spi: pic32: Retire dma_request_slave_channel_compat()
diff mbox series

Message ID 20191121080954.14915-1-peter.ujfalusi@ti.com
State Superseded
Headers show
Series
  • spi: pic32: Retire dma_request_slave_channel_compat()
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Commit Message

Peter Ujfalusi Nov. 21, 2019, 8:09 a.m. UTC
There is no reason to use the dma_request_slave_channel_compat() as no
filter function and parameter is provided.

Switch the driver to use dma_request_chan() instead.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
Hi,

Trying to crack down on the dma_request_slave_channel_compat() in the tree...

Only compile tested!

Regards,
Peter

 drivers/spi/spi-pic32.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

Comments

Geert Uytterhoeven Nov. 21, 2019, 8:30 a.m. UTC | #1
Hi Peter,

On Thu, Nov 21, 2019 at 9:11 AM Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
> There is no reason to use the dma_request_slave_channel_compat() as no
> filter function and parameter is provided.
>
> Switch the driver to use dma_request_chan() instead.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>

> --- a/drivers/spi/spi-pic32.c
> +++ b/drivers/spi/spi-pic32.c
> @@ -609,22 +609,18 @@ static void pic32_spi_cleanup(struct spi_device *spi)
>  static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
>  {
>         struct spi_master *master = pic32s->master;
> -       dma_cap_mask_t mask;
>
> -       dma_cap_zero(mask);
> -       dma_cap_set(DMA_SLAVE, mask);
> -
> -       master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
> -                                                         dev, "spi-rx");
> -       if (!master->dma_rx) {
> +       master->dma_rx = dma_request_chan(dev, "spi-rx");

Why not dma_request_slave_channel()?
That way you...

> +       if (IS_ERR(master->dma_rx)) {

... don't have to change the NULL check here, and...

>                 dev_warn(dev, "RX channel not found.\n");
> +               master->dma_rx = NULL;

...  don't have to override by NULL here.

(same for TX below).

Gr{oetje,eeting}s,

                        Geert
Peter Ujfalusi Nov. 21, 2019, 8:40 a.m. UTC | #2
Hi Geert,

On 21/11/2019 10.30, Geert Uytterhoeven wrote:
> Hi Peter,
> 
> On Thu, Nov 21, 2019 at 9:11 AM Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
>> There is no reason to use the dma_request_slave_channel_compat() as no
>> filter function and parameter is provided.
>>
>> Switch the driver to use dma_request_chan() instead.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> 
>> --- a/drivers/spi/spi-pic32.c
>> +++ b/drivers/spi/spi-pic32.c
>> @@ -609,22 +609,18 @@ static void pic32_spi_cleanup(struct spi_device *spi)
>>  static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
>>  {
>>         struct spi_master *master = pic32s->master;
>> -       dma_cap_mask_t mask;
>>
>> -       dma_cap_zero(mask);
>> -       dma_cap_set(DMA_SLAVE, mask);
>> -
>> -       master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
>> -                                                         dev, "spi-rx");
>> -       if (!master->dma_rx) {
>> +       master->dma_rx = dma_request_chan(dev, "spi-rx");
> 
> Why not dma_request_slave_channel()?

The longer term plan is to retire dma_request_slave_channel() as well.
With dma_request_chan() deferred probing against DMA drivers is possible
and it also supports legacy boot with dma_slave_map.

At the end we should be left with only dma_request_chan() for slave
channels in the kernel.

> That way you...
> 
>> +       if (IS_ERR(master->dma_rx)) {
> 
> ... don't have to change the NULL check here, and...
> 
>>                 dev_warn(dev, "RX channel not found.\n");
>> +               master->dma_rx = NULL;
> 
> ...  don't have to override by NULL here.

It is a small sacrifice, true, but if anyone cares the driver can
support deferred probing with dma_request_chan().

