[PATCH v3 0/5] drm/solomon: Add SSD130x OLED displays SPI support

[PATCH v3 0/5] drm/solomon: Add SSD130x OLED displays SPI support

[Javier Martinez Canillas]

Hello,

This series adds a ssd130x-spi driver that provides a 4-wire SPI transport
support for SSD130x OLED controllers that can be accessed over a SPI bus.

The driver is quite similar to existing ssd130x-i2c driver that is used by
I2C controllers, but there is a difference in the protocol used by SSD130x
depending on the transport used. The details are in patch #4 description.

Patch #1 just makes the current ssd130x-i2c compatible strings in the DT
binding to be deprecated, and add new ones that don't have an "fb-i2c".

Patch #2 extends the DT binding with the properties needed to support SPI.

Patch #3 adds the new compatible strings to the OF device ID table in the
ssd130x-i2c DRM driver and deprecate the old ones.

Patch #4 moves the device info for the different SSD130x variants from
the ssd130x-i2c transport driver to the ssd130x core driver.

Finally patch #5 adds the ssd130x-spi DRM driver for the OLED controllers
that come with a 4-wire SPI interface, instead of an I2C interface.

This is a v3 that addresses the issues pointed out in v2.

Best regards,
Javier

Changes in v3:
- Drop the "sinowealth,sh1106-i2c", wasn't in a released version (Chen-Yu Tsai)
- Continue enforcing required properties for deprecated strings (Maxime Ripard)
- Add a comment to the properties required for SPI (Geert Uytterhoeven)
- Drop the "sinowealth,sh1106-i2c", wasn't in a released version (Chen-Yu Tsai)
- s/it/they in the commit description (Geert Uytterhoeven)
- Drop unnecessary blank line (Geert Uytterhoeven)
- Export variants array and use &info[ID] in device table (Andy Shevchenko)
- Drop ssd130x_spi_get_dc() helper and open code it (Geert Uytterhoeven)
- Export variants array and use &info[ID] in device table (Andy Shevchenko)
- Add Geert Uytterhoeven's Reviewed-by tag to patches.

Changes in v2:
- Drop the -i2c suffixes from the compatible strings too (Geert Uytterhoeven)
- Don't add compatible strings with an "-spi" suffix (Geert Uytterhoeven)
- Use the compatible strings that don't have "fb-i2c" (Geert Uytterhoeven).
- Drop ssd13x_variant_to_info() and just use the array index (Neil Armstrong).
- Add the same compatible strings than I2C (Geert Uytterhoeven)
- Add Mark Brown's Acked-by tag to all patches.

Javier Martinez Canillas (5):
  dt-bindings: display: ssd1307fb: Deprecate "-i2c" compatible strings
  dt-bindings: display: ssd1307fb: Extend schema for SPI controllers
  drm/solomon: Add ssd130x new compatible strings and deprecate old
    ones.
  drm/solomon: Move device info from ssd130x-i2c to the core driver
  drm/solomon: Add SSD130x OLED displays SPI support

 .../bindings/display/solomon,ssd1307fb.yaml   |  82 ++++++--
 drivers/gpu/drm/solomon/Kconfig               |   9 +
 drivers/gpu/drm/solomon/Makefile              |   1 +
 drivers/gpu/drm/solomon/ssd130x-i2c.c         |  62 +++---
 drivers/gpu/drm/solomon/ssd130x-spi.c         | 177 ++++++++++++++++++
 drivers/gpu/drm/solomon/ssd130x.c             |  36 +++-
 drivers/gpu/drm/solomon/ssd130x.h             |  14 ++
 7 files changed, 324 insertions(+), 57 deletions(-)
 create mode 100644 drivers/gpu/drm/solomon/ssd130x-spi.c

-- 
2.35.1

[PATCH v3 1/5] dt-bindings: display: ssd1307fb: Deprecate "-i2c" compatible strings

[Javier Martinez Canillas]

The current compatible strings for SSD130x I2C controllers contain both an
"fb" and "-i2c" suffixes. It seems to indicate that are for a fbdev driver
and also that are for devices that can be accessed over an I2C bus.

But a DT is supposed to describe the hardware and not Linux implementation
details. So let's deprecate those compatible strings and add new ones that
only contain the vendor and device name, without any of these suffixes.

These will just describe the device and can be matched by both I2C and SPI
DRM drivers. The required properties should still be enforced for old ones.

