1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright 2015 Texas Instruments
3 // Copyright 2018 Sebastian Reichel
4 // Copyright 2018 Pavel Machek <pavel@ucw.cz>
5 // TI LMU LED common framework, based on previous work from
6 // Milo Kim <milo.kim@ti.com>
7
8 #include <linux/bitops.h>
9 #include <linux/err.h>
10 #include <linux/of_device.h>
11
12 #include <linux/leds-ti-lmu-common.h>
13
14 static const unsigned int ramp_table[16] = {2048, 262000, 524000, 1049000,
15 2090000, 4194000, 8389000, 16780000, 33550000,
16 41940000, 50330000, 58720000, 67110000,
17 83880000, 100660000, 117440000};
18
ti_lmu_common_update_brightness(struct ti_lmu_bank * lmu_bank,int brightness)19 static int ti_lmu_common_update_brightness(struct ti_lmu_bank *lmu_bank,
20 int brightness)
21 {
22 struct regmap *regmap = lmu_bank->regmap;
23 u8 reg, val;
24 int ret;
25
26 /*
27 * Brightness register update
28 *
29 * 11 bit dimming: update LSB bits and write MSB byte.
30 * MSB brightness should be shifted.
31 * 8 bit dimming: write MSB byte.
32 */
33 if (lmu_bank->max_brightness == MAX_BRIGHTNESS_11BIT) {
34 reg = lmu_bank->lsb_brightness_reg;
35 ret = regmap_update_bits(regmap, reg,
36 LMU_11BIT_LSB_MASK,
37 brightness);
38 if (ret)
39 return ret;
40
41 val = brightness >> LMU_11BIT_MSB_SHIFT;
42 } else {
43 val = brightness;
44 }
45
46 reg = lmu_bank->msb_brightness_reg;
47
48 return regmap_write(regmap, reg, val);
49 }
50
ti_lmu_common_set_brightness(struct ti_lmu_bank * lmu_bank,int brightness)51 int ti_lmu_common_set_brightness(struct ti_lmu_bank *lmu_bank, int brightness)
52 {
53 return ti_lmu_common_update_brightness(lmu_bank, brightness);
54 }
55 EXPORT_SYMBOL(ti_lmu_common_set_brightness);
56
ti_lmu_common_convert_ramp_to_index(unsigned int usec)57 static unsigned int ti_lmu_common_convert_ramp_to_index(unsigned int usec)
58 {
59 int size = ARRAY_SIZE(ramp_table);
60 int i;
61
62 if (usec <= ramp_table[0])
63 return 0;
64
65 if (usec > ramp_table[size - 1])
66 return size - 1;
67
68 for (i = 1; i < size; i++) {
69 if (usec == ramp_table[i])
70 return i;
71
72 /* Find an approximate index by looking up the table */
73 if (usec > ramp_table[i - 1] && usec < ramp_table[i]) {
74 if (usec - ramp_table[i - 1] < ramp_table[i] - usec)
75 return i - 1;
76 else
77 return i;
78 }
79 }
80
81 return 0;
82 }
83
ti_lmu_common_set_ramp(struct ti_lmu_bank * lmu_bank)84 int ti_lmu_common_set_ramp(struct ti_lmu_bank *lmu_bank)
85 {
86 struct regmap *regmap = lmu_bank->regmap;
87 u8 ramp, ramp_up, ramp_down;
88
89 if (lmu_bank->ramp_up_usec == 0 && lmu_bank->ramp_down_usec == 0) {
90 ramp_up = 0;
91 ramp_down = 0;
92 } else {
93 ramp_up = ti_lmu_common_convert_ramp_to_index(lmu_bank->ramp_up_usec);
94 ramp_down = ti_lmu_common_convert_ramp_to_index(lmu_bank->ramp_down_usec);
95 }
96
97 ramp = (ramp_up << 4) | ramp_down;
98
99 return regmap_write(regmap, lmu_bank->runtime_ramp_reg, ramp);
100
101 }
102 EXPORT_SYMBOL(ti_lmu_common_set_ramp);
103
ti_lmu_common_get_ramp_params(struct device * dev,struct fwnode_handle * child,struct ti_lmu_bank * lmu_data)104 int ti_lmu_common_get_ramp_params(struct device *dev,
105 struct fwnode_handle *child,
106 struct ti_lmu_bank *lmu_data)
107 {
108 int ret;
109
110 ret = fwnode_property_read_u32(child, "ramp-up-us",
111 &lmu_data->ramp_up_usec);
112 if (ret)
113 dev_warn(dev, "ramp-up-us property missing\n");
114
115
116 ret = fwnode_property_read_u32(child, "ramp-down-us",
117 &lmu_data->ramp_down_usec);
118 if (ret)
119 dev_warn(dev, "ramp-down-us property missing\n");
120
121 return 0;
122 }
123 EXPORT_SYMBOL(ti_lmu_common_get_ramp_params);
124
ti_lmu_common_get_brt_res(struct device * dev,struct fwnode_handle * child,struct ti_lmu_bank * lmu_data)125 int ti_lmu_common_get_brt_res(struct device *dev, struct fwnode_handle *child,
126 struct ti_lmu_bank *lmu_data)
127 {
128 int ret;
129
130 ret = device_property_read_u32(dev, "ti,brightness-resolution",
131 &lmu_data->max_brightness);
132 if (ret)
133 ret = fwnode_property_read_u32(child,
134 "ti,brightness-resolution",
135 &lmu_data->max_brightness);
136 if (lmu_data->max_brightness <= 0) {
137 lmu_data->max_brightness = MAX_BRIGHTNESS_8BIT;
138 return ret;
139 }
140
141 if (lmu_data->max_brightness > MAX_BRIGHTNESS_11BIT)
142 lmu_data->max_brightness = MAX_BRIGHTNESS_11BIT;
143
144
145 return 0;
146 }
147 EXPORT_SYMBOL(ti_lmu_common_get_brt_res);
148
149 MODULE_DESCRIPTION("TI LMU common LED framework");
150 MODULE_AUTHOR("Sebastian Reichel");
151 MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
152 MODULE_LICENSE("GPL v2");
153 MODULE_ALIAS("ti-lmu-led-common");
154