[U-Boot] [PATCH v3] dm: spi: Read default speed and mode values from DT

[Qianyu Gong]

Hi Vignesh,



> Date: Wed, 13 Apr 2016 15:40:53 +0530

> From: Vignesh R <vigneshr at ti.com<mailto:vigneshr at ti.com>>

> To: Jagan Teki <jteki at openedev.com<mailto:jteki at openedev.com>>, Tom Rini <trini at konsulko.com<mailto:trini at konsulko.com>>

> Cc: u-boot at lists.denx.de<mailto:u-boot at lists.denx.de>, Stefan Roese <sr at denx.de<mailto:sr at denx.de>>

> Subject: [U-Boot] [PATCH v3] dm: spi: Read default speed and mode

>             values    from DT

> Message-ID: <1460542253-10580-1-git-send-email-vigneshr at ti.com<mailto:1460542253-10580-1-git-send-email-vigneshr at ti.com>>

> Content-Type: text/plain

>

> In case of DT boot, don't read default speed and mode for SPI from

> CONFIG_*, instead read from DT node. This will make sure that boards

> with multiple SPI/QSPI controllers can be probed at different

> bus frequencies and SPI modes.

>

> Signed-off-by: Vignesh R <vigneshr at ti.com<mailto:vigneshr at ti.com>>

> ---

>

> v3: Update commit message to mention SPI mode changes

>

> v2: Initialize speed, mode to 0 instead of -1

>

>  cmd/sf.c                 | 2 ++

>  drivers/spi/spi-uclass.c | 8 ++++++--

>  2 files changed, 8 insertions(+), 2 deletions(-)

>

> diff --git a/cmd/sf.c b/cmd/sf.c

> index 42862d9d921a..286906c3a151 100644

> --- a/cmd/sf.c

> +++ b/cmd/sf.c

> @@ -88,6 +88,8 @@ static int do_spi_flash_probe(int argc, char * const argv[])

>  #ifdef CONFIG_DM_SPI_FLASH

>             struct udevice *new, *bus_dev;

>             int ret;

> +          /* In DM mode defaults will be taken from DT */

> +          speed = 0, mode = 0;

>  #else

>             struct spi_flash *new;

>  #endif

> diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c

> index 5561f36762f9..5fb5630e2981 100644

> --- a/drivers/spi/spi-uclass.c

> +++ b/drivers/spi/spi-uclass.c

> @@ -264,6 +264,7 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int

> mode,

>                                   struct udevice **busp, struct spi_slave **devp)

>  {

>             struct udevice *bus, *dev;

> +          struct dm_spi_slave_platdata *plat;

>             bool created = false;

>             int ret;

>

> @@ -280,8 +281,6 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int

> mode,

>              * SPI flash chip - we will bind to the correct driver.

>              */

>             if (ret == -ENODEV && drv_name) {

> -                         struct dm_spi_slave_platdata *plat;

> -

>                            debug("%s: Binding new device '%s', busnum=%d, cs=%d,

> driver=%s\n",

>                                  __func__, dev_name, busnum, cs, drv_name);

>                            ret = device_bind_driver(bus, drv_name, dev_name, &dev);

> @@ -308,6 +307,11 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int

> mode,

>                            slave->dev = dev;

>             }

>

> +          plat = dev_get_parent_platdata(dev);

> +          if (!speed) {

> +                         speed = plat->max_hz;

> +                         mode = plat->mode;

> +          }

>             ret = spi_set_speed_mode(bus, speed, mode);

>             if (ret)

>                            goto err;

> --

I just doubt if spi_set_speed_mode() has really made a difference to
the actual transfer.
Seems that if the device is inactive, calling device_probe() would also call
spi_set_speed_mode() and do the data transfer. Even if it's active, setting
speed and mode for it again would not be necessary.


Regards,
Qianyu