_NAME_SIZE);
213	sprintf(name, "backlight-%d", pdev->id);
214	data->port = pdev->id;
215	data->chip = chip;
216	data->i2c = (chip->id == CHIP_PM8606) ? chip->client : chip->companion;
217	data->current_brightness = MAX_BRIGHTNESS;
218	if (pm860x_backlight_dt_init(pdev, data, name)) {
219		if (pdata) {
220			data->pwm = pdata->pwm;
221			data->iset = pdata->iset;
222		}
223	}
224
225	memset(&props, 0, sizeof(struct backlight_properties));
226	props.type = BACKLIGHT_RAW;
227	props.max_brightness = MAX_BRIGHTNESS;
228	bl = devm_backlight_device_register(&pdev->dev, name, &pdev->dev, data,
229					&pm860x_backlight_ops, &props);
230	if (IS_ERR(bl)) {
231		dev_err(&pdev->dev, "failed to register backlight\n");
232		return PTR_ERR(bl);
233	}
234	bl->props.brightness = MAX_BRIGHTNESS;
235
236	platform_set_drvdata(pdev, bl);
237
238	/* read current backlight */
239	ret = pm860x_backlight_get_brightness(bl);
240	if (ret < 0)
241		return ret;
242
243	backlight_update_status(bl);
244	return 0;
245}
246
247static struct platform_driver pm860x_backlight_driver = {
248	.driver		= {
249		.name	= "88pm860x-backlight",
250	},
251	.probe		= pm860x_backlight_probe,
252};
253
254module_platform_driver(pm860x_backlight_driver);
255
256MODULE_DESCRIPTION("Backlight Driver for Marvell Semiconductor 88PM8606");
257MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
258MODULE_LICENSE("GPL");
259MODULE_ALIAS("platform:88pm860x-backlight");