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SubjectRe: [PATCH 1/4] spi: s3c64xx: modified error interrupt handling and init
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On Tue,  5 Feb 2013 15:09:41 -0800, Girish K S <girishks2000@gmail.com> wrote:
> The status of the interrupt is available in the status register,
> so reading the clear pending register and writing back the same
> value will not actually clear the pending interrupts. This patch
> modifies the interrupt handler to read the status register and
> clear the corresponding pending bit in the clear pending register.
>
> Modified the hwInit function to clear all the pending interrupts.
>
> Signed-off-by: Girish K S <ks.giri@samsung.com>
> ---
> drivers/spi/spi-s3c64xx.c | 41 +++++++++++++++++++++++++----------------
> 1 file changed, 25 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index ad93231..b770f88 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -997,25 +997,30 @@ static irqreturn_t s3c64xx_spi_irq(int irq, void *data)
> {
> struct s3c64xx_spi_driver_data *sdd = data;
> struct spi_master *spi = sdd->master;
> - unsigned int val;
> + unsigned int val, clr = 0;
>
> - val = readl(sdd->regs + S3C64XX_SPI_PENDING_CLR);
> + val = readl(sdd->regs + S3C64XX_SPI_STATUS);
>
> - val &= S3C64XX_SPI_PND_RX_OVERRUN_CLR |
> - S3C64XX_SPI_PND_RX_UNDERRUN_CLR |
> - S3C64XX_SPI_PND_TX_OVERRUN_CLR |
> - S3C64XX_SPI_PND_TX_UNDERRUN_CLR;
> -
> - writel(val, sdd->regs + S3C64XX_SPI_PENDING_CLR);
> -
> - if (val & S3C64XX_SPI_PND_RX_OVERRUN_CLR)
> + if (val & S3C64XX_SPI_ST_RX_OVERRUN_ERR) {
> + clr = S3C64XX_SPI_PND_RX_OVERRUN_CLR;
> dev_err(&spi->dev, "RX overrun\n");
> - if (val & S3C64XX_SPI_PND_RX_UNDERRUN_CLR)
> + }
> + if (val & S3C64XX_SPI_ST_RX_UNDERRUN_ERR) {
> + clr |= S3C64XX_SPI_PND_RX_UNDERRUN_CLR;
> dev_err(&spi->dev, "RX underrun\n");
> - if (val & S3C64XX_SPI_PND_TX_OVERRUN_CLR)
> + }
> + if (val & S3C64XX_SPI_ST_TX_OVERRUN_ERR) {
> + clr |= S3C64XX_SPI_PND_TX_OVERRUN_CLR;
> dev_err(&spi->dev, "TX overrun\n");
> - if (val & S3C64XX_SPI_PND_TX_UNDERRUN_CLR)
> + }
> + if (val & S3C64XX_SPI_ST_TX_UNDERRUN_ERR) {
> + clr |= S3C64XX_SPI_PND_TX_UNDERRUN_CLR;
> dev_err(&spi->dev, "TX underrun\n");
> + }
> +
> + /* Clear the pending irq by setting and then clearing it */
> + writel(clr, sdd->regs + S3C64XX_SPI_PENDING_CLR);
> + writel(clr & ~clr, sdd->regs + S3C64XX_SPI_PENDING_CLR);

Wait, what? clr & ~clr == 0 Always. What are you actually trying to do here?

>
> return IRQ_HANDLED;
> }
> @@ -1039,9 +1044,13 @@ static void s3c64xx_spi_hwinit(struct s3c64xx_spi_driver_data *sdd, int channel)
> writel(0, regs + S3C64XX_SPI_MODE_CFG);
> writel(0, regs + S3C64XX_SPI_PACKET_CNT);
>
> - /* Clear any irq pending bits */
> - writel(readl(regs + S3C64XX_SPI_PENDING_CLR),
> - regs + S3C64XX_SPI_PENDING_CLR);
> + /* Clear any irq pending bits, should set and clear the bits */
> + val = S3C64XX_SPI_PND_RX_OVERRUN_CLR |
> + S3C64XX_SPI_PND_RX_UNDERRUN_CLR |
> + S3C64XX_SPI_PND_TX_OVERRUN_CLR |
> + S3C64XX_SPI_PND_TX_UNDERRUN_CLR;
> + writel(val, regs + S3C64XX_SPI_PENDING_CLR);
> + writel(val & ~val, regs + S3C64XX_SPI_PENDING_CLR);

Ditto.

g.


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