From: Alan Chiang <[email protected]>
In at24.c, it uses 8-bit addressing by default. In this patch,
add a property address-width that provides a flexible method to
pass the information to the driver.
Alan Chiang (2):
dt-bindings: at24: Add address-width property
eeprom: at24: Add support for address-width property
Documentation/devicetree/bindings/eeprom/at24.txt | 2 ++
drivers/misc/eeprom/at24.c | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)
--
2.7.4
From: Alan Chiang <[email protected]>
The AT24 series chips use 8-bit address by default. If some
chips would like to support more than 8 bits, the at24 driver
should be added the compatible field for specfic chips.
Provide a flexible way to determine the addressing bits through
address-width in this patch.
Signed-off-by: Alan Chiang <[email protected]>
Signed-off-by: Andy Yeh <[email protected]>
---
since v1:
-- Remove the address-width field in the example.
since v2:
-- Remove redundant space.
---
Documentation/devicetree/bindings/eeprom/at24.txt | 2 ++
1 file changed, 2 insertions(+)
diff --git a/Documentation/devicetree/bindings/eeprom/at24.txt b/Documentation/devicetree/bindings/eeprom/at24.txt
index 61d833a..aededdb 100644
--- a/Documentation/devicetree/bindings/eeprom/at24.txt
+++ b/Documentation/devicetree/bindings/eeprom/at24.txt
@@ -72,6 +72,8 @@ Optional properties:
- wp-gpios: GPIO to which the write-protect pin of the chip is connected.
+ - address-width: number of address bits (one of 8, 16).
+
Example:
eeprom@52 {
--
2.7.4
From: Alan Chiang <[email protected]>
Provide a flexible way to determine the addressing bits of eeprom.
Pass the addressing bits to driver through address-width property.
Signed-off-by: Alan Chiang <[email protected]>
Signed-off-by: Andy Yeh <[email protected]>
---
since v1
-- Add a warn message for 8-bit addressing.
since v2
-- Modify the warning message for clear.
-- Move the clearing bit operation outside of a statement.
---
drivers/misc/eeprom/at24.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 0c125f2..d606f3b 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -478,6 +478,24 @@ static void at24_properties_to_pdata(struct device *dev,
if (device_property_present(dev, "no-read-rollover"))
chip->flags |= AT24_FLAG_NO_RDROL;
+ err = device_property_read_u32(dev, "address-width", &val);
+ if (!err) {
+ switch (val) {
+ case 8:
+ if (chip->flags & AT24_FLAG_ADDR16)
+ dev_warn(dev, "Override address width to be 8,"
+ "while default is 16\n");
+ chip->flags &= ~AT24_FLAG_ADDR16;
+ break;
+ case 16:
+ chip->flags |= AT24_FLAG_ADDR16;
+ break;
+ default:
+ dev_warn(dev, "Bad \"address-width\" property: %u\n",
+ val);
+ }
+ }
+
err = device_property_read_u32(dev, "size", &val);
if (!err)
chip->byte_len = val;
--
2.7.4
On Wed, Jun 27, 2018 at 01:46:25PM +0800, [email protected] wrote:
> From: Alan Chiang <[email protected]>
>
> Provide a flexible way to determine the addressing bits of eeprom.
> Pass the addressing bits to driver through address-width property.
>
> Signed-off-by: Alan Chiang <[email protected]>
> Signed-off-by: Andy Yeh <[email protected]>
>
> ---
> since v1
> -- Add a warn message for 8-bit addressing.
> since v2
> -- Modify the warning message for clear.
> -- Move the clearing bit operation outside of a statement.
>
> ---
> drivers/misc/eeprom/at24.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 0c125f2..d606f3b 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -478,6 +478,24 @@ static void at24_properties_to_pdata(struct device *dev,
> if (device_property_present(dev, "no-read-rollover"))
> chip->flags |= AT24_FLAG_NO_RDROL;
>
> + err = device_property_read_u32(dev, "address-width", &val);
> + if (!err) {
> + switch (val) {
> + case 8:
> + if (chip->flags & AT24_FLAG_ADDR16)
> + dev_warn(dev, "Override address width to be 8,"
> + "while default is 16\n");
Please don't wrap strings --- it breaks grep. Exceeding 80 is ok in this
case.
> + chip->flags &= ~AT24_FLAG_ADDR16;
> + break;
> + case 16:
> + chip->flags |= AT24_FLAG_ADDR16;
> + break;
> + default:
> + dev_warn(dev, "Bad \"address-width\" property: %u\n",
> + val);
> + }
> + }
> +
> err = device_property_read_u32(dev, "size", &val);
> if (!err)
> chip->byte_len = val;
> --
> 2.7.4
>
--
Sakari Ailus
[email protected]
2018-06-27 7:46 GMT+02:00 <[email protected]>:
> From: Alan Chiang <[email protected]>
>
> The AT24 series chips use 8-bit address by default. If some
> chips would like to support more than 8 bits, the at24 driver
> should be added the compatible field for specfic chips.
>
> Provide a flexible way to determine the addressing bits through
> address-width in this patch.
>
> Signed-off-by: Alan Chiang <[email protected]>
> Signed-off-by: Andy Yeh <[email protected]>
>
> ---
> since v1:
> -- Remove the address-width field in the example.
> since v2:
> -- Remove redundant space.
>
> ---
> Documentation/devicetree/bindings/eeprom/at24.txt | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/eeprom/at24.txt b/Documentation/devicetree/bindings/eeprom/at24.txt
> index 61d833a..aededdb 100644
> --- a/Documentation/devicetree/bindings/eeprom/at24.txt
> +++ b/Documentation/devicetree/bindings/eeprom/at24.txt
> @@ -72,6 +72,8 @@ Optional properties:
>
> - wp-gpios: GPIO to which the write-protect pin of the chip is connected.
>
> + - address-width: number of address bits (one of 8, 16).
> +
> Example:
>
> eeprom@52 {
> --
> 2.7.4
>
Rob,
we only have two possibilities here and the default is 8 bits.
What do you think about introducing a boolean property here called:
'address-width-16' instead of an integer?
Best regards,
Bartosz Golaszewski
On Wed, Jun 27, 2018 at 01:46:24PM +0800, [email protected] wrote:
> From: Alan Chiang <[email protected]>
>
> The AT24 series chips use 8-bit address by default. If some
> chips would like to support more than 8 bits, the at24 driver
> should be added the compatible field for specfic chips.
>
> Provide a flexible way to determine the addressing bits through
> address-width in this patch.
>
> Signed-off-by: Alan Chiang <[email protected]>
> Signed-off-by: Andy Yeh <[email protected]>
Acked-by: Sakari Ailus <[email protected]>
--
Sakari Ailus
[email protected]
On Wed, Jun 27, 2018 at 10:19:38AM +0200, Bartosz Golaszewski wrote:
> 2018-06-27 7:46 GMT+02:00 <[email protected]>:
> > From: Alan Chiang <[email protected]>
> >
> > The AT24 series chips use 8-bit address by default. If some
> > chips would like to support more than 8 bits, the at24 driver
> > should be added the compatible field for specfic chips.
> >
> > Provide a flexible way to determine the addressing bits through
> > address-width in this patch.
> >
> > Signed-off-by: Alan Chiang <[email protected]>
> > Signed-off-by: Andy Yeh <[email protected]>
> >
> > ---
> > since v1:
> > -- Remove the address-width field in the example.
> > since v2:
> > -- Remove redundant space.
> >
> > ---
> > Documentation/devicetree/bindings/eeprom/at24.txt | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/eeprom/at24.txt b/Documentation/devicetree/bindings/eeprom/at24.txt
> > index 61d833a..aededdb 100644
> > --- a/Documentation/devicetree/bindings/eeprom/at24.txt
> > +++ b/Documentation/devicetree/bindings/eeprom/at24.txt
> > @@ -72,6 +72,8 @@ Optional properties:
> >
> > - wp-gpios: GPIO to which the write-protect pin of the chip is connected.
> >
> > + - address-width: number of address bits (one of 8, 16).
> > +
> > Example:
> >
> > eeprom@52 {
> > --
> > 2.7.4
> >
>
> Rob,
>
> we only have two possibilities here and the default is 8 bits.
>
> What do you think about introducing a boolean property here called:
> 'address-width-16' instead of an integer?
I'd have thought the same, but it turns out address-width is already being
used by the at25 bindings:
Documentation/devicetree/bindings/eeprom/at25.txt
--
Sakari Ailus
[email protected]
On Wed, 2018-06-27 at 12:40 +0300, Sakari Ailus wrote:
> On Wed, Jun 27, 2018 at 10:19:38AM +0200, Bartosz Golaszewski wrote:
> > 2018-06-27 7:46 GMT+02:00 <[email protected]>:
> > > From: Alan Chiang <[email protected]>
> > >
> > > The AT24 series chips use 8-bit address by default. If some
> > > chips would like to support more than 8 bits, the at24 driver
> > > should be added the compatible field for specfic chips.
> > >
> > > Provide a flexible way to determine the addressing bits through
> > > address-width in this patch.
> > >
> > > Signed-off-by: Alan Chiang <[email protected]>
> > > Signed-off-by: Andy Yeh <[email protected]>
> > >
> > > ---
> > > since v1:
> > > -- Remove the address-width field in the example.
> > > since v2:
> > > -- Remove redundant space.
> > >
> > > ---
> > > Documentation/devicetree/bindings/eeprom/at24.txt | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/eeprom/at24.txt
> > > b/Documentation/devicetree/bindings/eeprom/at24.txt
> > > index 61d833a..aededdb 100644
> > > --- a/Documentation/devicetree/bindings/eeprom/at24.txt
> > > +++ b/Documentation/devicetree/bindings/eeprom/at24.txt
> > > @@ -72,6 +72,8 @@ Optional properties:
> > >
> > > - wp-gpios: GPIO to which the write-protect pin of the chip is
> > > connected.
> > >
> > > + - address-width: number of address bits (one of 8, 16).
> > > +
> > > Example:
> > >
> > > eeprom@52 {
> > > --
> > > 2.7.4
> > >
> >
> > Rob,
> >
> > we only have two possibilities here and the default is 8 bits.
> >
> > What do you think about introducing a boolean property here called:
> > 'address-width-16' instead of an integer?
>
> I'd have thought the same, but it turns out address-width is already
> being
> used by the at25 bindings:
>
> Documentation/devicetree/bindings/eeprom/at25.txt
>
Agree with Sakari, there is no need to evolve a chaos in DT bindings. We
have too many semi-hemi-duplications in bindings. Especially in this
case we have already established property by a similar driver.
--
Andy Shevchenko <[email protected]>
Intel Finland Oy