12.01.2021 22:02, Sowjanya Komatineni пишет:
> VI I2C controller has known hardware bug where immediate multiple
> writes to TX_FIFO register gets stuck.
>
> Recommended software work around is to read I2C register after
> each write to TX_FIFO register to flush out the data.
>
> This patch implements this work around for VI I2C controller.
You could have kept Thierry's ack since it was given to the fix in
general. No need to make v4.
> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-tegra.c | 22 +++++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 6f08c0c..4a27782 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -326,6 +326,8 @@ static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned int reg)
> /* read back register to make sure that register writes completed */
> if (reg != I2C_TX_FIFO)
> readl_relaxed(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
> + else if (i2c_dev->is_vi)
> + readl_relaxed(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, I2C_INT_STATUS));
> }
>
> static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned int reg)
> @@ -339,6 +341,21 @@ static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
> writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
> }
>
> +static void i2c_writesl_vi(struct tegra_i2c_dev *i2c_dev, void *data,
> + unsigned int reg, unsigned int len)
> +{
> + u32 *data32 = data;
> +
> + /*
> + * VI I2C controller has known hardware bug where writes get stuck
> + * when immediate multiple writes happen to TX_FIFO register.
> + * Recommended software work around is to read I2C register after
> + * each write to TX_FIFO register to flush out the data.
> + */
> + while (len--)
> + i2c_writel(i2c_dev, *data32++, reg);
> +}
> +
> static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
> unsigned int reg, unsigned int len)
> {
> @@ -811,7 +828,10 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
> i2c_dev->msg_buf_remaining = buf_remaining;
> i2c_dev->msg_buf = buf + words_to_transfer * BYTES_PER_FIFO_WORD;
>
> - i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
> + if (i2c_dev->is_vi)
> + i2c_writesl_vi(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
> + else
> + i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
>
> buf += words_to_transfer * BYTES_PER_FIFO_WORD;
> }
>
Reviewed-by: Dmitry Osipenko <digetx@xxxxxxxxx>
