* [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays @ 2022-02-14 13:37 Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() Javier Martinez Canillas ` (6 more replies) 0 siblings, 7 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:37 UTC (permalink / raw) To: linux-kernel Cc: linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Maxime Ripard, Noralf Trønnes, Javier Martinez Canillas, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Rob Herring, Thierry Reding, Uwe Kleine-König, devicetree, linux-pwm This patch series adds a DRM driver for the Solomon OLED SSD1305, SSD1306, SSD1307 and SSD1309 displays. It is a port of the ssd1307fb fbdev driver. Using the DRM fbdev emulation, all the tests from Geert Uytterhoeven repo (https://git.kernel.org/pub/scm/linux/kernel/git/geert/fbtest.git) passes. I've also tested it using the display as a VT output and even though fbcon seems to work, it is mostly unusable on a 128x64 SSD1306 display. This is a v6 that addresses the issues pointed in v5. Thanks a lot to all reviewers that gave me feedback and comments. I didn't include the patch that adds the SPI support this time, because it will require changes in the existing Device Tree binding. And I wanted to avoid that bikesheeding for now, to focus on the core and I2C parts. Once this series land, I'll post patches for the SPI support. But the WIP patch posted in v3 should still apply cleanly on top of this v6: https://patchwork.kernel.org/project/dri-devel/patch/20220209091204.2513437-1-javierm@redhat.com/ Patch #1 splits per-line conversion logic in drm_fb_xrgb8888_to_gray8() to a separate drm_fb_xrgb8888_to_gray8_line() helper function. Patch #2 adds a new drm_fb_xrgb8888_to_mono_reversed() helper function to convert from XR24 to reversed monochrome. The latter internally converts each line first to 8-bit grayscale and then to 1-bit reversed monochrome. Patch #3 adds the driver. This only has the core support and doesn't have any bus specific code, separate drivers are needed for the transport used. Patch #4 adds a driver to use the I2C bus to communicate with the device. Patch #5 adds a MAINTAINERS entry for the DRM driver and patch #6 adds myself as co-maintainer of the existing DT binding for the ssd1307fb, since the same DT binding is used for both the fbdev and DRM drivers. Best regards, Javier Changes in v6: - Add Andy Shevchenko's Reviewed-by to patch #1. - Add Andy Shevchenko's Reviewed-by to patch #2. - Just return regmap_bulk_write() in ssd130x_write_data() (Andy Shevchenko) - Remove unnecessary cast in ssd130x_write_cmd() (Andy Shevchenko) - Return ERR_PTR(dev_err_probe(...)) everywhere in probe (Andy Shevchenko) Changes in v5: - Add Thomas Zimmermann's Reviewed-by to patch #1. - Use drm_WARN_ON* macros instead of deprecated ones (Thomas Zimmermann) - Include <linux/bits.h> header (Andy Shevchenko) - Drop parenthesis for command options macros (Andy Shevchenko) - Explain in ssd130x_write_cmd() comment how commands are sent (Andy Shevchenko) - The pwm_*() functions check for NULL already (Andy Shevchenko) - Remove unnecesary blank line (Andy Shevchenko) - Simplify error handling for backlight registration failure (Geert Uytterhoeven) - Don't clear screen on enable, instead send the full buffer (Thomas Zimmermann) - Add Andy Shevchenko's Reviewed-by tag to patch #4. - Add Andy Shevchenko's Reviewed-by tag to patch #5. - Add Andy Shevchenko's Reviewed-by tag to patch #6. Changes in v4: - Rename end_offset to end_len (Thomas Zimmermann) - Warn once if dst_pitch is not a multiple of 8 (Thomas Zimmermann) - Drop drm_fb_gray8_to_mono_reversed() that's not used (Thomas Zimmermann) - Allocate single buffer for both copy cma memory and gray8 (Thomas Zimmermann) - Add Thomas Zimmermann Reviewed-by tag to patch adding XR24 -> mono helper. - Rename vbat supply to vcc since is how's labeled in the device (Mark Brown) - Don't make the regulator option since is always needed (Mark Brown) - Add solomon Kconfig source and directory inclusion sorted (Andy Shevchenko) - Use SSD130x instead of SSD130X to denote is not a model name (Andy Shevchenko) - Check if there's a reset pin in the callee and not the caller (Andy Shevchenko) - Define missing commands instead of using magic numbers (Andy Shevchenko) - Use GENMASK() and FIELD_PREP() macros when possible (Andy Shevchenko) - Avoid using ternary operators to ease code readablity (Andy Shevchenko) - Use i++ instead of --i on some for loops (Andy Shevchenko) - Remove redundant blank lines (Andy Shevchenko) - Rename power_off label to out_power_off (Andy Shevchenko) - Use dev_err_probe() even if no -EPROBE_DEFER (Andy Shevchenko) - Don't use plural Authors if there's only one (Andy Shevchenko) - Remove unnecessary casting (Geert Uytterhoeven) - Remove redundant blank lines (Andy Shevchenko) - Remove comma after of_device_id table terminator (Andy Shevchenko) - Add Rob Herring Acked-by tag to patch adding as DT binding co-maintainer. Changes in v3: - Add a drm_fb_xrgb8888_to_gray8_line() helper function (Thomas Zimmermann) - Also add a drm_fb_xrgb8888_to_mono_reversed() helper (Thomas Zimmermann) - Split lines copy to drm_fb_gray8_to_mono_reversed_line() (Thomas Zimmermann) - Handle case where the source buffer is not aligned to 8 (Thomas Zimmermann) - Move driver from tiny sub-dir to drivers/gpu/drm/solomon (Sam Ravnborg) - Split driver in a bus agnostic core and bus specific (Andy Shevchenko) - Use regmap to access the chip registers (Andy Shevchenko) - Remove unnecessary blank lines (Andy Shevchenko) - Remove unneeded inline specifier in functions (Andy Shevchenko) - Add a comment about always returning a single mode (Andy Shevchenko) - Change write command logic to use do while loop (Andy Shevchenko) - Use "firmware description" instead of "device tree" (Andy Shevchenko) - Use return foo() instead of returning the return value (Andy Shevchenko) - Don't split lines longer than 80 chars if makes less readable (Andy Shevchenko) - Remove redundant else statements in .mode_valid callback (Andy Shevchenko) - Rename powero{n,ff}() functions to power_o{n,ff)() (Andy Shevchenko) - Use dev_err_probe() to prevent spam logs on probe deferral (Andy Shevchenko) - Remove ',' after sentinel terminator in array (Andy Shevchenko) - Fix a bug when doing partial updates (Geert Uytterhoeven) - Add a separate driver for SSD130X chips I2C support (Andy Shevchenko) - Adapt MAINTAINERS entry to point to the new drivers/gpu/drm/solomon directory. Changes in v2: - Drop patch that was adding a DRM_MODE_CONNECTOR_I2C type. - Invert order of backlight {en,dis}able and display {on,off} (Sam Ravnborg) - Don't clear the screen and turn on display on probe (Sam Ravnborg) - Use backlight_get_brightness() macro to get BL brightness (Sam Ravnborg) - Use dev managed version of devm_backlight_device_register() (Sam Ravnborg) - Use dev_name(dev) for backlight name instead of an array (Sam Ravnborg) - Drop the .get_brightness callback since isn't needed (Sam Ravnborg) - Rename driver to ssd130x since supports a display family (Thomas Zimmermann) - Drop the TINY prefix from the Kconfig symbol (Thomas Zimmermann) - Sort the Kconfig symbol dependencies alphabetically (Thomas Zimmermann) - Rename struct ssd130x_array to struct ssd130x_i2c_msg (Thomas Zimmermann) - Rename struct ssd130x_i2c_msg .type member to .cmd (Thomas Zimmermann) - Use sizeof(*foo) instead of sizeof(struct foo) (Thomas Zimmermann) - Use struct_size() macro to calculate sizeof(*foo) + len (Thomas Zimmermann) - Use kcalloc() instead of kmalloc_array() + memset() (Thomas Zimmermann) - Use shadow plane helpers virtual screen support (Thomas Zimmermann) - Remove unused goto label in ssd1307_fb_blit_rect() (Thomas Zimmermann) - Use drm_set_preferred_mode() inset of manually set (Thomas Zimmermann) - Use shadow plane helpers virtual screen support (Thomas Zimmermann) - Remove unused goto label in ssd1307_fb_blit_rect() (Thomas Zimmermann) - Use drm_set_preferred_mode() inset of manually set (Thomas Zimmermann) - Reorganize code in probe to make it more legible (Thomas Zimmermann) - ssd130x_write_cmd() uses varargs to simplify I2C code (Thomas Zimmermann) - Move regulator/pwm init logic to display pipe enable callback. - Add Sam Ravnborg's acked-by to patch adding a MAINTAINERS entry (Sam Ravnborg) - Add myself as co-maintainer of the ssd1370fb DT binding (Sam Ravnborg). Javier Martinez Canillas (6): drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() drm: Add driver for Solomon SSD130x OLED displays drm/solomon: Add SSD130x OLED displays I2C support MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer .../bindings/display/solomon,ssd1307fb.yaml | 1 + MAINTAINERS | 7 + drivers/gpu/drm/Kconfig | 2 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_format_helper.c | 141 ++- drivers/gpu/drm/solomon/Kconfig | 21 + drivers/gpu/drm/solomon/Makefile | 2 + drivers/gpu/drm/solomon/ssd130x-i2c.c | 116 +++ drivers/gpu/drm/solomon/ssd130x.c | 843 ++++++++++++++++++ drivers/gpu/drm/solomon/ssd130x.h | 76 ++ include/drm/drm_format_helper.h | 4 + 11 files changed, 1202 insertions(+), 12 deletions(-) create mode 100644 drivers/gpu/drm/solomon/Kconfig create mode 100644 drivers/gpu/drm/solomon/Makefile create mode 100644 drivers/gpu/drm/solomon/ssd130x-i2c.c create mode 100644 drivers/gpu/drm/solomon/ssd130x.c create mode 100644 drivers/gpu/drm/solomon/ssd130x.h -- 2.34.1 ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas @ 2022-02-14 13:37 ` Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard 2022-02-14 13:37 ` [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() Javier Martinez Canillas ` (5 subsequent siblings) 6 siblings, 1 reply; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:37 UTC (permalink / raw) To: linux-kernel Cc: linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Maxime Ripard, Noralf Trønnes, Javier Martinez Canillas, Daniel Vetter, David Airlie, Maarten Lankhorst, Maxime Ripard Pull the per-line conversion logic into a separate helper function. This will allow to do line-by-line conversion in other helpers that convert to a gray8 format. Suggested-by: Thomas Zimmermann <tzimmermann@suse.de> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- Changes in v6: - Add Andy Shevchenko's Reviewed-by to patch #1. Changes in v5: - Add Thomas Zimmermann's Reviewed-by to patch #1. Changes in v3: - Add a drm_fb_xrgb8888_to_gray8_line() helper function (Thomas Zimmermann) drivers/gpu/drm/drm_format_helper.c | 31 ++++++++++++++++++----------- 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 0f28dd2bdd72..b981712623d3 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -464,6 +464,21 @@ void drm_fb_xrgb8888_to_xrgb2101010_toio(void __iomem *dst, } EXPORT_SYMBOL(drm_fb_xrgb8888_to_xrgb2101010_toio); +static void drm_fb_xrgb8888_to_gray8_line(u8 *dst, const u32 *src, unsigned int pixels) +{ + unsigned int x; + + for (x = 0; x < pixels; x++) { + u8 r = (*src & 0x00ff0000) >> 16; + u8 g = (*src & 0x0000ff00) >> 8; + u8 b = *src & 0x000000ff; + + /* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */ + *dst++ = (3 * r + 6 * g + b) / 10; + src++; + } +} + /** * drm_fb_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale * @dst: 8-bit grayscale destination buffer @@ -484,8 +499,9 @@ EXPORT_SYMBOL(drm_fb_xrgb8888_to_xrgb2101010_toio); void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vaddr, const struct drm_framebuffer *fb, const struct drm_rect *clip) { - unsigned int len = (clip->x2 - clip->x1) * sizeof(u32); - unsigned int x, y; + unsigned int linepixels = clip->x2 - clip->x1; + unsigned int len = linepixels * sizeof(u32); + unsigned int y; void *buf; u8 *dst8; u32 *src32; @@ -508,16 +524,7 @@ void drm_fb_xrgb8888_to_gray8(void *dst, unsigned int dst_pitch, const void *vad for (y = clip->y1; y < clip->y2; y++) { dst8 = dst; src32 = memcpy(buf, vaddr, len); - for (x = clip->x1; x < clip->x2; x++) { - u8 r = (*src32 & 0x00ff0000) >> 16; - u8 g = (*src32 & 0x0000ff00) >> 8; - u8 b = *src32 & 0x000000ff; - - /* ITU BT.601: Y = 0.299 R + 0.587 G + 0.114 B */ - *dst8++ = (3 * r + 6 * g + b) / 10; - src32++; - } - + drm_fb_xrgb8888_to_gray8_line(dst8, src32, linepixels); vaddr += fb->pitches[0]; dst += dst_pitch; } -- 2.34.1 ^ permalink raw reply related [flat|nested] 30+ messages in thread
* Re: [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() 2022-02-14 13:37 ` [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() Javier Martinez Canillas @ 2022-02-16 9:16 ` Maxime Ripard 0 siblings, 0 replies; 30+ messages in thread From: Maxime Ripard @ 2022-02-16 9:16 UTC (permalink / raw) To: Javier Martinez Canillas Cc: linux-kernel, linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Noralf Trønnes, Daniel Vetter, David Airlie, Maarten Lankhorst [-- Attachment #1: Type: text/plain, Size: 558 bytes --] On Mon, Feb 14, 2022 at 02:37:05PM +0100, Javier Martinez Canillas wrote: > Pull the per-line conversion logic into a separate helper function. > > This will allow to do line-by-line conversion in other helpers that > convert to a gray8 format. > > Suggested-by: Thomas Zimmermann <tzimmermann@suse.de> > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Maxime Ripard <maxime@cerno.tech> Maxime [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() Javier Martinez Canillas @ 2022-02-14 13:37 ` Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard 2022-03-08 16:13 ` Geert Uytterhoeven 2022-02-14 13:37 ` [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas ` (4 subsequent siblings) 6 siblings, 2 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:37 UTC (permalink / raw) To: linux-kernel Cc: linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Maxime Ripard, Noralf Trønnes, Javier Martinez Canillas, Daniel Vetter, David Airlie, Maarten Lankhorst, Maxime Ripard Add support to convert from XR24 to reversed monochrome for drivers that control monochromatic display panels, that only have 1 bit per pixel. The function does a line-by-line conversion doing an intermediate step first from XR24 to 8-bit grayscale and then to reversed monochrome. The drm_fb_gray8_to_mono_reversed_line() helper was based on code from drivers/gpu/drm/tiny/repaper.c driver. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- Changes in v6: - Add Andy Shevchenko's Reviewed-by to patch #2. Changes in v5: - Use drm_WARN_ON* macros instead of deprecated ones (Thomas Zimmermann) Changes in v4: - Rename end_offset to end_len (Thomas Zimmermann) - Warn once if dst_pitch is not a multiple of 8 (Thomas Zimmermann) - Drop drm_fb_gray8_to_mono_reversed() that's not used (Thomas Zimmermann) - Allocate single buffer for both copy cma memory and gray8 (Thomas Zimmermann) - Add Thomas Zimmermann Reviewed-by tag to patch adding XR24 -> mono helper. Changes in v3: - Also add a drm_fb_xrgb8888_to_mono_reversed() helper (Thomas Zimmermann) - Split lines copy to drm_fb_gray8_to_mono_reversed_line() (Thomas Zimmermann) - Handle case where the source buffer is not aligned to 8 (Thomas Zimmermann) drivers/gpu/drm/drm_format_helper.c | 110 ++++++++++++++++++++++++++++ include/drm/drm_format_helper.h | 4 + 2 files changed, 114 insertions(+) diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index b981712623d3..bc0f49773868 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -12,9 +12,11 @@ #include <linux/slab.h> #include <linux/io.h> +#include <drm/drm_device.h> #include <drm/drm_format_helper.h> #include <drm/drm_framebuffer.h> #include <drm/drm_fourcc.h> +#include <drm/drm_print.h> #include <drm/drm_rect.h> static unsigned int clip_offset(const struct drm_rect *clip, unsigned int pitch, unsigned int cpp) @@ -591,3 +593,111 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for return -EINVAL; } EXPORT_SYMBOL(drm_fb_blit_toio); + +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels, + unsigned int start_offset, unsigned int end_len) +{ + unsigned int xb, i; + + for (xb = 0; xb < pixels; xb++) { + unsigned int start = 0, end = 8; + u8 byte = 0x00; + + if (xb == 0 && start_offset) + start = start_offset; + + if (xb == pixels - 1 && end_len) + end = end_len; + + for (i = start; i < end; i++) { + unsigned int x = xb * 8 + i; + + byte >>= 1; + if (src[x] >> 7) + byte |= BIT(7); + } + *dst++ = byte; + } +} + +/** + * drm_fb_xrgb8888_to_mono_reversed - Convert XRGB8888 to reversed monochrome + * @dst: reversed monochrome destination buffer + * @dst_pitch: Number of bytes between two consecutive scanlines within dst + * @src: XRGB8888 source buffer + * @fb: DRM framebuffer + * @clip: Clip rectangle area to copy + * + * DRM doesn't have native monochrome support. + * Such drivers can announce the commonly supported XR24 format to userspace + * and use this function to convert to the native format. + * + * This function uses drm_fb_xrgb8888_to_gray8() to convert to grayscale and + * then the result is converted from grayscale to reversed monohrome. + */ +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr, + const struct drm_framebuffer *fb, const struct drm_rect *clip) +{ + unsigned int linepixels = drm_rect_width(clip); + unsigned int lines = clip->y2 - clip->y1; + unsigned int cpp = fb->format->cpp[0]; + unsigned int len_src32 = linepixels * cpp; + struct drm_device *dev = fb->dev; + unsigned int start_offset, end_len; + unsigned int y; + u8 *mono = dst, *gray8; + u32 *src32; + + if (drm_WARN_ON(dev, fb->format->format != DRM_FORMAT_XRGB8888)) + return; + + /* + * The reversed mono destination buffer contains 1 bit per pixel + * and destination scanlines have to be in multiple of 8 pixels. + */ + if (!dst_pitch) + dst_pitch = DIV_ROUND_UP(linepixels, 8); + + drm_WARN_ONCE(dev, dst_pitch % 8 != 0, "dst_pitch is not a multiple of 8\n"); + + /* + * The cma memory is write-combined so reads are uncached. + * Speed up by fetching one line at a time. + * + * Also, format conversion from XR24 to reversed monochrome + * are done line-by-line but are converted to 8-bit grayscale + * as an intermediate step. + * + * Allocate a buffer to be used for both copying from the cma + * memory and to store the intermediate grayscale line pixels. + */ + src32 = kmalloc(len_src32 + linepixels, GFP_KERNEL); + if (!src32) + return; + + gray8 = (u8 *)src32 + len_src32; + + /* + * For damage handling, it is possible that only parts of the source + * buffer is copied and this could lead to start and end pixels that + * are not aligned to multiple of 8. + * + * Calculate if the start and end pixels are not aligned and set the + * offsets for the reversed mono line conversion function to adjust. + */ + start_offset = clip->x1 % 8; + end_len = clip->x2 % 8; + + vaddr += clip_offset(clip, fb->pitches[0], cpp); + for (y = 0; y < lines; y++) { + src32 = memcpy(src32, vaddr, len_src32); + drm_fb_xrgb8888_to_gray8_line(gray8, src32, linepixels); + drm_fb_gray8_to_mono_reversed_line(mono, gray8, dst_pitch, + start_offset, end_len); + vaddr += fb->pitches[0]; + mono += dst_pitch; + } + + kfree(src32); +} +EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono_reversed); diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h index b30ed5de0a33..0b0937c0b2f6 100644 --- a/include/drm/drm_format_helper.h +++ b/include/drm/drm_format_helper.h @@ -43,4 +43,8 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for const void *vmap, const struct drm_framebuffer *fb, const struct drm_rect *rect); +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *src, + const struct drm_framebuffer *fb, + const struct drm_rect *clip); + #endif /* __LINUX_DRM_FORMAT_HELPER_H */ -- 2.34.1 ^ permalink raw reply related [flat|nested] 30+ messages in thread
* Re: [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() 2022-02-14 13:37 ` [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() Javier Martinez Canillas @ 2022-02-16 9:16 ` Maxime Ripard 2022-03-08 16:13 ` Geert Uytterhoeven 1 sibling, 0 replies; 30+ messages in thread From: Maxime Ripard @ 2022-02-16 9:16 UTC (permalink / raw) To: Javier Martinez Canillas Cc: linux-kernel, linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Noralf Trønnes, Daniel Vetter, David Airlie, Maarten Lankhorst [-- Attachment #1: Type: text/plain, Size: 745 bytes --] On Mon, Feb 14, 2022 at 02:37:06PM +0100, Javier Martinez Canillas wrote: > Add support to convert from XR24 to reversed monochrome for drivers that > control monochromatic display panels, that only have 1 bit per pixel. > > The function does a line-by-line conversion doing an intermediate step > first from XR24 to 8-bit grayscale and then to reversed monochrome. > > The drm_fb_gray8_to_mono_reversed_line() helper was based on code from > drivers/gpu/drm/tiny/repaper.c driver. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Maxime Ripard <maxime@cerno.tech> Maxime [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() 2022-02-14 13:37 ` [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard @ 2022-03-08 16:13 ` Geert Uytterhoeven 2022-03-09 12:03 ` Javier Martinez Canillas 1 sibling, 1 reply; 30+ messages in thread From: Geert Uytterhoeven @ 2022-03-08 16:13 UTC (permalink / raw) To: Javier Martinez Canillas Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Maarten Lankhorst, Maxime Ripard Hi Javier, On Mon, Feb 14, 2022 at 2:37 PM Javier Martinez Canillas <javierm@redhat.com> wrote: > Add support to convert from XR24 to reversed monochrome for drivers that > control monochromatic display panels, that only have 1 bit per pixel. > > The function does a line-by-line conversion doing an intermediate step > first from XR24 to 8-bit grayscale and then to reversed monochrome. > > The drm_fb_gray8_to_mono_reversed_line() helper was based on code from > drivers/gpu/drm/tiny/repaper.c driver. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Thanks for your patch, which is now commit bcf8b616deb87941 ("drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed()") in drm/drm-next. > --- a/drivers/gpu/drm/drm_format_helper.c > +++ b/drivers/gpu/drm/drm_format_helper.c > @@ -12,9 +12,11 @@ > #include <linux/slab.h> > #include <linux/io.h> > > +#include <drm/drm_device.h> > #include <drm/drm_format_helper.h> > #include <drm/drm_framebuffer.h> > #include <drm/drm_fourcc.h> > +#include <drm/drm_print.h> > #include <drm/drm_rect.h> > > static unsigned int clip_offset(const struct drm_rect *clip, unsigned int pitch, unsigned int cpp) > @@ -591,3 +593,111 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for > return -EINVAL; > } > EXPORT_SYMBOL(drm_fb_blit_toio); > + > +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels, "pixels" is not the number of pixels to process, but the number of bytes in the monochrome destination buffer. > + unsigned int start_offset, unsigned int end_len) > +{ > + unsigned int xb, i; > + > + for (xb = 0; xb < pixels; xb++) { > + unsigned int start = 0, end = 8; > + u8 byte = 0x00; > + > + if (xb == 0 && start_offset) > + start = start_offset; > + > + if (xb == pixels - 1 && end_len) > + end = end_len; > + > + for (i = start; i < end; i++) { > + unsigned int x = xb * 8 + i; > + > + byte >>= 1; > + if (src[x] >> 7) > + byte |= BIT(7); > + } > + *dst++ = byte; > + } The above is IMHO very hard to read. I think it can be made simpler by passing the total number of pixels to process instead of "pixels" (which is bytes) and "end_len". > +} > + > +/** > + * drm_fb_xrgb8888_to_mono_reversed - Convert XRGB8888 to reversed monochrome > + * @dst: reversed monochrome destination buffer > + * @dst_pitch: Number of bytes between two consecutive scanlines within dst > + * @src: XRGB8888 source buffer > + * @fb: DRM framebuffer > + * @clip: Clip rectangle area to copy > + * > + * DRM doesn't have native monochrome support. > + * Such drivers can announce the commonly supported XR24 format to userspace > + * and use this function to convert to the native format. > + * > + * This function uses drm_fb_xrgb8888_to_gray8() to convert to grayscale and > + * then the result is converted from grayscale to reversed monohrome. > + */ > +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr, > + const struct drm_framebuffer *fb, const struct drm_rect *clip) > +{ > + unsigned int linepixels = drm_rect_width(clip); > + unsigned int lines = clip->y2 - clip->y1; drm_rect_height(clip)? > + unsigned int cpp = fb->format->cpp[0]; > + unsigned int len_src32 = linepixels * cpp; > + struct drm_device *dev = fb->dev; > + unsigned int start_offset, end_len; > + unsigned int y; > + u8 *mono = dst, *gray8; > + u32 *src32; > + > + if (drm_WARN_ON(dev, fb->format->format != DRM_FORMAT_XRGB8888)) > + return; > + > + /* > + * The reversed mono destination buffer contains 1 bit per pixel > + * and destination scanlines have to be in multiple of 8 pixels. > + */ > + if (!dst_pitch) > + dst_pitch = DIV_ROUND_UP(linepixels, 8); This is not correct when clip->x1 is not a multiple of 8 pixels. Should be: DIV_ROUND_UP(linepixels + clip->x1 % 8, 8); > + > + drm_WARN_ONCE(dev, dst_pitch % 8 != 0, "dst_pitch is not a multiple of 8\n"); This triggers for me: dst_pitch = 1. Which is perfectly fine, when flashing an 8-pixel wide cursor ;-) > + > + /* > + * The cma memory is write-combined so reads are uncached. > + * Speed up by fetching one line at a time. > + * > + * Also, format conversion from XR24 to reversed monochrome > + * are done line-by-line but are converted to 8-bit grayscale > + * as an intermediate step. > + * > + * Allocate a buffer to be used for both copying from the cma > + * memory and to store the intermediate grayscale line pixels. > + */ > + src32 = kmalloc(len_src32 + linepixels, GFP_KERNEL); > + if (!src32) > + return; > + > + gray8 = (u8 *)src32 + len_src32; > + > + /* > + * For damage handling, it is possible that only parts of the source > + * buffer is copied and this could lead to start and end pixels that > + * are not aligned to multiple of 8. > + * > + * Calculate if the start and end pixels are not aligned and set the > + * offsets for the reversed mono line conversion function to adjust. > + */ > + start_offset = clip->x1 % 8; > + end_len = clip->x2 % 8; > + > + vaddr += clip_offset(clip, fb->pitches[0], cpp); > + for (y = 0; y < lines; y++) { > + src32 = memcpy(src32, vaddr, len_src32); > + drm_fb_xrgb8888_to_gray8_line(gray8, src32, linepixels); > + drm_fb_gray8_to_mono_reversed_line(mono, gray8, dst_pitch, > + start_offset, end_len); > + vaddr += fb->pitches[0]; > + mono += dst_pitch; > + } > + > + kfree(src32); > +} > +EXPORT_SYMBOL(drm_fb_xrgb8888_to_mono_reversed); 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 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() 2022-03-08 16:13 ` Geert Uytterhoeven @ 2022-03-09 12:03 ` Javier Martinez Canillas 0 siblings, 0 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-03-09 12:03 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Maarten Lankhorst, Maxime Ripard Hello Geert, Thanks a lot for your feedback. On 3/8/22 17:13, Geert Uytterhoeven wrote: [snip] >> + >> +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, unsigned int pixels, > > "pixels" is not the number of pixels to process, but the number of > bytes in the monochrome destination buffer. > Right, that parameter name is misleading / incorrect indeed. Probably should be changed by dst_pitch or dst_stride. >> + unsigned int start_offset, unsigned int end_len) >> +{ >> + unsigned int xb, i; >> + >> + for (xb = 0; xb < pixels; xb++) { >> + unsigned int start = 0, end = 8; >> + u8 byte = 0x00; >> + >> + if (xb == 0 && start_offset) >> + start = start_offset; >> + >> + if (xb == pixels - 1 && end_len) >> + end = end_len; >> + >> + for (i = start; i < end; i++) { >> + unsigned int x = xb * 8 + i; >> + >> + byte >>= 1; >> + if (src[x] >> 7) >> + byte |= BIT(7); >> + } >> + *dst++ = byte; >> + } > > The above is IMHO very hard to read. > I think it can be made simpler by passing the total number of pixels > to process instead of "pixels" (which is bytes) and "end_len". > Agreed that's hard to read. I think is better if you propose a patch with your idea to make it simpler. [snip] >> +void drm_fb_xrgb8888_to_mono_reversed(void *dst, unsigned int dst_pitch, const void *vaddr, >> + const struct drm_framebuffer *fb, const struct drm_rect *clip) >> +{ >> + unsigned int linepixels = drm_rect_width(clip); >> + unsigned int lines = clip->y2 - clip->y1; > > drm_rect_height(clip)? > Yes, unsure why didn't use it since used drm_rect_width() for the width. >> + unsigned int cpp = fb->format->cpp[0]; >> + unsigned int len_src32 = linepixels * cpp; >> + struct drm_device *dev = fb->dev; >> + unsigned int start_offset, end_len; >> + unsigned int y; >> + u8 *mono = dst, *gray8; >> + u32 *src32; >> + >> + if (drm_WARN_ON(dev, fb->format->format != DRM_FORMAT_XRGB8888)) >> + return; >> + >> + /* >> + * The reversed mono destination buffer contains 1 bit per pixel >> + * and destination scanlines have to be in multiple of 8 pixels. >> + */ >> + if (!dst_pitch) >> + dst_pitch = DIV_ROUND_UP(linepixels, 8); > > This is not correct when clip->x1 is not a multiple of 8 pixels. > Should be: > > DIV_ROUND_UP(linepixels + clip->x1 % 8, 8); > Agreed. >> + >> + drm_WARN_ONCE(dev, dst_pitch % 8 != 0, "dst_pitch is not a multiple of 8\n"); > > This triggers for me: dst_pitch = 1. > Which is perfectly fine, when flashing an 8-pixel wide cursor ;-) > Indeed. I think we should just drop that warn. Do you want me to post patches for all these or would you do it when simplifying the drm_fb_gray8_to_mono_reversed_line() logic ? -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() Javier Martinez Canillas @ 2022-02-14 13:37 ` Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard ` (2 more replies) 2022-02-14 13:37 ` [PATCH v6 4/6] drm/solomon: Add SSD130x OLED displays I2C support Javier Martinez Canillas ` (3 subsequent siblings) 6 siblings, 3 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:37 UTC (permalink / raw) To: linux-kernel Cc: linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Maxime Ripard, Noralf Trønnes, Javier Martinez Canillas, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, linux-pwm This adds a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon OLED display controllers. It's only the core part of the driver and a bus specific driver is needed for each transport interface supported by the display controllers. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> --- Changes in v6: - Just return regmap_bulk_write() in ssd130x_write_data() (Andy Shevchenko) - Remove unnecessary cast in ssd130x_write_cmd() (Andy Shevchenko) - Return ERR_PTR(dev_err_probe(...)) everywhere in probe (Andy Shevchenko) Changes in v5: - Include <linux/bits.h> header (Andy Shevchenko) - Drop parenthesis for command options macros (Andy Shevchenko) - Explain in ssd130x_write_cmd() comment how commands are sent (Andy Shevchenko) - The pwm_*() functions check for NULL already (Andy Shevchenko) - Remove unnecesary blank line (Andy Shevchenko) - Simplify error handling for backlight registration failure (Geert Uytterhoeven) - Don't clear screen on enable, instead send the full buffer (Thomas Zimmermann) Changes in v4: - Rename vbat supply to vcc since is how's labeled in the device (Mark Brown) - Don't make the regulator option since is always needed (Mark Brown) - Add solomon Kconfig source and directory inclusion sorted (Andy Shevchenko) - Use SSD130x instead of SSD130X to denote is not a model name (Andy Shevchenko) - Check if there's a reset pin in the callee and not the caller (Andy Shevchenko) - Define missing commands instead of using magic numbers (Andy Shevchenko) - Use GENMASK() and FIELD_PREP() macros when possible (Andy Shevchenko) - Avoid using ternary operators to ease code readablity (Andy Shevchenko) - Use i++ instead of --i on some for loops (Andy Shevchenko) - Remove redundant blank lines (Andy Shevchenko) - Rename power_off label to out_power_off (Andy Shevchenko) - Use dev_err_probe() even if no -EPROBE_DEFER (Andy Shevchenko) - Don't use plural Authors if there's only one (Andy Shevchenko) Changes in v3: - Move driver from tiny sub-dir to drivers/gpu/drm/solomon (Sam Ravnborg) - Split driver in a bus agnostic core and bus specific (Andy Shevchenko) - Use regmap to access the chip registers (Andy Shevchenko) - Remove unnecessary blank lines (Andy Shevchenko) - Remove unneeded inline specifier in functions (Andy Shevchenko) - Add a comment about always returning a single mode (Andy Shevchenko) - Change write command logic to use do while loop (Andy Shevchenko) - Use "firmware description" instead of "device tree" (Andy Shevchenko) - Use return foo() instead of returning the return value (Andy Shevchenko) - Don't split lines longer than 80 chars if makes less readable (Andy Shevchenko) - Remove redundant else statements in .mode_valid callback (Andy Shevchenko) - Rename powero{n,ff}() functions to power_o{n,ff)() (Andy Shevchenko) - Use dev_err_probe() to prevent spam logs on probe deferral (Andy Shevchenko) - Remove ',' after sentinel terminator in array (Andy Shevchenko) - Fix a bug when doing partial updates (Geert Uytterhoeven) Changes in v2: - Drop patch that was adding a DRM_MODE_CONNECTOR_I2C type. - Invert order of backlight {en,dis}able and display {on,off} (Sam Ravnborg) - Don't clear the screen and turn on display on probe (Sam Ravnborg) - Use backlight_get_brightness() macro to get BL brightness (Sam Ravnborg) - Use dev managed version of devm_backlight_device_register() (Sam Ravnborg) - Use dev_name(dev) for backlight name instead of an array (Sam Ravnborg) - Drop the .get_brightness callback since isn't needed (Sam Ravnborg) - Rename driver to ssd130x since supports a display family (Thomas Zimmermann) - Drop the TINY prefix from the Kconfig symbol (Thomas Zimmermann) - Sort the Kconfig symbol dependencies alphabetically (Thomas Zimmermann) - Rename struct ssd130x_array to struct ssd130x_i2c_msg (Thomas Zimmermann) - Rename struct ssd130x_i2c_msg .type member to .cmd (Thomas Zimmermann) - Use sizeof(*foo) instead of sizeof(struct foo) (Thomas Zimmermann) - Use struct_size() macro to calculate sizeof(*foo) + len (Thomas Zimmermann) - Use kcalloc() instead of kmalloc_array() + memset() (Thomas Zimmermann) - Use shadow plane helpers virtual screen support (Thomas Zimmermann) - Remove unused goto label in ssd1307_fb_blit_rect() (Thomas Zimmermann) - Use drm_set_preferred_mode() inset of manually set (Thomas Zimmermann) - Use shadow plane helpers virtual screen support (Thomas Zimmermann) - Remove unused goto label in ssd1307_fb_blit_rect() (Thomas Zimmermann) - Use drm_set_preferred_mode() inset of manually set (Thomas Zimmermann) - Reorganize code in probe to make it more legible (Thomas Zimmermann) - ssd130x_write_cmd() uses varargs to simplify I2C code (Thomas Zimmermann) - Move regulator/pwm init logic to display pipe enable callback. drivers/gpu/drm/Kconfig | 2 + drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/solomon/Kconfig | 12 + drivers/gpu/drm/solomon/Makefile | 1 + drivers/gpu/drm/solomon/ssd130x.c | 843 ++++++++++++++++++++++++++++++ drivers/gpu/drm/solomon/ssd130x.h | 76 +++ 6 files changed, 935 insertions(+) create mode 100644 drivers/gpu/drm/solomon/Kconfig create mode 100644 drivers/gpu/drm/solomon/Makefile create mode 100644 drivers/gpu/drm/solomon/ssd130x.c create mode 100644 drivers/gpu/drm/solomon/ssd130x.h diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index dfdd3ec5f793..763355330b17 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -403,6 +403,8 @@ source "drivers/gpu/drm/xlnx/Kconfig" source "drivers/gpu/drm/gud/Kconfig" +source "drivers/gpu/drm/solomon/Kconfig" + source "drivers/gpu/drm/sprd/Kconfig" config DRM_HYPERV diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 8675c2af7ae1..c2ef5f9fce54 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -132,4 +132,5 @@ obj-$(CONFIG_DRM_TIDSS) += tidss/ obj-y += xlnx/ obj-y += gud/ obj-$(CONFIG_DRM_HYPERV) += hyperv/ +obj-y += solomon/ obj-$(CONFIG_DRM_SPRD) += sprd/ diff --git a/drivers/gpu/drm/solomon/Kconfig b/drivers/gpu/drm/solomon/Kconfig new file mode 100644 index 000000000000..7720a7039e8d --- /dev/null +++ b/drivers/gpu/drm/solomon/Kconfig @@ -0,0 +1,12 @@ +config DRM_SSD130X + tristate "DRM support for Solomon SSD130x OLED displays" + depends on DRM + select BACKLIGHT_CLASS_DEVICE + select DRM_GEM_SHMEM_HELPER + select DRM_KMS_HELPER + help + DRM driver for the SSD1305, SSD1306, SSD1307 and SSD1309 Solomon + OLED controllers. This is only for the core driver, a driver for + the appropriate bus transport in your chip also must be selected. + + If M is selected the module will be called ssd130x. diff --git a/drivers/gpu/drm/solomon/Makefile b/drivers/gpu/drm/solomon/Makefile new file mode 100644 index 000000000000..f685addb19fe --- /dev/null +++ b/drivers/gpu/drm/solomon/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_DRM_SSD130X) += ssd130x.o diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c new file mode 100644 index 000000000000..2fcda1972e1e --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x.c @@ -0,0 +1,843 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DRM driver for Solomon SSD130x OLED displays + * + * Copyright 2022 Red Hat Inc. + * Author: Javier Martinez Canillas <javierm@redhat.com> + * + * Based on drivers/video/fbdev/ssd1307fb.c + * Copyright 2012 Free Electrons + */ + +#include <linux/backlight.h> +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/delay.h> +#include <linux/gpio/consumer.h> +#include <linux/property.h> +#include <linux/pwm.h> +#include <linux/regulator/consumer.h> + +#include <drm/drm_atomic_helper.h> +#include <drm/drm_damage_helper.h> +#include <drm/drm_fb_cma_helper.h> +#include <drm/drm_fb_helper.h> +#include <drm/drm_format_helper.h> +#include <drm/drm_gem_atomic_helper.h> +#include <drm/drm_gem_framebuffer_helper.h> +#include <drm/drm_gem_shmem_helper.h> +#include <drm/drm_managed.h> +#include <drm/drm_modes.h> +#include <drm/drm_rect.h> +#include <drm/drm_probe_helper.h> + +#include "ssd130x.h" + +#define DRIVER_NAME "ssd130x" +#define DRIVER_DESC "DRM driver for Solomon SSD130x OLED displays" +#define DRIVER_DATE "20220131" +#define DRIVER_MAJOR 1 +#define DRIVER_MINOR 0 + +#define SSD130X_DATA 0x40 +#define SSD130X_COMMAND 0x80 + +#define SSD130X_SET_ADDRESS_MODE 0x20 +#define SSD130X_SET_COL_RANGE 0x21 +#define SSD130X_SET_PAGE_RANGE 0x22 +#define SSD130X_CONTRAST 0x81 +#define SSD130X_SET_LOOKUP_TABLE 0x91 +#define SSD130X_CHARGE_PUMP 0x8d +#define SSD130X_SEG_REMAP_ON 0xa1 +#define SSD130X_DISPLAY_OFF 0xae +#define SSD130X_SET_MULTIPLEX_RATIO 0xa8 +#define SSD130X_DISPLAY_ON 0xaf +#define SSD130X_START_PAGE_ADDRESS 0xb0 +#define SSD130X_SET_COM_SCAN_DIR 0xc0 +#define SSD130X_SET_DISPLAY_OFFSET 0xd3 +#define SSD130X_SET_CLOCK_FREQ 0xd5 +#define SSD130X_SET_AREA_COLOR_MODE 0xd8 +#define SSD130X_SET_PRECHARGE_PERIOD 0xd9 +#define SSD130X_SET_COM_PINS_CONFIG 0xda +#define SSD130X_SET_VCOMH 0xdb + +#define SSD130X_SET_COM_SCAN_DIR_MASK GENMASK(3, 2) +#define SSD130X_SET_COM_SCAN_DIR_SET(val) FIELD_PREP(SSD130X_SET_COM_SCAN_DIR_MASK, (val)) +#define SSD130X_SET_CLOCK_DIV_MASK GENMASK(3, 0) +#define SSD130X_SET_CLOCK_DIV_SET(val) FIELD_PREP(SSD130X_SET_CLOCK_DIV_MASK, (val)) +#define SSD130X_SET_CLOCK_FREQ_MASK GENMASK(7, 4) +#define SSD130X_SET_CLOCK_FREQ_SET(val) FIELD_PREP(SSD130X_SET_CLOCK_FREQ_MASK, (val)) +#define SSD130X_SET_PRECHARGE_PERIOD1_MASK GENMASK(3, 0) +#define SSD130X_SET_PRECHARGE_PERIOD1_SET(val) FIELD_PREP(SSD130X_SET_PRECHARGE_PERIOD1_MASK, (val)) +#define SSD130X_SET_PRECHARGE_PERIOD2_MASK GENMASK(7, 4) +#define SSD130X_SET_PRECHARGE_PERIOD2_SET(val) FIELD_PREP(SSD130X_SET_PRECHARGE_PERIOD2_MASK, (val)) +#define SSD130X_SET_COM_PINS_CONFIG1_MASK GENMASK(4, 4) +#define SSD130X_SET_COM_PINS_CONFIG1_SET(val) FIELD_PREP(SSD130X_SET_COM_PINS_CONFIG1_MASK, (!val)) +#define SSD130X_SET_COM_PINS_CONFIG2_MASK GENMASK(5, 5) +#define SSD130X_SET_COM_PINS_CONFIG2_SET(val) FIELD_PREP(SSD130X_SET_COM_PINS_CONFIG2_MASK, (val)) + +#define SSD130X_SET_ADDRESS_MODE_HORIZONTAL 0x00 +#define SSD130X_SET_ADDRESS_MODE_VERTICAL 0x01 +#define SSD130X_SET_ADDRESS_MODE_PAGE 0x02 + +#define SSD130X_SET_AREA_COLOR_MODE_ENABLE 0x1e +#define SSD130X_SET_AREA_COLOR_MODE_LOW_POWER 0x05 + +#define MAX_CONTRAST 255 + +static inline struct ssd130x_device *drm_to_ssd130x(struct drm_device *drm) +{ + return container_of(drm, struct ssd130x_device, drm); +} + +/* + * Helper to write data (SSD130X_DATA) to the device. + */ +static int ssd130x_write_data(struct ssd130x_device *ssd130x, u8 *values, int count) +{ + return regmap_bulk_write(ssd130x->regmap, SSD130X_DATA, values, count); +} + +/* + * Helper to write command (SSD130X_COMMAND). The fist variadic argument + * is the command to write and the following are the command options. + * + * Note that the ssd130x protocol requires each command and option to be + * written as a SSD130X_COMMAND device register value. That is why a call + * to regmap_write(..., SSD130X_COMMAND, ...) is done for each argument. + */ +static int ssd130x_write_cmd(struct ssd130x_device *ssd130x, int count, + /* u8 cmd, u8 option, ... */...) +{ + va_list ap; + u8 value; + int ret; + + va_start(ap, count); + + do { + value = va_arg(ap, int); + ret = regmap_write(ssd130x->regmap, SSD130X_COMMAND, value); + if (ret) + goto out_end; + } while (--count); + +out_end: + va_end(ap); + + return ret; +} + +static int ssd130x_set_col_range(struct ssd130x_device *ssd130x, + u8 col_start, u8 cols) +{ + u8 col_end = col_start + cols - 1; + int ret; + + if (col_start == ssd130x->col_start && col_end == ssd130x->col_end) + return 0; + + ret = ssd130x_write_cmd(ssd130x, 3, SSD130X_SET_COL_RANGE, col_start, col_end); + if (ret < 0) + return ret; + + ssd130x->col_start = col_start; + ssd130x->col_end = col_end; + return 0; +} + +static int ssd130x_set_page_range(struct ssd130x_device *ssd130x, + u8 page_start, u8 pages) +{ + u8 page_end = page_start + pages - 1; + int ret; + + if (page_start == ssd130x->page_start && page_end == ssd130x->page_end) + return 0; + + ret = ssd130x_write_cmd(ssd130x, 3, SSD130X_SET_PAGE_RANGE, page_start, page_end); + if (ret < 0) + return ret; + + ssd130x->page_start = page_start; + ssd130x->page_end = page_end; + return 0; +} + +static int ssd130x_pwm_enable(struct ssd130x_device *ssd130x) +{ + struct device *dev = ssd130x->dev; + struct pwm_state pwmstate; + + ssd130x->pwm = pwm_get(dev, NULL); + if (IS_ERR(ssd130x->pwm)) { + dev_err(dev, "Could not get PWM from firmware description!\n"); + return PTR_ERR(ssd130x->pwm); + } + + pwm_init_state(ssd130x->pwm, &pwmstate); + pwm_set_relative_duty_cycle(&pwmstate, 50, 100); + pwm_apply_state(ssd130x->pwm, &pwmstate); + + /* Enable the PWM */ + pwm_enable(ssd130x->pwm); + + dev_dbg(dev, "Using PWM%d with a %lluns period.\n", + ssd130x->pwm->pwm, pwm_get_period(ssd130x->pwm)); + + return 0; +} + +static void ssd130x_reset(struct ssd130x_device *ssd130x) +{ + if (!ssd130x->reset) + return; + + /* Reset the screen */ + gpiod_set_value_cansleep(ssd130x->reset, 1); + udelay(4); + gpiod_set_value_cansleep(ssd130x->reset, 0); + udelay(4); +} + +static int ssd130x_power_on(struct ssd130x_device *ssd130x) +{ + struct device *dev = ssd130x->dev; + int ret; + + ssd130x_reset(ssd130x); + + ret = regulator_enable(ssd130x->vcc_reg); + if (ret) { + dev_err(dev, "Failed to enable VCC: %d\n", ret); + return ret; + } + + if (ssd130x->device_info->need_pwm) { + ret = ssd130x_pwm_enable(ssd130x); + if (ret) { + dev_err(dev, "Failed to enable PWM: %d\n", ret); + regulator_disable(ssd130x->vcc_reg); + return ret; + } + } + + return 0; +} + +static void ssd130x_power_off(struct ssd130x_device *ssd130x) +{ + pwm_disable(ssd130x->pwm); + pwm_put(ssd130x->pwm); + + regulator_disable(ssd130x->vcc_reg); +} + +static int ssd130x_init(struct ssd130x_device *ssd130x) +{ + u32 precharge, dclk, com_invdir, compins, chargepump; + int ret; + + /* Set initial contrast */ + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_CONTRAST, ssd130x->contrast); + if (ret < 0) + return ret; + + /* Set segment re-map */ + if (ssd130x->seg_remap) { + ret = ssd130x_write_cmd(ssd130x, 1, SSD130X_SEG_REMAP_ON); + if (ret < 0) + return ret; + } + + /* Set COM direction */ + com_invdir = (SSD130X_SET_COM_SCAN_DIR | + SSD130X_SET_COM_SCAN_DIR_SET(ssd130x->com_invdir)); + ret = ssd130x_write_cmd(ssd130x, 1, com_invdir); + if (ret < 0) + return ret; + + /* Set multiplex ratio value */ + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_MULTIPLEX_RATIO, ssd130x->height - 1); + if (ret < 0) + return ret; + + /* set display offset value */ + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_DISPLAY_OFFSET, ssd130x->com_offset); + if (ret < 0) + return ret; + + /* Set clock frequency */ + dclk = (SSD130X_SET_CLOCK_DIV_SET(ssd130x->dclk_div - 1) | + SSD130X_SET_CLOCK_FREQ_SET(ssd130x->dclk_frq)); + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_CLOCK_FREQ, dclk); + if (ret < 0) + return ret; + + /* Set Area Color Mode ON/OFF & Low Power Display Mode */ + if (ssd130x->area_color_enable || ssd130x->low_power) { + u32 mode = 0; + + if (ssd130x->area_color_enable) + mode |= SSD130X_SET_AREA_COLOR_MODE_ENABLE; + + if (ssd130x->low_power) + mode |= SSD130X_SET_AREA_COLOR_MODE_LOW_POWER; + + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_AREA_COLOR_MODE, mode); + if (ret < 0) + return ret; + } + + /* Set precharge period in number of ticks from the internal clock */ + precharge = (SSD130X_SET_PRECHARGE_PERIOD1_SET(ssd130x->prechargep1) | + SSD130X_SET_PRECHARGE_PERIOD1_SET(ssd130x->prechargep2)); + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_PRECHARGE_PERIOD, precharge); + if (ret < 0) + return ret; + + /* Set COM pins configuration */ + compins = BIT(1); + compins |= (SSD130X_SET_COM_PINS_CONFIG1_SET(ssd130x->com_seq) | + SSD130X_SET_COM_PINS_CONFIG2_SET(ssd130x->com_lrremap)); + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_COM_PINS_CONFIG, compins); + if (ret < 0) + return ret; + + /* Set VCOMH */ + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_VCOMH, ssd130x->vcomh); + if (ret < 0) + return ret; + + /* Turn on the DC-DC Charge Pump */ + chargepump = BIT(4); + + if (ssd130x->device_info->need_chargepump) + chargepump |= BIT(2); + + ret = ssd130x_write_cmd(ssd130x, 2, SSD130X_CHARGE_PUMP, chargepump); + if (ret < 0) + return ret; + + /* Set lookup table */ + if (ssd130x->lookup_table_set) { + int i; + + ret = ssd130x_write_cmd(ssd130x, 1, SSD130X_SET_LOOKUP_TABLE); + if (ret < 0) + return ret; + + for (i = 0; i < ARRAY_SIZE(ssd130x->lookup_table); i++) { + u8 val = ssd130x->lookup_table[i]; + + if (val < 31 || val > 63) + dev_warn(ssd130x->dev, + "lookup table index %d value out of range 31 <= %d <= 63\n", + i, val); + ret = ssd130x_write_cmd(ssd130x, 1, val); + if (ret < 0) + return ret; + } + } + + /* Switch to horizontal addressing mode */ + return ssd130x_write_cmd(ssd130x, 2, SSD130X_SET_ADDRESS_MODE, + SSD130X_SET_ADDRESS_MODE_HORIZONTAL); +} + +static int ssd130x_update_rect(struct ssd130x_device *ssd130x, u8 *buf, + struct drm_rect *rect) +{ + unsigned int x = rect->x1; + unsigned int y = rect->y1; + unsigned int width = drm_rect_width(rect); + unsigned int height = drm_rect_height(rect); + unsigned int line_length = DIV_ROUND_UP(width, 8); + unsigned int pages = DIV_ROUND_UP(y % 8 + height, 8); + u32 array_idx = 0; + int ret, i, j, k; + u8 *data_array = NULL; + + data_array = kcalloc(width, pages, GFP_KERNEL); + if (!data_array) + return -ENOMEM; + + /* + * The screen is divided in pages, each having a height of 8 + * pixels, and the width of the screen. When sending a byte of + * data to the controller, it gives the 8 bits for the current + * column. I.e, the first byte are the 8 bits of the first + * column, then the 8 bits for the second column, etc. + * + * + * Representation of the screen, assuming it is 5 bits + * wide. Each letter-number combination is a bit that controls + * one pixel. + * + * A0 A1 A2 A3 A4 + * B0 B1 B2 B3 B4 + * C0 C1 C2 C3 C4 + * D0 D1 D2 D3 D4 + * E0 E1 E2 E3 E4 + * F0 F1 F2 F3 F4 + * G0 G1 G2 G3 G4 + * H0 H1 H2 H3 H4 + * + * If you want to update this screen, you need to send 5 bytes: + * (1) A0 B0 C0 D0 E0 F0 G0 H0 + * (2) A1 B1 C1 D1 E1 F1 G1 H1 + * (3) A2 B2 C2 D2 E2 F2 G2 H2 + * (4) A3 B3 C3 D3 E3 F3 G3 H3 + * (5) A4 B4 C4 D4 E4 F4 G4 H4 + */ + + ret = ssd130x_set_col_range(ssd130x, ssd130x->col_offset + x, width); + if (ret < 0) + goto out_free; + + ret = ssd130x_set_page_range(ssd130x, ssd130x->page_offset + y / 8, pages); + if (ret < 0) + goto out_free; + + for (i = y / 8; i < y / 8 + pages; i++) { + int m = 8; + + /* Last page may be partial */ + if (8 * (i + 1) > ssd130x->height) + m = ssd130x->height % 8; + for (j = x; j < x + width; j++) { + u8 data = 0; + + for (k = 0; k < m; k++) { + u8 byte = buf[(8 * i + k) * line_length + j / 8]; + u8 bit = (byte >> (j % 8)) & 1; + + data |= bit << k; + } + data_array[array_idx++] = data; + } + } + + ret = ssd130x_write_data(ssd130x, data_array, width * pages); + +out_free: + kfree(data_array); + return ret; +} + +static void ssd130x_clear_screen(struct ssd130x_device *ssd130x) +{ + u8 *buf = NULL; + struct drm_rect fullscreen = { + .x1 = 0, + .x2 = ssd130x->width, + .y1 = 0, + .y2 = ssd130x->height, + }; + + buf = kcalloc(ssd130x->width, ssd130x->height, GFP_KERNEL); + if (!buf) + return; + + ssd130x_update_rect(ssd130x, buf, &fullscreen); + + kfree(buf); +} + +static int ssd130x_fb_blit_rect(struct drm_framebuffer *fb, const struct dma_buf_map *map, + struct drm_rect *rect) +{ + struct ssd130x_device *ssd130x = drm_to_ssd130x(fb->dev); + void *vmap = map->vaddr; /* TODO: Use mapping abstraction properly */ + int ret = 0; + u8 *buf = NULL; + + buf = kcalloc(fb->width, fb->height, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + drm_fb_xrgb8888_to_mono_reversed(buf, 0, vmap, fb, rect); + + ssd130x_update_rect(ssd130x, buf, rect); + + kfree(buf); + + return ret; +} + +static int ssd130x_display_pipe_mode_valid(struct drm_simple_display_pipe *pipe, + const struct drm_display_mode *mode) +{ + struct ssd130x_device *ssd130x = drm_to_ssd130x(pipe->crtc.dev); + + if (mode->hdisplay != ssd130x->mode.hdisplay && + mode->vdisplay != ssd130x->mode.vdisplay) + return MODE_ONE_SIZE; + + if (mode->hdisplay != ssd130x->mode.hdisplay) + return MODE_ONE_WIDTH; + + if (mode->vdisplay != ssd130x->mode.vdisplay) + return MODE_ONE_HEIGHT; + + return MODE_OK; +} + +static void ssd130x_display_pipe_enable(struct drm_simple_display_pipe *pipe, + struct drm_crtc_state *crtc_state, + struct drm_plane_state *plane_state) +{ + struct ssd130x_device *ssd130x = drm_to_ssd130x(pipe->crtc.dev); + struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state); + struct drm_device *drm = &ssd130x->drm; + int idx, ret; + + ret = ssd130x_power_on(ssd130x); + if (ret) + return; + + ret = ssd130x_init(ssd130x); + if (ret) + goto out_power_off; + + if (!drm_dev_enter(drm, &idx)) + goto out_power_off; + + ssd130x_fb_blit_rect(plane_state->fb, &shadow_plane_state->data[0], &plane_state->dst); + + ssd130x_write_cmd(ssd130x, 1, SSD130X_DISPLAY_ON); + + backlight_enable(ssd130x->bl_dev); + + drm_dev_exit(idx); + + return; +out_power_off: + ssd130x_power_off(ssd130x); +} + +static void ssd130x_display_pipe_disable(struct drm_simple_display_pipe *pipe) +{ + struct ssd130x_device *ssd130x = drm_to_ssd130x(pipe->crtc.dev); + struct drm_device *drm = &ssd130x->drm; + int idx; + + if (!drm_dev_enter(drm, &idx)) + return; + + ssd130x_clear_screen(ssd130x); + + backlight_disable(ssd130x->bl_dev); + + ssd130x_write_cmd(ssd130x, 1, SSD130X_DISPLAY_OFF); + + ssd130x_power_off(ssd130x); + + drm_dev_exit(idx); +} + +static void ssd130x_display_pipe_update(struct drm_simple_display_pipe *pipe, + struct drm_plane_state *old_plane_state) +{ + struct ssd130x_device *ssd130x = drm_to_ssd130x(pipe->crtc.dev); + struct drm_plane_state *plane_state = pipe->plane.state; + struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state); + struct drm_framebuffer *fb = plane_state->fb; + struct drm_device *drm = &ssd130x->drm; + struct drm_rect src_clip, dst_clip; + int idx; + + if (!fb) + return; + + if (!pipe->crtc.state->active) + return; + + if (!drm_atomic_helper_damage_merged(old_plane_state, plane_state, &src_clip)) + return; + + dst_clip = plane_state->dst; + if (!drm_rect_intersect(&dst_clip, &src_clip)) + return; + + if (!drm_dev_enter(drm, &idx)) + return; + + ssd130x_fb_blit_rect(plane_state->fb, &shadow_plane_state->data[0], &dst_clip); + + drm_dev_exit(idx); +} + +static const struct drm_simple_display_pipe_funcs ssd130x_pipe_funcs = { + .mode_valid = ssd130x_display_pipe_mode_valid, + .enable = ssd130x_display_pipe_enable, + .disable = ssd130x_display_pipe_disable, + .update = ssd130x_display_pipe_update, + DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS, +}; + +static int ssd130x_connector_get_modes(struct drm_connector *connector) +{ + struct ssd130x_device *ssd130x = drm_to_ssd130x(connector->dev); + struct drm_display_mode *mode = &ssd130x->mode; + struct device *dev = ssd130x->dev; + + mode = drm_mode_duplicate(connector->dev, &ssd130x->mode); + if (!mode) { + dev_err(dev, "Failed to duplicated mode\n"); + return 0; + } + + drm_mode_probed_add(connector, mode); + drm_set_preferred_mode(connector, mode->hdisplay, mode->vdisplay); + + /* There is only a single mode */ + return 1; +} + +static const struct drm_connector_helper_funcs ssd130x_connector_helper_funcs = { + .get_modes = ssd130x_connector_get_modes, +}; + +static const struct drm_connector_funcs ssd130x_connector_funcs = { + .reset = drm_atomic_helper_connector_reset, + .fill_modes = drm_helper_probe_single_connector_modes, + .destroy = drm_connector_cleanup, + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, +}; + +static const struct drm_mode_config_funcs ssd130x_mode_config_funcs = { + .fb_create = drm_gem_fb_create_with_dirty, + .atomic_check = drm_atomic_helper_check, + .atomic_commit = drm_atomic_helper_commit, +}; + +static const uint32_t ssd130x_formats[] = { + DRM_FORMAT_XRGB8888, +}; + +DEFINE_DRM_GEM_FOPS(ssd130x_fops); + +static const struct drm_driver ssd130x_drm_driver = { + DRM_GEM_SHMEM_DRIVER_OPS, + .name = DRIVER_NAME, + .desc = DRIVER_DESC, + .date = DRIVER_DATE, + .major = DRIVER_MAJOR, + .minor = DRIVER_MINOR, + .driver_features = DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET, + .fops = &ssd130x_fops, +}; + +static int ssd130x_update_bl(struct backlight_device *bdev) +{ + struct ssd130x_device *ssd130x = bl_get_data(bdev); + int brightness = backlight_get_brightness(bdev); + int ret; + + ssd130x->contrast = brightness; + + ret = ssd130x_write_cmd(ssd130x, 1, SSD130X_CONTRAST); + if (ret < 0) + return ret; + + ret = ssd130x_write_cmd(ssd130x, 1, ssd130x->contrast); + if (ret < 0) + return ret; + + return 0; +} + +static const struct backlight_ops ssd130xfb_bl_ops = { + .update_status = ssd130x_update_bl, +}; + +static void ssd130x_parse_properties(struct ssd130x_device *ssd130x) +{ + struct device *dev = ssd130x->dev; + + if (device_property_read_u32(dev, "solomon,width", &ssd130x->width)) + ssd130x->width = 96; + + if (device_property_read_u32(dev, "solomon,height", &ssd130x->height)) + ssd130x->height = 16; + + if (device_property_read_u32(dev, "solomon,page-offset", &ssd130x->page_offset)) + ssd130x->page_offset = 1; + + if (device_property_read_u32(dev, "solomon,col-offset", &ssd130x->col_offset)) + ssd130x->col_offset = 0; + + if (device_property_read_u32(dev, "solomon,com-offset", &ssd130x->com_offset)) + ssd130x->com_offset = 0; + + if (device_property_read_u32(dev, "solomon,prechargep1", &ssd130x->prechargep1)) + ssd130x->prechargep1 = 2; + + if (device_property_read_u32(dev, "solomon,prechargep2", &ssd130x->prechargep2)) + ssd130x->prechargep2 = 2; + + if (!device_property_read_u8_array(dev, "solomon,lookup-table", + ssd130x->lookup_table, + ARRAY_SIZE(ssd130x->lookup_table))) + ssd130x->lookup_table_set = 1; + + ssd130x->seg_remap = !device_property_read_bool(dev, "solomon,segment-no-remap"); + ssd130x->com_seq = device_property_read_bool(dev, "solomon,com-seq"); + ssd130x->com_lrremap = device_property_read_bool(dev, "solomon,com-lrremap"); + ssd130x->com_invdir = device_property_read_bool(dev, "solomon,com-invdir"); + ssd130x->area_color_enable = + device_property_read_bool(dev, "solomon,area-color-enable"); + ssd130x->low_power = device_property_read_bool(dev, "solomon,low-power"); + + ssd130x->contrast = 127; + ssd130x->vcomh = ssd130x->device_info->default_vcomh; + + /* Setup display timing */ + if (device_property_read_u32(dev, "solomon,dclk-div", &ssd130x->dclk_div)) + ssd130x->dclk_div = ssd130x->device_info->default_dclk_div; + if (device_property_read_u32(dev, "solomon,dclk-frq", &ssd130x->dclk_frq)) + ssd130x->dclk_frq = ssd130x->device_info->default_dclk_frq; +} + +static int ssd130x_init_modeset(struct ssd130x_device *ssd130x) +{ + struct drm_display_mode *mode = &ssd130x->mode; + struct device *dev = ssd130x->dev; + struct drm_device *drm = &ssd130x->drm; + unsigned long max_width, max_height; + int ret; + + ret = drmm_mode_config_init(drm); + if (ret) { + dev_err(dev, "DRM mode config init failed: %d\n", ret); + return ret; + } + + mode->type = DRM_MODE_TYPE_DRIVER; + mode->clock = 1; + mode->hdisplay = mode->htotal = ssd130x->width; + mode->hsync_start = mode->hsync_end = ssd130x->width; + mode->vdisplay = mode->vtotal = ssd130x->height; + mode->vsync_start = mode->vsync_end = ssd130x->height; + mode->width_mm = 27; + mode->height_mm = 27; + + max_width = max_t(unsigned long, mode->hdisplay, DRM_SHADOW_PLANE_MAX_WIDTH); + max_height = max_t(unsigned long, mode->vdisplay, DRM_SHADOW_PLANE_MAX_HEIGHT); + + drm->mode_config.min_width = mode->hdisplay; + drm->mode_config.max_width = max_width; + drm->mode_config.min_height = mode->vdisplay; + drm->mode_config.max_height = max_height; + drm->mode_config.preferred_depth = 32; + drm->mode_config.funcs = &ssd130x_mode_config_funcs; + + ret = drm_connector_init(drm, &ssd130x->connector, &ssd130x_connector_funcs, + DRM_MODE_CONNECTOR_Unknown); + if (ret) { + dev_err(dev, "DRM connector init failed: %d\n", ret); + return ret; + } + + drm_connector_helper_add(&ssd130x->connector, &ssd130x_connector_helper_funcs); + + ret = drm_simple_display_pipe_init(drm, &ssd130x->pipe, &ssd130x_pipe_funcs, + ssd130x_formats, ARRAY_SIZE(ssd130x_formats), + NULL, &ssd130x->connector); + if (ret) { + dev_err(dev, "DRM simple display pipeline init failed: %d\n", ret); + return ret; + } + + drm_plane_enable_fb_damage_clips(&ssd130x->pipe.plane); + + drm_mode_config_reset(drm); + + return 0; +} + +static int ssd130x_get_resources(struct ssd130x_device *ssd130x) +{ + struct device *dev = ssd130x->dev; + + ssd130x->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW); + if (IS_ERR(ssd130x->reset)) + return dev_err_probe(dev, PTR_ERR(ssd130x->reset), + "Failed to get reset gpio\n"); + + ssd130x->vcc_reg = devm_regulator_get(dev, "vcc"); + if (IS_ERR(ssd130x->vcc_reg)) + return dev_err_probe(dev, PTR_ERR(ssd130x->vcc_reg), + "Failed to get VCC regulator\n"); + + return 0; +} + +struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap) +{ + struct ssd130x_device *ssd130x; + struct backlight_device *bl; + struct drm_device *drm; + int ret; + + ssd130x = devm_drm_dev_alloc(dev, &ssd130x_drm_driver, + struct ssd130x_device, drm); + if (IS_ERR(ssd130x)) + return ERR_PTR(dev_err_probe(dev, PTR_ERR(ssd130x), + "Failed to allocate DRM device\n")); + + drm = &ssd130x->drm; + + ssd130x->dev = dev; + ssd130x->regmap = regmap; + ssd130x->device_info = device_get_match_data(dev); + + ssd130x_parse_properties(ssd130x); + + ret = ssd130x_get_resources(ssd130x); + if (ret) + return ERR_PTR(ret); + + bl = devm_backlight_device_register(dev, dev_name(dev), dev, ssd130x, + &ssd130xfb_bl_ops, NULL); + if (IS_ERR(bl)) + return ERR_PTR(dev_err_probe(dev, PTR_ERR(bl), + "Unable to register backlight device\n")); + + bl->props.brightness = ssd130x->contrast; + bl->props.max_brightness = MAX_CONTRAST; + ssd130x->bl_dev = bl; + + ret = ssd130x_init_modeset(ssd130x); + if (ret) + return ERR_PTR(ret); + + ret = drm_dev_register(drm, 0); + if (ret) + return ERR_PTR(dev_err_probe(dev, ret, "DRM device register failed\n")); + + drm_fbdev_generic_setup(drm, 0); + + return ssd130x; +} +EXPORT_SYMBOL_GPL(ssd130x_probe); + +int ssd130x_remove(struct ssd130x_device *ssd130x) +{ + drm_dev_unplug(&ssd130x->drm); + + return 0; +} +EXPORT_SYMBOL_GPL(ssd130x_remove); + +void ssd130x_shutdown(struct ssd130x_device *ssd130x) +{ + drm_atomic_helper_shutdown(&ssd130x->drm); +} +EXPORT_SYMBOL_GPL(ssd130x_shutdown); + +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_AUTHOR("Javier Martinez Canillas <javierm@redhat.com>"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/gpu/drm/solomon/ssd130x.h b/drivers/gpu/drm/solomon/ssd130x.h new file mode 100644 index 000000000000..cd21cdccb566 --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Header file for: + * DRM driver for Solomon SSD130x OLED displays + * + * Copyright 2022 Red Hat Inc. + * Author: Javier Martinez Canillas <javierm@redhat.com> + * + * Based on drivers/video/fbdev/ssd1307fb.c + * Copyright 2012 Free Electrons + */ + +#ifndef __SSD1307X_H__ +#define __SSD1307X_H__ + +#include <drm/drm_drv.h> +#include <drm/drm_simple_kms_helper.h> + +#include <linux/regmap.h> + +struct ssd130x_deviceinfo { + u32 default_vcomh; + u32 default_dclk_div; + u32 default_dclk_frq; + int need_pwm; + int need_chargepump; +}; + +struct ssd130x_device { + struct drm_device drm; + struct device *dev; + struct drm_simple_display_pipe pipe; + struct drm_display_mode mode; + struct drm_connector connector; + struct i2c_client *client; + + struct regmap *regmap; + + const struct ssd130x_deviceinfo *device_info; + + unsigned area_color_enable : 1; + unsigned com_invdir : 1; + unsigned com_lrremap : 1; + unsigned com_seq : 1; + unsigned lookup_table_set : 1; + unsigned low_power : 1; + unsigned seg_remap : 1; + u32 com_offset; + u32 contrast; + u32 dclk_div; + u32 dclk_frq; + u32 height; + u8 lookup_table[4]; + u32 page_offset; + u32 col_offset; + u32 prechargep1; + u32 prechargep2; + + struct backlight_device *bl_dev; + struct pwm_device *pwm; + struct gpio_desc *reset; + struct regulator *vcc_reg; + u32 vcomh; + u32 width; + /* Cached address ranges */ + u8 col_start; + u8 col_end; + u8 page_start; + u8 page_end; +}; + +struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap); +int ssd130x_remove(struct ssd130x_device *ssd130x); +void ssd130x_shutdown(struct ssd130x_device *ssd130x); + +#endif /* __SSD1307X_H__ */ -- 2.34.1 ^ permalink raw reply related [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-02-14 13:37 ` [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas @ 2022-02-16 9:16 ` Maxime Ripard 2022-03-08 16:30 ` Geert Uytterhoeven 2022-03-09 20:04 ` Geert Uytterhoeven 2 siblings, 0 replies; 30+ messages in thread From: Maxime Ripard @ 2022-02-16 9:16 UTC (permalink / raw) To: Javier Martinez Canillas Cc: linux-kernel, linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Thierry Reding, Uwe Kleine-König, linux-pwm [-- Attachment #1: Type: text/plain, Size: 459 bytes --] On Mon, Feb 14, 2022 at 02:37:07PM +0100, Javier Martinez Canillas wrote: > This adds a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon > OLED display controllers. > > It's only the core part of the driver and a bus specific driver is needed > for each transport interface supported by the display controllers. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Maxime Ripard <maxime@cerno.tech> Maxime [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-02-14 13:37 ` [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard @ 2022-03-08 16:30 ` Geert Uytterhoeven 2022-03-09 12:14 ` Javier Martinez Canillas 2022-03-09 20:04 ` Geert Uytterhoeven 2 siblings, 1 reply; 30+ messages in thread From: Geert Uytterhoeven @ 2022-03-08 16:30 UTC (permalink / raw) To: Javier Martinez Canillas Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, Linux PWM List Hi Javier, On Mon, Feb 14, 2022 at 2:37 PM Javier Martinez Canillas <javierm@redhat.com> wrote: > This adds a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon > OLED display controllers. > > It's only the core part of the driver and a bus specific driver is needed > for each transport interface supported by the display controllers. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Thanks for your patch, which is now commit a61732e808672cfa ("drm: Add driver for Solomon SSD130x OLED displays") in drm/drm-next Sorry for the delay, but finally I gave it a try on my Adafruit FeatherWing 128x32 OLED. Some of the weird issues (cursor disappears after printing some text, more text also doesn't appear until I clear the display) are still there. Unfortunately a regression was introduced since your v3: printed text is mirrored upside-down. I.e. "E" is rendered correctly, but "L" turns into "Γ" (Greek Gamma). I suspect something went wrong with the display initialization sequence. 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 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-03-08 16:30 ` Geert Uytterhoeven @ 2022-03-09 12:14 ` Javier Martinez Canillas 2022-03-09 12:56 ` Geert Uytterhoeven 0 siblings, 1 reply; 30+ messages in thread From: Javier Martinez Canillas @ 2022-03-09 12:14 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, Linux PWM List On 3/8/22 17:30, Geert Uytterhoeven wrote: > Hi Javier, > > On Mon, Feb 14, 2022 at 2:37 PM Javier Martinez Canillas > <javierm@redhat.com> wrote: >> This adds a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon >> OLED display controllers. >> >> It's only the core part of the driver and a bus specific driver is needed >> for each transport interface supported by the display controllers. >> >> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > > Thanks for your patch, which is now commit a61732e808672cfa ("drm: > Add driver for Solomon SSD130x OLED displays") in drm/drm-next > > Sorry for the delay, but finally I gave it a try on my Adafruit > FeatherWing 128x32 OLED. > Some of the weird issues (cursor disappears after printing some text, > more text also doesn't appear until I clear the display) are still there. I see. Thought that I tested using it as a console and it did work correctly for me. I'll do more tests again. > Unfortunately a regression was introduced since your v3: printed > text is mirrored upside-down. I.e. "E" is rendered correctly, but "L" > turns into "Γ" (Greek Gamma). > I suspect something went wrong with the display initialization > sequence. > Could you please try Chen-Yu's fix for the COM scan direction mask ? https://lists.freedesktop.org/archives/dri-devel/2022-March/345915.html I made a mistake when converting to use the GENMASK() and FIELD_PREP() macros in v4 as suggested by Andy. The SSD130X_SET_COM_SCAN_DIR_MASK wasn't correct which would explain the output to be vertically flipped. -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-03-09 12:14 ` Javier Martinez Canillas @ 2022-03-09 12:56 ` Geert Uytterhoeven 2022-03-09 13:43 ` Javier Martinez Canillas 0 siblings, 1 reply; 30+ messages in thread From: Geert Uytterhoeven @ 2022-03-09 12:56 UTC (permalink / raw) To: Javier Martinez Canillas Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, Linux PWM List Hi Javier, On Wed, Mar 9, 2022 at 1:14 PM Javier Martinez Canillas <javierm@redhat.com> wrote: > On 3/8/22 17:30, Geert Uytterhoeven wrote: > > Unfortunately a regression was introduced since your v3: printed > > text is mirrored upside-down. I.e. "E" is rendered correctly, but "L" > > turns into "Γ" (Greek Gamma). > > I suspect something went wrong with the display initialization > > sequence. > > > > Could you please try Chen-Yu's fix for the COM scan direction mask ? > > https://lists.freedesktop.org/archives/dri-devel/2022-March/345915.html > > I made a mistake when converting to use the GENMASK() and FIELD_PREP() > macros in v4 as suggested by Andy. The SSD130X_SET_COM_SCAN_DIR_MASK > wasn't correct which would explain the output to be vertically flipped. Thanks, confirmed fixed. 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 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-03-09 12:56 ` Geert Uytterhoeven @ 2022-03-09 13:43 ` Javier Martinez Canillas 0 siblings, 0 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-03-09 13:43 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, Linux PWM List Hello Geert, On 3/9/22 13:56, Geert Uytterhoeven wrote: > Hi Javier, > > On Wed, Mar 9, 2022 at 1:14 PM Javier Martinez Canillas > <javierm@redhat.com> wrote: >> On 3/8/22 17:30, Geert Uytterhoeven wrote: >>> Unfortunately a regression was introduced since your v3: printed >>> text is mirrored upside-down. I.e. "E" is rendered correctly, but "L" >>> turns into "Γ" (Greek Gamma). >>> I suspect something went wrong with the display initialization >>> sequence. >>> >> >> Could you please try Chen-Yu's fix for the COM scan direction mask ? >> >> https://lists.freedesktop.org/archives/dri-devel/2022-March/345915.html >> >> I made a mistake when converting to use the GENMASK() and FIELD_PREP() >> macros in v4 as suggested by Andy. The SSD130X_SET_COM_SCAN_DIR_MASK >> wasn't correct which would explain the output to be vertically flipped. > > Thanks, confirmed fixed. > Great, thanks a lot for testing and the confirmation! -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-02-14 13:37 ` [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard 2022-03-08 16:30 ` Geert Uytterhoeven @ 2022-03-09 20:04 ` Geert Uytterhoeven 2022-03-09 20:13 ` Javier Martinez Canillas 2 siblings, 1 reply; 30+ messages in thread From: Geert Uytterhoeven @ 2022-03-09 20:04 UTC (permalink / raw) To: Javier Martinez Canillas Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, Linux PWM List Hi Javier, On Mon, Feb 14, 2022 at 2:37 PM Javier Martinez Canillas <javierm@redhat.com> wrote: > This adds a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon > OLED display controllers. > > It's only the core part of the driver and a bus specific driver is needed > for each transport interface supported by the display controllers. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > --- /dev/null > +++ b/drivers/gpu/drm/solomon/ssd130x.c > +static int ssd130x_update_rect(struct ssd130x_device *ssd130x, u8 *buf, > + struct drm_rect *rect) > +{ > + unsigned int x = rect->x1; > + unsigned int y = rect->y1; > + unsigned int width = drm_rect_width(rect); > + unsigned int height = drm_rect_height(rect); > + unsigned int line_length = DIV_ROUND_UP(width, 8); > + unsigned int pages = DIV_ROUND_UP(y % 8 + height, 8); > + u32 array_idx = 0; > + int ret, i, j, k; > + u8 *data_array = NULL; > + > + data_array = kcalloc(width, pages, GFP_KERNEL); > + if (!data_array) > + return -ENOMEM; > + > + /* > + * The screen is divided in pages, each having a height of 8 > + * pixels, and the width of the screen. When sending a byte of > + * data to the controller, it gives the 8 bits for the current > + * column. I.e, the first byte are the 8 bits of the first > + * column, then the 8 bits for the second column, etc. > + * > + * > + * Representation of the screen, assuming it is 5 bits > + * wide. Each letter-number combination is a bit that controls > + * one pixel. > + * > + * A0 A1 A2 A3 A4 > + * B0 B1 B2 B3 B4 > + * C0 C1 C2 C3 C4 > + * D0 D1 D2 D3 D4 > + * E0 E1 E2 E3 E4 > + * F0 F1 F2 F3 F4 > + * G0 G1 G2 G3 G4 > + * H0 H1 H2 H3 H4 > + * > + * If you want to update this screen, you need to send 5 bytes: > + * (1) A0 B0 C0 D0 E0 F0 G0 H0 > + * (2) A1 B1 C1 D1 E1 F1 G1 H1 > + * (3) A2 B2 C2 D2 E2 F2 G2 H2 > + * (4) A3 B3 C3 D3 E3 F3 G3 H3 > + * (5) A4 B4 C4 D4 E4 F4 G4 H4 > + */ > + > + ret = ssd130x_set_col_range(ssd130x, ssd130x->col_offset + x, width); > + if (ret < 0) > + goto out_free; > + > + ret = ssd130x_set_page_range(ssd130x, ssd130x->page_offset + y / 8, pages); > + if (ret < 0) > + goto out_free; > + > + for (i = y / 8; i < y / 8 + pages; i++) { > + int m = 8; > + > + /* Last page may be partial */ > + if (8 * (i + 1) > ssd130x->height) > + m = ssd130x->height % 8; > + for (j = x; j < x + width; j++) { > + u8 data = 0; > + > + for (k = 0; k < m; k++) { > + u8 byte = buf[(8 * i + k) * line_length + j / 8]; As buf does not point to (0, 0), the above is not correct if rect.x1 != 0 or rect.y1 != 0. After fixing that, writing more than one text line to the console works, but I still see an issue with updates where the rectangle size and/or position are not aligned to 8 pixels horizontally. Will do more investigation, and send fixes... > + u8 bit = (byte >> (j % 8)) & 1; > + > + data |= bit << k; > + } > + data_array[array_idx++] = data; > + } > + } > + > + ret = ssd130x_write_data(ssd130x, data_array, width * pages); > + > +out_free: > + kfree(data_array); > + return ret; > +} > + > +static void ssd130x_clear_screen(struct ssd130x_device *ssd130x) > +{ > + u8 *buf = NULL; > + struct drm_rect fullscreen = { > + .x1 = 0, > + .x2 = ssd130x->width, > + .y1 = 0, > + .y2 = ssd130x->height, > + }; > + > + buf = kcalloc(ssd130x->width, ssd130x->height, GFP_KERNEL); This buffer is larger than needed. Will send a fix. > + if (!buf) > + return; > + > + ssd130x_update_rect(ssd130x, buf, &fullscreen); > + > + kfree(buf); > +} > + > +static int ssd130x_fb_blit_rect(struct drm_framebuffer *fb, const struct dma_buf_map *map, > + struct drm_rect *rect) > +{ > + struct ssd130x_device *ssd130x = drm_to_ssd130x(fb->dev); > + void *vmap = map->vaddr; /* TODO: Use mapping abstraction properly */ > + int ret = 0; > + u8 *buf = NULL; > + > + buf = kcalloc(fb->width, fb->height, GFP_KERNEL); This buffer is much larger than needed. Will send a fix. > + if (!buf) > + return -ENOMEM; > + > + drm_fb_xrgb8888_to_mono_reversed(buf, 0, vmap, fb, rect); > + > + ssd130x_update_rect(ssd130x, buf, rect); > + > + kfree(buf); > + > + return ret; > +} 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 ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-03-09 20:04 ` Geert Uytterhoeven @ 2022-03-09 20:13 ` Javier Martinez Canillas 0 siblings, 0 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-03-09 20:13 UTC (permalink / raw) To: Geert Uytterhoeven Cc: Linux Kernel Mailing List, Linux Fbdev development list, Andy Shevchenko, Daniel Vetter, Thomas Zimmermann, Sam Ravnborg, DRI Development, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Thierry Reding, Uwe Kleine-König, Linux PWM List Hello Geert, On 3/9/22 21:04, Geert Uytterhoeven wrote: [snip] >> + >> + /* Last page may be partial */ >> + if (8 * (i + 1) > ssd130x->height) >> + m = ssd130x->height % 8; >> + for (j = x; j < x + width; j++) { >> + u8 data = 0; >> + >> + for (k = 0; k < m; k++) { >> + u8 byte = buf[(8 * i + k) * line_length + j / 8]; > > As buf does not point to (0, 0), the above is not correct if rect.x1 != > 0 or rect.y1 != 0. After fixing that, writing more than one text line > to the console works, but I still see an issue with updates where the > rectangle size and/or position are not aligned to 8 pixels horizontally. > Will do more investigation, and send fixes... > Right, I believe this is a consequence of introducing shadow buffers at some point and not adjusting the logic in this function. Thanks a lot for tracking down the issues and working on fixes for them! -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v6 4/6] drm/solomon: Add SSD130x OLED displays I2C support 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas ` (2 preceding siblings ...) 2022-02-14 13:37 ` [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas @ 2022-02-14 13:37 ` Javier Martinez Canillas 2022-02-16 9:17 ` Maxime Ripard 2022-02-14 13:39 ` [PATCH v6 5/6] MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver Javier Martinez Canillas ` (2 subsequent siblings) 6 siblings, 1 reply; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:37 UTC (permalink / raw) To: linux-kernel Cc: linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Maxime Ripard, Noralf Trønnes, Javier Martinez Canillas, Daniel Vetter, David Airlie The ssd130x driver only provides the core support for these devices but it does not have any bus transport logic. Add a driver to interface over I2C. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- (no changes since v5) Changes in v5: - Add Andy Shevchenko's Reviewed-by tag to patch #4. Changes in v4: - Remove unnecessary casting (Geert Uytterhoeven) - Remove redundant blank lines (Andy Shevchenko) - Remove comma after of_device_id table terminator (Andy Shevchenko) Changes in v3: - Add a separate driver for SSD130X chips I2C support (Andy Shevchenko) drivers/gpu/drm/solomon/Kconfig | 9 ++ drivers/gpu/drm/solomon/Makefile | 1 + drivers/gpu/drm/solomon/ssd130x-i2c.c | 116 ++++++++++++++++++++++++++ 3 files changed, 126 insertions(+) create mode 100644 drivers/gpu/drm/solomon/ssd130x-i2c.c diff --git a/drivers/gpu/drm/solomon/Kconfig b/drivers/gpu/drm/solomon/Kconfig index 7720a7039e8d..5861c3ab7c45 100644 --- a/drivers/gpu/drm/solomon/Kconfig +++ b/drivers/gpu/drm/solomon/Kconfig @@ -10,3 +10,12 @@ config DRM_SSD130X the appropriate bus transport in your chip also must be selected. If M is selected the module will be called ssd130x. + +config DRM_SSD130X_I2C + tristate "DRM support for Solomon SSD130x OLED displays (I2C bus)" + depends on DRM_SSD130X && I2C + select REGMAP_I2C + help + Say Y here if the SSD130x OLED display is connected via I2C bus. + + If M is selected the module will be called ssd130x-i2c. diff --git a/drivers/gpu/drm/solomon/Makefile b/drivers/gpu/drm/solomon/Makefile index f685addb19fe..4bfc5acb0447 100644 --- a/drivers/gpu/drm/solomon/Makefile +++ b/drivers/gpu/drm/solomon/Makefile @@ -1 +1,2 @@ obj-$(CONFIG_DRM_SSD130X) += ssd130x.o +obj-$(CONFIG_DRM_SSD130X_I2C) += ssd130x-i2c.o diff --git a/drivers/gpu/drm/solomon/ssd130x-i2c.c b/drivers/gpu/drm/solomon/ssd130x-i2c.c new file mode 100644 index 000000000000..3126aeda4ced --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x-i2c.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DRM driver for Solomon SSD130x OLED displays (I2C bus) + * + * Copyright 2022 Red Hat Inc. + * Author: Javier Martinez Canillas <javierm@redhat.com> + * + * Based on drivers/video/fbdev/ssd1307fb.c + * Copyright 2012 Free Electrons + */ +#include <linux/i2c.h> +#include <linux/module.h> + +#include "ssd130x.h" + +#define DRIVER_NAME "ssd130x-i2c" +#define DRIVER_DESC "DRM driver for Solomon SSD130x OLED displays (I2C)" + +static const struct regmap_config ssd130x_i2c_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +static int ssd130x_i2c_probe(struct i2c_client *client) +{ + struct ssd130x_device *ssd130x; + struct regmap *regmap; + + regmap = devm_regmap_init_i2c(client, &ssd130x_i2c_regmap_config); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + ssd130x = ssd130x_probe(&client->dev, regmap); + if (IS_ERR(ssd130x)) + return PTR_ERR(ssd130x); + + i2c_set_clientdata(client, ssd130x); + + return 0; +} + +static int ssd130x_i2c_remove(struct i2c_client *client) +{ + struct ssd130x_device *ssd130x = i2c_get_clientdata(client); + + return ssd130x_remove(ssd130x); +} + +static void ssd130x_i2c_shutdown(struct i2c_client *client) +{ + struct ssd130x_device *ssd130x = i2c_get_clientdata(client); + + ssd130x_shutdown(ssd130x); +} + +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 = "solomon,ssd1305fb-i2c", + .data = &ssd130x_ssd1305_deviceinfo, + }, + { + .compatible = "solomon,ssd1306fb-i2c", + .data = &ssd130x_ssd1306_deviceinfo, + }, + { + .compatible = "solomon,ssd1307fb-i2c", + .data = &ssd130x_ssd1307_deviceinfo, + }, + { + .compatible = "solomon,ssd1309fb-i2c", + .data = &ssd130x_ssd1309_deviceinfo, + }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ssd130x_of_match); + +static struct i2c_driver ssd130x_i2c_driver = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = ssd130x_of_match, + }, + .probe_new = ssd130x_i2c_probe, + .remove = ssd130x_i2c_remove, + .shutdown = ssd130x_i2c_shutdown, +}; +module_i2c_driver(ssd130x_i2c_driver); + +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_AUTHOR("Javier Martinez Canillas <javierm@redhat.com>"); +MODULE_LICENSE("GPL v2"); -- 2.34.1 ^ permalink raw reply related [flat|nested] 30+ messages in thread
* Re: [PATCH v6 4/6] drm/solomon: Add SSD130x OLED displays I2C support 2022-02-14 13:37 ` [PATCH v6 4/6] drm/solomon: Add SSD130x OLED displays I2C support Javier Martinez Canillas @ 2022-02-16 9:17 ` Maxime Ripard 0 siblings, 0 replies; 30+ messages in thread From: Maxime Ripard @ 2022-02-16 9:17 UTC (permalink / raw) To: Javier Martinez Canillas Cc: linux-kernel, linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Noralf Trønnes, Daniel Vetter, David Airlie [-- Attachment #1: Type: text/plain, Size: 427 bytes --] On Mon, Feb 14, 2022 at 02:37:08PM +0100, Javier Martinez Canillas wrote: > The ssd130x driver only provides the core support for these devices but it > does not have any bus transport logic. Add a driver to interface over I2C. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Maxime Ripard <maxime@cerno.tech> Maxime [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v6 5/6] MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas ` (3 preceding siblings ...) 2022-02-14 13:37 ` [PATCH v6 4/6] drm/solomon: Add SSD130x OLED displays I2C support Javier Martinez Canillas @ 2022-02-14 13:39 ` Javier Martinez Canillas 2022-02-16 9:17 ` Maxime Ripard 2022-02-14 13:39 ` [PATCH v6 6/6] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer Javier Martinez Canillas 2022-02-16 12:34 ` [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 6 siblings, 1 reply; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:39 UTC (permalink / raw) To: linux-kernel Cc: Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Maxime Ripard, Noralf Trønnes, dri-devel, linux-fbdev, Javier Martinez Canillas, Sam Ravnborg To make sure that tools like the get_maintainer.pl script will suggest to Cc me if patches are posted for this driver. Also include the Device Tree binding for the old ssd1307fb fbdev driver since the new DRM driver was made compatible with the existing binding. Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- (no changes since v5) Changes in v5: - Add Andy Shevchenko's Reviewed-by tag to patch #5. Changes in v3: - Adapt MAINTAINERS entry to point to the new drivers/gpu/drm/solomon directory. Changes in v2: - Add Sam Ravnborg's acked-by to patch adding a MAINTAINERS entry (Sam Ravnborg) MAINTAINERS | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index d03ad8da1f36..05c306986ab0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -6102,6 +6102,13 @@ T: git git://anongit.freedesktop.org/drm/drm-misc F: Documentation/devicetree/bindings/display/repaper.txt F: drivers/gpu/drm/tiny/repaper.c +DRM DRIVER FOR SOLOMON SSD130X OLED DISPLAYS +M: Javier Martinez Canillas <javierm@redhat.com> +S: Maintained +T: git git://anongit.freedesktop.org/drm/drm-misc +F: Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml +F: drivers/gpu/drm/solomon/ssd130x* + DRM DRIVER FOR QEMU'S CIRRUS DEVICE M: Dave Airlie <airlied@redhat.com> M: Gerd Hoffmann <kraxel@redhat.com> -- 2.34.1 ^ permalink raw reply related [flat|nested] 30+ messages in thread
* Re: [PATCH v6 5/6] MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver 2022-02-14 13:39 ` [PATCH v6 5/6] MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver Javier Martinez Canillas @ 2022-02-16 9:17 ` Maxime Ripard 0 siblings, 0 replies; 30+ messages in thread From: Maxime Ripard @ 2022-02-16 9:17 UTC (permalink / raw) To: Javier Martinez Canillas Cc: linux-kernel, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Noralf Trønnes, dri-devel, linux-fbdev, Sam Ravnborg [-- Attachment #1: Type: text/plain, Size: 590 bytes --] On Mon, Feb 14, 2022 at 02:39:15PM +0100, Javier Martinez Canillas wrote: > To make sure that tools like the get_maintainer.pl script will suggest > to Cc me if patches are posted for this driver. > > Also include the Device Tree binding for the old ssd1307fb fbdev driver > since the new DRM driver was made compatible with the existing binding. > > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Acked-by: Sam Ravnborg <sam@ravnborg.org> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Maxime Ripard <maxime@cerno.tech> Maxime [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v6 6/6] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas ` (4 preceding siblings ...) 2022-02-14 13:39 ` [PATCH v6 5/6] MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver Javier Martinez Canillas @ 2022-02-14 13:39 ` Javier Martinez Canillas 2022-02-16 9:17 ` Maxime Ripard 2022-02-16 12:34 ` [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 6 siblings, 1 reply; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-14 13:39 UTC (permalink / raw) To: linux-kernel Cc: Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Maxime Ripard, Noralf Trønnes, dri-devel, linux-fbdev, Javier Martinez Canillas, Sam Ravnborg, Rob Herring The ssd130x DRM driver also makes use of this Device Tree binding to allow existing users of the fbdev driver to migrate without the need to change their Device Trees. Add myself as another maintainer of the binding, to make sure that I will be on Cc when patches are proposed for it. Suggested-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- (no changes since v5) Changes in v5: - Add Andy Shevchenko's Reviewed-by tag to patch #6. Changes in v4: - Add Rob Herring Acked-by tag to patch adding as DT binding co-maintainer. Changes in v2: - Add myself as co-maintainer of the ssd1370fb DT binding (Sam Ravnborg). Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml | 1 + 1 file changed, 1 insertion(+) diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml index 2ed2a7d0ca2f..9baafd0c42dd 100644 --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml @@ -8,6 +8,7 @@ title: Solomon SSD1307 OLED Controller Framebuffer maintainers: - Maxime Ripard <mripard@kernel.org> + - Javier Martinez Canillas <javierm@redhat.com> properties: compatible: -- 2.34.1 ^ permalink raw reply related [flat|nested] 30+ messages in thread
* Re: [PATCH v6 6/6] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer 2022-02-14 13:39 ` [PATCH v6 6/6] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer Javier Martinez Canillas @ 2022-02-16 9:17 ` Maxime Ripard 0 siblings, 0 replies; 30+ messages in thread From: Maxime Ripard @ 2022-02-16 9:17 UTC (permalink / raw) To: Javier Martinez Canillas Cc: linux-kernel, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Noralf Trønnes, dri-devel, linux-fbdev, Sam Ravnborg, Rob Herring [-- Attachment #1: Type: text/plain, Size: 662 bytes --] On Mon, Feb 14, 2022 at 02:39:35PM +0100, Javier Martinez Canillas wrote: > The ssd130x DRM driver also makes use of this Device Tree binding to allow > existing users of the fbdev driver to migrate without the need to change > their Device Trees. > > Add myself as another maintainer of the binding, to make sure that I will > be on Cc when patches are proposed for it. > > Suggested-by: Sam Ravnborg <sam@ravnborg.org> > Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> > Acked-by: Rob Herring <robh@kernel.org> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Maxime Ripard <maxime@cerno.tech> Maxime [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 228 bytes --] ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas ` (5 preceding siblings ...) 2022-02-14 13:39 ` [PATCH v6 6/6] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer Javier Martinez Canillas @ 2022-02-16 12:34 ` Javier Martinez Canillas 6 siblings, 0 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-02-16 12:34 UTC (permalink / raw) To: linux-kernel Cc: linux-fbdev, Andy Shevchenko, Daniel Vetter, Geert Uytterhoeven, Thomas Zimmermann, Sam Ravnborg, dri-devel, Maxime Ripard, Noralf Trønnes, Daniel Vetter, David Airlie, Lee Jones, Maarten Lankhorst, Maxime Ripard, Rob Herring, Thierry Reding, Uwe Kleine-König, devicetree, linux-pwm On 2/14/22 14:37, Javier Martinez Canillas wrote: > This patch series adds a DRM driver for the Solomon OLED SSD1305, SSD1306, > SSD1307 and SSD1309 displays. It is a port of the ssd1307fb fbdev driver. > > Using the DRM fbdev emulation, all the tests from Geert Uytterhoeven repo > (https://git.kernel.org/pub/scm/linux/kernel/git/geert/fbtest.git) passes. > > I've also tested it using the display as a VT output and even though fbcon > seems to work, it is mostly unusable on a 128x64 SSD1306 display. > > This is a v6 that addresses the issues pointed in v5. Thanks a lot to all > reviewers that gave me feedback and comments. > Pushed this series to drm-misc (drm-misc-next). Thanks all! Best regards, -- Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays @ 2022-03-10 13:11 Dominik Kierner 2022-05-25 19:46 ` Javier Martinez Canillas 0 siblings, 1 reply; 30+ messages in thread From: Dominik Kierner @ 2022-03-10 13:11 UTC (permalink / raw) To: javierm Cc: airlied, andriy.shevchenko, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig Hello Javier, I was working on a SSD130x driver as well, although with a different (drm_panel) approach and hit a bit of a roadblock. Now that Your driver is quite a bit maturer than mine, I will happily provide You with the source of my draft, so that any useful bits can be incorporated in Your driver. I know that links are a bit frowned upon, but I'd rather avoid cluttering the thread with my draft code, which is unfinished and incompatible with the code in this thread. https://github.com/dh-electronics/panel-solomon-ssd130x-draft https://github.com/dh-electronics/panel-solomon-ssd130x-draft/tree/drm-ssd130x/drivers/gpu/drm/panel The code was designed as a rewrite from scratch, as I assumed that a new DRM driver that accommodates for I2C, 3- and 4-wire-SPI, will probably need a new DTS interface for differentiating the protocol-specific drivers, which would obviously break compatibility. I do have few suggestions though: # Atomic Configuration of Display Driving Regulator and the Charge Pump The regulator VBAT is the SSD1306-specific low-voltage (3.3 V to 5 V) regulator for the charge pump and takes the place of the voltage regulator VCC, that would otherwise supply the OLED driver block with 7 V to 15 V. The charge pump is never enabled when a VCC with 7 V to 15 V is present. Configuring the charge pump based on the available regulators, would provide an atomic configuration for either low-voltage + charge pump or the regular voltage. This way, the device tree boolean for enabling the charge pump could be removed by probing for an optional VBAT first, which replaces VCC, and falling back to a mandatory VCC otherwise: ``` [...] struct ssd130x_panel { ... struct regulator *vdd; /* Core logic supply */ union { struct regulator *vcc; /* Panel driving supply */ struct regulator *vbat; /* Charge pump regulator supply */ }; struct backlight_device *backlight; struct { unsigned int com_scan_dir_inv : 1; unsigned int com_seq_pin_cfg : 1; unsigned int com_lr_remap : 1; unsigned int seg_remap : 1; unsigned int inverse_display : 1; unsigned int use_charge_pump : 1; uint8_t height; uint8_t width; uint8_t height_mm; uint8_t width_mm; uint8_t display_start_line; uint8_t com_offset ; uint8_t contrast; uint8_t pre_charge_period_dclocks_phase1; uint8_t pre_charge_period_dclocks_phase2; uint8_t vcomh_deselect_level; uint8_t clock_divide_ratio; uint8_t oscillator_frequency; } display_settings; bool prepared; bool enabled; [...] ssd130x->vbat = devm_regulator_get_optional(dev, "vbat"); if (IS_ERR(ssd130x->vbat)) { ret = PTR_ERR(ssd130x->vbat); if (ret != -ENODEV) { if (ret != -EPROBE_DEFER) dev_err(dev, "failed to request regulator: %d\n", ret); return ret; } ssd130x->vbat = NULL; } else { ssd130x->display_settings.use_charge_pump = true; } /* Get panel driving supply */ If (!ssd130x->vbat) { ssd130x->vcc = devm_regulator_get(dev, "vcc"); if (IS_ERR(ssd130x->vcc)){ ret = PTR_ERR(ssd130x->vcc); return ret; } else { ssd130x->display_settings.use_charge_pump = false; } } ``` Splitting in VCC/VBAT and VDD and enforcing their presence is of course compatibility breaking. https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm-ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.h#L85 https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm-ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.c#L80 # Static or Dynamic Configuration for SPI-Modes 3-Wire and 4-Wire For the SPI-protocol drivers I see two possible approaches: * Dynamic configuration by determining the presence/absence of the D/C-GPIO and assigning the functions accordingly. This way a single driver file for both SPI modes could be sufficient. * Static configuration by using the device-tree names (ssd130x-spi-3wire/-4wire) to differentiate between the SPI protocol drivers. This would obviously necessitate two drivers files. Which one do you think would be the best approach for this? # DRM Mode Configuration via Device Tree In the old fbdev driver, the display modes are hard-coded, which means for every new display configuration, a new patch needs to be mainlined, which slows down official Kernel support and puts burden on the maintainers. Additionally, with the DRM-subsystem supporting height and length information, for scaling, this opens up a lot of new combinations. The SSD1306 for example, is available in multiple resolutions like 128x64 and 96x16 and comes in different sizes per resolution as well. Just to name a few: * 128x64 0.96" (22x11mm) * 128x64 1.3" (30x15mm) * 96x16 0.69" (18x3mm) Instead of hard-coding, I would suggest something along the lines of of_get_drm_display_mode(). The displays won't need to support multiple modes at the same time, let alone support for switching between them, so the one-time invocation of this expensive function might be worth it. maybe a new and simpler function that could be named: of_get_drm_display_mode_simple() Providing a mode could later prove useful for a conversion to drm_panel, if that is feasible. But for a function like this, I have to chicken out. # DRM Panel The reason why I decided for the drm_panel approach in my code, was power management and a clean handling of the software backlight dependency, which requires powered display regulators to be powered. Prepare/unprepare would power on/off the display logic regulator VDD. Enable/disable would power on/off VCC/VBAT, optionally turn on/off the charge pump and send the DISPLAY_ON/OFF commands. The SSD1305's PWM part would likely be placed in enable/disable as well. What is Your opinion on using drm_panel for Your driver? Mit freundlichen Grüßen / Best regards Dominik Kierner Student Employee Research & Development DH electronics ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-03-10 13:11 [PATCH v6 3/6] " Dominik Kierner @ 2022-05-25 19:46 ` Javier Martinez Canillas 2022-06-01 16:58 ` andriy.shevchenko 0 siblings, 1 reply; 30+ messages in thread From: Javier Martinez Canillas @ 2022-05-25 19:46 UTC (permalink / raw) To: Dominik Kierner Cc: airlied, andriy.shevchenko, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig Hello Dominik, I missed this email before and never answered. Sorry about that. On 3/10/22 14:11, Dominik Kierner wrote: > Hello Javier, > > I was working on a SSD130x driver as well, although with a different > (drm_panel) approach and hit a bit of a roadblock. My first attempt also was using a panel driver but then decided that it didn't fit that well and a standalone DRM driver would be a better option. > Now that Your driver is quite a bit maturer than mine, > I will happily provide You with the source of my draft, > so that any useful bits can be incorporated in Your driver. > I know that links are a bit frowned upon, > but I'd rather avoid cluttering the thread with my draft code, > which is unfinished and incompatible with the code in this thread. > > https://github.com/dh-electronics/panel-solomon-ssd130x-draft > https://github.com/dh-electronics/panel-solomon-ssd130x-draft/tree/drm-ssd130x/drivers/gpu/drm/panel > Thanks, I looked at the code briefly and think that there are things there that we could use. I.e the 3-wire SPI support that's in panel-solomon-ssd130x-spi-3wire.c. > The code was designed as a rewrite from scratch, as I assumed that a new > DRM driver that accommodates for I2C, 3- and 4-wire-SPI, > will probably need a new DTS interface for differentiating the > protocol-specific drivers, which would obviously break compatibility. > I wondered this too but then the drivers/staging/fbtft/fb_ssd1306.c supports both both 4-wire/8-bit shift register and 3-wire/9-bits shift register SPI transports. The driver does this by using a "buswidth" DT property to figure out which mode is used. Since 4-wire seems to be the most common case and (at least with all the SPI OLED displays I could find) one need to do some hardware modifications to support the 3-wire SPI mode, I decided to just support 4-wire in the ssd130x-spi.c that is going to be in v5.19. > I do have few suggestions though: > > # Atomic Configuration of Display Driving Regulator and the Charge Pump > > The regulator VBAT is the SSD1306-specific low-voltage (3.3 V to 5 V) > regulator for the charge pump and takes the place of the voltage > regulator VCC, that would otherwise supply the OLED driver block with > 7 V to 15 V. > The charge pump is never enabled when a VCC with 7 V to 15 V is present. > Configuring the charge pump based on the available regulators, > would provide an atomic configuration for either low-voltage + > charge pump or the regular voltage. > Ah I see, I didn't notice this when reading the ssd1306 datasheet. > This way, the device tree boolean for enabling the charge pump could be > removed by probing for an optional VBAT first, which replaces VCC, > and falling back to a mandatory VCC otherwise: > Interesting, this makes sense to me. > ``` > [...] > struct ssd130x_panel { > ... > struct regulator *vdd; /* Core logic supply */ > union { > struct regulator *vcc; /* Panel driving supply */ > struct regulator *vbat; /* Charge pump regulator supply */ > }; > struct backlight_device *backlight; > struct { > unsigned int com_scan_dir_inv : 1; > unsigned int com_seq_pin_cfg : 1; > unsigned int com_lr_remap : 1; > unsigned int seg_remap : 1; > unsigned int inverse_display : 1; > unsigned int use_charge_pump : 1; > uint8_t height; > uint8_t width; > uint8_t height_mm; > uint8_t width_mm; > uint8_t display_start_line; > uint8_t com_offset ; > uint8_t contrast; > uint8_t pre_charge_period_dclocks_phase1; > uint8_t pre_charge_period_dclocks_phase2; > uint8_t vcomh_deselect_level; > uint8_t clock_divide_ratio; > uint8_t oscillator_frequency; > } display_settings; > bool prepared; > bool enabled; > > [...] > > ssd130x->vbat = devm_regulator_get_optional(dev, "vbat"); > if (IS_ERR(ssd130x->vbat)) { > ret = PTR_ERR(ssd130x->vbat); > > if (ret != -ENODEV) { > if (ret != -EPROBE_DEFER) > dev_err(dev, > "failed to request regulator: %d\n", > ret); > return ret; > } > > ssd130x->vbat = NULL; > } > else { > ssd130x->display_settings.use_charge_pump = true; > } > > /* Get panel driving supply */ > If (!ssd130x->vbat) { > ssd130x->vcc = devm_regulator_get(dev, "vcc"); > if (IS_ERR(ssd130x->vcc)){ > ret = PTR_ERR(ssd130x->vcc); > return ret; > } > else { > ssd130x->display_settings.use_charge_pump = false; > } > } > ``` > > Splitting in VCC/VBAT and VDD and enforcing their presence is > of course compatibility breaking. > > https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm-ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.h#L85 > https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm-ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.c#L80 > It is a break in the DT binding indeed but on the other hand it seems that the regulator story is lacking in the current solomon,ssd1307fb.yaml anyways. That is, the binding schema only mentions a "vbat-supply" but the DRM driver is not looking for that but instead for "vcc-supply" (I think that was changed due some feedback I got on some revisions, but didn't update the DT binding). The fbdev drivers/video/fbdev/ssd1307fb.c driver does lookup "vbat-supply" but all the DTS and DTS overlays I find don't set one. Also the "vbat-supply" is not a required property in the current binding. One thing to notice is that regulator_get() and regulator_get_optional() semantics are confusing (at least for me). Since doesn't mean whether the regulator must be present or not but rather if a dummy regulator must be provided if a supply is not found. In other words, I don't think that any of these supplies should be made required in the DT binding but just leave the current "vbat-supply" and add properties for "vcc-supply" and explain the relationship between these and just make the logic in the driver to override struct ssd130x_deviceinfo .need_chargepump if are present. > > # Static or Dynamic Configuration for SPI-Modes 3-Wire and 4-Wire > > For the SPI-protocol drivers I see two possible approaches: > * Dynamic configuration by determining the presence/absence of the > D/C-GPIO and assigning the functions accordingly. > This way a single driver file for both SPI modes could be sufficient. > * Static configuration by using the device-tree names > (ssd130x-spi-3wire/-4wire) to differentiate between the SPI protocol > drivers. > This would obviously necessitate two drivers files. > > Which one do you think would be the best approach for this? > I think that prefer the first approach. As mentioned the staging driver has a "buswidth" property but as you said we could just use the "dc-gpios" presence as indication on whether is a 4-wire or 3-wire SPI mode. > > # DRM Mode Configuration via Device Tree > > In the old fbdev driver, the display modes are hard-coded, which means > for every new display configuration, a new patch needs to be mainlined, > which slows down official Kernel support and > puts burden on the maintainers. > Additionally, with the DRM-subsystem supporting height and length > information, for scaling, this opens up a lot of new combinations. > The SSD1306 for example, is available in multiple resolutions like > 128x64 and 96x16 and comes in different sizes per resolution as well. > Just to name a few: > * 128x64 0.96" (22x11mm) > * 128x64 1.3" (30x15mm) > * 96x16 0.69" (18x3mm) >> Instead of hard-coding, I would suggest something along the lines of > of_get_drm_display_mode(). > The displays won't need to support multiple modes at the same time, > let alone support for switching between them, > so the one-time invocation of this expensive function might be worth it. > maybe a new and simpler function that could be named: > of_get_drm_display_mode_simple() > This makes sense to me as well. > Providing a mode could later prove useful for a conversion to > drm_panel, if that is feasible. > > But for a function like this, I have to chicken out. > > > # DRM Panel > > The reason why I decided for the drm_panel approach in my code, > was power management and a clean handling of the software backlight > dependency, which requires powered display regulators to be powered. > > Prepare/unprepare would power on/off the display logic regulator VDD. > > Enable/disable would power on/off VCC/VBAT, optionally turn on/off > the charge pump and send the DISPLAY_ON/OFF commands. Yes, that's the reason why I started with a drm_panel driver as well. > The SSD1305's PWM part would likely be placed in enable/disable as well. > > What is Your opinion on using drm_panel for Your driver? > I can't remember exactly why I decided to stop using drm_panel, but I think that was because struct drm_panel doesn't have a DRM device and so couldn't use any of the helper functions that needed one? At the end I found that having a standalone DRM driver and using the simple display pipeline infrastructure was a much better way to implement it. -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-05-25 19:46 ` Javier Martinez Canillas @ 2022-06-01 16:58 ` andriy.shevchenko 0 siblings, 0 replies; 30+ messages in thread From: andriy.shevchenko @ 2022-06-01 16:58 UTC (permalink / raw) To: Javier Martinez Canillas Cc: Dominik Kierner, airlied, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig On Wed, May 25, 2022 at 09:46:24PM +0200, Javier Martinez Canillas wrote: > On 3/10/22 14:11, Dominik Kierner wrote: ... > > # DRM Mode Configuration via Device Tree > > > > In the old fbdev driver, the display modes are hard-coded, which means > > for every new display configuration, a new patch needs to be mainlined, > > which slows down official Kernel support and > > puts burden on the maintainers. > > Additionally, with the DRM-subsystem supporting height and length > > information, for scaling, this opens up a lot of new combinations. > > The SSD1306 for example, is available in multiple resolutions like > > 128x64 and 96x16 and comes in different sizes per resolution as well. > > Just to name a few: > > * 128x64 0.96" (22x11mm) > > * 128x64 1.3" (30x15mm) > > * 96x16 0.69" (18x3mm) > >> Instead of hard-coding, I would suggest something along the lines of > > of_get_drm_display_mode(). > > The displays won't need to support multiple modes at the same time, > > let alone support for switching between them, > > so the one-time invocation of this expensive function might be worth it. > > maybe a new and simpler function that could be named: > > of_get_drm_display_mode_simple() > > This makes sense to me as well. What about non-OF platforms? Please, do not spread OF-only interfaces, and use fwnode instead. > > Providing a mode could later prove useful for a conversion to > > drm_panel, if that is feasible. > > > > But for a function like this, I have to chicken out. -- With Best Regards, Andy Shevchenko ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays @ 2022-06-13 11:39 Dominik Kierner 2022-06-13 15:35 ` andriy.shevchenko 2022-06-13 18:17 ` Javier Martinez Canillas 0 siblings, 2 replies; 30+ messages in thread From: Dominik Kierner @ 2022-06-13 11:39 UTC (permalink / raw) To: Javier Martinez Canillas Cc: airlied, andriy.shevchenko, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig Hello Javier, On 5/25/2022 21:46, Javier Martinez Canillas wrote: > > Now that Your driver is quite a bit maturer than mine, I will happily > > provide You with the source of my draft, so that any useful bits can > > be incorporated in Your driver. > > I know that links are a bit frowned upon, but I'd rather avoid > > cluttering the thread with my draft code, which is unfinished and > > incompatible with the code in this thread. > > > > https://github.com/dh-electronics/panel-solomon-ssd130x-draft > > https://github.com/dh-electronics/panel-solomon-ssd130x-draft/tree/drm-ssd130x/drivers/gpu/drm/panel > > > > Thanks, I looked at the code briefly and think that there are things there that we > could use. I.e the 3-wire SPI support that's in panel-solomon-ssd130x-spi-3wire.c. When writing my driver code, I wasn't even considering using regmaps, like You did in Your I2C-Code. If that's applicable for 3-wire-SPI, it would likely be the better, more generic option. Your SPI-code reuses these parts to some extent. For that case, ssd130x_spi_regmap_config.reg_bits would need be changed to 1, as the "register address" has a length of 1 bit and we are sending 9 bits over the line and not 16. Since we still have 2 bytes of host memory, it should still be compatible with the 4-wire write, right? Or would 3-wire SPI require a second regmap? > > Splitting in VCC/VBAT and VDD and enforcing their presence is of > > course compatibility breaking. > > > > https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm > > -ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.h#L85 > > https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm > > -ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.c#L80 > > > > It is a break in the DT binding indeed but on the other hand it seems that the > regulator story is lacking in the current solomon,ssd1307fb.yaml anyways. > > That is, the binding schema only mentions a "vbat-supply" but the DRM driver is not > looking for that but instead for "vcc-supply" (I think that was changed due some > feedback I got on some revisions, but didn't update the DT binding). The fbdev > drivers/video/fbdev/ssd1307fb.c driver does lookup "vbat-supply" but all the DTS and > DTS overlays I find don't set one. > > Also the "vbat-supply" is not a required property in the current binding. One thing to > notice is that regulator_get() and regulator_get_optional() semantics are confusing > (at least for me). Since doesn't mean whether the regulator must be present or not > but rather if a dummy regulator must be provided if a supply is not found. I always understood regulator_get_optional() as a way of not having to rely on a dummy, when a regulator is not present, but please correct me, if I am wrong on this. The dummies would only be necessary for the mandatory supplies VCC and VDD. You mean this part of the documentation of regulator_get_optional(), correct?: > * This is intended for use by consumers for devices which can have > * some supplies unconnected in normal use, such as some MMC devices. > * It can allow the regulator core to provide stub supplies for other > * supplies requested using normal regulator_get() calls without > * disrupting the operation of drivers that can handle absent > * supplies. > In other words, I don't think that any of these supplies should be made required in > the DT binding but just leave the current "vbat-supply" and add properties for "vcc- > supply" and explain the relationship between these and just make the logic in the > driver to override struct ssd130x_deviceinfo .need_chargepump if are present. My idea was to require these supplies, so that the binding correctly reflects the manuals. Driving supply VCC and logic supply VDD, are present throughout the SSD130x family. Only the VBAT supply is an optional SSD1306 specific and would therefore use an optional regulator. The only other device specific supply is the SSD1305's VDDIO supply, which is mandatory and seems to be commonly connected to VDD, so including that is likely unnecessary. I Just wanted to mention it for completeness. If the device isn't controllable by Linux, a dummy would be connected instead, just like the dummy regulator documentation states: > * This is useful for systems with mixed controllable and > * non-controllable regulators, as well as for allowing testing on > * systems with no controllable regulators. Which would be the case, with the SSD130x controllers. Sometimes they are connected to external, non-controllable regulators. I figured that the kernel developers might be more open to a compatibility breaking change, under the circumstance, that this is more or less a new driver for DRM, that it provides atomic charge pump configuration for the SSD1306 and that some (embedded) user space software might need to be rewritten to accommodate for the transition from fbdev to DRM anyway. But I might be wrong on this. > > # Static or Dynamic Configuration for SPI-Modes 3-Wire and 4-Wire > > > > For the SPI-protocol drivers I see two possible approaches: > > * Dynamic configuration by determining the presence/absence of the > > D/C-GPIO and assigning the functions accordingly. > > This way a single driver file for both SPI modes could be sufficient. > > * Static configuration by using the device-tree names > > (ssd130x-spi-3wire/-4wire) to differentiate between the SPI protocol > > drivers. > > This would obviously necessitate two drivers files. > > > > Which one do you think would be the best approach for this? > > > > I think that prefer the first approach. As mentioned the staging driver has a > "buswidth" property but as you said we could just use the "dc-gpios" presence as > indication on whether is a 4-wire or 3-wire SPI mode. You are correct, I do prefer the first approach. It would cut the additional file and code required for the second approach and eliminate an additional device tree name, that would have been necessary otherwise. > > What is Your opinion on using drm_panel for Your driver? > > > > I can't remember exactly why I decided to stop using drm_panel, but I think that > was because struct drm_panel doesn't have a DRM device and so couldn't use any of > the helper functions that needed one? I likely hit the same roadblock. I would say, this approach should be revisited, when appropriate helpers for this approach exist, as it would further clean up and generify the ssd130x device configuration. -- Best regards Dominik Kierner Research & Development DH electronics ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-06-13 11:39 Dominik Kierner @ 2022-06-13 15:35 ` andriy.shevchenko 2022-06-13 17:41 ` Javier Martinez Canillas 2022-06-13 18:17 ` Javier Martinez Canillas 1 sibling, 1 reply; 30+ messages in thread From: andriy.shevchenko @ 2022-06-13 15:35 UTC (permalink / raw) To: Dominik Kierner Cc: Javier Martinez Canillas, airlied, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig On Mon, Jun 13, 2022 at 11:39:30AM +0000, Dominik Kierner wrote: > On 5/25/2022 21:46, Javier Martinez Canillas wrote: ... > > Thanks, I looked at the code briefly and think that there are things there that we > > could use. I.e the 3-wire SPI support that's in panel-solomon-ssd130x-spi-3wire.c. > > When writing my driver code, I wasn't even considering using regmaps, > like You did in Your I2C-Code. If that's applicable for 3-wire-SPI, > it would likely be the better, more generic option. Your SPI-code > reuses these parts to some extent. For that case, > ssd130x_spi_regmap_config.reg_bits would need be changed to 1, > as the "register address" has a length of 1 bit and we are sending > 9 bits over the line and not 16. > Since we still have 2 bytes of host memory, > it should still be compatible with the 4-wire write, right? > Or would 3-wire SPI require a second regmap? I believe the cleanest solution is to have different regmap configurations. -- With Best Regards, Andy Shevchenko ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-06-13 15:35 ` andriy.shevchenko @ 2022-06-13 17:41 ` Javier Martinez Canillas 0 siblings, 0 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-06-13 17:41 UTC (permalink / raw) To: andriy.shevchenko, Dominik Kierner Cc: airlied, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig On 6/13/22 17:35, andriy.shevchenko@linux.intel.com wrote: > On Mon, Jun 13, 2022 at 11:39:30AM +0000, Dominik Kierner wrote: >> On 5/25/2022 21:46, Javier Martinez Canillas wrote: > > ... > >>> Thanks, I looked at the code briefly and think that there are things there that we >>> could use. I.e the 3-wire SPI support that's in panel-solomon-ssd130x-spi-3wire.c. >> >> When writing my driver code, I wasn't even considering using regmaps, >> like You did in Your I2C-Code. If that's applicable for 3-wire-SPI, >> it would likely be the better, more generic option. Your SPI-code >> reuses these parts to some extent. For that case, >> ssd130x_spi_regmap_config.reg_bits would need be changed to 1, >> as the "register address" has a length of 1 bit and we are sending >> 9 bits over the line and not 16. >> Since we still have 2 bytes of host memory, >> it should still be compatible with the 4-wire write, right? >> Or would 3-wire SPI require a second regmap? > > I believe the cleanest solution is to have different regmap configurations. > I agree with this. -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays 2022-06-13 11:39 Dominik Kierner 2022-06-13 15:35 ` andriy.shevchenko @ 2022-06-13 18:17 ` Javier Martinez Canillas 1 sibling, 0 replies; 30+ messages in thread From: Javier Martinez Canillas @ 2022-06-13 18:17 UTC (permalink / raw) To: Dominik Kierner Cc: airlied, andriy.shevchenko, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig Hello Dominik, On 6/13/22 13:39, Dominik Kierner wrote: Removed the regmap part since Andy already commented and I agree with him. >>> Splitting in VCC/VBAT and VDD and enforcing their presence is of >>> course compatibility breaking. >>> >>> https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm >>> -ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.h#L85 >>> https://github.com/dh-electronics/panel-solomon-ssd130x-draft/blob/drm >>> -ssd130x/drivers/gpu/drm/panel/panel-solomon-ssd130x.c#L80 >>> >> >> It is a break in the DT binding indeed but on the other hand it seems that the >> regulator story is lacking in the current solomon,ssd1307fb.yaml anyways. >> >> That is, the binding schema only mentions a "vbat-supply" but the DRM driver is not >> looking for that but instead for "vcc-supply" (I think that was changed due some >> feedback I got on some revisions, but didn't update the DT binding). The fbdev >> drivers/video/fbdev/ssd1307fb.c driver does lookup "vbat-supply" but all the DTS and >> DTS overlays I find don't set one. >> >> Also the "vbat-supply" is not a required property in the current binding. One thing to >> notice is that regulator_get() and regulator_get_optional() semantics are confusing >> (at least for me). Since doesn't mean whether the regulator must be present or not >> but rather if a dummy regulator must be provided if a supply is not found. > > I always understood regulator_get_optional() as a way of not having to rely on a dummy, > when a regulator is not present, but please correct me, if I am wrong on this. > The dummies would only be necessary for the mandatory supplies VCC and VDD. > Yes, that's what I tried to say. That's regulator_get() and not _optional() the function that will provide a dummy regulator if isn't physically present: https://elixir.bootlin.com/linux/latest/source/drivers/regulator/core.c#L2067 > You mean this part of the documentation of regulator_get_optional(), correct?: > >> * This is intended for use by consumers for devices which can have >> * some supplies unconnected in normal use, such as some MMC devices. >> * It can allow the regulator core to provide stub supplies for other >> * supplies requested using normal regulator_get() calls without >> * disrupting the operation of drivers that can handle absent >> * supplies. > > >> In other words, I don't think that any of these supplies should be made required in >> the DT binding but just leave the current "vbat-supply" and add properties for "vcc- >> supply" and explain the relationship between these and just make the logic in the >> driver to override struct ssd130x_deviceinfo .need_chargepump if are present. > > My idea was to require these supplies, so that the binding correctly > reflects the manuals. Driving supply VCC and logic supply VDD, are > present throughout the SSD130x family. Only the VBAT supply is an > optional SSD1306 specific and would therefore use an optional > regulator. > > The only other device specific supply is the SSD1305's VDDIO supply, > which is mandatory and seems to be commonly connected to VDD, > so including that is likely unnecessary. > I Just wanted to mention it for completeness. > > If the device isn't controllable by Linux, a dummy would be connected > instead, just like the dummy regulator documentation states: > >> * This is useful for systems with mixed controllable and >> * non-controllable regulators, as well as for allowing testing on >> * systems with no controllable regulators. > > Which would be the case, with the SSD130x controllers. > Sometimes they are connected to external, non-controllable regulators. > > I figured that the kernel developers might be more open to a compatibility > breaking change, under the circumstance, that this is more or less a new > driver for DRM, that it provides atomic charge pump configuration for the > SSD1306 and that some (embedded) user space software might need to be > rewritten to accommodate for the transition from fbdev to DRM anyway. > But I might be wrong on this. > So for example when you just use a voltage rail in let's say a board pin header then you will need to define supply nodes with compatible = "regulator-fixed" ? That is indeed more accurate from a hardware description point of view but I'm not convinced that this is something worth to break DT backward compatibility. You also mentioned (IIUC) that the regulators could be made optional and their presence be used as an indication that an atomic charge pump configuration can be made instead of using the current ssd130x->display_settings.use_charge_pump. I think that would prefer that the latter option, but will let others to chime in since maybe I'm not correct on the preferred approach. > >>> # Static or Dynamic Configuration for SPI-Modes 3-Wire and 4-Wire >>> >>> For the SPI-protocol drivers I see two possible approaches: >>> * Dynamic configuration by determining the presence/absence of the >>> D/C-GPIO and assigning the functions accordingly. >>> This way a single driver file for both SPI modes could be sufficient. >>> * Static configuration by using the device-tree names >>> (ssd130x-spi-3wire/-4wire) to differentiate between the SPI protocol >>> drivers. >>> This would obviously necessitate two drivers files. >>> >>> Which one do you think would be the best approach for this? >>> >> >> I think that prefer the first approach. As mentioned the staging driver has a >> "buswidth" property but as you said we could just use the "dc-gpios" presence as >> indication on whether is a 4-wire or 3-wire SPI mode. > > You are correct, I do prefer the first approach. > It would cut the additional file and code required for the second > approach and eliminate an additional device tree name, > that would have been necessary otherwise. > Great that we are on the same page here. > >>> What is Your opinion on using drm_panel for Your driver? >>> >> >> I can't remember exactly why I decided to stop using drm_panel, but I think that >> was because struct drm_panel doesn't have a DRM device and so couldn't use any of >> the helper functions that needed one? > > I likely hit the same roadblock. > I would say, this approach should be revisited, when appropriate > helpers for this approach exist, as it would further clean up and > generify the ssd130x device configuration. > It's unlikely that drm_panel will get a drm_device since that was the case but was changed by commit aa6c43644bc5 ("drm/panel: drop drm_device from drm_panel"). But yes, I agree that we could revisit if there are helpers in the future to manage a backlight device that is handled by a DRM driver. -- Best regards, Javier Martinez Canillas Linux Engineering Red Hat ^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays @ 2022-06-14 14:05 Dominik Kierner 0 siblings, 0 replies; 30+ messages in thread From: Dominik Kierner @ 2022-06-14 14:05 UTC (permalink / raw) To: Javier Martinez Canillas Cc: airlied, andriy.shevchenko, daniel.vetter, dri-devel, geert, lee.jones, linux-fbdev, linux-kernel, linux-pwm, maxime, noralf, sam, thierry.reding, tzimmermann, u.kleine-koenig Hello Javier On 6/14/22 13:39, Javier Martinez Canillas wrote: > > I always understood regulator_get_optional() as a way of not having to rely on a dummy, > > when a regulator is not present, but please correct me, if I am wrong on this. > > The dummies would only be necessary for the mandatory supplies VCC and VDD. > > > > Yes, that's what I tried to say. That's regulator_get() and not _optional() > the function that will provide a dummy regulator if isn't physically present: > > https://elixir.bootlin.com/linux/latest/source/drivers/regulator/core.c#L2067 > > > You mean this part of the documentation of regulator_get_optional(), correct?: > > > >> * This is intended for use by consumers for devices which can have > >> * some supplies unconnected in normal use, such as some MMC devices. > >> * It can allow the regulator core to provide stub supplies for other > >> * supplies requested using normal regulator_get() calls without > >> * disrupting the operation of drivers that can handle absent > >> * supplies. > > > > > So for example when you just use a voltage rail in let's say a board pin header > then you will need to define supply nodes with compatible = "regulator- > fixed" ? Exactly. > That is indeed more accurate from a hardware description point of view but I'm > not convinced that this is something worth to break DT backward compatibility. > You also mentioned (IIUC) that the regulators could be made optional and their > presence be used as an indication that an atomic charge pump configuration can > be made instead of using the current ssd130x->display_settings.use_charge_pump. > > I think that would prefer that the latter option, but will let others to chime > in since maybe I'm not correct on the preferred approach. Yes, here the reference for the former approach: Chapter 2 "Charge Pump Regulator" on Page 62 of the SSD1306 datasheet: https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf Just a TL;DR of the former approach for easier discussion: The logic supply VDD would always be mandatory. The low voltage supply VBAT would be optional and probed first. If found, it would supersede the "high" voltage driving supply VCC and the charge pump would be enabled. If VBAT is not found, then VCC is mandatory and the charge pump will not be enabled. -- Best regards Dominik Kierner Research & Development DH electronics ^ permalink raw reply [flat|nested] 30+ messages in thread
end of thread, other threads:[~2022-06-14 14:31 UTC | newest] Thread overview: 30+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-02-14 13:37 [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 1/6] drm/format-helper: Add drm_fb_xrgb8888_to_gray8_line() Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard 2022-02-14 13:37 ` [PATCH v6 2/6] drm/format-helper: Add drm_fb_xrgb8888_to_mono_reversed() Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard 2022-03-08 16:13 ` Geert Uytterhoeven 2022-03-09 12:03 ` Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 3/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-02-16 9:16 ` Maxime Ripard 2022-03-08 16:30 ` Geert Uytterhoeven 2022-03-09 12:14 ` Javier Martinez Canillas 2022-03-09 12:56 ` Geert Uytterhoeven 2022-03-09 13:43 ` Javier Martinez Canillas 2022-03-09 20:04 ` Geert Uytterhoeven 2022-03-09 20:13 ` Javier Martinez Canillas 2022-02-14 13:37 ` [PATCH v6 4/6] drm/solomon: Add SSD130x OLED displays I2C support Javier Martinez Canillas 2022-02-16 9:17 ` Maxime Ripard 2022-02-14 13:39 ` [PATCH v6 5/6] MAINTAINERS: Add entry for Solomon SSD130x OLED displays DRM driver Javier Martinez Canillas 2022-02-16 9:17 ` Maxime Ripard 2022-02-14 13:39 ` [PATCH v6 6/6] dt-bindings: display: ssd1307fb: Add myself as binding co-maintainer Javier Martinez Canillas 2022-02-16 9:17 ` Maxime Ripard 2022-02-16 12:34 ` [PATCH v6 0/6] drm: Add driver for Solomon SSD130x OLED displays Javier Martinez Canillas 2022-03-10 13:11 [PATCH v6 3/6] " Dominik Kierner 2022-05-25 19:46 ` Javier Martinez Canillas 2022-06-01 16:58 ` andriy.shevchenko 2022-06-13 11:39 Dominik Kierner 2022-06-13 15:35 ` andriy.shevchenko 2022-06-13 17:41 ` Javier Martinez Canillas 2022-06-13 18:17 ` Javier Martinez Canillas 2022-06-14 14:05 Dominik Kierner
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