[PATCH v2 8/8] dt-binding: mtd: Document gpio-addr-flash

[PATCH v2 8/8] dt-binding: mtd: Document gpio-addr-flash

[Ricardo Ribalda Delgado]

Add documentation for gpio-addr-flash. This binding allow creating
flash devices that are paged using GPIOs.

Cc: devicetree@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
 .../bindings/mtd/gpio-addr-flash.txt          | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt

diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
new file mode 100644
index 000000000000..4279e8cad09b
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
@@ -0,0 +1,46 @@
+Memory Mapped flash with some address lines addressed using GPIOs
+
+Handle the case where a flash device is mostly addressed using physical
+line and supplemented by GPIOs.  This way you can hook up say a 8MiB flash
+to a 2MiB memory range and use the GPIOs to select a particular range.
+
+ - compatible : "cfi-gpio-addr-flash"
+ - reg : Address range of the mtd chip that is memory mapped, this is,
+   on the previous example 2MiB.
+ - bank-width : Width (in bytes) of the bank.  Equal to the
+   device width times the number of interleaved chips.
+ - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip
+   is going to be probed. If omitted, assumed to be equal to "cfi_probe".
+ - #address-cells, #size-cells : Must be present if the device has
+   sub-nodes representing partitions (see below).  In this case
+   both #address-cells and #size-cells must be equal to 1.
+
+The device tree may optionally contain sub-nodes describing partitions of the
+address space. See partition.txt for more detail.
+
+Example:
+
+	cfi_flash_0: cfi_flash {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "cfi-gpio-addr-flash";
+		bank-width = <2>;
+		reg = < 0x00300000 0x00200000 >;
+		gpios = <&gpio_0 3 0>, <&gpio_0 4 0>;
+		partition@0 {
+			reg = < 0x0 0x200000 >;
+			label = "Golden Bitstream";
+		};
+		partition@200000 {
+			reg = < 0x200000 0x200000 >;
+			label = "User Bitstream";
+		};
+		partition@400000 {
+			reg = < 0x400000 0x200000 >;
+			label = "V4L Controls";
+		};
+		partition@600000 {
+			reg = < 0x600000 0x200000 >;
+			label = "Production Data";
+		};
+	} ;
-- 
2.18.0

Re: [PATCH v2 8/8] dt-binding: mtd: Document gpio-addr-flash

[Rob Herring]

On Wed, Sep 05, 2018 at 04:36:43PM +0200, Ricardo Ribalda Delgado wrote:
> Add documentation for gpio-addr-flash. This binding allow creating
> flash devices that are paged using GPIOs.
> 
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
>  .../bindings/mtd/gpio-addr-flash.txt          | 46 +++++++++++++++++++
>  1 file changed, 46 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> 
> diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> new file mode 100644
> index 000000000000..4279e8cad09b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> @@ -0,0 +1,46 @@
> +Memory Mapped flash with some address lines addressed using GPIOs
> +
> +Handle the case where a flash device is mostly addressed using physical
> +line and supplemented by GPIOs.  This way you can hook up say a 8MiB flash
> +to a 2MiB memory range and use the GPIOs to select a particular range.
> +
> + - compatible : "cfi-gpio-addr-flash"
> + - reg : Address range of the mtd chip that is memory mapped, this is,
> +   on the previous example 2MiB.
> + - bank-width : Width (in bytes) of the bank.  Equal to the
> +   device width times the number of interleaved chips.
> + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip
> +   is going to be probed. If omitted, assumed to be equal to "cfi_probe".

Why not just a bool prop for jedec mode? As-is, the '_probe' part is 
redundant.

> + - #address-cells, #size-cells : Must be present if the device has
> +   sub-nodes representing partitions (see below).  In this case
> +   both #address-cells and #size-cells must be equal to 1.

Perhaps most importantly, where's 'gpios' property?

> +
> +The device tree may optionally contain sub-nodes describing partitions of the
> +address space. See partition.txt for more detail.
> +
> +Example:
> +
> +	cfi_flash_0: cfi_flash {

flash@300000

> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		compatible = "cfi-gpio-addr-flash";
> +		bank-width = <2>;
> +		reg = < 0x00300000 0x00200000 >;
> +		gpios = <&gpio_0 3 0>, <&gpio_0 4 0>;
> +		partition@0 {

All these under a partitions node is now recommended.

> +			reg = < 0x0 0x200000 >;
> +			label = "Golden Bitstream";
> +		};
> +		partition@200000 {
> +			reg = < 0x200000 0x200000 >;
> +			label = "User Bitstream";
> +		};
> +		partition@400000 {
> +			reg = < 0x400000 0x200000 >;
> +			label = "V4L Controls";
> +		};
> +		partition@600000 {
> +			reg = < 0x600000 0x200000 >;
> +			label = "Production Data";
> +		};
> +	} ;
> -- 
> 2.18.0
> 

Re: [PATCH v2 8/8] dt-binding: mtd: Document gpio-addr-flash

[Ricardo Ribalda Delgado]

Hi Rob
On Tue, Sep 25, 2018 at 10:48 PM Rob Herring <robh@kernel.org> wrote:
>
> On Wed, Sep 05, 2018 at 04:36:43PM +0200, Ricardo Ribalda Delgado wrote:
> > Add documentation for gpio-addr-flash. This binding allow creating
> > flash devices that are paged using GPIOs.
> >
> > Cc: devicetree@vger.kernel.org
> > Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> > ---
> >  .../bindings/mtd/gpio-addr-flash.txt          | 46 +++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> >
> > diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> > new file mode 100644
> > index 000000000000..4279e8cad09b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> > @@ -0,0 +1,46 @@
> > +Memory Mapped flash with some address lines addressed using GPIOs
> > +
> > +Handle the case where a flash device is mostly addressed using physical
> > +line and supplemented by GPIOs.  This way you can hook up say a 8MiB flash
> > +to a 2MiB memory range and use the GPIOs to select a particular range.
> > +
> > + - compatible : "cfi-gpio-addr-flash"
> > + - reg : Address range of the mtd chip that is memory mapped, this is,
> > +   on the previous example 2MiB.
> > + - bank-width : Width (in bytes) of the bank.  Equal to the
> > +   device width times the number of interleaved chips.
> > + - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip
> > +   is going to be probed. If omitted, assumed to be equal to "cfi_probe".
>
> Why not just a bool prop for jedec mode? As-is, the '_probe' part is
> redundant.

