* Ilkka Koskinen <ilkka.koski...@nokia.com> [101019 06:55]:
> In case of TX only with DMA, the driver assumes that the data
> has been transferred once DMA callback in invoked. However,
> SPI's shift register may still contain data. Thus, the driver
> is supposed to verify that the register is empty and the end of
> the SPI transfer has been reached.
>
> Signed-off-by: Ilkka Koskinen <ilkka.koski...@nokia.com>
> Tested-by: Tuomas Katila <ext-tuomas.2.kat...@nokia.com>
Grant, can you please queue this one?
Acked-by: Tony Lindgren <t...@atomide.com>
> ---
> drivers/spi/omap2_mcspi.c | 39 ++++++++++++++++++++++++++-------------
> 1 files changed, 26 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
> index b3a94ca..a2e053c 100644
> --- a/drivers/spi/omap2_mcspi.c
> +++ b/drivers/spi/omap2_mcspi.c
> @@ -296,6 +296,19 @@ static int omap2_mcspi_enable_clocks(struct omap2_mcspi
> *mcspi)
> return 0;
> }
>
> +static int mcspi_wait_for_reg_bit(void __iomem *reg, unsigned long bit)
> +{
> + unsigned long timeout;
> +
> + timeout = jiffies + msecs_to_jiffies(1000);
> + while (!(__raw_readl(reg) & bit)) {
> + if (time_after(jiffies, timeout))
> + return -1;
> + cpu_relax();
> + }
> + return 0;
> +}
> +
> static unsigned
> omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
> {
> @@ -309,11 +322,14 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct
> spi_transfer *xfer)
> u32 l;
> u8 * rx;
> const u8 * tx;
> + void __iomem *chstat_reg;
>
> mcspi = spi_master_get_devdata(spi->master);
> mcspi_dma = &mcspi->dma_channels[spi->chip_select];
> l = mcspi_cached_chconf0(spi);
>
> + chstat_reg = cs->base + OMAP2_MCSPI_CHSTAT0;
> +
> count = xfer->len;
> c = count;
> word_len = cs->word_len;
> @@ -382,6 +398,16 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct
> spi_transfer *xfer)
> if (tx != NULL) {
> wait_for_completion(&mcspi_dma->dma_tx_completion);
> dma_unmap_single(NULL, xfer->tx_dma, count, DMA_TO_DEVICE);
> +
> + /* for TX_ONLY mode, be sure all words have shifted out */
> + if (rx == NULL) {
> + if (mcspi_wait_for_reg_bit(chstat_reg,
> + OMAP2_MCSPI_CHSTAT_TXS) < 0)
> + dev_err(&spi->dev, "TXS timed out\n");
> + else if (mcspi_wait_for_reg_bit(chstat_reg,
> + OMAP2_MCSPI_CHSTAT_EOT) < 0)
> + dev_err(&spi->dev, "EOT timed out\n");
> + }
> }
>
> if (rx != NULL) {
> @@ -435,19 +461,6 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct
> spi_transfer *xfer)
> return count;
> }
>
> -static int mcspi_wait_for_reg_bit(void __iomem *reg, unsigned long bit)
> -{
> - unsigned long timeout;
> -
> - timeout = jiffies + msecs_to_jiffies(1000);
> - while (!(__raw_readl(reg) & bit)) {
> - if (time_after(jiffies, timeout))
> - return -1;
> - cpu_relax();
> - }
> - return 0;
> -}
> -
> static unsigned
> omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
> {
> --
> 1.6.0.4
>
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