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d258f8a788
This chip controls the keyboard backlight. The backlight level is set through PWM, but the chip needs to be enabled and configured before PWM settings are recognized. This will be initially used for grunt and zoombini. BUG=b:69379749 BRANCH=none TEST=In EC console for grunt: kblight 100; kblight 0 Change-Id: I5576d709687d8f61b5757485baa239ffd6b41a74 Signed-off-by: Benjamin Gordon <bmgordon@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/879082 Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: Aseda Aboagye <aaboagye@chromium.org> Reviewed-by: Edward Hill <ecgh@chromium.org>
70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
/* Copyright 2018 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*
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* TI LM3630A LED driver.
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*/
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#include "i2c.h"
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#include "lm3630a.h"
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/* 8-bit I2C address */
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#define LM3630A_I2C_ADDR (0x36 << 1)
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static inline int lm3630a_write(uint8_t reg, uint8_t val)
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{
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return i2c_write8(I2C_PORT_KBLIGHT, LM3630A_I2C_ADDR, reg, val);
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}
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static inline int lm3630a_read(uint8_t reg, int *val)
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{
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return i2c_read8(I2C_PORT_KBLIGHT, LM3630A_I2C_ADDR, reg, val);
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}
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int lm3630a_poweron(void)
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{
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int ret = 0;
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/* Sample PWM every 8 periods. */
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ret |= lm3630a_write(LM3630A_REG_FILTER_STRENGTH, 0x3);
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/* Enable feedback and PWM for banks A & B. */
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ret |= lm3630a_write(LM3630A_REG_CONFIG,
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LM3630A_CFG_BIT_FB_EN_A |
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LM3630A_CFG_BIT_FB_EN_B |
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LM3630A_CFG_BIT_PWM_EN_A |
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LM3630A_CFG_BIT_PWM_EN_B);
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/* 24V, 800mA overcurrent protection, 500kHz boost frequency. */
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ret |= lm3630a_write(LM3630A_REG_BOOST_CONTROL,
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LM3630A_BOOST_OVP_24V |
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LM3630A_BOOST_OCP_800MA |
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LM3630A_FMODE_500KHZ);
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/* Limit current to 24.5mA */
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ret |= lm3630a_write(LM3630A_REG_A_CURRENT, 0x1a);
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ret |= lm3630a_write(LM3630A_REG_B_CURRENT, 0x1a);
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/* Enable both banks, put in linear mode, and connect LED2 to bank A. */
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ret |= lm3630a_write(LM3630A_REG_CONTROL,
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LM3630A_CTRL_BIT_LINEAR_A |
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LM3630A_CTRL_BIT_LINEAR_B |
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LM3630A_CTRL_BIT_LED_EN_A |
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LM3630A_CTRL_BIT_LED_EN_B |
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LM3630A_CTRL_BIT_LED2_ON_A);
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/*
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* Set full brightness so that PWM will control. This needs to happen
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* after setting the control register, because enabling the banks
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* resets the value to 0.
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*/
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ret |= lm3630a_write(LM3630A_REG_A_BRIGHTNESS, 0xff);
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return ret;
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}
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int lm3630a_poweroff(void)
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{
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return lm3630a_write(LM3630A_REG_CONTROL, LM3630A_CTRL_BIT_SLEEP_CMD);
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}
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