141 lines
3.1 KiB
C
141 lines
3.1 KiB
C
/*
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* Copyright (c) 2017 Linaro Ltd.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Driver for ARM's SBCon 2-wire serial bus interface
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*
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* SBCon is a simple device which allows directly setting and getting the
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* hardware state of two-bit serial interfaces like I2C.
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*/
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#include <board.h>
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#include <device.h>
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#include <errno.h>
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#include <i2c.h>
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#include <i2c_bitbang.h>
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/* SBCon hardware registers layout */
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struct sbcon {
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union {
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volatile u32_t SB_CONTROLS; /* Write to set pins high */
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volatile u32_t SB_CONTROL; /* Read for state of pins */
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};
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volatile u32_t SB_CONTROLC; /* Write to set pins low */
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};
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/* Bits values for SCL and SDA lines in struct sbcon registers */
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#define SCL BIT(0)
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#define SDA BIT(1)
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/* Driver config */
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struct i2c_sbcon_config {
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struct sbcon *sbcon; /* Address of hardware registers */
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};
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/* Driver instance data */
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struct i2c_sbcon_context {
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struct i2c_bitbang bitbang; /* Bit-bang library data */
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};
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static void i2c_sbcon_set_scl(void *io_context, int state)
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{
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struct sbcon *sbcon = io_context;
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if (state) {
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sbcon->SB_CONTROLS = SCL;
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} else {
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sbcon->SB_CONTROLC = SCL;
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}
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}
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static void i2c_sbcon_set_sda(void *io_context, int state)
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{
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struct sbcon *sbcon = io_context;
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if (state) {
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sbcon->SB_CONTROLS = SDA;
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} else {
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sbcon->SB_CONTROLC = SDA;
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}
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}
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static int i2c_sbcon_get_sda(void *io_context)
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{
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struct sbcon *sbcon = io_context;
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return sbcon->SB_CONTROL & SDA;
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}
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static const struct i2c_bitbang_io io_fns = {
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.set_scl = &i2c_sbcon_set_scl,
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.set_sda = &i2c_sbcon_set_sda,
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.get_sda = &i2c_sbcon_get_sda,
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};
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static int i2c_sbcon_configure(struct device *dev, u32_t dev_config)
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{
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struct i2c_sbcon_context *context = dev->driver_data;
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return i2c_bitbang_configure(&context->bitbang, dev_config);
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}
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static int i2c_sbcon_transfer(struct device *dev, struct i2c_msg *msgs,
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u8_t num_msgs, u16_t slave_address)
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{
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struct i2c_sbcon_context *context = dev->driver_data;
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return i2c_bitbang_transfer(&context->bitbang, msgs, num_msgs,
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slave_address);
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}
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static struct i2c_driver_api api = {
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.configure = i2c_sbcon_configure,
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.transfer = i2c_sbcon_transfer,
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};
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static int i2c_sbcon_init(struct device *dev)
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{
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struct i2c_sbcon_context *context = dev->driver_data;
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const struct i2c_sbcon_config *config = dev->config->config_info;
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i2c_bitbang_init(&context->bitbang, &io_fns, config->sbcon);
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dev->driver_api = &api;
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return 0;
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}
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#define DEFINE_I2C_SBCON(_num) \
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\
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static struct i2c_sbcon_context i2c_sbcon_dev_data_##_num; \
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\
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static const struct i2c_sbcon_config i2c_sbcon_dev_cfg_##_num = { \
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.sbcon = (void *)I2C_SBCON_##_num##_BASE_ADDR, \
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}; \
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\
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DEVICE_INIT(i2c_sbcon_##_num, CONFIG_I2C_SBCON_##_num##_NAME, \
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i2c_sbcon_init, \
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&i2c_sbcon_dev_data_##_num, \
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&i2c_sbcon_dev_cfg_##_num, \
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PRE_KERNEL_2, CONFIG_I2C_INIT_PRIORITY)
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#ifdef CONFIG_I2C_SBCON_0
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DEFINE_I2C_SBCON(0);
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#endif
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#ifdef CONFIG_I2C_SBCON_1
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DEFINE_I2C_SBCON(1);
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#endif
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#ifdef CONFIG_I2C_SBCON_2
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DEFINE_I2C_SBCON(2);
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#endif
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#ifdef CONFIG_I2C_SBCON_3
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DEFINE_I2C_SBCON(3);
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#endif
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