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SubjectRe: [PATCH 1/4] spi: s3c64xx: modified error interrupt handling and init
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On Wed, Feb 6, 2013 at 2:26 AM, Grant Likely <grant.likely@secretlab.ca> wrote:
> 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?
The user manual says, wirting 1 to the pending clear register clears
the interrupt (its not auto clear to 0). so i need to explicitly reset
those bits thats what the 2nd write does
>
>>
>> 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.
same as above
>
> g.


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