1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Backlight driver for the Kinetic KTZ8866
4 *
5 * Copyright (C) 2022, 2023 Jianhua Lu <lujianhua000@gmail.com>
6 */
7
8#include <linux/backlight.h>
9#include <linux/err.h>
10#include <linux/gpio/consumer.h>
11#include <linux/i2c.h>
12#include <linux/module.h>
13#include <linux/of.h>
14#include <linux/regmap.h>
15
16#define DEFAULT_BRIGHTNESS 1500
17#define MAX_BRIGHTNESS 2047
18#define REG_MAX 0x15
19
20/* reg */
21#define DEVICE_ID 0x01
22#define BL_CFG1 0x02
23#define BL_CFG2 0x03
24#define BL_BRT_LSB 0x04
25#define BL_BRT_MSB 0x05
26#define BL_EN 0x08
27#define LCD_BIAS_CFG1 0x09
28#define LCD_BIAS_CFG2 0x0A
29#define LCD_BIAS_CFG3 0x0B
30#define LCD_BOOST_CFG 0x0C
31#define OUTP_CFG 0x0D
32#define OUTN_CFG 0x0E
33#define FLAG 0x0F
34#define BL_OPTION1 0x10
35#define BL_OPTION2 0x11
36#define PWM2DIG_LSBs 0x12
37#define PWM2DIG_MSBs 0x13
38#define BL_DIMMING 0x14
39#define PWM_RAMP_TIME 0x15
40
41/* definition */
42#define BL_EN_BIT BIT(6)
43#define LCD_BIAS_EN 0x9F
44#define PWM_HYST 0x5
45
46struct ktz8866 {
47 struct i2c_client *client;
48 struct regmap *regmap;
49 bool led_on;
50 struct gpio_desc *enable_gpio;
51};
52
53static const struct regmap_config ktz8866_regmap_config = {
54 .reg_bits = 8,
55 .val_bits = 8,
56 .max_register = REG_MAX,
57};
58
59static int ktz8866_write(struct ktz8866 *ktz, unsigned int reg,
60 unsigned int val)
61{
62 return regmap_write(map: ktz->regmap, reg, val);
63}
64
65static int ktz8866_update_bits(struct ktz8866 *ktz, unsigned int reg,
66 unsigned int mask, unsigned int val)
67{
68 return regmap_update_bits(map: ktz->regmap, reg, mask, val);
69}
70
71static int ktz8866_backlight_update_status(struct backlight_device *backlight_dev)
72{
73 struct ktz8866 *ktz = bl_get_data(bl_dev: backlight_dev);
74 unsigned int brightness = backlight_get_brightness(bd: backlight_dev);
75
76 if (!ktz->led_on && brightness > 0) {
77 ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, BL_EN_BIT);
78 ktz->led_on = true;
79 } else if (brightness == 0) {
80 ktz8866_update_bits(ktz, BL_EN, BL_EN_BIT, val: 0);
81 ktz->led_on = false;
82 }
83
84 /* Set brightness */
85 ktz8866_write(ktz, BL_BRT_LSB, val: brightness & 0x7);
86 ktz8866_write(ktz, BL_BRT_MSB, val: (brightness >> 3) & 0xFF);
87
88 return 0;
89}
90
91static const struct backlight_ops ktz8866_backlight_ops = {
92 .options = BL_CORE_SUSPENDRESUME,
93 .update_status = ktz8866_backlight_update_status,
94};
95
96static void ktz8866_init(struct ktz8866 *ktz)
97{
98 unsigned int val = 0;
99
100 if (!of_property_read_u32(np: ktz->client->dev.of_node, propname: "current-num-sinks", out_value: &val))
101 ktz8866_write(ktz, BL_EN, BIT(val) - 1);
102 else
103 /* Enable all 6 current sinks if the number of current sinks isn't specified. */
104 ktz8866_write(ktz, BL_EN, BIT(6) - 1);
105
106 if (!of_property_read_u32(np: ktz->client->dev.of_node, propname: "kinetic,current-ramp-delay-ms", out_value: &val)) {
107 if (val <= 128)
108 ktz8866_write(ktz, BL_CFG2, BIT(7) | (ilog2(val) << 3) | PWM_HYST);
109 else
110 ktz8866_write(ktz, BL_CFG2, BIT(7) | ((5 + val / 64) << 3) | PWM_HYST);
111 }
112
113 if (!of_property_read_u32(np: ktz->client->dev.of_node, propname: "kinetic,led-enable-ramp-delay-ms", out_value: &val)) {
