Hello,
This series adds a ssd130x-spi driver that provides a 4-wire SPI transport
support for SSD130x OLED controllers that can be accessed through a SPI.
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 suffix.
Patch #2 extends the DT binding with the compatible string and properties
needed to support the ssd130x-spi devices.
Patch #3 adds the new compatible strings to the OF device ID table in the
ssd130x-i2c DRM driver.
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.
Best regards,
Javier
Javier Martinez Canillas (5):
dt-bindings: display: ssd1307fb: Deprecate fbdev compatible strings
dt-bindings: display: ssd1307fb: Extend schema for SPI controllers
drm/solomon: Add ssd130x-i2c compatible strings without an -fb suffix
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 | 117 ++++++++---
drivers/gpu/drm/solomon/Kconfig | 9 +
drivers/gpu/drm/solomon/Makefile | 1 +
drivers/gpu/drm/solomon/ssd130x-i2c.c | 60 +++---
drivers/gpu/drm/solomon/ssd130x-spi.c | 184 ++++++++++++++++++
drivers/gpu/drm/solomon/ssd130x.c | 60 +++++-
drivers/gpu/drm/solomon/ssd130x.h | 13 ++
7 files changed, 376 insertions(+), 68 deletions(-)
create mode 100644 drivers/gpu/drm/solomon/ssd130x-spi.c
--
2.35.1
These are declared in the ssd130x-i2c transport driver but the information
is not I2C specific and could be used by other SSD130x transport drivers.
Move them to the ssd130x core driver and just set the OF device entries to
an ID that could be used to lookup the correct device into from an array.
While being there, also move the SSD130X_DATA and SSD130X_COMMAND control
bytes. Since even though are used by the I2C interface, it could also be
useful for other transport protocols such as SPI.
Suggested-by: Chen-Yu Tsai <[email protected]>
Signed-off-by: Javier Martinez Canillas <[email protected]>
---
drivers/gpu/drm/solomon/ssd130x-i2c.c | 51 ++++-------------------
drivers/gpu/drm/solomon/ssd130x.c | 60 +++++++++++++++++++++++++--
drivers/gpu/drm/solomon/ssd130x.h | 13 ++++++
3 files changed, 78 insertions(+), 46 deletions(-)
diff --git a/drivers/gpu/drm/solomon/ssd130x-i2c.c b/drivers/gpu/drm/solomon/ssd130x-i2c.c
index a469679548f8..aa6cc2cb54f9 100644
--- a/drivers/gpu/drm/solomon/ssd130x-i2c.c
+++ b/drivers/gpu/drm/solomon/ssd130x-i2c.c
@@ -53,76 +53,43 @@ static void ssd130x_i2c_shutdown(struct i2c_client *client)
ssd130x_shutdown(ssd130x);
}
-static struct ssd130x_deviceinfo ssd130x_sh1106_deviceinfo = {
- .default_vcomh = 0x40,
- .default_dclk_div = 1,
- .default_dclk_frq = 5,
- .page_mode_only = 1,
-};
-
-static struct ssd130x_deviceinfo ssd130x_ssd1305_deviceinfo = {
- .default_vcomh = 0x34,
- .default_dclk_div = 1,
- .default_dclk_frq = 7,
-};
-
-static struct ssd130x_deviceinfo ssd130x_ssd1306_deviceinfo = {
- .default_vcomh = 0x20,
- .default_dclk_div = 1,
- .default_dclk_frq = 8,
- .need_chargepump = 1,
-};
-
-static struct ssd130x_deviceinfo ssd130x_ssd1307_deviceinfo = {
- .default_vcomh = 0x20,
- .default_dclk_div = 2,
- .default_dclk_frq = 12,
- .need_pwm = 1,
-};
-
-static struct ssd130x_deviceinfo ssd130x_ssd1309_deviceinfo = {
- .default_vcomh = 0x34,
- .default_dclk_div = 1,
