Re: [PATCH] spi: bcm-qspi: when tx/rx buffer is NULL set to 0

From: Kamal Dasu
Date: Sun Mar 31 2019 - 10:40:50 EST


On Thu, Feb 7, 2019 at 3:47 PM <justinpopo6@xxxxxxxxx> wrote:
>
> From: Justin Chen <justinpopo6@xxxxxxxxx>
>
> Currently we set the tx/rx buffer to 0xff when NULL. This causes
> problems with some spi slaves where 0xff is a valid command. Looking
> at other drivers, the tx/rx buffer is usually set to 0x00 when NULL.
> Following this convention solves the issue.
>
> Fixes: fa236a7ef240 ("spi: bcm-qspi: Add Broadcom MSPI driver")
> Signed-off-by: Justin Chen <justinpopo6@xxxxxxxxx>

Signed-off-by: Kamal Dasu <kdasu.kdev@xxxxxxxxx>

> ---
> drivers/spi/spi-bcm-qspi.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
> index 584bcb0..79456aa 100644
> --- a/drivers/spi/spi-bcm-qspi.c
> +++ b/drivers/spi/spi-bcm-qspi.c
> @@ -681,7 +681,7 @@ static void read_from_hw(struct bcm_qspi *qspi, int slots)
> if (buf)
> buf[tp.byte] = read_rxram_slot_u8(qspi, slot);
> dev_dbg(&qspi->pdev->dev, "RD %02x\n",
> - buf ? buf[tp.byte] : 0xff);
> + buf ? buf[tp.byte] : 0x00);
> } else {
> u16 *buf = tp.trans->rx_buf;
>
> @@ -689,7 +689,7 @@ static void read_from_hw(struct bcm_qspi *qspi, int slots)
> buf[tp.byte / 2] = read_rxram_slot_u16(qspi,
> slot);
> dev_dbg(&qspi->pdev->dev, "RD %04x\n",
> - buf ? buf[tp.byte] : 0xffff);
> + buf ? buf[tp.byte] : 0x0000);
> }
>
> update_qspi_trans_byte_count(qspi, &tp,
> @@ -744,13 +744,13 @@ static int write_to_hw(struct bcm_qspi *qspi, struct spi_device *spi)
> while (!tstatus && slot < MSPI_NUM_CDRAM) {
> if (tp.trans->bits_per_word <= 8) {
> const u8 *buf = tp.trans->tx_buf;
> - u8 val = buf ? buf[tp.byte] : 0xff;
> + u8 val = buf ? buf[tp.byte] : 0x00;
>
> write_txram_slot_u8(qspi, slot, val);
> dev_dbg(&qspi->pdev->dev, "WR %02x\n", val);
> } else {
> const u16 *buf = tp.trans->tx_buf;
> - u16 val = buf ? buf[tp.byte / 2] : 0xffff;
> + u16 val = buf ? buf[tp.byte / 2] : 0x0000;
>
> write_txram_slot_u16(qspi, slot, val);
> dev_dbg(&qspi->pdev->dev, "WR %04x\n", val);
> --
> 2.7.4
>