LXR linux/drivers/leds/leds-ti-lmu-common.c

   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
  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