- .default_dclk_frq = 10,
-};
-
static const struct of_device_id ssd130x_of_match[] = {
{
.compatible = "sinowealth,sh1106-i2c",
- .data = &ssd130x_sh1106_deviceinfo,
+ .data = SH1106_ID,
},
{
.compatible = "solomon,ssd1305-i2c",
- .data = &ssd130x_ssd1305_deviceinfo,
+ .data = (void *)SSD1305_ID,
},
{
.compatible = "solomon,ssd1306-i2c",
- .data = &ssd130x_ssd1306_deviceinfo,
+ .data = (void *)SSD1306_ID,
},
{
.compatible = "solomon,ssd1307-i2c",
- .data = &ssd130x_ssd1307_deviceinfo,
+ .data = (void *)SSD1307_ID,
},
{
.compatible = "solomon,ssd1309-i2c",
- .data = &ssd130x_ssd1309_deviceinfo,
+ .data = (void *)SSD1309_ID,
},
/* Deprecated but remain for backward compatibility */
{
.compatible = "solomon,ssd1305fb-i2c",
- .data = &ssd130x_ssd1305_deviceinfo,
+ .data = (void *)SSD1305_ID,
},
{
.compatible = "solomon,ssd1306fb-i2c",
- .data = &ssd130x_ssd1306_deviceinfo,
+ .data = (void *)SSD1306_ID,
},
{
.compatible = "solomon,ssd1307fb-i2c",
- .data = &ssd130x_ssd1307_deviceinfo,
+ .data = (void *)SSD1307_ID,
},
{
.compatible = "solomon,ssd1309fb-i2c",
- .data = &ssd130x_ssd1309_deviceinfo,
+ .data = (void *)SSD1309_ID,
},
{ /* sentinel */ }
};
diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index a7e784518c69..1f00fd3c0023 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -39,11 +39,9 @@
#define DRIVER_MAJOR 1
#define DRIVER_MINOR 0
-#define SSD130X_DATA 0x40
-#define SSD130X_COMMAND 0x80
-
#define SSD130X_PAGE_COL_START_LOW 0x00
#define SSD130X_PAGE_COL_START_HIGH 0x10
+
#define SSD130X_SET_ADDRESS_MODE 0x20
#define SSD130X_SET_COL_RANGE 0x21
#define SSD130X_SET_PAGE_RANGE 0x22
@@ -94,6 +92,55 @@
#define MAX_CONTRAST 255
+static struct ssd130x_deviceinfo ssd130x_variants[] = {
+ {
+ .default_vcomh = 0x40,
+ .default_dclk_div = 1,
+ .default_dclk_frq = 5,
+ .page_mode_only = 1,
+ },
+ {
+ .variant = SSD1305_ID,
+ .default_vcomh = 0x34,
+ .default_dclk_div = 1,
+ .default_dclk_frq = 7,
+ },
+ {
+ .variant = SSD1306_ID,
+ .default_vcomh = 0x20,
+ .default_dclk_div = 1,
+ .default_dclk_frq = 8,
+ .need_chargepump = 1,
+ },
+ {
+ .variant = SSD1307_ID,
+ .default_vcomh = 0x20,
+ .default_dclk_div = 2,
+ .default_dclk_frq = 12,
+ .need_pwm = 1,
+ },
+ {
+ .variant = SSD1309_ID,
+ .default_vcomh = 0x34,
+ .default_dclk_div = 1,
+ .default_dclk_frq = 10,
+ }
+};
+
+static const struct ssd130x_deviceinfo *ssd13x_variant_to_info(enum ssd130x_variants variant)
+{
+ int i;
+ const struct ssd130x_deviceinfo *info;
+
+ for (i = 0; i < ARRAY_SIZE(ssd130x_variants); i++) {
+ info = &ssd130x_variants[i];
+ if (info->variant == variant)
+ return info;
+ }
+
+ return NULL;
+}
+
static inline struct ssd130x_device *drm_to_ssd130x(struct drm_device *drm)
{
return container_of(drm, struct ssd130x_device, drm);
@@ -846,6 +893,7 @@ static int ssd130x_get_resources(struct ssd130x_device *ssd130x)
struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
{
struct ssd130x_device *ssd130x;
+ enum ssd130x_variants variant;
struct backlight_device *bl;
struct drm_device *drm;
int ret;
@@ -860,7 +908,11 @@ struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
ssd130x->dev = dev;
ssd130x->regmap = regmap;
