* [PATCH 1/5] video: fbdev: ssd1307fb: Propagate errors via ssd1307fb_update_display()
2021-05-18 8:28 [PATCH 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Geert Uytterhoeven
@ 2021-05-18 8:28 ` Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 2/5] video: fbdev: ssd1307fb: Simplify ssd1307fb_update_display() Geert Uytterhoeven
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2021-05-18 8:28 UTC (permalink / raw)
To: Maxime Ripard, David Airlie, Daniel Vetter
Cc: linux-fbdev, dri-devel, linux-kernel, Geert Uytterhoeven
Make ssd1307fb_update_display() return an error code, so callers that
can handle failures can propagate it.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/fbdev/ssd1307fb.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index eda448b7a0c9d8ce..e6b6263e3bef847f 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -152,17 +152,17 @@ static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
return ret;
}
-static void ssd1307fb_update_display(struct ssd1307fb_par *par)
+static int ssd1307fb_update_display(struct ssd1307fb_par *par)
{
struct ssd1307fb_array *array;
u8 *vmem = par->info->screen_buffer;
unsigned int line_length = par->info->fix.line_length;
unsigned int pages = DIV_ROUND_UP(par->height, 8);
- int i, j, k;
+ int ret, i, j, k;
array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
if (!array)
- return;
+ return -ENOMEM;
/*
* The screen is divided in pages, each having a height of 8
@@ -210,8 +210,9 @@ static void ssd1307fb_update_display(struct ssd1307fb_par *par)
}
}
- ssd1307fb_write_array(par->client, array, par->width * pages);
+ ret = ssd1307fb_write_array(par->client, array, par->width * pages);
kfree(array);
+ return ret;
}
@@ -222,6 +223,7 @@ static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
unsigned long total_size;
unsigned long p = *ppos;
void *dst;
+ int ret;
total_size = info->fix.smem_len;
@@ -239,7 +241,9 @@ static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
if (copy_from_user(dst, buf, count))
return -EFAULT;
- ssd1307fb_update_display(par);
+ ret = ssd1307fb_update_display(par);
+ if (ret < 0)
+ return ret;
*ppos += count;
@@ -483,7 +487,9 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
return ret;
/* Clear the screen */
- ssd1307fb_update_display(par);
+ ret = ssd1307fb_update_display(par);
+ if (ret < 0)
+ return ret;
/* Turn on the display */
ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/5] video: fbdev: ssd1307fb: Simplify ssd1307fb_update_display()
2021-05-18 8:28 [PATCH 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 1/5] video: fbdev: ssd1307fb: Propagate errors via ssd1307fb_update_display() Geert Uytterhoeven
@ 2021-05-18 8:28 ` Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 3/5] video: fbdev: ssd1307fb: Extract ssd1307fb_set_address_range() Geert Uytterhoeven
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2021-05-18 8:28 UTC (permalink / raw)
To: Maxime Ripard, David Airlie, Daniel Vetter
Cc: linux-fbdev, dri-devel, linux-kernel, Geert Uytterhoeven
Simplify the nested loops to handle conversion from linear frame buffer
to ssd1307 page layout:
1. Move last page handling one level up, as the value of "m" is the
same inside a page,
2. array->data[] is filled linearly, so there is no need to
recalculate array_idx over and over again; a simple increment is
sufficient.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/fbdev/ssd1307fb.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index e6b6263e3bef847f..6d7bd025bca1a175 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -158,6 +158,7 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par)
u8 *vmem = par->info->screen_buffer;
unsigned int line_length = par->info->fix.line_length;
unsigned int pages = DIV_ROUND_UP(par->height, 8);
+ u32 array_idx = 0;
int ret, i, j, k;
array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
@@ -194,19 +195,21 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par)
*/
for (i = 0; i < pages; i++) {
+ int m = 8;
+
+ /* Last page may be partial */
+ if (i + 1 == pages && par->height % 8)
+ m = par->height % 8;
for (j = 0; j < par->width; j++) {
- int m = 8;
- u32 array_idx = i * par->width + j;
- array->data[array_idx] = 0;
- /* Last page may be partial */
- if (i + 1 == pages && par->height % 8)
- m = par->height % 8;
+ u8 data = 0;
+
for (k = 0; k < m; k++) {
u8 byte = vmem[(8 * i + k) * line_length +
j / 8];
u8 bit = (byte >> (j % 8)) & 1;
- array->data[array_idx] |= bit << k;
+ data |= bit << k;
}
+ array->data[array_idx++] = data;
}
}
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/5] video: fbdev: ssd1307fb: Extract ssd1307fb_set_address_range()
2021-05-18 8:28 [PATCH 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 1/5] video: fbdev: ssd1307fb: Propagate errors via ssd1307fb_update_display() Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 2/5] video: fbdev: ssd1307fb: Simplify ssd1307fb_update_display() Geert Uytterhoeven
@ 2021-05-18 8:28 ` Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 4/5] video: fbdev: ssd1307fb: Optimize screen updates Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 5/5] video: fbdev: ssd1307fb: Cache address ranges Geert Uytterhoeven
4 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2021-05-18 8:28 UTC (permalink / raw)
To: Maxime Ripard, David Airlie, Daniel Vetter
Cc: linux-fbdev, dri-devel, linux-kernel, Geert Uytterhoeven
Extract the code to set the column and page ranges into a helper
function.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/fbdev/ssd1307fb.c | 61 +++++++++++++++++++--------------
1 file changed, 36 insertions(+), 25 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 6d7bd025bca1a175..cfa27ea0feab4f01 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -152,6 +152,38 @@ static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
return ret;
}
+static int ssd1307fb_set_address_range(struct ssd1307fb_par *par, u8 col_start,
+ u8 cols, u8 page_start, u8 pages)
+{
+ u8 col_end = col_start + cols - 1;
+ u8 page_end = page_start + pages - 1;
+ int ret;
+
+ /* Set column range */
+ ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, col_start);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, col_end);
+ if (ret < 0)
+ return ret;
+
+ /* Set page range */
+ ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, page_start);
+ if (ret < 0)
+ return ret;
+
+ return ssd1307fb_write_cmd(par->client, page_end);
+}
+
static int ssd1307fb_update_display(struct ssd1307fb_par *par)
{
struct ssd1307fb_array *array;
@@ -461,31 +493,10 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
if (ret < 0)
return ret;
- /* Set column range */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
- if (ret < 0)
- return ret;
-
- ret = ssd1307fb_write_cmd(par->client, par->col_offset);
- if (ret < 0)
- return ret;
-
- ret = ssd1307fb_write_cmd(par->client, par->col_offset + par->width - 1);
- if (ret < 0)
- return ret;
-
- /* Set page range */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
- if (ret < 0)
- return ret;
-
- ret = ssd1307fb_write_cmd(par->client, par->page_offset);
- if (ret < 0)
- return ret;
-
- ret = ssd1307fb_write_cmd(par->client,
- par->page_offset +
- DIV_ROUND_UP(par->height, 8) - 1);
+ /* Set column and page range */
+ ret = ssd1307fb_set_address_range(par, par->col_offset, par->width,
+ par->page_offset,
+ DIV_ROUND_UP(par->height, 8));
if (ret < 0)
return ret;
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 4/5] video: fbdev: ssd1307fb: Optimize screen updates
2021-05-18 8:28 [PATCH 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Geert Uytterhoeven
` (2 preceding siblings ...)
2021-05-18 8:28 ` [PATCH 3/5] video: fbdev: ssd1307fb: Extract ssd1307fb_set_address_range() Geert Uytterhoeven
@ 2021-05-18 8:28 ` Geert Uytterhoeven
2021-05-18 8:28 ` [PATCH 5/5] video: fbdev: ssd1307fb: Cache address ranges Geert Uytterhoeven
4 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2021-05-18 8:28 UTC (permalink / raw)
To: Maxime Ripard, David Airlie, Daniel Vetter
Cc: linux-fbdev, dri-devel, linux-kernel, Geert Uytterhoeven
Currently, each screen update triggers an I2C transfer of all screen
data, up to 1 KiB of data for a 128x64 display, which takes at least 20
ms in Fast mode.
Reduce the amount of transferred data by only updating the rectangle
that changed. Remove the call to ssd1307fb_set_address_range() during
initialization, as ssd1307fb_update_rect() now takes care of that.
Note that for now the optimized operation is only used for fillrect,
copyarea, and imageblit, which are used by fbcon.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/fbdev/ssd1307fb.c | 43 ++++++++++++++++++++-------------
1 file changed, 26 insertions(+), 17 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index cfa27ea0feab4f01..8e3d4be74723b9bf 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -184,16 +184,18 @@ static int ssd1307fb_set_address_range(struct ssd1307fb_par *par, u8 col_start,
return ssd1307fb_write_cmd(par->client, page_end);
}
-static int ssd1307fb_update_display(struct ssd1307fb_par *par)
+static int ssd1307fb_update_rect(struct ssd1307fb_par *par, unsigned int x,
+ unsigned int y, unsigned int width,
+ unsigned int height)
{
struct ssd1307fb_array *array;
u8 *vmem = par->info->screen_buffer;
unsigned int line_length = par->info->fix.line_length;
- unsigned int pages = DIV_ROUND_UP(par->height, 8);
+ unsigned int pages = DIV_ROUND_UP(height + y % 8, 8);
u32 array_idx = 0;
int ret, i, j, k;
- array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
+ array = ssd1307fb_alloc_array(width * pages, SSD1307FB_DATA);
if (!array)
return -ENOMEM;
@@ -226,13 +228,18 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par)
* (5) A4 B4 C4 D4 E4 F4 G4 H4
*/
- for (i = 0; i < pages; i++) {
+ ret = ssd1307fb_set_address_range(par, par->col_offset + x, width,
+ par->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 (i + 1 == pages && par->height % 8)
+ if (8 * (i + 1) > par->height)
m = par->height % 8;
- for (j = 0; j < par->width; j++) {
+ for (j = x; j < x + width; j++) {
u8 data = 0;
for (k = 0; k < m; k++) {
@@ -245,11 +252,17 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par)
}
}
- ret = ssd1307fb_write_array(par->client, array, par->width * pages);
+ ret = ssd1307fb_write_array(par->client, array, width * pages);
+
+out_free:
kfree(array);
return ret;
}
+static int ssd1307fb_update_display(struct ssd1307fb_par *par)
+{
+ return ssd1307fb_update_rect(par, 0, 0, par->width, par->height);
+}
static ssize_t ssd1307fb_write(struct fb_info *info, const char __user *buf,
size_t count, loff_t *ppos)
@@ -299,21 +312,24 @@ static void ssd1307fb_fillrect(struct fb_info *info, const struct fb_fillrect *r
{
struct ssd1307fb_par *par = info->par;
sys_fillrect(info, rect);
- ssd1307fb_update_display(par);
+ ssd1307fb_update_rect(par, rect->dx, rect->dy, rect->width,
+ rect->height);
}
static void ssd1307fb_copyarea(struct fb_info *info, const struct fb_copyarea *area)
{
struct ssd1307fb_par *par = info->par;
sys_copyarea(info, area);
- ssd1307fb_update_display(par);
+ ssd1307fb_update_rect(par, area->dx, area->dy, area->width,
+ area->height);
}
static void ssd1307fb_imageblit(struct fb_info *info, const struct fb_image *image)
{
struct ssd1307fb_par *par = info->par;
sys_imageblit(info, image);
- ssd1307fb_update_display(par);
+ ssd1307fb_update_rect(par, image->dx, image->dy, image->width,
+ image->height);
}
static const struct fb_ops ssd1307fb_ops = {
@@ -493,13 +509,6 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
if (ret < 0)
return ret;
- /* Set column and page range */
- ret = ssd1307fb_set_address_range(par, par->col_offset, par->width,
- par->page_offset,
- DIV_ROUND_UP(par->height, 8));
- if (ret < 0)
- return ret;
-
/* Clear the screen */
ret = ssd1307fb_update_display(par);
if (ret < 0)
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 5/5] video: fbdev: ssd1307fb: Cache address ranges
2021-05-18 8:28 [PATCH 0/5] video: fbdev: ssd1307fb: Optimizations and improvements Geert Uytterhoeven
` (3 preceding siblings ...)
2021-05-18 8:28 ` [PATCH 4/5] video: fbdev: ssd1307fb: Optimize screen updates Geert Uytterhoeven
@ 2021-05-18 8:28 ` Geert Uytterhoeven
4 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2021-05-18 8:28 UTC (permalink / raw)
To: Maxime Ripard, David Airlie, Daniel Vetter
Cc: linux-fbdev, dri-devel, linux-kernel, Geert Uytterhoeven
Cache the column and page ranges, to avoid doing unneeded I2C transfers
when the values haven't changed.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/fbdev/ssd1307fb.c | 52 +++++++++++++++++++++++----------
1 file changed, 36 insertions(+), 16 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 8e3d4be74723b9bf..23b43ce479898813 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -82,6 +82,11 @@ struct ssd1307fb_par {
struct regulator *vbat_reg;
u32 vcomh;
u32 width;
+ /* Cached address ranges */
+ u8 col_start;
+ u8 col_end;
+ u8 page_start;
+ u8 page_end;
};
struct ssd1307fb_array {
@@ -160,28 +165,43 @@ static int ssd1307fb_set_address_range(struct ssd1307fb_par *par, u8 col_start,
int ret;
/* Set column range */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
- if (ret < 0)
- return ret;
+ if (col_start != par->col_start || col_end != par->col_end) {
+ ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
+ if (ret < 0)
+ return ret;
- ret = ssd1307fb_write_cmd(par->client, col_start);
- if (ret < 0)
- return ret;
+ ret = ssd1307fb_write_cmd(par->client, col_start);
+ if (ret < 0)
+ return ret;
- ret = ssd1307fb_write_cmd(par->client, col_end);
- if (ret < 0)
- return ret;
+ ret = ssd1307fb_write_cmd(par->client, col_end);
+ if (ret < 0)
+ return ret;
+
+ par->col_start = col_start;
+ par->col_end = col_end;
+ }
/* Set page range */
- ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
- if (ret < 0)
- return ret;
+ if (page_start != par->page_start || page_end != par->page_end) {
+ ret = ssd1307fb_write_cmd(par->client,
+ SSD1307FB_SET_PAGE_RANGE);
+ if (ret < 0)
+ return ret;
- ret = ssd1307fb_write_cmd(par->client, page_start);
- if (ret < 0)
- return ret;
+ ret = ssd1307fb_write_cmd(par->client, page_start);
+ if (ret < 0)
+ return ret;
+
+ ret = ssd1307fb_write_cmd(par->client, page_end);
+ if (ret < 0)
+ return ret;
- return ssd1307fb_write_cmd(par->client, page_end);
+ par->page_start = page_start;
+ par->page_end = page_end;
+ }
+
+ return 0;
}
static int ssd1307fb_update_rect(struct ssd1307fb_par *par, unsigned int x,
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread