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/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2019-07-29 zdzn first version
*/
#include "drv_i2c.h"
rt_uint8_t i2c_read_or_write(volatile rt_uint32_t base, rt_uint8_t* buf, rt_uint32_t len, rt_uint8_t flag)
{
rt_uint32_t status;
rt_uint32_t remaining = len;
rt_uint32_t i = 0;
rt_uint8_t reason = BCM283X_I2C_REASON_OK;
/* Clear FIFO */
BCM283X_BSC_C(base) |= (BSC_C_CLEAR_1 & BSC_C_CLEAR_1);
/* Clear Status */
BCM283X_BSC_S(base) = BSC_S_CLKT | BSC_S_ERR | BSC_S_DONE;
/* Set Data Length */
BCM283X_BSC_DLEN(base) = len;
if (flag)
{
/* Start read */
BCM283X_BSC_C(base) = BSC_C_I2CEN | BSC_C_ST | BSC_C_READ;
/* wait for transfer to complete */
while (!(BCM283X_BSC_S(base) & BSC_S_DONE))
{
/* we must empty the FIFO as it is populated and not use any delay */
while (remaining && (BCM283X_BSC_S(base) & BSC_S_RXD))
{
/* Read from FIFO, no barrier */
buf[i] = BCM283X_BSC_FIFO(base);
i++;
remaining--;
}
}
/* transfer has finished - grab any remaining stuff in FIFO */
while (remaining && (BCM283X_BSC_S(base) & BSC_S_RXD))
{
/* Read from FIFO, no barrier */
buf[i] = BCM283X_BSC_FIFO(base);
i++;
remaining--;
}
}
else
{
/* pre populate FIFO with max buffer */
while (remaining && (i < BSC_FIFO_SIZE))
{
BCM283X_BSC_FIFO(base) = buf[i];
i++;
remaining--;
}
/* Enable device and start transfer */
BCM283X_BSC_C(base) = BSC_C_I2CEN | BSC_C_ST;
/* Transfer is over when BCM2835_BSC_S_DONE */
while (!(BCM283X_BSC_S(base) & BSC_S_DONE))
{
while (remaining && (BCM283X_BSC_S(base) & BSC_S_TXD))
{
/* Write to FIFO */
BCM283X_BSC_FIFO(base) = buf[i];
i++;
remaining--;
}
}
}
status = BCM283X_BSC_S(base);
if (status & BSC_S_ERR)
{
reason = BCM283X_I2C_REASON_ERROR_NACK;
}
else if (status & BSC_S_CLKT)
{
reason = BCM283X_I2C_REASON_ERROR_CLKT;
}
else if (remaining)
{
reason = BCM283X_I2C_REASON_ERROR_DATA;
}
BCM283X_BSC_C(base) |= (BSC_S_DONE & BSC_S_DONE);
return reason;
}
struct raspi_i2c_hw_config
{
rt_uint8_t bsc_num;
rt_uint8_t sdl_pin;
rt_uint8_t scl_pin;
rt_uint8_t sdl_mode;
rt_uint8_t scl_mode;
};
#if (defined(BSP_USING_I2C0) || defined(BSP_USING_I2C1))
static rt_ssize_t raspi_i2c_mst_xfer(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num);
static rt_ssize_t raspi_i2c_slv_xfer(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num);
static rt_err_t raspi_i2c_bus_control(struct rt_i2c_bus_device *bus,
int cmd,
void *args);
static rt_uint32_t i2c_byte_wait_us = 0;
static rt_ssize_t raspi_i2c_mst_xfer(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num)
{
rt_size_t i;
rt_uint8_t reason;
RT_ASSERT(bus != RT_NULL);
volatile rt_uint32_t base = (volatile rt_uint32_t)(bus->parent.user_data);
if (bus->parent.user_data == 0)
base = BCM283X_BSC0_BASE;
else
base = BCM283X_BSC1_BASE;
BCM283X_BSC_A(base) = msgs->addr;
for (i = 0; i < num; i++)
{
if (msgs[i].flags & RT_I2C_RD)
reason = i2c_read_or_write(base, msgs->buf, msgs->len, 1);
else
reason = i2c_read_or_write(base, msgs->buf, msgs->len, 0);
}
return (reason == 0)? i : 0;
}
static rt_ssize_t raspi_i2c_slv_xfer(struct rt_i2c_bus_device *bus,
struct rt_i2c_msg msgs[],
rt_uint32_t num)
{
return 0;
}
static rt_err_t raspi_i2c_bus_control(struct rt_i2c_bus_device *bus,
int cmd,
void *args)
{
return RT_EOK;
}
static const struct rt_i2c_bus_device_ops raspi_i2c_ops =
{
.master_xfer = raspi_i2c_mst_xfer,
.slave_xfer = raspi_i2c_slv_xfer,
.i2c_bus_control = raspi_i2c_bus_control,
};
static rt_err_t raspi_i2c_configure(struct raspi_i2c_hw_config *cfg)
{
RT_ASSERT(cfg != RT_NULL);
volatile rt_uint32_t base = cfg->scl_mode ? BCM283X_BSC1_BASE : BCM283X_BSC0_BASE;
GPIO_FSEL(cfg->sdl_pin, cfg->sdl_mode); /* SDA */
GPIO_FSEL(cfg->scl_pin, cfg->scl_mode); /* SCL */
/* use 0xFFFE mask to limit a max value and round down any odd number */
rt_uint32_t divider = (BCM283X_CORE_CLK_HZ / 10000) & 0xFFFE;
BCM283X_BSC_DIV(base) = (rt_uint16_t) divider;
i2c_byte_wait_us = (divider * 1000000 * 9 / BCM283X_CORE_CLK_HZ);
return RT_EOK;
}
#endif
#if defined (BSP_USING_I2C0)
#define I2C0_BUS_NAME "i2c0"
static struct raspi_i2c_hw_config hw_device0 =
{
.bsc_num = 0,
.sdl_pin = RPI_GPIO_P1_27,
.scl_pin = RPI_GPIO_P1_28,
.sdl_mode = BCM283X_GPIO_FSEL_ALT0,
.scl_mode = BCM283X_GPIO_FSEL_ALT0,
};
struct rt_i2c_bus_device device0 =
{
.ops = &raspi_i2c_ops,
};
#endif
#if defined (BSP_USING_I2C1)
#define I2C1_BUS_NAME "i2c1"
static struct raspi_i2c_hw_config hw_device1 =
{
.bsc_num = 1,
.sdl_pin = RPI_GPIO_P1_03,
.scl_pin = RPI_GPIO_P1_05,
.sdl_mode = BCM283X_GPIO_FSEL_ALT0,
.scl_mode = BCM283X_GPIO_FSEL_ALT0,
};
struct rt_i2c_bus_device device1 =
{
.ops = &raspi_i2c_ops,
};
#endif
int rt_hw_i2c_init(void)
{
#if defined(BSP_USING_I2C0)
device0.parent.user_data = (void *)0;
raspi_i2c_configure(&hw_device0);
rt_i2c_bus_device_register(&device0, I2C0_BUS_NAME);
#endif
#if defined(BSP_USING_I2C1)
device1.parent.user_data = (void *)1;
raspi_i2c_configure(&hw_device1);
rt_i2c_bus_device_register(&device1, I2C1_BUS_NAME);
#endif
return 0;
}
INIT_DEVICE_EXPORT(rt_hw_i2c_init);
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