- ssd130x->device_info = device_get_match_data(dev);
+
+ variant = (enum ssd130x_variants)device_get_match_data(dev);
+ ssd130x->device_info = ssd13x_variant_to_info(variant);
+ if (!ssd130x->device_info)
+ return ERR_PTR(-EINVAL);
if (ssd130x->device_info->page_mode_only)
ssd130x->page_address_mode = 1;
diff --git a/drivers/gpu/drm/solomon/ssd130x.h b/drivers/gpu/drm/solomon/ssd130x.h
index f5b062576fdf..4e0b62a41aa3 100644
--- a/drivers/gpu/drm/solomon/ssd130x.h
+++ b/drivers/gpu/drm/solomon/ssd130x.h
@@ -18,7 +18,20 @@
#include <linux/regmap.h>
+#define SSD130X_DATA 0x40
+#define SSD130X_COMMAND 0x80
+
+enum ssd130x_variants {
+ SH1106_ID,
+ SSD1305_ID,
+ SSD1306_ID,
+ SSD1307_ID,
+ SSD1309_ID,
+ NR_SSD130X_VARIANTS
+};
+
struct ssd130x_deviceinfo {
+ enum ssd130x_variants variant;
u32 default_vcomh;
u32 default_dclk_div;
u32 default_dclk_frq;
--
2.35.1
The current compatible strings for SSD130x I2C controllers contain an -fb
suffix, this seems to indicate that are for a fbdev driver. But the DT is
supposed to describe the hardware and not Linux implementation details.
Let's deprecate those compatible strings and add a new enum that contains
compatible strings that don't have a -fb suffix. These will be matched by
the ssd130x-i2c DRM driver.
Signed-off-by: Javier Martinez Canillas <[email protected]>
---
.../bindings/display/solomon,ssd1307fb.yaml | 36 ++++++++++++-------
1 file changed, 24 insertions(+), 12 deletions(-)
diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
index ade61d502edd..46207f2c12b8 100644
--- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
+++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
@@ -12,12 +12,24 @@ 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
+
+ # SSD130x I2C controllers
+ - items:
+ - enum:
+ - sinowealth,sh1106-i2c
+ - solomon,ssd1305-i2c
+ - solomon,ssd1306-i2c
+ - solomon,ssd1307-i2c
+ - solomon,ssd1309-i2c
reg:
maxItems: 1
@@ -148,7 +160,7 @@ allOf:
properties:
compatible:
contains:
- const: solomon,ssd1305fb-i2c
+ const: solomon,ssd1305-i2c
then:
properties:
solomon,dclk-div:
@@ -160,7 +172,7 @@ allOf:
properties:
compatible:
contains:
- const: solomon,ssd1306fb-i2c
+ const: solomon,ssd1306-i2c
then:
properties:
solomon,dclk-div:
@@ -172,7 +184,7 @@ allOf:
properties:
compatible:
contains:
- const: solomon,ssd1307fb-i2c
+ const: solomon,ssd1307-i2c
then:
properties:
solomon,dclk-div:
@@ -186,7 +198,7 @@ allOf:
properties:
compatible:
contains:
- const: solomon,ssd1309fb-i2c
+ const: solomon,ssd1309-i2c
then:
properties:
solomon,dclk-div:
@@ -203,14 +215,14 @@ examples:
#size-cells = <0>;
ssd1307: oled@3c {
- compatible = "solomon,ssd1307fb-i2c";
+ compatible = "solomon,ssd1307-i2c";
reg = <0x3c>;
pwms = <&pwm 4 3000>;
reset-gpios = <&gpio2 7>;
};
ssd1306: oled@3d {
- compatible = "solomon,ssd1306fb-i2c";
+ compatible = "solomon,ssd1306-i2c";
reg = <0x3c>;
pwms = <&pwm 4 3000>;
reset-gpios = <&gpio2 7>;
--
2.35.1
Hi,
On 07/04/2022 22:02, Javier Martinez Canillas wrote:
> These are declared in the ssd130x-i2c transport driver but the information
> is not I2C specific and could be used by other SSD130x transport drivers.
