[PATCH v2 2/3] spi: Add slices for SPI controllers

[Gerald Loacker]

Am 08.09.2023 um 15:11 schrieb Sascha Hauer:
> Add a slice for SPI controllers so that devices using SPI in the background
> can check if a SPI bus is busy.
> 
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>

Tested-by: Gerald Loacker <gerald.loacker at wolfvision.net>

> ---
> 
> Notes:
>     Changes since v1:
>     - Add forgotten slice_init()
> 
>  drivers/spi/spi.c | 12 +++++++++++-
>  include/spi/spi.h |  8 ++++++++
>  2 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index 584d4ab777..83f2b0ee1b 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -12,6 +12,7 @@
>  #include <spi/spi.h>
>  #include <xfuncs.h>
>  #include <malloc.h>
> +#include <slice.h>
>  #include <errno.h>
>  #include <init.h>
>  #include <of.h>
> @@ -269,6 +270,8 @@ int spi_register_controller(struct spi_controller *ctrl)
>  	if (status)
>  		return status;
>  
> +	slice_init(&ctrl->slice, dev_name(ctrl->dev));
> +
>  	/* even if it's just one always-selected device, there must
>  	 * be at least one chipselect
>  	 */
> @@ -352,12 +355,19 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
>  int spi_sync(struct spi_device *spi, struct spi_message *message)
>  {
>  	int status;
> +	int ret;
>  
>  	status = __spi_validate(spi, message);
>  	if (status != 0)
>  		return status;
>  
> -	return spi->controller->transfer(spi, message);
> +	slice_acquire(&spi->controller->slice);
> +
> +	ret = spi->controller->transfer(spi, message);
> +
> +	slice_release(&spi->controller->slice);
> +
> +	return ret;
>  }
>  
>  /**
> diff --git a/include/spi/spi.h b/include/spi/spi.h
> index f806c7a30b..45d6f5931c 100644
> --- a/include/spi/spi.h
> +++ b/include/spi/spi.h
> @@ -3,6 +3,7 @@
>  #define __INCLUDE_SPI_H
>  
>  #include <driver.h>
> +#include <slice.h>
>  #include <linux/err.h>
>  #include <linux/kernel.h>
>  #include <linux/string.h>
> @@ -161,6 +162,8 @@ struct spi_message;
>  struct spi_controller {
>  	struct device *dev;
>  
> +	struct slice		slice;
> +
>  	/* other than negative (== assign one dynamically), bus_num is fully
>  	 * board-specific.  usually that simplifies to being SOC-specific.
>  	 * example:  one SOC has three SPI controllers, numbered 0..2,
> @@ -601,6 +604,11 @@ static inline int spi_driver_register(struct driver *drv)
>  	return register_driver(drv);
>  }
>  
> +static inline struct slice *spi_device_slice(struct spi_device *spi)
> +{
> +	return &spi->controller->slice;
> +}
> +
>  #ifdef CONFIG_SPI
>  #define coredevice_spi_driver(drv)	\
>  	register_driver_macro(coredevice,spi,drv)