fb_ssd1331.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/module.h>
  3#include <linux/kernel.h>
  4#include <linux/init.h>
  5#include <linux/gpio/consumer.h>
  6#include <linux/spi/spi.h>
  7#include <linux/delay.h>
  8
  9#include "fbtft.h"
 10
 11#define DRVNAME		"fb_ssd1331"
 12#define WIDTH		96
 13#define HEIGHT		64
 14#define GAMMA_NUM	1
 15#define GAMMA_LEN	63
 16#define DEFAULT_GAMMA	"0 2 2 2 2 2 2 2 " \
 17			"2 2 2 2 2 2 2 2 " \
 18			"2 2 2 2 2 2 2 2 " \
 19			"2 2 2 2 2 2 2 2 " \
 20			"2 2 2 2 2 2 2 2 " \
 21			"2 2 2 2 2 2 2 2 " \
 22			"2 2 2 2 2 2 2 2 " \
 23			"2 2 2 2 2 2 2" \
 24
 25static int init_display(struct fbtft_par *par)
 26{
 27	par->fbtftops.reset(par);
 28
 29	write_reg(par, 0xae); /* Display Off */
 30
 31	/* Set Column Address Mapping, COM Scan Direction and Colour Depth */
 32	if (par->info->var.rotate == 180)
 33		write_reg(par, 0xa0, 0x60 | (par->bgr << 2));
 34	else
 35		write_reg(par, 0xa0, 0x72 | (par->bgr << 2));
 36
 37	write_reg(par, 0x72); /* RGB colour */
 38	write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
 39	write_reg(par, 0xa2, 0x00); /* Set Display Offset */
 40	write_reg(par, 0xa4); /* NORMALDISPLAY */
 41	write_reg(par, 0xa8, 0x3f); /* Set multiplex */
 42	write_reg(par, 0xad, 0x8e); /* Set master */
 43	/* write_reg(par, 0xb0, 0x0b);  Set power mode */
 44	write_reg(par, 0xb1, 0x31); /* Precharge */
 45	write_reg(par, 0xb3, 0xf0); /* Clock div */
 46	write_reg(par, 0x8a, 0x64); /* Precharge A */
 47	write_reg(par, 0x8b, 0x78); /* Precharge B */
 48	write_reg(par, 0x8c, 0x64); /* Precharge C */
 49	write_reg(par, 0xbb, 0x3a); /* Precharge level */
 50	write_reg(par, 0xbe, 0x3e); /* vcomh */
 51	write_reg(par, 0x87, 0x06); /* Master current */
 52	write_reg(par, 0x81, 0x91); /* Contrast A */
 53	write_reg(par, 0x82, 0x50); /* Contrast B */
 54	write_reg(par, 0x83, 0x7d); /* Contrast C */
 55	write_reg(par, 0xaf); /* Set Sleep Mode Display On */
 56
 57	return 0;
 58}
 59
 60static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
 61{
 62	write_reg(par, 0x15, xs, xe);
 63	write_reg(par, 0x75, ys, ye);
 64}
 65
 66static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
 67{
 68	va_list args;
 69	int i, ret;
 70	u8 *buf = par->buf;
 71
 72	if (unlikely(par->debug & DEBUG_WRITE_REGISTER)) {
 73		va_start(args, len);
 74		for (i = 0; i < len; i++)
 75			buf[i] = (u8)va_arg(args, unsigned int);
 76		va_end(args);
 77		fbtft_par_dbg_hex(DEBUG_WRITE_REGISTER, par, par->info->device,
 78				  u8, buf, len, "%s: ", __func__);
 79	}
 80
 81	va_start(args, len);
 82
 83	*buf = (u8)va_arg(args, unsigned int);
 84	gpiod_set_value(par->gpio.dc, 0);
 85	ret = par->fbtftops.write(par, par->buf, sizeof(u8));
 86	if (ret < 0) {
 87		va_end(args);
 88		dev_err(par->info->device,
 89			"write() failed and returned %d\n", ret);
 90		return;
 91	}
 92	len--;
 93
 94	if (len) {
 95		i = len;
 96		while (i--)
 97			*buf++ = (u8)va_arg(args, unsigned int);
 98		ret = par->fbtftops.write(par, par->buf, len * (sizeof(u8)));
 99		if (ret < 0) {
100			va_end(args);
101			dev_err(par->info->device,
102				"write() failed and returned %d\n", ret);
103			return;
104		}
105	}
106	gpiod_set_value(par->gpio.dc, 1);
107	va_end(args);
108}
109
110/*
111 * Grayscale Lookup Table
112 * GS1 - GS63
113 * The driver Gamma curve contains the relative values between the entries
114 * in the Lookup table.
