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video: fbdev: ssd1307fb: Simplify ssd1307fb_update_display()
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> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20210727134730.3765898-3-geert@linux-m68k.org
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1 changed files with 10 additions and 7 deletions
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@ -158,6 +158,7 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par)
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u8 *vmem = par->info->screen_buffer;
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unsigned int line_length = par->info->fix.line_length;
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unsigned int pages = DIV_ROUND_UP(par->height, 8);
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u32 array_idx = 0;
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int ret, i, j, k;
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array = ssd1307fb_alloc_array(par->width * pages, SSD1307FB_DATA);
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@ -194,19 +195,21 @@ static int ssd1307fb_update_display(struct ssd1307fb_par *par)
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*/
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for (i = 0; i < pages; i++) {
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int m = 8;
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/* Last page may be partial */
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if (i + 1 == pages && par->height % 8)
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m = par->height % 8;
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for (j = 0; j < par->width; j++) {
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int m = 8;
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u32 array_idx = i * par->width + j;
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array->data[array_idx] = 0;
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/* Last page may be partial */
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if (i + 1 == pages && par->height % 8)
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m = par->height % 8;
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u8 data = 0;
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for (k = 0; k < m; k++) {
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u8 byte = vmem[(8 * i + k) * line_length +
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j / 8];
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u8 bit = (byte >> (j % 8)) & 1;
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array->data[array_idx] |= bit << k;
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data |= bit << k;
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}
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array->data[array_idx++] = data;
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}
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}
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