>
> Move them to the ssd130x core driver and just set the OF device entries to
> an ID that could be used to lookup the correct device into from an array.
>
> While being there, also move the SSD130X_DATA and SSD130X_COMMAND control
> bytes. Since even though are used by the I2C interface, it could also be
> useful for other transport protocols such as SPI.
>
> Suggested-by: Chen-Yu Tsai <[email protected]>
> Signed-off-by: Javier Martinez Canillas <[email protected]>
> ---
>
> drivers/gpu/drm/solomon/ssd130x-i2c.c | 51 ++++-------------------
> drivers/gpu/drm/solomon/ssd130x.c | 60 +++++++++++++++++++++++++--
> drivers/gpu/drm/solomon/ssd130x.h | 13 ++++++
> 3 files changed, 78 insertions(+), 46 deletions(-)
>
> diff --git a/drivers/gpu/drm/solomon/ssd130x-i2c.c b/drivers/gpu/drm/solomon/ssd130x-i2c.c
> index a469679548f8..aa6cc2cb54f9 100644
> --- a/drivers/gpu/drm/solomon/ssd130x-i2c.c
> +++ b/drivers/gpu/drm/solomon/ssd130x-i2c.c
> @@ -53,76 +53,43 @@ static void ssd130x_i2c_shutdown(struct i2c_client *client)
> ssd130x_shutdown(ssd130x);
> }
>
> -static struct ssd130x_deviceinfo ssd130x_sh1106_deviceinfo = {
> - .default_vcomh = 0x40,
> - .default_dclk_div = 1,
> - .default_dclk_frq = 5,
> - .page_mode_only = 1,
> -};
> -
> -static struct ssd130x_deviceinfo ssd130x_ssd1305_deviceinfo = {
> - .default_vcomh = 0x34,
> - .default_dclk_div = 1,
> - .default_dclk_frq = 7,
> -};
> -
> -static struct ssd130x_deviceinfo ssd130x_ssd1306_deviceinfo = {
> - .default_vcomh = 0x20,
> - .default_dclk_div = 1,
> - .default_dclk_frq = 8,
> - .need_chargepump = 1,
> -};
> -
> -static struct ssd130x_deviceinfo ssd130x_ssd1307_deviceinfo = {
> - .default_vcomh = 0x20,
> - .default_dclk_div = 2,
> - .default_dclk_frq = 12,
> - .need_pwm = 1,
> -};
> -
> -static struct ssd130x_deviceinfo ssd130x_ssd1309_deviceinfo = {
> - .default_vcomh = 0x34,
> - .default_dclk_div = 1,
> - .default_dclk_frq = 10,
> -};
> -
> static const struct of_device_id ssd130x_of_match[] = {
> {
> .compatible = "sinowealth,sh1106-i2c",
> - .data = &ssd130x_sh1106_deviceinfo,
> + .data = SH1106_ID,
> },
> {
> .compatible = "solomon,ssd1305-i2c",
> - .data = &ssd130x_ssd1305_deviceinfo,
> + .data = (void *)SSD1305_ID,
> },
> {
> .compatible = "solomon,ssd1306-i2c",
> - .data = &ssd130x_ssd1306_deviceinfo,
> + .data = (void *)SSD1306_ID,
> },
> {
> .compatible = "solomon,ssd1307-i2c",
> - .data = &ssd130x_ssd1307_deviceinfo,
> + .data = (void *)SSD1307_ID,
> },
> {
> .compatible = "solomon,ssd1309-i2c",
> - .data = &ssd130x_ssd1309_deviceinfo,
> + .data = (void *)SSD1309_ID,
> },
> /* Deprecated but remain for backward compatibility */
> {
> .compatible = "solomon,ssd1305fb-i2c",
> - .data = &ssd130x_ssd1305_deviceinfo,
> + .data = (void *)SSD1305_ID,
> },
> {
> .compatible = "solomon,ssd1306fb-i2c",
> - .data = &ssd130x_ssd1306_deviceinfo,
> + .data = (void *)SSD1306_ID,
> },
> {
> .compatible = "solomon,ssd1307fb-i2c",
> - .data = &ssd130x_ssd1307_deviceinfo,
> + .data = (void *)SSD1307_ID,
> },
> {
> .compatible = "solomon,ssd1309fb-i2c",
> - .data = &ssd130x_ssd1309_deviceinfo,
> + .data = (void *)SSD1309_ID,
> },
> { /* sentinel */ }
> };
> diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
> index a7e784518c69..1f00fd3c0023 100644
> --- a/drivers/gpu/drm/solomon/ssd130x.c
> +++ b/drivers/gpu/drm/solomon/ssd130x.c
> @@ -39,11 +39,9 @@
> #define DRIVER_MAJOR 1
> #define DRIVER_MINOR 0
>
> -#define SSD130X_DATA 0x40
> -#define SSD130X_COMMAND 0x80
> -
> #define SSD130X_PAGE_COL_START_LOW 0x00
> #define SSD130X_PAGE_COL_START_HIGH 0x10
> +
> #define SSD130X_SET_ADDRESS_MODE 0x20
> #define SSD130X_SET_COL_RANGE 0x21
> #define SSD130X_SET_PAGE_RANGE 0x22
> @@ -94,6 +92,55 @@
>
> #define MAX_CONTRAST 255
>
> +static struct ssd130x_deviceinfo ssd130x_variants[] = {
> + {
> + .default_vcomh = 0x40,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 5,
> + .page_mode_only = 1,
> + },
Why not [SH1106_ID] = {
and later:
if (variant < NR_SSD130X_VARIANTS)
ssd130x->device_info = ssd130x_variants[variant];
instead of less efficient ssd13x_variant_to_info ?
> + {
> + .variant = SSD1305_ID,
> + .default_vcomh = 0x34,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 7,
> + },
> + {
> + .variant = SSD1306_ID,
> + .default_vcomh = 0x20,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 8,
> + .need_chargepump = 1,
> + },
> + {
> + .variant = SSD1307_ID,
> + .default_vcomh = 0x20,
> + .default_dclk_div = 2,
> + .default_dclk_frq = 12,
> + .need_pwm = 1,
> + },
> + {
> + .variant = SSD1309_ID,
> + .default_vcomh = 0x34,
> + .default_dclk_div = 1,
> + .default_dclk_frq = 10,
> + }
> +};
> +
> +static const struct ssd130x_deviceinfo *ssd13x_variant_to_info(enum ssd130x_variants variant)
> +{
> + int i;
> + const struct ssd130x_deviceinfo *info;
> +
> + for (i = 0; i < ARRAY_SIZE(ssd130x_variants); i++) {
> + info = &ssd130x_variants[i];
> + if (info->variant == variant)
> + return info;
> + }
> +
> + return NULL;
> +}
> +
> static inline struct ssd130x_device *drm_to_ssd130x(struct drm_device *drm)
> {
> return container_of(drm, struct ssd130x_device, drm);
> @@ -846,6 +893,7 @@ static int ssd130x_get_resources(struct ssd130x_device *ssd130x)
> struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
> {
> struct ssd130x_device *ssd130x;
> + enum ssd130x_variants variant;
> struct backlight_device *bl;
> struct drm_device *drm;
> int ret;
> @@ -860,7 +908,11 @@ struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)
>
> ssd130x->dev = dev;
> ssd130x->regmap = regmap;
> - ssd130x->device_info = device_get_match_data(dev);
> +
> + variant = (enum ssd130x_variants)device_get_match_data(dev);
> + ssd130x->device_info = ssd13x_variant_to_info(variant);
> + if (!ssd130x->device_info)
> + return ERR_PTR(-EINVAL);
>
> if (ssd130x->device_info->page_mode_only)
> ssd130x->page_address_mode = 1;
> diff --git a/drivers/gpu/drm/solomon/ssd130x.h b/drivers/gpu/drm/solomon/ssd130x.h
> index f5b062576fdf..4e0b62a41aa3 100644
> --- a/drivers/gpu/drm/solomon/ssd130x.h
> +++ b/drivers/gpu/drm/solomon/ssd130x.h
> @@ -18,7 +18,20 @@
>
> #include <linux/regmap.h>
>
> +#define SSD130X_DATA 0x40
> +#define SSD130X_COMMAND 0x80
> +
> +enum ssd130x_variants {
> + SH1106_ID,
> + SSD1305_ID,
> + SSD1306_ID,
> + SSD1307_ID,
> + SSD1309_ID,
> + NR_SSD130X_VARIANTS
> +};
> +
> struct ssd130x_deviceinfo {