While being there, just drop the "sinowealth,sh1106-i2c" compatible string
since that was never present in a released Linux version.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---

Changes in v3:
- Drop the "sinowealth,sh1106-i2c", wasn't in a released version (Chen-Yu Tsai)
- Continue enforcing required properties for deprecated strings (Maxime Ripard)

Changes in v2:
- Drop the -i2c suffixes from the compatible strings too (Geert Uytterhoeven)

 .../bindings/display/solomon,ssd1307fb.yaml   | 44 +++++++++++++------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
index ade61d502edd..7653b6c3fcb6 100644
--- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
+++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
@@ -12,12 +12,22 @@ maintainers:
 
 properties:
   compatible:
-    enum:
-      - sinowealth,sh1106-i2c
-      - solomon,ssd1305fb-i2c
-      - solomon,ssd1306fb-i2c
-      - solomon,ssd1307fb-i2c
-      - solomon,ssd1309fb-i2c
+    oneOf:
+      # Deprecated compatible strings
+      - items:
+          - enum:
+              - solomon,ssd1305fb-i2c
+              - solomon,ssd1306fb-i2c
+              - solomon,ssd1307fb-i2c
+              - solomon,ssd1309fb-i2c
+        deprecated: true
+      - items:
+          - enum:
+              - sinowealth,sh1106
+              - solomon,ssd1305
+              - solomon,ssd1306
+              - solomon,ssd1307
+              - solomon,ssd1309
 
   reg:
     maxItems: 1
@@ -136,7 +146,7 @@ allOf:
       properties:
         compatible:
           contains:
-            const: sinowealth,sh1106-i2c
+            const: sinowealth,sh1106
     then:
       properties:
         solomon,dclk-div:
@@ -148,7 +158,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: solomon,ssd1305fb-i2c
+            enum:
+              - solomon,ssd1305-i2c
+              - solomon,ssd1305
     then:
       properties:
         solomon,dclk-div:
@@ -160,7 +172,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: solomon,ssd1306fb-i2c
+            enum:
+              - solomon,ssd1306-i2c
+              - solomon,ssd1306
     then:
       properties:
         solomon,dclk-div:
@@ -172,7 +186,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: solomon,ssd1307fb-i2c
+            enum:
+              - solomon,ssd1307-i2c
+              - solomon,ssd1307
     then:
       properties:
         solomon,dclk-div:
@@ -186,7 +202,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: solomon,ssd1309fb-i2c
+            enum:
+              - solomon,ssd1309-i2c
+              - solomon,ssd1309
     then:
       properties:
         solomon,dclk-div:
@@ -203,14 +221,14 @@ examples:
             #size-cells = <0>;
 
             ssd1307: oled@3c {
-                    compatible = "solomon,ssd1307fb-i2c";
+                    compatible = "solomon,ssd1307";
                     reg = <0x3c>;
                     pwms = <&pwm 4 3000>;
                     reset-gpios = <&gpio2 7>;
             };
 
             ssd1306: oled@3d {
-                    compatible = "solomon,ssd1306fb-i2c";
+                    compatible = "solomon,ssd1306";
                     reg = <0x3c>;
                     pwms = <&pwm 4 3000>;
                     reset-gpios = <&gpio2 7>;
-- 
2.35.1

[PATCH v3 2/5] dt-bindings: display: ssd1307fb: Extend schema for SPI controllers

[Javier Martinez Canillas]

The Solomon SSD130x OLED displays can either have an I2C or SPI interface,
add to the schema the properties and examples for OLED devices under SPI.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
---

Changes in v3:
- Add a comment to the properties required for SPI (Geert Uytterhoeven)

Changes in v2:
- Don't add compatible strings with an "-spi" suffix (Geert Uytterhoeven)

 .../bindings/display/solomon,ssd1307fb.yaml   | 38 ++++++++++++++++++-
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
index 7653b6c3fcb6..7d7de92df86f 100644
--- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
+++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
@@ -38,9 +38,16 @@ properties:
   reset-gpios:
     maxItems: 1
 
+  # Only required for SPI
+  dc-gpios:
+    maxItems: 1
+
   vbat-supply:
     description: The supply for VBAT
 
+  # Only required for SPI
+  spi-max-frequency: true
+
   solomon,height:
     $ref: /schemas/types.yaml#/definitions/uint32
     default: 16
@@ -220,14 +227,14 @@ examples:
             #address-cells = <1>;
             #size-cells = <0>;
 
-            ssd1307: oled@3c {
+            ssd1307_i2c: oled@3c {
                     compatible = "solomon,ssd1307";
                     reg = <0x3c>;
                     pwms = <&pwm 4 3000>;
                     reset-gpios = <&gpio2 7>;
             };
 
-            ssd1306: oled@3d {
+            ssd1306_i2c: oled@3d {
                     compatible = "solomon,ssd1306";
                     reg = <0x3c>;
                     pwms = <&pwm 4 3000>;
@@ -238,3 +245,30 @@ examples:
                     solomon,lookup-table = /bits/ 8 <0x3f 0x3f 0x3f 0x3f>;
             };
     };
+  - |
+    spi {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            ssd1307_spi: oled@0 {
+                    compatible = "solomon,ssd1307";
+                    reg = <0x0>;
+                    pwms = <&pwm 4 3000>;
+                    reset-gpios = <&gpio2 7>;
+                    dc-gpios = <&gpio2 8>;
+                    spi-max-frequency = <10000000>;
+            };
+
+            ssd1306_spi: oled@1 {
+                    compatible = "solomon,ssd1306";
+                    reg = <0x1>;
+                    pwms = <&pwm 4 3000>;
+                    reset-gpios = <&gpio2 7>;
+                    dc-gpios = <&gpio2 8>;
+                    spi-max-frequency = <10000000>;
+                    solomon,com-lrremap;
+                    solomon,com-invdir;
+                    solomon,com-offset = <32>;
+                    solomon,lookup-table = /bits/ 8 <0x3f 0x3f 0x3f 0x3f>;
+            };
+    };
-- 
2.35.1