115 *
116 * From datasheet:
117 * 8.8 Gray Scale Decoder
118 *
119 * there are total 180 Gamma Settings (Setting 0 to Setting 180)
120 * available for the Gray Scale table.
121 *
122 * The gray scale is defined in incremental way, with reference
123 * to the length of previous table entry:
124 * Setting of GS1 has to be >= 0
125 * Setting of GS2 has to be > Setting of GS1 +1
126 * Setting of GS3 has to be > Setting of GS2 +1
127 * :
128 * Setting of GS63 has to be > Setting of GS62 +1
129 *
130 */
131static int set_gamma(struct fbtft_par *par, u32 *curves)
132{
133	unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
134	int i, acc = 0;
135
136	for (i = 0; i < 63; i++) {
137		if (i > 0 && curves[i] < 2) {
138			dev_err(par->info->device,
139				"Illegal value in Grayscale Lookup Table at index %d. Must be greater than 1\n",
140				i);
141			return -EINVAL;
142		}
143		acc += curves[i];
144		tmp[i] = acc;
145		if (acc > 180) {
146			dev_err(par->info->device,
147				"Illegal value(s) in Grayscale Lookup Table. At index=%d, the accumulated value has exceeded 180\n",
148				i);
149			return -EINVAL;
150		}
151	}
152
153	write_reg(par, 0xB8,
154		  tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6],
155		  tmp[7], tmp[8], tmp[9], tmp[10], tmp[11], tmp[12], tmp[13],
156		  tmp[14], tmp[15], tmp[16], tmp[17], tmp[18], tmp[19], tmp[20],
157		  tmp[21], tmp[22], tmp[23], tmp[24], tmp[25], tmp[26],	tmp[27],
158		  tmp[28], tmp[29], tmp[30], tmp[31], tmp[32], tmp[33], tmp[34],
159		  tmp[35], tmp[36], tmp[37], tmp[38], tmp[39], tmp[40], tmp[41],
160		  tmp[42], tmp[43], tmp[44], tmp[45], tmp[46], tmp[47], tmp[48],
161		  tmp[49], tmp[50], tmp[51], tmp[52], tmp[53], tmp[54], tmp[55],
162		  tmp[56], tmp[57], tmp[58], tmp[59], tmp[60], tmp[61],
163		  tmp[62]);
164
165	return 0;
166}
167
168static int blank(struct fbtft_par *par, bool on)
169{
170	if (on)
171		write_reg(par, 0xAE);
172	else
173		write_reg(par, 0xAF);
174	return 0;
175}
176
177static struct fbtft_display display = {
178	.regwidth = 8,
179	.width = WIDTH,
180	.height = HEIGHT,
181	.gamma_num = GAMMA_NUM,
182	.gamma_len = GAMMA_LEN,
183	.gamma = DEFAULT_GAMMA,
184	.fbtftops = {
185		.write_register = write_reg8_bus8,
186		.init_display = init_display,
187		.set_addr_win = set_addr_win,
188		.set_gamma = set_gamma,
189		.blank = blank,
190	},
191};
192
193FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1331", &display);
194
195MODULE_ALIAS("spi:" DRVNAME);
196MODULE_ALIAS("platform:" DRVNAME);
197MODULE_ALIAS("spi:ssd1331");
198MODULE_ALIAS("platform:ssd1331");
199
200MODULE_DESCRIPTION("SSD1331 OLED Driver");
201MODULE_AUTHOR("Alec Smecher (adapted from SSD1351 by James Davies)");
202MODULE_LICENSE("GPL");