> + enum ssd130x_variants variant;
> u32 default_vcomh;
> u32 default_dclk_div;
> u32 default_dclk_frq;
Neil
On 4/8/22 21:19, Javier Martinez Canillas wrote:
[snip]
>>
>> There's also no reason to put the bus interface into the compatible as
>> the same compatible will work on different buses. But since you want to
>> add SPI, just using the 'i2c' one will confuse people. For that reason
>> you could add 'solomon,ssd1305', etc. for both SPI support and I2C DRM.
>
> That's not really true. There's a reason to add per bus compatible strings
> at least in Linux. And is that there's no information about the bus types
> in module aliases that are reported to user-space for module auto-loading.
>
Forgot to mention that in this particular case it will work but just because
the SPI subsystem always report a module alias of the form "spi:device" even
for devices that are registered through OF.
So having a single "solomon,ssd1306" would work because for I2C the module
alias will be "of:NoledT(null)Csolomon,ssd1306" and for SPI it will be
"spi:ssd1306".
But if ever the SPI subsystem is fixed to report proper OF module aliases
things will break. And since the DT bindings is an ABI, it's safer to have
"-i2c" and "-spi" compatible strings variants.
--
Best regards,
Javier Martinez Canillas
Linux Engineering
Red Hat
On Thu, Apr 07, 2022 at 10:02:00PM +0200, Javier Martinez Canillas wrote:
> The current compatible strings for SSD130x I2C controllers contain an -fb
> suffix, this seems to indicate that are for a fbdev driver. But the DT is
> supposed to describe the hardware and not Linux implementation details.
True, but compatible is just an identifier. There's no reason to
deprecate unless the binding as a whole needs to be redone.
I imagine you also want 2 compatibles for 2 drivers. That's saying you
should change your firmware to switch drivers. The fact that we have 2
drivers for the same h/w is a kernel problem. Don't bring DT into it.
> Let's deprecate those compatible strings and add a new enum that contains
> compatible strings that don't have a -fb suffix. These will be matched by
> the ssd130x-i2c DRM driver.
>
> Signed-off-by: Javier Martinez Canillas <[email protected]>
> ---
>
> .../bindings/display/solomon,ssd1307fb.yaml | 36 ++++++++++++-------
> 1 file changed, 24 insertions(+), 12 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> index ade61d502edd..46207f2c12b8 100644
> --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> @@ -12,12 +12,24 @@ 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
> +
> + # SSD130x I2C controllers
> + - items:
> + - enum:
> + - sinowealth,sh1106-i2c
> + - solomon,ssd1305-i2c
> + - solomon,ssd1306-i2c
> + - solomon,ssd1307-i2c
> + - solomon,ssd1309-i2c
There's also no reason to put the bus interface into the compatible as
the same compatible will work on different buses. But since you want to
add SPI, just using the 'i2c' one will confuse people. For that reason
you could add 'solomon,ssd1305', etc. for both SPI support and I2C DRM.
(You should also support the 'fb-i2c' variant in DRM IMO, but doubtful
that I'll review that.)
Rob
Hello Neil,
Thanks for your feedback.
On 4/8/22 09:49, Neil Armstrong wrote:
[snip]
>>
>> +static struct ssd130x_deviceinfo ssd130x_variants[] = {
>> + {
>> + .default_vcomh = 0x40,
>> + .default_dclk_div = 1,
>> + .default_dclk_frq = 5,
>> + .page_mode_only = 1,
>> + },
>
> Why not [SH1106_ID] = {
>
> and later:
>
> if (variant < NR_SSD130X_VARIANTS)
> ssd130x->device_info = ssd130x_variants[variant];
>
> instead of less efficient ssd13x_variant_to_info ?
>
Indeed. I'll change that in v2.
--
Best regards,
Javier Martinez Canillas
Linux Engineering
Red Hat
Hello Rob,
On 4/8/22 20:22, Rob Herring wrote:
> On Thu, Apr 07, 2022 at 10:02:00PM +0200, Javier Martinez Canillas wrote:
>> The current compatible strings for SSD130x I2C controllers contain an -fb
>> suffix, this seems to indicate that are for a fbdev driver. But the DT is
>> supposed to describe the hardware and not Linux implementation details.
>
> True, but compatible is just an identifier. There's no reason to
> deprecate unless the binding as a whole needs to be redone.
>
> I imagine you also want 2 compatibles for 2 drivers. That's saying you
> should change your firmware to switch drivers. The fact that we have 2
> drivers for the same h/w is a kernel problem. Don't bring DT into it.
>
No, that's not what I meant. In fact, we currently have two drivers that
match against the same set of compatible strings. These drivers are:
* drivers/video/fbdev/ssd1307fb.c
* drivers/gpu/drm/solomon/ssd130x-i2c.c
what I don't personally like about the current compatible strings is that
the *driver* name was encoded on those, rather than the IC names. So for
instance there's a "solomon,ssd1307fb-i2c" (notice the fb suffix) instead
of just "solomon,ssd1307-i2c" or "solomon,ssd1307".
When I ported the fbdev driver to DRM, I considered using different values
for the compatible strings but decided to just use the same for backward
compatibility.
But now I want to add compatible strings for OLED controllers that use a
SPI interface instead, and I don't really want to add a compatible string
"solomon,ssd1307fb-spi" but just without the "fb".
I want the SPI compatible strings to be consistent with the I2C ones though,
hence the deprecation so new DTS could just use the ones without a "fb".
Now, if you say that I can't do add new ones for I2C, then I will just add
"solomon,ssd1307fb-spi" and similar even though I don't like the "fb" there.
And just to make clear, the DRM driver will continue matching against both
compatible strings, but the fbdev will only match the old "fb" ones.
[snip]
>> +
>> + # SSD130x I2C controllers
>> + - items:
>> + - enum:
>> + - sinowealth,sh1106-i2c
>> + - solomon,ssd1305-i2c
>> + - solomon,ssd1306-i2c
>> + - solomon,ssd1307-i2c
>> + - solomon,ssd1309-i2c
>
> There's also no reason to put the bus interface into the compatible as
> the same compatible will work on different buses. But since you want to
> add SPI, just using the 'i2c' one will confuse people. For that reason
> you could add 'solomon,ssd1305', etc. for both SPI support and I2C DRM.
That's not really true. There's a reason to add per bus compatible strings
at least in Linux. And is that there's no information about the bus types
in module aliases that are reported to user-space for module auto-loading.
For example,
$ cat /sys/devices/platform/soc/fe804000.i2c/i2c-1/1-003c/modalias
of:NoledT(null)Csolomon,ssd1306fb-i2c
$ cat /sys/devices/platform/soc/fe804000.i2c/i2c-1/1-003c/uevent
DRIVER=ssd130x-i2c
OF_NAME=oled
OF_FULLNAME=/soc/i2c@7e804000/oled@3c
OF_COMPATIBLE_0=solomon,ssd1306fb-i2c
OF_COMPATIBLE_N=1
MODALIAS=of:NoledT(null)Csolomon,ssd1306fb-i2c
and
$ modinfo ssd130x-i2c | grep alias
alias: of:N*T*Csolomon,ssd1309fb-i2cC*
alias: of:N*T*Csolomon,ssd1309fb-i2c
alias: of:N*T*Csolomon,ssd1307fb-i2cC*
alias: of:N*T*Csolomon,ssd1307fb-i2c
alias: of:N*T*Csolomon,ssd1306fb-i2cC*
alias: of:N*T*Csolomon,ssd1306fb-i2c
alias: of:N*T*Csolomon,ssd1305fb-i2cC*
alias: of:N*T*Csolomon,ssd1305fb-i2c
alias: of:N*T*Csinowealth,sh1106-i2cC*
alias: of:N*T*Csinowealth,sh1106-i2c
this module will match against any MODALIAS uevent that has one of the
listed compatible strings in "C" and any node name in "N". But also for
any type "T".
