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"); 154