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/property.h>
11
12#include <linux/leds-ti-lmu-common.h>
13
14static 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
19static 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
51int 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}
55EXPORT_SYMBOL(ti_lmu_common_set_brightness);
56
57static 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
84int 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}
102EXPORT_SYMBOL(ti_lmu_common_set_ramp);
103
104int 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}
123EXPORT_SYMBOL(ti_lmu_common_get_ramp_params);
124
125int 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}
147EXPORT_SYMBOL(ti_lmu_common_get_brt_res);
148
149MODULE_DESCRIPTION("TI LMU common LED framework");
150MODULE_AUTHOR("Sebastian Reichel");
151MODULE_AUTHOR("Dan Murphy <dmurphy@ti.com>");
152MODULE_LICENSE("GPL v2");
153MODULE_ALIAS("ti-lmu-led-common");
154