Re: [PATCH v3 2/5] dt-bindings: display: ssd1307fb: Extend schema for SPI controllers

[Geert Uytterhoeven]

Hi Javier,

On Tue, Apr 12, 2022 at 6:27 PM Javier Martinez Canillas
<javierm@redhat.com> wrote:
> The Solomon SSD130x OLED displays can either have an I2C or SPI interface,
> add to the schema the properties and examples for OLED devices under SPI.
>
> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> Acked-by: Mark Brown <broonie@kernel.org>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
>
> Changes in v3:
> - Add a comment to the properties required for SPI (Geert Uytterhoeven)

Thanks for the update!

> --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> @@ -38,9 +38,16 @@ properties:
>    reset-gpios:
>      maxItems: 1
>
> +  # Only required for SPI
> +  dc-gpios:
> +    maxItems: 1

Actually I meant to also add a description, like for vbat-supply below,
to explain the meaning of "dc".

> +
>    vbat-supply:
>      description: The supply for VBAT

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3 2/5] dt-bindings: display: ssd1307fb: Extend schema for SPI controllers

[Javier Martinez Canillas]

Hello Geert,

On 4/13/22 10:04, Geert Uytterhoeven wrote:
> Hi Javier,
> 
> On Tue, Apr 12, 2022 at 6:27 PM Javier Martinez Canillas
> <javierm@redhat.com> wrote:
>> The Solomon SSD130x OLED displays can either have an I2C or SPI interface,
>> add to the schema the properties and examples for OLED devices under SPI.
>>
>> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
>> Acked-by: Mark Brown <broonie@kernel.org>
>> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
>> ---
>>
>> Changes in v3:
>> - Add a comment to the properties required for SPI (Geert Uytterhoeven)
> 
> Thanks for the update!
> 
>> --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
>> +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
>> @@ -38,9 +38,16 @@ properties:
>>    reset-gpios:
>>      maxItems: 1
>>
>> +  # Only required for SPI
>> +  dc-gpios:
>> +    maxItems: 1
> 
> Actually I meant to also add a description, like for vbat-supply below,
> to explain the meaning of "dc".
>

Ahh, sorry for misunderstanding you! Something like the following looks good ?

  # Only required for SPI
  dc-gpios:
    description:
      GPIO connected to the controller's D/C# (Data/Command) pin,
      that is needed for 4-wire SPI to tell the controller if the
      data sent is for a command register or the display data RAM
    maxItems: 1

If you agree with that, then can squash before pushing or add it to a v4
if another revision is needed.

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat

Re: [PATCH v3 2/5] dt-bindings: display: ssd1307fb: Extend schema for SPI controllers

[Geert Uytterhoeven]

Hi Javier,

On Wed, Apr 13, 2022 at 11:44 AM Javier Martinez Canillas
<javierm@redhat.com> wrote:
> On 4/13/22 10:04, Geert Uytterhoeven wrote:
> > On Tue, Apr 12, 2022 at 6:27 PM Javier Martinez Canillas
> > <javierm@redhat.com> wrote:
> >> The Solomon SSD130x OLED displays can either have an I2C or SPI interface,
> >> add to the schema the properties and examples for OLED devices under SPI.
> >>
> >> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
> >> Acked-by: Mark Brown <broonie@kernel.org>
> >> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
> >> ---
> >>
> >> Changes in v3:
> >> - Add a comment to the properties required for SPI (Geert Uytterhoeven)
> >
> > Thanks for the update!
> >
> >> --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> >> +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> >> @@ -38,9 +38,16 @@ properties:
> >>    reset-gpios:
> >>      maxItems: 1
> >>
> >> +  # Only required for SPI
> >> +  dc-gpios:
> >> +    maxItems: 1
> >
> > Actually I meant to also add a description, like for vbat-supply below,
> > to explain the meaning of "dc".
> >
>
> Ahh, sorry for misunderstanding you! Something like the following looks good ?
>
>   # Only required for SPI
>   dc-gpios:
>     description:
>       GPIO connected to the controller's D/C# (Data/Command) pin,
>       that is needed for 4-wire SPI to tell the controller if the
>       data sent is for a command register or the display data RAM
>     maxItems: 1
>
> If you agree with that, then can squash before pushing or add it to a v4
> if another revision is needed.

Thanks, LGTM.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds