[U-Boot] [PATCH 2/3] spi/kirkwood: support spi_claim/release_bus functions

[Prafulla Wadaskar]

> -----Original Message-----
> From: Valentin Longchamp [mailto:valentin.longchamp at keymile.com]
> Sent: 16 May 2012 16:24
> To: Prafulla Wadaskar; holger.brunck at keymile.com
> Cc: Valentin Longchamp; u-boot at lists.denx.de; Holger Brunck; Prafulla
> Wadaskar
> Subject: [PATCH 2/3] spi/kirkwood: support spi_claim/release_bus
> functions
> 
> These two function nows ensure that the MPP is configured correctly
> for
> the SPI controller before any SPI access, and restore the initial
> configuration when the access is over.
> 
> Since the used pins for the SPI controller can differ (2 possibilities
> for each signal), the used pins are configured with
> CONFIG_SYS_KW_SPI_MPP.
> 
> Signed-off-by: Valentin Longchamp <valentin.longchamp at keymile.com>
> cc: Holger Brunck <holger.brunck at keymile.com>
> cc: Prafulla Wadaskar <prafulla at marvell.com>
> ---
>  arch/arm/include/asm/arch-kirkwood/spi.h |    9 ++++++++
>  drivers/spi/kirkwood_spi.c               |   34
> ++++++++++++++++++++++++++++++
>  2 files changed, 43 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/include/asm/arch-kirkwood/spi.h
> b/arch/arm/include/asm/arch-kirkwood/spi.h
> index 1d5043f..305c573 100644
> --- a/arch/arm/include/asm/arch-kirkwood/spi.h
> +++ b/arch/arm/include/asm/arch-kirkwood/spi.h
> @@ -37,6 +37,15 @@ struct kwspi_registers {
>  	u32 irq_mask;	/* 0x10614 */
>  };
> 
> +#define CSn_MPP7	0x1
> +#define MOSI_MPP6	0x2
> +#define SCK_MPP10	0x4
> +#define MISO_MPP11	0x8

Let's define above as (1 << x) to make it more readable.

> +
> +#ifndef CONFIG_SYS_KW_SPI_MPP
> +#define CONFIG_SYS_KW_SPI_MPP	0x0

Some more documentation is needed, you need to explain how each bit we are using to configure the SPI-MPPs

> +#endif
> +
>  #define KWSPI_CLKPRESCL_MASK	0x1f
>  #define KWSPI_CSN_ACT		1 /* Activates serial memory interface
> */
>  #define KWSPI_SMEMRDY		(1 << 1) /* SerMem Data xfer ready */
> diff --git a/drivers/spi/kirkwood_spi.c b/drivers/spi/kirkwood_spi.c
> index db8ba8b..0877915 100644
> --- a/drivers/spi/kirkwood_spi.c
> +++ b/drivers/spi/kirkwood_spi.c
> @@ -88,11 +88,45 @@ void spi_free_slave(struct spi_slave *slave)
> 
>  int spi_claim_bus(struct spi_slave *slave)
>  {

Instead define here
#ifdef CONFIG_SYS_KW_SPI_MPP, otherwise build with default.

> +	u32 config;
> +	u32 spi_mpp_config[5];
> +
> +	config = CONFIG_SYS_KW_SPI_MPP;
> +
> +	if (config & CSn_MPP7)
> +		spi_mpp_config[0] = MPP7_SPI_SCn;
> +	else
> +		spi_mpp_config[0] = MPP0_SPI_SCn;
> +
> +	if (config & MOSI_MPP6)
> +		spi_mpp_config[1] = MPP6_SPI_MOSI;
> +	else
> +		spi_mpp_config[1] = MPP1_SPI_MOSI;
> +
> +	if (config & SCK_MPP10)
> +		spi_mpp_config[2] = MPP10_SPI_SCK;
> +	else
> +		spi_mpp_config[2] = MPP2_SPI_SCK;
> +
> +	if (config & MISO_MPP11)
> +		spi_mpp_config[3] = MPP11_SPI_MISO;
> +	else
> +		spi_mpp_config[3] = MPP3_SPI_MISO;
> +
> +	spi_mpp_config[4] = 0;
> +
> +	/* save current mpp configuration */
> +	kirkwood_mpp_save();
> +
> +	/* finally set chosen mpp spi configuration */
> +	kirkwood_mpp_conf(spi_mpp_config);
> +
>  	return 0;
>  }
> 
>  void spi_release_bus(struct spi_slave *slave)
>  {
> +	kirkwood_mpp_restore();
>  }
> 
>  #ifndef CONFIG_SPI_CS_IS_VALID
> --

Regards..
Prafulla . . .
> 1.7.1