drivers/staging/fbtft/fb_ssd1331.c

Source file repositories/reference/linux-study-clean/drivers/staging/fbtft/fb_ssd1331.c

File Facts

System
Linux kernel
Corpus path
drivers/staging/fbtft/fb_ssd1331.c
Extension
.c
Size
5501 bytes
Lines
203
Domain
Driver Families
Bucket
drivers/staging
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (ret < 0) {
			va_end(args);
			dev_err(par->info->device,
				"write() failed and returned %d\n", ret);
			return;
		}
	}
	gpiod_set_value(par->gpio.dc, 1);
	va_end(args);
}

/*
 * Grayscale Lookup Table
 * GS1 - GS63
 * The driver Gamma curve contains the relative values between the entries
 * in the Lookup table.
 *
 * From datasheet:
 * 8.8 Gray Scale Decoder
 *
 * there are total 180 Gamma Settings (Setting 0 to Setting 180)
 * available for the Gray Scale table.
 *
 * The gray scale is defined in incremental way, with reference
 * to the length of previous table entry:
 * Setting of GS1 has to be >= 0
 * Setting of GS2 has to be > Setting of GS1 +1
 * Setting of GS3 has to be > Setting of GS2 +1
 * :
 * Setting of GS63 has to be > Setting of GS62 +1
 *
 */
static int set_gamma(struct fbtft_par *par, u32 *curves)
{
	unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
	int i, acc = 0;

	for (i = 0; i < 63; i++) {
		if (i > 0 && curves[i] < 2) {
			dev_err(par->info->device,
				"Illegal value in Grayscale Lookup Table at index %d. Must be greater than 1\n",
				i);
			return -EINVAL;
		}
		acc += curves[i];
		tmp[i] = acc;
		if (acc > 180) {
			dev_err(par->info->device,
				"Illegal value(s) in Grayscale Lookup Table. At index=%d, the accumulated value has exceeded 180\n",
				i);
			return -EINVAL;
		}
	}

	write_reg(par, 0xB8,
		  tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6],
		  tmp[7], tmp[8], tmp[9], tmp[10], tmp[11], tmp[12], tmp[13],
		  tmp[14], tmp[15], tmp[16], tmp[17], tmp[18], tmp[19], tmp[20],
		  tmp[21], tmp[22], tmp[23], tmp[24], tmp[25], tmp[26],	tmp[27],
		  tmp[28], tmp[29], tmp[30], tmp[31], tmp[32], tmp[33], tmp[34],
		  tmp[35], tmp[36], tmp[37], tmp[38], tmp[39], tmp[40], tmp[41],
		  tmp[42], tmp[43], tmp[44], tmp[45], tmp[46], tmp[47], tmp[48],
		  tmp[49], tmp[50], tmp[51], tmp[52], tmp[53], tmp[54], tmp[55],
		  tmp[56], tmp[57], tmp[58], tmp[59], tmp[60], tmp[61],
		  tmp[62]);

	return 0;
}

static int blank(struct fbtft_par *par, bool on)
{
	if (on)
		write_reg(par, 0xAE);
	else
		write_reg(par, 0xAF);
	return 0;
}

static struct fbtft_display display = {
	.regwidth = 8,
	.width = WIDTH,
	.height = HEIGHT,
	.gamma_num = GAMMA_NUM,
	.gamma_len = GAMMA_LEN,
	.gamma = DEFAULT_GAMMA,
	.fbtftops = {
		.write_register = write_reg8_bus8,
		.init_display = init_display,
		.set_addr_win = set_addr_win,
		.set_gamma = set_gamma,

Annotation

Implementation Notes