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staging: fbtft: fb_sh1106: use own implementation of write_register 

The default implementation of write_register keeps DC low for the first
byte only. SH1106 requires DC to be low for all bytes of a multi-byte
command. To deal with this limitation we currently use a separate call
to write_reg for each single command byte what is not really efficient.

Therefore override the default implementation of write_register with an
own one which keeps DC low for all bytes.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heiner Kallweit 2017-03-02 21:03:44 +01:00 committed by Greg Kroah-Hartman
parent 18c6142168
commit 82472b8618
1 changed files with 33 additions and 32 deletions
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65
drivers/staging/fbtft/fb_sh1106.c
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@ -27,17 +27,6 @@
#define WIDTH 128 #define WIDTH 128
#define HEIGHT 64 #define HEIGHT 64
/*
* write_reg() caveat:
*
* This doesn't work because D/C has to be LOW for both values:
* write_reg(par, val1, val2);
*
* Do it like this:
* write_reg(par, val1);
* write_reg(par, val2);
*/
/* Init sequence based on the Adafruit SSD1306 Arduino library */ /* Init sequence based on the Adafruit SSD1306 Arduino library */
static int init_display(struct fbtft_par *par) static int init_display(struct fbtft_par *par)
{ {
@ -59,16 +48,13 @@ static int init_display(struct fbtft_par *par)
write_reg(par, 0xAE); write_reg(par, 0xAE);
/* Set Display Clock Divide Ratio/ Oscillator Frequency */ /* Set Display Clock Divide Ratio/ Oscillator Frequency */
write_reg(par, 0xD5); write_reg(par, 0xD5, 0x80);
write_reg(par, 0x80);
/* Set Multiplex Ratio */ /* Set Multiplex Ratio */
write_reg(par, 0xA8); write_reg(par, 0xA8, par->info->var.yres - 1);
write_reg(par, par->info->var.yres - 1);
/* Set Display Offset */ /* Set Display Offset */
write_reg(par, 0xD3); write_reg(par, 0xD3, 0x00);
write_reg(par, 0x0);
/* Set Display Start Line */ /* Set Display Start Line */
write_reg(par, 0x40 | 0x0); write_reg(par, 0x40 | 0x0);
@ -82,24 +68,21 @@ static int init_display(struct fbtft_par *par)
write_reg(par, 0xC8); write_reg(par, 0xC8);
/* Set COM Pins Hardware Configuration */ /* Set COM Pins Hardware Configuration */
write_reg(par, 0xDA);
if (par->info->var.yres == 64) if (par->info->var.yres == 64)
/* A[4]=1b, Alternative COM pin configuration */ /* A[4]=1b, Alternative COM pin configuration */
write_reg(par, 0x12); write_reg(par, 0xDA, 0x12);
else if (par->info->var.yres == 48) else if (par->info->var.yres == 48)
/* A[4]=1b, Alternative COM pin configuration */ /* A[4]=1b, Alternative COM pin configuration */
write_reg(par, 0x12); write_reg(par, 0xDA, 0x12);
else else
/* A[4]=0b, Sequential COM pin configuration */ /* A[4]=0b, Sequential COM pin configuration */
write_reg(par, 0x02); write_reg(par, 0xDA, 0x02);
/* Set Pre-charge Period */ /* Set Pre-charge Period */
write_reg(par, 0xD9); write_reg(par, 0xD9, 0xF1);
write_reg(par, 0xF1);
/* Set VCOMH Deselect Level */ /* Set VCOMH Deselect Level */
write_reg(par, 0xDB); write_reg(par, 0xDB, 0x40);
write_reg(par, 0x40);
/* Set Display ON */ /* Set Display ON */
write_reg(par, 0xAF); write_reg(par, 0xAF);
@ -130,8 +113,7 @@ static int set_gamma(struct fbtft_par *par, u32 *curves)
curves[0] &= 0xFF; curves[0] &= 0xFF;
/* Set Contrast Control for BANK0 */ /* Set Contrast Control for BANK0 */
write_reg(par, 0x81); write_reg(par, 0x81, curves[0]);
write_reg(par, curves[0]);
return 0; return 0;
} }
@ -148,11 +130,8 @@ static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres); page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres);
for (page = page_start; page < page_end; page++) { for (page = page_start; page < page_end; page++) {
/* set page */ /* set page and set column to 2 because of vidmem width 132 */
write_reg(par, 0xb0 | page); write_reg(par, 0xb0 | page, 0x00 | 2, 0x10 | 0);
/* set column to 2 to compensate for vidmem width 132 */
write_reg(par, 0x00 | 2);
write_reg(par, 0x10 | 0);
memset(buf, 0, xres); memset(buf, 0, xres);
for (x = 0; x < xres; x++) for (x = 0; x < xres; x++)
@ -173,6 +152,27 @@ static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
return 0; return 0;
} }
static void write_register(struct fbtft_par *par, int len, ...)
{
va_list args;
int i, ret;
va_start(args, len);
for (i = 0; i < len; i++)
par->buf[i] = va_arg(args, unsigned int);
/* keep DC low for all command bytes to transfer */
gpio_set_value(par->gpio.dc, 0);
ret = par->fbtftops.write(par, par->buf, len);
if (ret < 0)
dev_err(par->info->device,
"write() failed and returned %d\n", ret);
va_end(args);
}
static struct fbtft_display display = { static struct fbtft_display display = {
.regwidth = 8, .regwidth = 8,
.width = WIDTH, .width = WIDTH,
@ -184,6 +184,7 @@ static struct fbtft_display display = {
.gamma = "cd", .gamma = "cd",
.fbtftops = { .fbtftops = {
.write_vmem = write_vmem, .write_vmem = write_vmem,
.write_register = write_register,
.init_display = init_display, .init_display = init_display,
.set_addr_win = set_addr_win, .set_addr_win = set_addr_win,
.blank = blank, .blank = blank,