Commit 079306e9 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Greg Kroah-Hartman
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staging: fbtft: add adriver for SH1106 



This patch adds support for the SH1106 OLED controller chip.

It's similar to the SSD1306, however it supports only a subset of
commands and the internal video memory has a different width.

Major differences:
- Internal video memory has a width of 132 pixels
- Only a subset of commands is supported
- Only page addressing mode is supported, no support for vertical and
  horizontal addressing
- SPI frequency limited to 2 MHz according to the datasheet

Successfully tested with a 1.3" OLED display with this chip and
SPI interface.

Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2fad3142

drivers/staging/fbtft/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -111,6 +111,12 @@ config FB_TFT_S6D1121 
	help

	  Generic Framebuffer support for S6D1121



config FB_TFT_SH1106

	tristate "FB driver for the SH1106 OLED Controller"

	depends on FB_TFT

	help

	  Framebuffer support for SH1106



config FB_TFT_SSD1289

	tristate "FB driver for the SSD1289 LCD Controller"

	depends on FB_TFT

drivers/staging/fbtft/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ obj-$(CONFIG_FB_TFT_PCD8544) += fb_pcd8544.o 
obj-$(CONFIG_FB_TFT_RA8875)      += fb_ra8875.o

obj-$(CONFIG_FB_TFT_S6D02A1)     += fb_s6d02a1.o

obj-$(CONFIG_FB_TFT_S6D1121)     += fb_s6d1121.o

obj-$(CONFIG_FB_TFT_SH1106)      += fb_sh1106.o

obj-$(CONFIG_FB_TFT_SSD1289)     += fb_ssd1289.o

obj-$(CONFIG_FB_TFT_SSD1305)     += fb_ssd1305.o

obj-$(CONFIG_FB_TFT_SSD1306)     += fb_ssd1306.o

drivers/staging/fbtft/fb_sh1106.c

0 → 100644
+203 −0
Original line number Diff line number Diff line 
/*

 * FB driver for the SH1106 OLED Controller

 * Based on the SSD1306 driver by Noralf Tronnes

 *

 * Copyright (C) 2017 Heiner Kallweit

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/gpio.h>

#include <linux/delay.h>



#include "fbtft.h"



#define DRVNAME		"fb_sh1106"

#define WIDTH		128

#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 */

static int init_display(struct fbtft_par *par)

{

	if (!par->info->var.xres || par->info->var.xres > WIDTH ||

	    !par->info->var.yres || par->info->var.yres > HEIGHT ||

	    par->info->var.yres % 8) {

		dev_err(par->info->device, "Invalid screen size\n");

		return -EINVAL;

	}



	if (par->info->var.rotate) {

		dev_err(par->info->device, "Display rotation not supported\n");

		return -EINVAL;

	}



	par->fbtftops.reset(par);



	/* Set Display OFF */

	write_reg(par, 0xAE);



	/* Set Display Clock Divide Ratio/ Oscillator Frequency */

	write_reg(par, 0xD5);

	write_reg(par, 0x80);



	/* Set Multiplex Ratio */

	write_reg(par, 0xA8);

	write_reg(par, par->info->var.yres - 1);



	/* Set Display Offset */

	write_reg(par, 0xD3);

	write_reg(par, 0x0);



	/* Set Display Start Line */

	write_reg(par, 0x40 | 0x0);



	/* Set Segment Re-map */

	/* column address 127 is mapped to SEG0 */

	write_reg(par, 0xA0 | 0x1);



	/* Set COM Output Scan Direction */

	/* remapped mode. Scan from COM[N-1] to COM0 */

	write_reg(par, 0xC8);



	/* Set COM Pins Hardware Configuration */

	write_reg(par, 0xDA);

	if (par->info->var.yres == 64)

		/* A[4]=1b, Alternative COM pin configuration */

		write_reg(par, 0x12);

	else if (par->info->var.yres == 48)

		/* A[4]=1b, Alternative COM pin configuration */

		write_reg(par, 0x12);

	else

		/* A[4]=0b, Sequential COM pin configuration */

		write_reg(par, 0x02);



	/* Set Pre-charge Period */

	write_reg(par, 0xD9);

	write_reg(par, 0xF1);



	/* Set VCOMH Deselect Level */

	write_reg(par, 0xDB);

	write_reg(par, 0x40);



	/* Set Display ON */

	write_reg(par, 0xAF);



	msleep(150);



	return 0;

}



static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)

{

}



static int blank(struct fbtft_par *par, bool on)

{

	fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",

		      __func__, on ? "true" : "false");



	write_reg(par, on ? 0xAE : 0xAF);



	return 0;

}



/* Gamma is used to control Contrast */

static int set_gamma(struct fbtft_par *par, u32 *curves)

{

	/* apply mask */

	curves[0] &= 0xFF;



	/* Set Contrast Control for BANK0 */

	write_reg(par, 0x81);

	write_reg(par, curves[0]);



	return 0;

}



static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)

{

	u16 *vmem16 = (u16 *)par->info->screen_buffer;

	u32 xres = par->info->var.xres;

	int page, page_start, page_end, x, i, ret;

	u8 *buf = par->txbuf.buf;



	/* offset refers to vmem with 2 bytes element size */

	page_start = offset / (8 * 2 * xres);

	page_end = DIV_ROUND_UP(offset + len, 8 * 2 * xres);



	for (page = page_start; page < page_end; page++) {

		/* set page */

		write_reg(par, 0xb0 | page);

		/* set column to 2 to compensate for vidmem width 132 */

		write_reg(par, 0x00 | 2);

		write_reg(par, 0x10 | 0);



		memset(buf, 0, xres);

		for (x = 0; x < xres; x++)

			for (i = 0; i < 8; i++)

				if (vmem16[(page * 8 + i) * xres + x])

					buf[x] |= BIT(i);



		/* Write data */

		gpio_set_value(par->gpio.dc, 1);

		ret = par->fbtftops.write(par, buf, xres);

		if (ret < 0) {

			dev_err(par->info->device,

				"write failed and returned: %d\n", ret);

			return ret;

		}

	}



	return 0;

}



static struct fbtft_display display = {

	.regwidth = 8,

	.width = WIDTH,

	.height = HEIGHT,

	.txbuflen = WIDTH,

	.gamma_num = 1,

	.gamma_len = 1,

	/* set default contrast to 0xcd = 80% */

	.gamma = "cd",

	.fbtftops = {

		.write_vmem = write_vmem,

		.init_display = init_display,

		.set_addr_win = set_addr_win,

		.blank = blank,

		.set_gamma = set_gamma,

	},

};



FBTFT_REGISTER_DRIVER(DRVNAME, "sinowealth,sh1106", &display);



MODULE_ALIAS("spi:" DRVNAME);

MODULE_ALIAS("platform:" DRVNAME);

MODULE_ALIAS("spi:sh1106");

MODULE_ALIAS("platform:sh1106");



MODULE_DESCRIPTION("SH1106 OLED Driver");

MODULE_AUTHOR("Heiner Kallweit");

MODULE_LICENSE("GPL");

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