140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
/*
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* Copyright (c) 2019 Antmicro <www.antmicro.com>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#define DT_DRV_COMPAT litex_i2c
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#include <device.h>
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#include <drivers/i2c.h>
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#include "i2c_bitbang.h"
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#define SCL_BIT_POS 0
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#define SDA_DIR_BIT_POS 1
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#define SDA_BIT_W_POS 2
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#define SDA_BIT_R_POS 0
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#define SDA_DIR_OUTPUT 1
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#define SDA_DIR_INPUT 0
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#define HIGH_STATE_ON_I2C_LINES 0x7
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struct i2c_litex_cfg {
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volatile uint32_t *w_reg;
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volatile const uint32_t *r_reg;
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};
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#define GET_I2C_CFG(dev) \
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((const struct i2c_litex_cfg *) dev->config)
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#define GET_I2C_BITBANG(dev) \
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((struct i2c_bitbang *) dev->data)
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static inline void set_bit(volatile uint32_t *reg, uint32_t bit, uint32_t val)
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{
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uint32_t mask = BIT(bit);
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if (val) {
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*reg |= mask;
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} else {
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*reg &= ~mask;
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}
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}
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static inline int get_bit(volatile const uint32_t *reg, uint32_t bit)
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{
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uint32_t mask = BIT(bit);
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return !!((*reg) & mask);
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}
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static void i2c_litex_bitbang_set_scl(void *context, int state)
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{
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const struct i2c_litex_cfg *config =
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(const struct i2c_litex_cfg *) context;
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set_bit(config->w_reg, SCL_BIT_POS, state);
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}
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static void i2c_litex_bitbang_set_sda(void *context, int state)
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{
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const struct i2c_litex_cfg *config =
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(const struct i2c_litex_cfg *) context;
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set_bit(config->w_reg, SDA_DIR_BIT_POS, SDA_DIR_OUTPUT);
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set_bit(config->w_reg, SDA_BIT_W_POS, state);
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}
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static int i2c_litex_bitbang_get_sda(void *context)
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{
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const struct i2c_litex_cfg *config =
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(const struct i2c_litex_cfg *) context;
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set_bit(config->w_reg, SDA_DIR_BIT_POS, SDA_DIR_INPUT);
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return get_bit(config->r_reg, SDA_BIT_R_POS);
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}
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static const struct i2c_bitbang_io i2c_litex_bitbang_io = {
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.set_scl = i2c_litex_bitbang_set_scl,
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.set_sda = i2c_litex_bitbang_set_sda,
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.get_sda = i2c_litex_bitbang_get_sda,
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};
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static int i2c_litex_init(const struct device *dev)
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{
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const struct i2c_litex_cfg *config = GET_I2C_CFG(dev);
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struct i2c_bitbang *bitbang = GET_I2C_BITBANG(dev);
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*(config->w_reg) |= HIGH_STATE_ON_I2C_LINES;
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i2c_bitbang_init(bitbang, &i2c_litex_bitbang_io, (void *)config);
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return 0;
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}
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static int i2c_litex_configure(const struct device *dev, uint32_t dev_config)
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{
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struct i2c_bitbang *bitbang = GET_I2C_BITBANG(dev);
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return i2c_bitbang_configure(bitbang, dev_config);
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}
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static int i2c_litex_transfer(const struct device *dev, struct i2c_msg *msgs,
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uint8_t num_msgs, uint16_t addr)
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{
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struct i2c_bitbang *bitbang = GET_I2C_BITBANG(dev);
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return i2c_bitbang_transfer(bitbang, msgs, num_msgs, addr);
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}
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static const struct i2c_driver_api i2c_litex_driver_api = {
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.configure = i2c_litex_configure,
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.transfer = i2c_litex_transfer,
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.slave_register = NULL,
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.slave_unregister = NULL,
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};
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/* Device Instantiation */
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#define I2C_LITEX_INIT(n) \
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static const struct i2c_litex_cfg i2c_litex_cfg_##n = { \
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.w_reg = \
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(volatile uint32_t *) DT_INST_REG_ADDR_BY_NAME(n, write),\
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.r_reg = \
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(volatile uint32_t *) DT_INST_REG_ADDR_BY_NAME(n, read), \
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}; \
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\
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static struct i2c_bitbang i2c_bitbang_##n; \
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\
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DEVICE_DT_INST_DEFINE(n, \
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i2c_litex_init, \
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device_pm_control_nop, \
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&i2c_bitbang_##n, \
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&i2c_litex_cfg_##n, \
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POST_KERNEL, \
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CONFIG_I2C_INIT_PRIORITY, \
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&i2c_litex_driver_api \
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);
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DT_INST_FOREACH_STATUS_OKAY(I2C_LITEX_INIT)
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