[PATCH v5 02/16] spi/spi-atmel: detect the capabilities of SPI core by reading the VERSION register.
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Sun Mar 3 05:28:59 EST 2013
On 14:47 Tue 26 Feb , Wenyou Yang wrote:
> the "has_dma_support" needed for future use with dmaengine driver.
>
> Signed-off-by: Wenyou Yang <wenyou.yang at atmel.com>
> Cc: spi-devel-general at lists.sourceforge.net
> Cc: linux-kernel at vger.kernel.org
> ---
> drivers/spi/spi-atmel.c | 70 ++++++++++++++++++++++++++++++++++++++---------
> 1 file changed, 57 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
> index 5bf3786..a8e091b 100644
> --- a/drivers/spi/spi-atmel.c
> +++ b/drivers/spi/spi-atmel.c
> @@ -39,6 +39,7 @@
> #define SPI_CSR1 0x0034
> #define SPI_CSR2 0x0038
> #define SPI_CSR3 0x003c
> +#define SPI_VERSION 0x00fc
> #define SPI_RPR 0x0100
> #define SPI_RCR 0x0104
> #define SPI_TPR 0x0108
> @@ -71,6 +72,8 @@
> #define SPI_FDIV_SIZE 1
> #define SPI_MODFDIS_OFFSET 4
> #define SPI_MODFDIS_SIZE 1
> +#define SPI_WDRBT_OFFSET 5
> +#define SPI_WDRBT_SIZE 1
> #define SPI_LLB_OFFSET 7
> #define SPI_LLB_SIZE 1
> #define SPI_PCS_OFFSET 16
> @@ -180,6 +183,11 @@
> #define spi_writel(port,reg,value) \
> __raw_writel((value), (port)->regs + SPI_##reg)
>
> +struct atmel_spi_caps {
> + bool is_spi2;
> + bool has_wdrbt;
> + bool has_dma_support;
> +};
>
> /*
> * The core SPI transfer engine just talks to a register bank to set up
> @@ -204,6 +212,8 @@ struct atmel_spi {
>
> void *buffer;
> dma_addr_t buffer_dma;
> +
> + struct atmel_spi_caps caps;
> };
>
> /* Controller-specific per-slave state */
> @@ -222,14 +232,10 @@ struct atmel_spi_device {
> * - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
> * - SPI_CSRx.CSAAT
> * - SPI_CSRx.SBCR allows faster clocking
> - *
> - * We can determine the controller version by reading the VERSION
> - * register, but I haven't checked that it exists on all chips, and
> - * this is cheaper anyway.
> */
> -static bool atmel_spi_is_v2(void)
> +static bool atmel_spi_is_v2(struct atmel_spi *as)
> {
> - return !cpu_is_at91rm9200();
> + return as->caps.is_spi2;
> }
>
> /*
> @@ -263,15 +269,20 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
> unsigned active = spi->mode & SPI_CS_HIGH;
> u32 mr;
>
> - if (atmel_spi_is_v2()) {
> + if (atmel_spi_is_v2(as)) {
> /*
> * Always use CSR0. This ensures that the clock
> * switches to the correct idle polarity before we
> * toggle the CS.
> */
> spi_writel(as, CSR0, asd->csr);
> - spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
> + if (as->caps.has_wdrbt) {
> + spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(WDRBT)
> + | SPI_BIT(MODFDIS) | SPI_BIT(MSTR));
> + } else {
> + spi_writel(as, MR, SPI_BF(PCS, 0x0e) | SPI_BIT(MODFDIS)
> | SPI_BIT(MSTR));
> + }
> mr = spi_readl(as, MR);
> gpio_set_value(asd->npcs_pin, active);
> } else {
> @@ -318,7 +329,7 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
> asd->npcs_pin, active ? " (low)" : "",
> mr);
>
> - if (atmel_spi_is_v2() || spi->chip_select != 0)
> + if (atmel_spi_is_v2(as) || spi->chip_select != 0)
> gpio_set_value(asd->npcs_pin, !active);
> }
>
> @@ -719,7 +730,7 @@ static int atmel_spi_setup(struct spi_device *spi)
> }
>
> /* see notes above re chipselect */
> - if (!atmel_spi_is_v2()
> + if (!atmel_spi_is_v2(as)
> && spi->chip_select == 0
> && (spi->mode & SPI_CS_HIGH)) {
> dev_dbg(&spi->dev, "setup: can't be active-high\n");
> @@ -728,7 +739,7 @@ static int atmel_spi_setup(struct spi_device *spi)
>
> /* v1 chips start out at half the peripheral bus speed. */
> bus_hz = clk_get_rate(as->clk);
> - if (!atmel_spi_is_v2())
> + if (!atmel_spi_is_v2(as))
> bus_hz /= 2;
>
> if (spi->max_speed_hz) {
> @@ -804,7 +815,7 @@ static int atmel_spi_setup(struct spi_device *spi)
> "setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
> bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
>
> - if (!atmel_spi_is_v2())
> + if (!atmel_spi_is_v2(as))
> spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
>
> return 0;
> @@ -910,6 +921,32 @@ static void atmel_spi_cleanup(struct spi_device *spi)
> kfree(asd);
> }
>
> +static inline unsigned int atmel_get_version(struct atmel_spi *as)
> +{
> + return spi_readl(as, VERSION) & 0x00000fff;
> +}
> +
> +static void __init atmel_get_caps(struct atmel_spi *as)
> +{
> + unsigned int version;
> +
> + version = atmel_get_version(as);
> + dev_info(&as->pdev->dev, "version: 0x%x\n", version);
> +
> + as->caps.is_spi2 = false;
> + as->caps.has_wdrbt = false;
> + as->caps.has_dma_support = false;
> +
> + if (version > 0x121)
> + as->caps.is_spi2 = true;
> +
> + if (version >= 0x210)
> + as->caps.has_wdrbt = true;
> +
> + if (version >= 0x212)
> + as->caps.has_dma_support = true;
use switch here
or filled struct
> +}
> +
> /*-------------------------------------------------------------------------*/
>
> static int atmel_spi_probe(struct platform_device *pdev)
> @@ -970,6 +1007,8 @@ static int atmel_spi_probe(struct platform_device *pdev)
> as->irq = irq;
> as->clk = clk;
>
> + atmel_get_caps(as);
> +
> ret = request_irq(irq, atmel_spi_interrupt, 0,
> dev_name(&pdev->dev), master);
> if (ret)
> @@ -979,7 +1018,12 @@ static int atmel_spi_probe(struct platform_device *pdev)
> clk_enable(clk);
> spi_writel(as, CR, SPI_BIT(SWRST));
> spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
> - spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
> + if (as->caps.has_wdrbt) {
> + spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
> + | SPI_BIT(MSTR));
> + } else {
> + spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
> + }
> spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
> spi_writel(as, CR, SPI_BIT(SPIEN));
>
> --
> 1.7.9.5
>
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