This patch adds a module parameter 'bitsperpixel' to adjust the colordepth
of the framebuffer. All values >1 will result in memory map of the requested
color depth. However only the MSB of each pixel will be sent to the device.
The framebuffer identifies itself as a grayscale display with the specified
depth.
Signed-off-by: Thomas Niederprüm <nied...@physik.uni-kl.de>
---
drivers/video/fbdev/ssd1307fb.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 7c8e627..3cf4da1 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -44,6 +44,10 @@
#define SSD1307FB_SET_VCOMH 0xdb
#define REFRASHRATE 1
+#define BITSPERPIXEL 1
+
+static u_int bitsperpixel = BITSPERPIXEL;
+module_param(bitsperpixel, uint, 0);
static u_int refreshrate = REFRASHRATE;
module_param(refreshrate, uint, 0);
@@ -99,7 +103,8 @@ static struct fb_fix_screeninfo ssd1307fb_fix = {
};
static struct fb_var_screeninfo ssd1307fb_var = {
- .bits_per_pixel = 1,
+ .bits_per_pixel = BITSPERPIXEL,
+ .grayscale = 1,
};
static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
@@ -194,10 +199,11 @@ static void ssd1307fb_update_display(struct ssd1307fb_par
*par)
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;
+ u32 index = page_length * bitsperpixel +
(par->width * k + j) * bitsperpixel / 8;
u8 byte = *(vmem + index);
- u8 bit = byte & (1 << (j % 8));
- bit = bit >> (j % 8);
+ u8 bit = byte & (((1 << (bitsperpixel))-1) <<
(j % 8/bitsperpixel));
+
+ bit = (bit >> (j % 8/bitsperpixel)) >>
(bitsperpixel-1);
array->data[array_idx] |= bit << k;
}
}
@@ -536,7 +542,7 @@ 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 = par->width * par->height * bitsperpixel / 8;
vmem = vzalloc(vmem_size);
if (!vmem) {
@@ -557,20 +563,21 @@ 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 = par->width * bitsperpixel / 8;
info->fbdefio = ssd1307fb_defio;
info->var = ssd1307fb_var;
+ info->var.bits_per_pixel = bitsperpixel;
info->var.xres = par->width;
info->var.xres_virtual = par->width;
info->var.yres = par->height;
info->var.yres_virtual = par->height;
- info->var.red.length = 1;
+ info->var.red.length = bitsperpixel;
info->var.red.offset = 0;
- info->var.green.length = 1;
+ info->var.green.length = bitsperpixel;
info->var.green.offset = 0;
- info->var.blue.length = 1;
+ info->var.blue.length = bitsperpixel;
info->var.blue.offset = 0;
info->screen_base = (u8 __force __iomem *)vmem;
--
2.3.0
--
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