Re: [PATCH] spi: add a bits_per_word to struct spi_board_info

[Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>]

On Wed, Sep 01, 2010 at 02:24:49PM +0800, Feng Tang wrote:
> Currently a spi device's bits_per_word can only be inited
> inside protocol driver's probe func, this patch will enable
> platform code to specify this info when registering the
> spi_board_info

What is the use case that you would want to do this.  Knowing what the bits_per_word should be is the responsibility of the spi device driver.  What is the use-case where the driver wouldn't know what bits_per_word should be?

g.

> 
> Signed-off-by: Feng Tang <feng.tang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Cc: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
> Cc: Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
> ---
>  drivers/spi/spi.c       |    1 +
>  include/linux/spi/spi.h |    3 +++
>  2 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index a9e5c79..a8690e7 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -350,6 +350,7 @@ struct spi_device *spi_new_device(struct spi_master *master,
>  	proxy->chip_select = chip->chip_select;
>  	proxy->max_speed_hz = chip->max_speed_hz;
>  	proxy->mode = chip->mode;
> +	proxy->bits_per_word = chip->bits_per_word;
>  	proxy->irq = chip->irq;
>  	strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
>  	proxy->dev.platform_data = (void *) chip->platform_data;
> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> index 92e52a1..f36d0d5 100644
> --- a/include/linux/spi/spi.h
> +++ b/include/linux/spi/spi.h
> @@ -698,6 +698,8 @@ static inline ssize_t spi_w8r16(struct spi_device *spi, u8 cmd)
>   * @mode: Initializes spi_device.mode; based on the chip datasheet, board
>   *	wiring (some devices support both 3WIRE and standard modes), and
>   *	possibly presence of an inverter in the chipselect path.
> + * @bits_per_word: Initializes spi_device.bits_per_word, usually it will
> + * be from 8 to 32 bits
>   *
>   * When adding new SPI devices to the device tree, these structures serve
>   * as a partial device template.  They hold information which can't always
> @@ -742,6 +744,7 @@ struct spi_board_info {
>  	 * where the default of SPI_CS_HIGH = 0 is wrong.
>  	 */
>  	u8		mode;
> +	u8		bits_per_word;
>  
>  	/* ... may need additional spi_device chip config data here.
>  	 * avoid stuff protocol drivers can set; but include stuff
> -- 
> 1.7.0.4
> 

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