MAX7301 GPIO: Do not force SPI speed when using OF Platform

DISCUSSION Roland Stigge 2 participants 6 messages Jul 24, 2013 – Aug 7, 2013 SPI

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Roland Stigge

author

2013-07-24 10:19 UTC #0 lore raw

Hi,

commit 047b93a35961f7a6561e6f5dcb040738f822b892 introduced the following to gpio-max7301.c:

	/* bits_per_word cannot be configured in platform data */

- spi->bits_per_word = 16;
+ if (spi->dev.platform_data)
+ spi->bits_per_word = 16;
ret = spi_setup(spi);

Comment is: "The bit_per_word can be set in the OF Device tree, so no need to force it as with the platform_data when using OF Platform"

Can you please point me to the respective OF option? I couldn't find it under drivers/spi/spi* or Documentation/devicetree/bindings/spi/*.

Thanks in advance,

Roland

leroy christophe

2013-08-07 11:31 UTC #1 lore raw

Hi,

You have to add the following in your dts:

spi-bits = <16>;

Regards
Christophe

Le 24/07/2013 12:19, Roland Stigge a ?crit :

Quoted 21 lines

Hi,
commit 047b93a35961f7a6561e6f5dcb040738f822b892 introduced the following to gpio-max7301.c:
	/* bits_per_word cannot be configured in platform data */
(quoted diff) +2 -1
-	spi->bits_per_word = 16;
+	if (spi->dev.platform_data)
+		spi->bits_per_word = 16;
  	ret = spi_setup(spi);
Comment is: "The bit_per_word can be set in the OF Device tree, so no need to force it as with the platform_data when using OF Platform"
Can you please point me to the respective OF option? I couldn't find it under drivers/spi/spi* or Documentation/devicetree/bindings/spi/*.
Thanks in advance,
Roland

Roland Stigge

author

2013-08-07 12:17 UTC #2 lore raw

Hi,

Quoted 13 lines · leroy christophe

Le 24/07/2013 12:19, Roland Stigge a ?crit :
Quoted 12 lines
commit 047b93a35961f7a6561e6f5dcb040738f822b892 introduced the following to gpio-max7301.c:
    /* bits_per_word cannot be configured in platform data */
(quoted diff) +2 -1
-    spi->bits_per_word = 16;
+    if (spi->dev.platform_data)
+        spi->bits_per_word = 16;
      ret = spi_setup(spi);
Comment is: "The bit_per_word can be set in the OF Device tree, so no need to force it as with the platform_data when using OF Platform"

Quoted 6 lines

Quoted 2 lines
Can you please point me to the respective OF option? I couldn't find it under drivers/spi/spi* or Documentation/devicetree/bindings/spi/*.
You have to add the following in your dts:
spi-bits = <16>;

I tried this, both in the device's and in the controller's node. But it didn't work. However, as described, I didn't expect it to work, because there is no code present to handle "spi-bits". At least not in 3.10.

Am I missing something? Otherwise, maybe something of the tree that you are talking about is missing from mainline still?

Thanks in advance,

Roland

leroy christophe

2013-08-07 12:35 UTC #3 lore raw

Le 07/08/2013 14:17, Roland Stigge a ?crit :

Quoted 25 lines

Hi,
Quoted 10 lines · leroy christophe
Le 24/07/2013 12:19, Roland Stigge a ?crit :
Quoted 9 lines
commit 047b93a35961f7a6561e6f5dcb040738f822b892 introduced the following to gpio-max7301.c:
     /* bits_per_word cannot be configured in platform data */
(quoted diff) +2 -1
-    spi->bits_per_word = 16;
+    if (spi->dev.platform_data)
+        spi->bits_per_word = 16;
       ret = spi_setup(spi);
Quoted 8 lines
Quoted 5 lines
Comment is: "The bit_per_word can be set in the OF Device tree, so no need to force it as with the platform_data when using OF Platform"
Can you please point me to the respective OF option? I couldn't find it under drivers/spi/spi* or Documentation/devicetree/bindings/spi/*.
You have to add the following in your dts:
spi-bits = <16>;
I tried this, both in the device's and in the controller's node. But it didn't work. However, as described, I didn't expect it to work, because there is no code present to handle "spi-bits". At least not in 3.10.

Quoted 7 lines

Am I missing something? Otherwise, maybe something of the tree that you are talking about is missing from mainline still?
Thanks in advance,
Roland

Strange. I'm using 3.8.13
I have it handled in drivers/spi/spi.c in function of_register_spi_devices()

Christophe

Roland Stigge

author

2013-08-07 12:46 UTC #4 lore raw

Hi,

Quoted 5 lines · leroy christophe

Quoted 5 lines
Quoted 1 line
spi-bits = <16>;
I tried this, both in the device's and in the controller's node. But it didn't work. However, as described, I didn't expect it to work, because there is no code present to handle "spi-bits". At least not in 3.10.

Quoted 7 lines

Quoted 4 lines
Am I missing something? Otherwise, maybe something of the tree that you are talking about is missing from mainline still?
Strange. I'm using 3.8.13
I have it handled in drivers/spi/spi.c in function of_register_spi_devices()

3.8.13's (as well as newer ones') drivers/spi/spi.c doesn't handle "spi-bits", see also

https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/drivers/spi/spi.c?h=linux-3.8.y

Maybe you have additional patches that are not in mainline, yet?

Thanks,

Roland

leroy christophe

2013-08-07 15:20 UTC #5 lore raw

Hi,

Le 07/08/2013 14:46, Roland Stigge a ?crit :

Quoted 18 lines

Hi,
Quoted 5 lines · leroy christophe
Quoted 5 lines
Quoted 1 line
spi-bits = <16>;
I tried this, both in the device's and in the controller's node. But it didn't work. However, as described, I didn't expect it to work, because there is no code present to handle "spi-bits". At least not in 3.10.
Quoted 7 lines
Quoted 4 lines
Am I missing something? Otherwise, maybe something of the tree that you are talking about is missing from mainline still?
Strange. I'm using 3.8.13
I have it handled in drivers/spi/spi.c in function of_register_spi_devices()
3.8.13's (as well as newer ones') drivers/spi/spi.c doesn't handle "spi-bits", see also

Quoted 8 lines

https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/drivers/spi/spi.c?h=linux-3.8.y
Maybe you have additional patches that are not in mainline, yet?
Thanks,
Roland

Yes you are right, I have the attached patch in addition which have been in our code for long time and which has never been submitted for inclusion in the mainline kernel.
Sorry about that, I will submit it.

Regards
Christophe
-------------- next part --------------

drivers/spi/spi.c +5 -0

@@ -870,6 +870,11 @@
 		if (of_find_property(nc, "spi-3wire", NULL))
 			spi->mode |= SPI_3WIRE;
 
+		/* Bits per word */
+		prop = of_get_property(nc, "spi-bits", &len);
+		if (prop && len >= sizeof(*prop)) {
+			spi->bits_per_word = prop[0];
+		}
 		/* Device speed */
 		prop = of_get_property(nc, "spi-max-frequency", &len);
 		if (!prop || len < sizeof(*prop)) {