And even if the module alias was more restrictive and say only matched
against 'of:N*Ti2cCsolomon,ssd1307fb-i2c', the type information is not
filled by the bus drivers.
So, if we just had a "solomon,ssd1307" compatible string, then a device
registered through OF could lead to the wrong kernel module to be loaded.
In other words, it's true that having a single compatible strings for all
bus drivers will work for device -> driver matching but may not work for
module auto-loading.
> (You should also support the 'fb-i2c' variant in DRM IMO, but doubtful
> that I'll review that.)
>
As mentioned above, it does even after adding support for the new strings,
for backward compatibility.
> Rob
>
--
Best regards,
Javier Martinez Canillas
Linux Engineering
Red Hat
Hello Geert,
On 4/11/22 15:47, Geert Uytterhoeven wrote:
> Hi Javier,
>
> On Thu, Apr 7, 2022 at 10:03 PM Javier Martinez Canillas
> <[email protected]> wrote:
>> The current compatible strings for SSD130x I2C controllers contain an -fb
>> suffix, this seems to indicate that are for a fbdev driver. But the DT is
>> supposed to describe the hardware and not Linux implementation details.
>>
>> Let's deprecate those compatible strings and add a new enum that contains
>> compatible strings that don't have a -fb suffix. These will be matched by
>> the ssd130x-i2c DRM driver.
>>
>> Signed-off-by: Javier Martinez Canillas <[email protected]>
>
>> --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
>> +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
>> @@ -12,12 +12,24 @@ 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
>
> Please drop the "-i2c" suffixes, too.
> We already have plenty of IIO sensors and audio codecs using the
> same compatible value for spi and i2c, cfr.
> 'git grep compatible -- "*-[si][p2][ic].c"'
>
Yes, I know but was worried about the potential issues that mentioned in a
previous email in this thread. But after the discussion we had over IRC, I
think that is safe to assume that the SPI subsystem won't change how the
modaliases are reported, so there won't be conflict between I2C and SPI.
And if that is ever changed, there's a plan to add the bus type to the data
reported by the modalias uevent so user-space could figure out what to load.
So I'll go ahead with Rob and yours suggestion, and just deprecate the old
ones and drop both the "fb" and "-i2c" part of the compatible strings, to
use the same compatible strings for both the I2C and SPI drivers.
After all, that's the correct way to describe the hardware and not encode
any Linux implementation details in the DT binding.
--
Best regards,
Javier Martinez Canillas
Linux Engineering
Red Hat
Hi Javier,
On Thu, Apr 7, 2022 at 10:03 PM Javier Martinez Canillas
<[email protected]> wrote:
> The current compatible strings for SSD130x I2C controllers contain an -fb
> suffix, this seems to indicate that are for a fbdev driver. But the DT is
> supposed to describe the hardware and not Linux implementation details.
>
> Let's deprecate those compatible strings and add a new enum that contains
> compatible strings that don't have a -fb suffix. These will be matched by
> the ssd130x-i2c DRM driver.
>
> Signed-off-by: Javier Martinez Canillas <[email protected]>
> --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml
> @@ -12,12 +12,24 @@ 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
Please drop the "-i2c" suffixes, too.
We already have plenty of IIO sensors and audio codecs using the
same compatible value for spi and i2c, cfr.
'git grep compatible -- "*-[si][p2][ic].c"'
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
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