1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Backlight driver for Maxim MAX8925 |
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/platform_device.h> |
12 | #include <linux/fb.h> |
13 | #include <linux/i2c.h> |
14 | #include <linux/backlight.h> |
15 | #include <linux/mfd/max8925.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/module.h> |
18 | |
19 | #define MAX_BRIGHTNESS (0xff) |
20 | #define MIN_BRIGHTNESS (0) |
21 | |
22 | #define LWX_FREQ(x) (((x - 601) / 100) & 0x7) |
23 | |
24 | struct max8925_backlight_data { |
25 | struct max8925_chip *chip; |
26 | |
27 | int current_brightness; |
28 | int reg_mode_cntl; |
29 | int reg_cntl; |
30 | }; |
31 | |
32 | static int max8925_backlight_set(struct backlight_device *bl, int brightness) |
33 | { |
34 | struct max8925_backlight_data *data = bl_get_data(bl_dev: bl); |
35 | struct max8925_chip *chip = data->chip; |
36 | unsigned char value; |
37 | int ret; |
38 | |
39 | if (brightness > MAX_BRIGHTNESS) |
40 | value = MAX_BRIGHTNESS; |
41 | else |
42 | value = brightness; |
43 | |
44 | ret = max8925_reg_write(chip->i2c, data->reg_cntl, value); |
45 | if (ret < 0) |
46 | goto out; |
47 | |
48 | if (!data->current_brightness && brightness) |
49 | /* enable WLED output */ |
50 | ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1); |
51 | else if (!brightness) |
52 | /* disable WLED output */ |
53 | ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0); |
54 | if (ret < 0) |
55 | goto out; |
56 | dev_dbg(chip->dev, "set brightness %d\n" , value); |
57 | data->current_brightness = value; |
58 | return 0; |
59 | out: |
60 | dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n" , |
61 | value, ret); |
62 | return ret; |
63 | } |
64 | |
65 | static int max8925_backlight_update_status(struct backlight_device *bl) |
66 | { |
67 | return max8925_backlight_set(bl, brightness: backlight_get_brightness(bd: bl)); |
68 | } |
69 | |
70 | static int max8925_backlight_get_brightness(struct backlight_device *bl) |
71 | { |
72 | struct max8925_backlight_data *data = bl_get_data(bl_dev: bl); |
73 | struct max8925_chip *chip = data->chip; |
74 | int ret; |
75 | |
76 | ret = max8925_reg_read(chip->i2c, data->reg_cntl); |
77 | if (ret < 0) |
78 | return -EINVAL; |
79 | data->current_brightness = ret; |
80 | dev_dbg(chip->dev, "get brightness %d\n" , data->current_brightness); |
81 | return ret; |
82 | } |
83 | |
84 | static const struct backlight_ops max8925_backlight_ops = { |
85 | .options = BL_CORE_SUSPENDRESUME, |
86 | .update_status = max8925_backlight_update_status, |
87 | .get_brightness = max8925_backlight_get_brightness, |
88 | }; |
89 | |
90 | static void max8925_backlight_dt_init(struct platform_device *pdev) |
91 | { |
92 | struct device_node *nproot = pdev->dev.parent->of_node, *np; |
93 | struct max8925_backlight_pdata *pdata; |
94 | u32 val; |
95 | |
96 | if (!nproot || !IS_ENABLED(CONFIG_OF)) |
97 | return; |
98 | |
99 | pdata = devm_kzalloc(dev: &pdev->dev, |
100 | size: sizeof(struct max8925_backlight_pdata), |
101 | GFP_KERNEL); |
102 | if (!pdata) |
103 | return; |
104 | |
105 | np = of_get_child_by_name(node: nproot, name: "backlight" ); |
106 | if (!np) { |
107 | dev_err(&pdev->dev, "failed to find backlight node\n" ); |
108 | return; |
109 | } |
110 | |
111 | if (!of_property_read_u32(np, propname: "maxim,max8925-dual-string" , out_value: &val)) |
112 | pdata->dual_string = val; |
113 | |
114 | of_node_put(node: np); |
115 | |
116 | pdev->dev.platform_data = pdata; |
117 | } |
118 | |
119 | static int max8925_backlight_probe(struct platform_device *pdev) |
120 | { |
121 | struct max8925_chip *chip = dev_get_drvdata(dev: pdev->dev.parent); |
122 | struct max8925_backlight_pdata *pdata; |
123 | struct max8925_backlight_data *data; |
124 | struct backlight_device *bl; |
125 | struct backlight_properties props; |
126 | struct resource *res; |
127 | unsigned char value; |
128 | int ret = 0; |
129 | |
130 | data = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct max8925_backlight_data), |
131 | GFP_KERNEL); |
132 | if (data == NULL) |
133 | return -ENOMEM; |
134 | |
135 | res = platform_get_resource(pdev, IORESOURCE_REG, 0); |
136 | if (!res) { |
137 | dev_err(&pdev->dev, "No REG resource for mode control!\n" ); |
138 | return -ENXIO; |
139 | } |
140 | data->reg_mode_cntl = res->start; |
141 | res = platform_get_resource(pdev, IORESOURCE_REG, 1); |
142 | if (!res) { |
143 | dev_err(&pdev->dev, "No REG resource for control!\n" ); |
144 | return -ENXIO; |
145 | } |
146 | data->reg_cntl = res->start; |
147 | |
148 | data->chip = chip; |
149 | data->current_brightness = 0; |
150 | |
151 | memset(&props, 0, sizeof(struct backlight_properties)); |
152 | props.type = BACKLIGHT_RAW; |
153 | props.max_brightness = MAX_BRIGHTNESS; |
154 | bl = devm_backlight_device_register(dev: &pdev->dev, name: "max8925-backlight" , |
155 | parent: &pdev->dev, devdata: data, |
156 | ops: &max8925_backlight_ops, props: &props); |
157 | if (IS_ERR(ptr: bl)) { |
158 | dev_err(&pdev->dev, "failed to register backlight\n" ); |
159 | return PTR_ERR(ptr: bl); |
160 | } |
161 | bl->props.brightness = MAX_BRIGHTNESS; |
162 | |
163 | platform_set_drvdata(pdev, data: bl); |
164 | |
165 | value = 0; |
166 | if (!pdev->dev.platform_data) |
167 | max8925_backlight_dt_init(pdev); |
168 | |
169 | pdata = pdev->dev.platform_data; |
170 | if (pdata) { |
171 | if (pdata->lxw_scl) |
172 | value |= (1 << 7); |
173 | if (pdata->lxw_freq) |
174 | value |= (LWX_FREQ(pdata->lxw_freq) << 4); |
175 | if (pdata->dual_string) |
176 | value |= (1 << 1); |
177 | } |
178 | ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value); |
179 | if (ret < 0) |
180 | return ret; |
181 | backlight_update_status(bd: bl); |
182 | return 0; |
183 | } |
184 | |
185 | static struct platform_driver max8925_backlight_driver = { |
186 | .driver = { |
187 | .name = "max8925-backlight" , |
188 | }, |
189 | .probe = max8925_backlight_probe, |
190 | }; |
191 | |
192 | module_platform_driver(max8925_backlight_driver); |
193 | |
194 | MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925" ); |
195 | MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>" ); |
196 | MODULE_LICENSE("GPL" ); |
197 | MODULE_ALIAS("platform:max8925-backlight" ); |
198 | |