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/* Copyright 2018 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* TI LM3509 LED driver.
*/
#include "compile_time_macros.h"
#include "i2c.h"
#include "keyboard_backlight.h"
#include "lm3509.h"
static inline int lm3509_write(uint8_t reg, uint8_t val)
{
return i2c_write8(I2C_PORT_KBLIGHT, LM3509_I2C_ADDR_FLAGS,
reg, val);
}
static inline int lm3509_read(uint8_t reg, int *val)
{
return i2c_read8(I2C_PORT_KBLIGHT, LM3509_I2C_ADDR_FLAGS,
reg, val);
}
/* Brightness level (0.0 to 100.0%) to brightness register conversion table */
static const uint16_t lm3509_brightness[32] = {
0, 1, 6, 10, 11, 13, 16, 20,
24, 28, 31, 37, 43, 52, 62, 75,
87, 100, 125, 150, 168, 187, 225, 262,
312, 375, 437, 525, 612, 700, 875, 1000
};
static int brightness_to_bmain(int percent)
{
int i;
int b = percent * 10;
for (i = 1; i < sizeof(lm3509_brightness); i++) {
int low = lm3509_brightness[i - 1];
int high = lm3509_brightness[i];
if (high < b)
continue;
/* rounding to the nearest */
return (b - low < high - b) ? i - 1 : i;
}
/* Brightness is out of range. Return the highest value. */
return i - 1;
}
static int lm3509_power(int enable)
{
/* Enable both MAIN and SUB in unison mode.
* Don't alter brightness here. It's not driver's business. */
return lm3509_write(LM3509_REG_GP, enable ? 0x7 : 0);
}
static int lm3509_set_brightness(int percent)
{
/* We don't need to read/mask/write BMAIN because bit6 and 7 are non
* functional read only bits.
*/
return lm3509_write(LM3509_REG_BMAIN, brightness_to_bmain(percent));
}
static int lm3509_get_brightness(void)
{
int rv, val;
rv = lm3509_read(LM3509_REG_BMAIN, &val);
if (rv)
return -1;
val &= LM3509_BMAIN_MASK;
return lm3509_brightness[val] / 10;
}
static int lm3509_init(void)
{
return EC_SUCCESS;
}
const struct kblight_drv kblight_lm3509 = {
.init = lm3509_init,
.set = lm3509_set_brightness,
.get = lm3509_get_brightness,
.enable = lm3509_power,
};
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