* [PATCH] i2c / ACPI: Pick the first address if device has multiple
@ 2014-12-29 13:48 Mika Westerberg
2015-01-13 15:50 ` Wolfram Sang
2015-01-14 10:55 ` Wolfram Sang
0 siblings, 2 replies; 6+ messages in thread
From: Mika Westerberg @ 2014-12-29 13:48 UTC (permalink / raw)
To: linux-i2c
Cc: Wolfram Sang, Srinivas Pandruvada, Mika Westerberg, linux-kernel
ACPI specification allows I2C devices with multiple addresses. The current
implementation goes over all addresses and assigns the last one to the
device. This is typically not the primary address of the device.
Instead of doing that we assign the first address to the device and then
let the driver handle rest of the addresses as it wishes.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
drivers/i2c/i2c-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 39d25a8cb1ad..a06be43b7842 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -102,7 +102,7 @@ static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
struct acpi_resource_i2c_serialbus *sb;
sb = &ares->data.i2c_serial_bus;
- if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
+ if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
info->addr = sb->slave_address;
if (sb->access_mode == ACPI_I2C_10BIT_MODE)
info->flags |= I2C_CLIENT_TEN;
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] i2c / ACPI: Pick the first address if device has multiple
2014-12-29 13:48 [PATCH] i2c / ACPI: Pick the first address if device has multiple Mika Westerberg
@ 2015-01-13 15:50 ` Wolfram Sang
2015-01-13 16:44 ` Srinivas Pandruvada
2015-01-14 10:55 ` Wolfram Sang
1 sibling, 1 reply; 6+ messages in thread
From: Wolfram Sang @ 2015-01-13 15:50 UTC (permalink / raw)
To: Mika Westerberg; +Cc: linux-i2c, Srinivas Pandruvada, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1655 bytes --]
On Mon, Dec 29, 2014 at 03:48:48PM +0200, Mika Westerberg wrote:
> ACPI specification allows I2C devices with multiple addresses. The current
> implementation goes over all addresses and assigns the last one to the
> device. This is typically not the primary address of the device.
>
> Instead of doing that we assign the first address to the device and then
> let the driver handle rest of the addresses as it wishes.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Yes, seems better than what we do know. But maybe taking the lowest
address is a bit better heuristic than taking the first address?
Not sure, though...
> ---
> drivers/i2c/i2c-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 39d25a8cb1ad..a06be43b7842 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -102,7 +102,7 @@ static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
> struct acpi_resource_i2c_serialbus *sb;
>
> sb = &ares->data.i2c_serial_bus;
> - if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> + if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> info->addr = sb->slave_address;
> if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> info->flags |= I2C_CLIENT_TEN;
> --
> 2.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] i2c / ACPI: Pick the first address if device has multiple
2015-01-13 15:50 ` Wolfram Sang
@ 2015-01-13 16:44 ` Srinivas Pandruvada
2015-01-13 16:48 ` Wolfram Sang
0 siblings, 1 reply; 6+ messages in thread
From: Srinivas Pandruvada @ 2015-01-13 16:44 UTC (permalink / raw)
To: Wolfram Sang; +Cc: Mika Westerberg, linux-i2c, linux-kernel
On Tue, 2015-01-13 at 16:50 +0100, Wolfram Sang wrote:
> On Mon, Dec 29, 2014 at 03:48:48PM +0200, Mika Westerberg wrote:
> > ACPI specification allows I2C devices with multiple addresses. The current
> > implementation goes over all addresses and assigns the last one to the
> > device. This is typically not the primary address of the device.
> >
> > Instead of doing that we assign the first address to the device and then
> > let the driver handle rest of the addresses as it wishes.
> >
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
>
> Yes, seems better than what we do know. But maybe taking the lowest
> address is a bit better heuristic than taking the first address?
> Not sure, though...
The problem in taking lowest is that in many cases in current devices,
the lowest address may end being 0x0C, which is reserved address for
SMBUS (ARA). This will require different handling. Unfortunately ACPI
doesn't have a way to distinguish whether SMBUS support is desired or
not.
The other option is to skip all reserved addresses for SMBUS also and
then create on the lowest.
