[PATCH v4 0/2] Add a property in at24.c

[PATCH v4 0/2] Add a property in at24.c

[alanx.chiang]

From: Alan Chiang <alanx.chiang@intel.com>

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                        | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

-- 
2.7.4

[PATCH v4 1/2] dt-bindings: at24: Add address-width property

[alanx.chiang]

From: Alan Chiang <alanx.chiang@intel.com>

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 <alanx.chiang@intel.com>
Signed-off-by: Andy Yeh <andy.yeh@intel.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

---
since v1:
-- Remove the address-width field in the example.
since v2:
-- Remove redundant space.
since v3:
-- Add Acked-by.

---
 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

[PATCH v4 2/2] eeprom: at24: Add support for address-width property

[alanx.chiang]

From: Alan Chiang <alanx.chiang@intel.com>

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 <alanx.chiang@intel.com>
Signed-off-by: Andy Yeh <andy.yeh@intel.com>

---
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.
since v3
-- Merge the warning message into one line.

---
 drivers/misc/eeprom/at24.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 0c125f2..7ea640b 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -478,6 +478,23 @@ 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

Re: [PATCH v4 2/2] eeprom: at24: Add support for address-width property

[Sakari Ailus]

On Fri, Jun 29, 2018 at 03:21:55PM +0800, alanx.chiang@intel.com wrote:
> From: Alan Chiang <alanx.chiang@intel.com>
> 
> 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 <alanx.chiang@intel.com>
> Signed-off-by: Andy Yeh <andy.yeh@intel.com>

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>

-- 
Sakari Ailus
sakari.ailus@linux.intel.com

Re: [PATCH v4 2/2] eeprom: at24: Add support for address-width property

[Andy Shevchenko]

On Fri, 2018-06-29 at 15:21 +0800, alanx.chiang@intel.com wrote:
> From: Alan Chiang <alanx.chiang@intel.com>
> 
> Provide a flexible way to determine the addressing bits of eeprom.
> Pass the addressing bits to driver through address-width property.
> 

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Signed-off-by: Alan Chiang <alanx.chiang@intel.com>
> Signed-off-by: Andy Yeh <andy.yeh@intel.com>
> 
> ---
> 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.
> since v3
> -- Merge the warning message into one line.
> 
> ---
>  drivers/misc/eeprom/at24.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 0c125f2..7ea640b 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -478,6 +478,23 @@ 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;

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy