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author | Marko Kohtala <marko.kohtala@okoko.fi> | 2019-06-18 10:41:09 +0300 |
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committer | Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> | 2019-07-23 17:18:19 +0200 |
commit | b0020d8af991a904de57dbd9a7bc7a61982a6a8c (patch) | |
tree | 8644811d4e2be773dcb84185f3c84e0053be198b /drivers/video | |
parent | dd9782834dd9dde3624ff1acea8859f3d3e792d4 (diff) | |
download | linux-b0020d8af991a904de57dbd9a7bc7a61982a6a8c.tar.gz linux-b0020d8af991a904de57dbd9a7bc7a61982a6a8c.tar.bz2 linux-b0020d8af991a904de57dbd9a7bc7a61982a6a8c.zip |
video: ssd1307fb: Handle width and height that are not multiple of 8
Some displays have dimensions that are not multiple of eight, for example
height of 36, but the driver divided the dimensions by 8. Defining display
to the next multiple of 8 is not good as then the display registers get
configured to dimensions that do not match. This contradicts intructions
by some display manufacturers.
Use DIV_ROUND_UP to multiple of 8 when needed so correct values can be
used.
The ssd1307fb_update_display bit reordering receives a simplification in
the process.
Signed-off-by: Marko Kohtala <marko.kohtala@okoko.fi>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Michal Vokáč <michal.vokac@ysoft.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190618074111.9309-5-marko.kohtala@okoko.fi
Diffstat (limited to 'drivers/video')
-rw-r--r-- | drivers/video/fbdev/ssd1307fb.c | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c index 4f911480f2eb..8e0720444467 100644 --- a/drivers/video/fbdev/ssd1307fb.c +++ b/drivers/video/fbdev/ssd1307fb.c @@ -150,10 +150,11 @@ static void 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; - array = ssd1307fb_alloc_array(par->width * par->height / 8, - SSD1307FB_DATA); + array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA); if (!array) return; @@ -186,22 +187,24 @@ static void ssd1307fb_update_display(struct ssd1307fb_par *par) * (5) A4 B4 C4 D4 E4 F4 G4 H4 */ - for (i = 0; i < (par->height / 8); i++) { + for (i = 0; i < pages; i++) { for (j = 0; j < par->width; j++) { + int m = 8; u32 array_idx = i * par->width + j; array->data[array_idx] = 0; - for (k = 0; k < 8; k++) { - u32 page_length = par->width * i; - u32 index = page_length + (par->width * k + j) / 8; - u8 byte = *(vmem + index); - u8 bit = byte & (1 << (j % 8)); - bit = bit >> (j % 8); + /* Last page may be partial */ + if (i + 1 == pages && par->height % 8) + m = par->height % 8; + 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; } } } - ssd1307fb_write_array(par->client, array, par->width * par->height / 8); + ssd1307fb_write_array(par->client, array, par->width * pages); kfree(array); } @@ -437,7 +440,8 @@ static int ssd1307fb_init(struct ssd1307fb_par *par) return ret; ret = ssd1307fb_write_cmd(par->client, - par->page_offset + (par->height / 8) - 1); + par->page_offset + + DIV_ROUND_UP(par->height, 8) - 1); if (ret < 0) return ret; @@ -615,7 +619,7 @@ static int ssd1307fb_probe(struct i2c_client *client, par->dclk_div = par->device_info->default_dclk_div; par->dclk_frq = par->device_info->default_dclk_frq; - vmem_size = par->width * par->height / 8; + vmem_size = DIV_ROUND_UP(par->width, 8) * par->height; vmem = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, get_order(vmem_size)); @@ -638,7 +642,7 @@ static int ssd1307fb_probe(struct i2c_client *client, info->fbops = &ssd1307fb_ops; info->fix = ssd1307fb_fix; - info->fix.line_length = par->width / 8; + info->fix.line_length = DIV_ROUND_UP(par->width, 8); info->fbdefio = ssd1307fb_defio; info->var = ssd1307fb_var; |