Hi Dinh,
On Tue, Jun 4, 2019 at 4:21 PM Dinh Nguyen <dinguyen@xxxxxxxxxx> wrote:
> On 6/4/19 7:14 AM, Vinod Koul wrote:
> > On 23-05-19, 19:28, Dinh Nguyen wrote:
> >> The DMA controller on some SoCs can be held in reset, and thus requires
> >> the reset signal(s) to deasserted. Most SoCs will have just one reset
> >> signal, but there are others, i.e. Arria10/Stratix10 will have an
> >> additional reset signal, referred to as the OCP.
> >>
> >> Add code to get the reset property from the device tree for deassert and
> >> assert.
> >>
> >> Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>
> >> ---
> >> drivers/dma/pl330.c | 38 ++++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 38 insertions(+)
> >>
> >> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> >> index 6e6837214210..6018c43e785d 100644
> >> --- a/drivers/dma/pl330.c
> >> +++ b/drivers/dma/pl330.c
> >> @@ -29,6 +29,7 @@
> >> #include <linux/err.h>
> >> #include <linux/pm_runtime.h>
> >> #include <linux/bug.h>
> >> +#include <linux/reset.h>
> >>
> >> #include "dmaengine.h"
> >> #define PL330_MAX_CHAN 8
> >> @@ -500,6 +501,9 @@ struct pl330_dmac {
> >> unsigned int num_peripherals;
> >> struct dma_pl330_chan *peripherals; /* keep at end */
> >> int quirks;
> >> +
> >> + struct reset_control *rstc;
> >> + struct reset_control *rstc_ocp;
> >> };
> >>
> >> static struct pl330_of_quirks {
> >> @@ -3028,6 +3032,30 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id)
> >>
> >> amba_set_drvdata(adev, pl330);
> >>
> >> + pl330->rstc = devm_reset_control_get_optional(&adev->dev, "dma");
> >> + if (IS_ERR(pl330->rstc)) {
> >> + dev_err(&adev->dev, "No reset controller specified.\n");
> >
> > Wasnt this optional??
>
> Yes, this is optional. The call devm_reset_control_get_optional() will
> just return NULL if the reset property is not there, but an error
> pointer if something really went wrong. Thus, I'm using IS_ERR() for the
> error checking.
So the error message is incorrect, as this is a real error condition?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
