[U-Boot] [PATCH] dm: spi: prevent setting a speed of 0 Hz

[Michael Nazzareno Trimarchi]

Hi

On Thu, Jan 18, 2018 at 9:15 AM, Simon Goldschmidt
<sgoldschmidt at de.pepperl-fuchs.com> wrote:
> When the device tree is missing a correct spi slave description below
> the bus, the 'set_speed' callback can be called with 'speed' == 0 Hz.
> At least with cadence qspi, this leads to a division by zero.
>
> Prevent this by initializing speed to 100 kHz in this case, as is
> done in 'dm_spi_claim_bus'.
>
> Signed-off-by: Simon Goldschmidt <sgoldschmidt at de.pepperl-fuchs.com>
> ---
>
>  drivers/spi/spi-uclass.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c
> index e06a603ab1..41ecef77db 100644
> --- a/drivers/spi/spi-uclass.c
> +++ b/drivers/spi/spi-uclass.c
> @@ -325,6 +325,8 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
>         if (!speed) {
>                 speed = plat->max_hz;
>                 mode = plat->mode;
> +               if (!speed)
> +                       speed = 100000;

You should add a warming message

Michael

>         }
>         ret = spi_set_speed_mode(bus, speed, mode);
>         if (ret)
> --
> 2.11.0
>
>
> Pepperl+Fuchs GmbH, Mannheim
> Geschaeftsfuehrer/Managing Directors: Dr.-Ing. Gunther Kegel (Vors./CEO), Werner Guthier, Mehmet Hatiboglu
> Vorsitzender des Aufsichtsrats/Chairman of the supervisory board: Claus Michael
> Registergericht/Register Court: AG Mannheim HRB 4713
>
> Wichtiger Hinweis:
> Diese E-Mail einschliesslich ihrer Anhaenge enthaelt vertrauliche und rechtlich geschuetzte Informationen, die nur fuer den Adressaten bestimmt sind.
> Sollten Sie nicht der bezeichnete Adressat sein, so teilen Sie dies bitte dem Absender umgehend mit und loeschen Sie diese Nachricht und ihre Anhaenge. Die unbefugte Weitergabe, das Anfertigen von Kopien und jede Veraenderung der E-Mail ist untersagt. Der Absender haftet nicht fuer Inhalte von veraenderten E-Mails.
>
>
> Important Information:
> This e-mail message including its attachments contains confidential and legally protected information solely intended for the addressee. If you are not the intended addressee of this message, please contact the addresser immediately and delete this message including its attachments. The unauthorized dissemination, copying and change of this e-mail are strictly forbidden. The addresser shall not be liable for the content of such changed e-mails.
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot



-- 
| Michael Nazzareno Trimarchi                     Amarula Solutions BV |
| COO  -  Founder                                      Cruquiuskade 47 |
| +31(0)851119172                                 Amsterdam 1018 AM NL |
|                  [`as] http://www.amarulasolutions.com               |