I wanted to mimic gpio-addr-flash. Which btw does not document this
property. Shall I send a patch adding it?

>
> > + - #address-cells, #size-cells : Must be present if the device has
> > +   sub-nodes representing partitions (see below).  In this case
> > +   both #address-cells and #size-cells must be equal to 1.
>
> Perhaps most importantly, where's 'gpios' property?
>
> > +
> > +The device tree may optionally contain sub-nodes describing partitions of the
> > +address space. See partition.txt for more detail.
> > +
> > +Example:
> > +
> > +     cfi_flash_0: cfi_flash {
>
> flash@300000
>
> > +             #address-cells = <1>;
> > +             #size-cells = <1>;
> > +             compatible = "cfi-gpio-addr-flash";
> > +             bank-width = <2>;
> > +             reg = < 0x00300000 0x00200000 >;
> > +             gpios = <&gpio_0 3 0>, <&gpio_0 4 0>;
> > +             partition@0 {
>
> All these under a partitions node is now recommended.
>
> > +                     reg = < 0x0 0x200000 >;
> > +                     label = "Golden Bitstream";
> > +             };
> > +             partition@200000 {
> > +                     reg = < 0x200000 0x200000 >;
> > +                     label = "User Bitstream";
> > +             };
> > +             partition@400000 {
> > +                     reg = < 0x400000 0x200000 >;
> > +                     label = "V4L Controls";
> > +             };
> > +             partition@600000 {
> > +                     reg = < 0x600000 0x200000 >;
> > +                     label = "Production Data";
> > +             };
> > +     } ;
> > --
> > 2.18.0
> >



-- 
Ricardo Ribalda

[PATCH v3 8/8] dt-binding: mtd: Document gpio-addr-flash

[Ricardo Ribalda Delgado]

Add documentation for gpio-addr-flash. This binding allow creating
flash devices that are paged using GPIOs.

Cc: devicetree@vger.kernel.org
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---

Changelog v3: 

- Changes suggested by Rob Herring (Thanks!)
  - Add gpio description
  - Improve partition

 .../bindings/mtd/gpio-addr-flash.txt          | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt

diff --git a/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
new file mode 100644
index 000000000000..5006a26e1753
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
@@ -0,0 +1,54 @@
+Memory Mapped flash with some address lines addressed using GPIOs
+
+Handle the case where a flash device is mostly addressed using physical
+line and supplemented by GPIOs.  This way you can hook up say a 8MiB flash
+to a 2MiB memory range and use the GPIOs to select a particular range.
+
+ - compatible : "cfi-gpio-addr-flash"
+ - reg : Address range of the mtd chip that is memory mapped, this is,
+   on the previous example 2MiB.
+ - bank-width : Width (in bytes) of the bank.  Equal to the
+   device width times the number of interleaved chips.
+ - gpios: List of GPIO specifiers that will be used to address the MSBs address
+   lines. The order goes from LSB to MSB.
+ - probe-type : (optional) "cfi_probe", "jedec_probe". How the mtd chip
+   is going to be probed. If omitted, assumed to be equal to "cfi_probe".
+ - #address-cells, #size-cells : Must be present if the device has
+   sub-nodes representing partitions (see below).  In this case
+   both #address-cells and #size-cells must be equal to 1.
+
+The device tree may optionally contain sub-nodes describing partitions of the
+address space. Check partition.txt for more details.
+
+Example:
+
+	flash@300000 {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		compatible = "cfi-gpio-addr-flash";
+		bank-width = <2>;
+		reg = < 0x00300000 0x00200000 >;
+		gpios = <&gpio_0 3 0>, <&gpio_0 4 0>;
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				reg = < 0x0 0x200000 >;
+				label = "Golden Bitstream";
+			};
+			partition@200000 {
+				reg = < 0x200000 0x200000 >;
+				label = "User Bitstream";
+			};
+			partition@400000 {
+				reg = < 0x400000 0x200000 >;
+				label = "V4L Controls";
+			};
+			partition@600000 {
+				reg = < 0x600000 0x200000 >;
+				label = "Production Data";
+			};
+		}
+	} ;
-- 
2.19.0

Re: [PATCH v3 8/8] dt-binding: mtd: Document gpio-addr-flash

[Rob Herring]

On Wed, 26 Sep 2018 08:39:34 +0200, Ricardo Ribalda Delgado wrote:
> Add documentation for gpio-addr-flash. This binding allow creating
> flash devices that are paged using GPIOs.
> 
> Cc: devicetree@vger.kernel.org
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
> ---
> 
> Changelog v3: 
> 
> - Changes suggested by Rob Herring (Thanks!)
>   - Add gpio description
>   - Improve partition
> 
>  .../bindings/mtd/gpio-addr-flash.txt          | 54 +++++++++++++++++++
>  1 file changed, 54 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mtd/gpio-addr-flash.txt
> 

Reviewed-by: Rob Herring <robh@kernel.org>