Linux下SPI读写外部寄存器的操作

SPI写寄存器操作：

staticvoid mcp251x_write_reg(struct spi_device *spi, uint8_t reg, uint8_t val)
{
struct mcp251x *chip = dev_get_drvdata(&spi->dev);
int ret;

down(&chip->lock);

chip->spi_transfer_buf[0] = INSTRUCTION_WRITE;
    chip->spi_transfer_buf[1] = reg;
    chip->spi_transfer_buf[2] = val;

ret = spi_write(spi, chip->spi_transfer_buf, 3);
if (ret < 0)
        dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __FUNCTION__, ret);

up(&chip->lock);
}

staticvoid mcp251x_write_bits(struct spi_device *spi, uint8_t reg, uint8_t mask, uint8_t val)
{
struct mcp251x *chip = dev_get_drvdata(&spi->dev);
int ret;

down(&chip->lock);

chip->spi_transfer_buf[0] = INSTRUCTION_BIT_MODIFY;
    chip->spi_transfer_buf[1] = reg;
    chip->spi_transfer_buf[2] = mask;
    chip->spi_transfer_buf[3] = val;

ret = spi_write(spi, chip->spi_transfer_buf, 4);
if (ret < 0)
        dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __FUNCTION__, ret);

up(&chip->lock);
}

SPI读寄存器操作：

static uint8_t mcp251x_read_reg(struct spi_device *spi, uint8_t reg)
{
struct mcp251x *chip = dev_get_drvdata(&spi->dev);
    uint8_t *tx_buf, *rx_buf;
    uint8_t val;
int ret;

tx_buf = chip->spi_transfer_buf;
rx_buf = chip->spi_transfer_buf + 8;

down(&chip->lock);

tx_buf[0] = INSTRUCTION_READ;
    tx_buf[1] = reg;
    ret = spi_write_then_read(spi, tx_buf, 2, rx_buf, 1);
if (ret < 0)
    {
        dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __FUNCTION__, ret);
        val = 0;
    }
else
        val = rx_buf[0];

up(&chip->lock);

return val;
}

static uint8_t mcp251x_read_state(struct spi_device *spi, uint8_t cmd)
{
struct mcp251x *chip = dev_get_drvdata(&spi->dev);
    uint8_t *tx_buf, *rx_buf;
    uint8_t val;
int ret;

tx_buf = chip->spi_transfer_buf;
rx_buf = chip->spi_transfer_buf + 8;

down(&chip->lock);

tx_buf[0] = cmd;
    ret = spi_write_then_read(spi, tx_buf, 1, rx_buf, 1);
if (ret < 0)
    {
        dev_dbg(&spi->dev, "%s: failed: ret = %d\n", __FUNCTION__, ret);
        val = 0;
    }
else
        val = rx_buf[0];

up(&chip->lock);

return val;
}

巴特西

Linux下SPI读写外部寄存器的操作

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