114 if (val == 0)
115 ktz8866_write(ktz, BL_DIMMING, val: 0);
116 else {
117 unsigned int ramp_off_time = ilog2(val) + 1;
118 unsigned int ramp_on_time = ramp_off_time << 4;
119 ktz8866_write(ktz, BL_DIMMING, val: ramp_on_time | ramp_off_time);
120 }
121 }
122
123 if (of_property_read_bool(np: ktz->client->dev.of_node, propname: "kinetic,enable-lcd-bias"))
124 ktz8866_write(ktz, LCD_BIAS_CFG1, LCD_BIAS_EN);
125}
126
127static int ktz8866_probe(struct i2c_client *client)
128{
129 struct backlight_device *backlight_dev;
130 struct backlight_properties props;
131 struct ktz8866 *ktz;
132 int ret = 0;
133
134 ktz = devm_kzalloc(dev: &client->dev, size: sizeof(*ktz), GFP_KERNEL);
135 if (!ktz)
136 return -ENOMEM;
137
138 ktz->client = client;
139 ktz->regmap = devm_regmap_init_i2c(client, &ktz8866_regmap_config);
140 if (IS_ERR(ptr: ktz->regmap))
141 return dev_err_probe(dev: &client->dev, err: PTR_ERR(ptr: ktz->regmap), fmt: "failed to init regmap\n");
142
143 ret = devm_regulator_get_enable(dev: &client->dev, id: "vddpos");
144 if (ret)
145 return dev_err_probe(dev: &client->dev, err: ret, fmt: "get regulator vddpos failed\n");
146 ret = devm_regulator_get_enable(dev: &client->dev, id: "vddneg");
147 if (ret)
148 return dev_err_probe(dev: &client->dev, err: ret, fmt: "get regulator vddneg failed\n");
149
150 ktz->enable_gpio = devm_gpiod_get_optional(dev: &client->dev, con_id: "enable", flags: GPIOD_OUT_HIGH);
151 if (IS_ERR(ptr: ktz->enable_gpio))
152 return PTR_ERR(ptr: ktz->enable_gpio);
153
154 memset(&props, 0, sizeof(props));
155 props.type = BACKLIGHT_RAW;
156 props.max_brightness = MAX_BRIGHTNESS;
157 props.brightness = DEFAULT_BRIGHTNESS;
158 props.scale = BACKLIGHT_SCALE_LINEAR;
159
160 backlight_dev = devm_backlight_device_register(dev: &client->dev, name: "ktz8866-backlight",
161 parent: &client->dev, devdata: ktz, ops: &ktz8866_backlight_ops, props: &props);
162 if (IS_ERR(ptr: backlight_dev))
163 return dev_err_probe(dev: &client->dev, err: PTR_ERR(ptr: backlight_dev),
164 fmt: "failed to register backlight device\n");
165
166 ktz8866_init(ktz);
167
168 i2c_set_clientdata(client, data: backlight_dev);
169 backlight_update_status(bd: backlight_dev);
170
171 return 0;
172}
173
174static void ktz8866_remove(struct i2c_client *client)
175{
176 struct backlight_device *backlight_dev = i2c_get_clientdata(client);
177 backlight_dev->props.brightness = 0;
178 backlight_update_status(bd: backlight_dev);
179}
180
181static const struct i2c_device_id ktz8866_ids[] = {
182 { "ktz8866", 0 },
183 {},
184};
185MODULE_DEVICE_TABLE(i2c, ktz8866_ids);
186
187static const struct of_device_id ktz8866_match_table[] = {
188 {
189 .compatible = "kinetic,ktz8866",
190 },
191 {},
192};
193
194static struct i2c_driver ktz8866_driver = {
195 .driver = {
196 .name = "ktz8866",
197 .of_match_table = ktz8866_match_table,
198 },
199 .probe = ktz8866_probe,
200 .remove = ktz8866_remove,
201 .id_table = ktz8866_ids,
202};
203
204module_i2c_driver(ktz8866_driver);
205
206MODULE_DESCRIPTION("Kinetic KTZ8866 Backlight Driver");
207MODULE_AUTHOR("Jianhua Lu <lujianhua000@gmail.com>");
208MODULE_LICENSE("GPL");
209

source code of linux/drivers/video/backlight/ktz8866.c