Thanks,
Srinivas
>
> > ---
> > drivers/i2c/i2c-core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > index 39d25a8cb1ad..a06be43b7842 100644
> > --- a/drivers/i2c/i2c-core.c
> > +++ b/drivers/i2c/i2c-core.c
> > @@ -102,7 +102,7 @@ static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
> > struct acpi_resource_i2c_serialbus *sb;
> >
> > sb = &ares->data.i2c_serial_bus;
> > - if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> > + if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
> > info->addr = sb->slave_address;
> > if (sb->access_mode == ACPI_I2C_10BIT_MODE)
> > info->flags |= I2C_CLIENT_TEN;
> > --
> > 2.1.4
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] i2c / ACPI: Pick the first address if device has multiple
2015-01-13 16:44 ` Srinivas Pandruvada
@ 2015-01-13 16:48 ` Wolfram Sang
2015-01-13 17:00 ` Mika Westerberg
0 siblings, 1 reply; 6+ messages in thread
From: Wolfram Sang @ 2015-01-13 16:48 UTC (permalink / raw)
To: Srinivas Pandruvada; +Cc: Mika Westerberg, linux-i2c, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1394 bytes --]
On Tue, Jan 13, 2015 at 08:44:37AM -0800, Srinivas Pandruvada wrote:
> On Tue, 2015-01-13 at 16:50 +0100, Wolfram Sang wrote:
> > On Mon, Dec 29, 2014 at 03:48:48PM +0200, Mika Westerberg wrote:
> > > ACPI specification allows I2C devices with multiple addresses. The current
> > > implementation goes over all addresses and assigns the last one to the
> > > device. This is typically not the primary address of the device.
> > >
> > > Instead of doing that we assign the first address to the device and then
> > > let the driver handle rest of the addresses as it wishes.
> > >
> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> >
> > Yes, seems better than what we do know. But maybe taking the lowest
> > address is a bit better heuristic than taking the first address?
> > Not sure, though...
> The problem in taking lowest is that in many cases in current devices,
> the lowest address may end being 0x0C, which is reserved address for
> SMBUS (ARA). This will require different handling. Unfortunately ACPI
> doesn't have a way to distinguish whether SMBUS support is desired or
> not.
> The other option is to skip all reserved addresses for SMBUS also and
> then create on the lowest.
Well, this makes me think that Mika's approach is probably the sanest
one...
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] i2c / ACPI: Pick the first address if device has multiple
2015-01-13 16:48 ` Wolfram Sang
@ 2015-01-13 17:00 ` Mika Westerberg
0 siblings, 0 replies; 6+ messages in thread
From: Mika Westerberg @ 2015-01-13 17:00 UTC (permalink / raw)
To: Wolfram Sang; +Cc: Srinivas Pandruvada, linux-i2c, linux-kernel
On Tue, Jan 13, 2015 at 05:48:29PM +0100, Wolfram Sang wrote:
> On Tue, Jan 13, 2015 at 08:44:37AM -0800, Srinivas Pandruvada wrote:
> > On Tue, 2015-01-13 at 16:50 +0100, Wolfram Sang wrote:
> > > On Mon, Dec 29, 2014 at 03:48:48PM +0200, Mika Westerberg wrote:
> > > > ACPI specification allows I2C devices with multiple addresses. The current
> > > > implementation goes over all addresses and assigns the last one to the
> > > > device. This is typically not the primary address of the device.
> > > >
> > > > Instead of doing that we assign the first address to the device and then
> > > > let the driver handle rest of the addresses as it wishes.
> > > >
> > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> > >
> > > Yes, seems better than what we do know. But maybe taking the lowest
> > > address is a bit better heuristic than taking the first address?
> > > Not sure, though...
> > The problem in taking lowest is that in many cases in current devices,
> > the lowest address may end being 0x0C, which is reserved address for
> > SMBUS (ARA). This will require different handling. Unfortunately ACPI
> > doesn't have a way to distinguish whether SMBUS support is desired or
> > not.
> > The other option is to skip all reserved addresses for SMBUS also and
> > then create on the lowest.
>
> Well, this makes me think that Mika's approach is probably the sanest
> one...
Also I think it is more consistent that way.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] i2c / ACPI: Pick the first address if device has multiple
2014-12-29 13:48 [PATCH] i2c / ACPI: Pick the first address if device has multiple Mika Westerberg
2015-01-13 15:50 ` Wolfram Sang
@ 2015-01-14 10:55 ` Wolfram Sang
1 sibling, 0 replies; 6+ messages in thread
From: Wolfram Sang @ 2015-01-14 10:55 UTC (permalink / raw)
To: Mika Westerberg; +Cc: linux-i2c, Srinivas Pandruvada, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 598 bytes --]
On Mon, Dec 29, 2014 at 03:48:48PM +0200, Mika Westerberg wrote:
> ACPI specification allows I2C devices with multiple addresses. The current
> implementation goes over all addresses and assigns the last one to the
> device. This is typically not the primary address of the device.
>
> Instead of doing that we assign the first address to the device and then
> let the driver handle rest of the addresses as it wishes.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Applied to for-next, thanks!
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2015-01-14 10:56 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-12-29 13:48 [PATCH] i2c / ACPI: Pick the first address if device has multiple Mika Westerberg
2015-01-13 15:50 ` Wolfram Sang
2015-01-13 16:44 ` Srinivas Pandruvada
2015-01-13 16:48 ` Wolfram Sang
2015-01-13 17:00 ` Mika Westerberg
2015-01-14 10:55 ` Wolfram Sang
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox