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
  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
  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
  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
  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
  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
 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
 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");