> 
> (same for TX below).
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 

- P├ęter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Geert Uytterhoeven Nov. 21, 2019, 8:54 a.m. UTC | #3
Hi Peter,

On Thu, Nov 21, 2019 at 9:40 AM Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
> On 21/11/2019 10.30, Geert Uytterhoeven wrote:
> > On Thu, Nov 21, 2019 at 9:11 AM Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
> >> There is no reason to use the dma_request_slave_channel_compat() as no
> >> filter function and parameter is provided.
> >>
> >> Switch the driver to use dma_request_chan() instead.
> >>
> >> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> >
> >> --- a/drivers/spi/spi-pic32.c
> >> +++ b/drivers/spi/spi-pic32.c
> >> @@ -609,22 +609,18 @@ static void pic32_spi_cleanup(struct spi_device *spi)
> >>  static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
> >>  {
> >>         struct spi_master *master = pic32s->master;
> >> -       dma_cap_mask_t mask;
> >>
> >> -       dma_cap_zero(mask);
> >> -       dma_cap_set(DMA_SLAVE, mask);
> >> -
> >> -       master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
> >> -                                                         dev, "spi-rx");
> >> -       if (!master->dma_rx) {
> >> +       master->dma_rx = dma_request_chan(dev, "spi-rx");
> >
> > Why not dma_request_slave_channel()?
>
> The longer term plan is to retire dma_request_slave_channel() as well.
> With dma_request_chan() deferred probing against DMA drivers is possible
> and it also supports legacy boot with dma_slave_map.
>
> At the end we should be left with only dma_request_chan() for slave
> channels in the kernel.

Thank you, deferred probing is a valid argument.
You may want to add that to the patch description.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> > That way you...
> >
> >> +       if (IS_ERR(master->dma_rx)) {
> >
> > ... don't have to change the NULL check here, and...
> >
> >>                 dev_warn(dev, "RX channel not found.\n");
> >> +               master->dma_rx = NULL;
> >
> > ...  don't have to override by NULL here.
>
> It is a small sacrifice, true, but if anyone cares the driver can
> support deferred probing with dma_request_chan().

Deferred probing in case of missing DMA controllers is always a bit
tricky, as there are multiple options:
  1. Defer probing of the slave driver,
  2a. Continue probing of the slave driver, fall back to PIO (which is
      what this driver does)
  2b. and Retry DMA setup later.

Gr{oetje,eeting}s,

                        Geert

Patch
diff mbox series

diff --git a/drivers/spi/spi-pic32.c b/drivers/spi/spi-pic32.c
index 69f517ec59c6..2f90ca5118af 100644
--- a/drivers/spi/spi-pic32.c
+++ b/drivers/spi/spi-pic32.c
@@ -609,22 +609,18 @@  static void pic32_spi_cleanup(struct spi_device *spi)
 static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
 {
 	struct spi_master *master = pic32s->master;
-	dma_cap_mask_t mask;
 
-	dma_cap_zero(mask);
-	dma_cap_set(DMA_SLAVE, mask);
-
-	master->dma_rx = dma_request_slave_channel_compat(mask, NULL, NULL,
-							  dev, "spi-rx");
-	if (!master->dma_rx) {
+	master->dma_rx = dma_request_chan(dev, "spi-rx");
+	if (IS_ERR(master->dma_rx)) {
 		dev_warn(dev, "RX channel not found.\n");
+		master->dma_rx = NULL;
 		goto out_err;
 	}
 
-	master->dma_tx = dma_request_slave_channel_compat(mask, NULL, NULL,
-							  dev, "spi-tx");
-	if (!master->dma_tx) {
+	master->dma_tx = dma_request_chan(dev, "spi-tx");
+	if (IS_ERR(master->dma_tx)) {
 		dev_warn(dev, "TX channel not found.\n");
+		master->dma_tx = NULL;
 		goto out_err;
 	}
 
@@ -637,11 +633,15 @@  static void pic32_spi_dma_prep(struct pic32_spi *pic32s, struct device *dev)
 	return;
 
 out_err:
-	if (master->dma_rx)
+	if (master->dma_rx) {
 		dma_release_channel(master->dma_rx);
+		master->dma_rx = NULL;
+	}
 
-	if (master->dma_tx)
+	if (master->dma_tx) {
 		dma_release_channel(master->dma_tx);
+		master->dma_tx = NULL;
+	}
 }
 
 static void pic32_spi_dma_unprep(struct pic32_spi *pic32s)