linux-stable/drivers/staging/fbtft/fb_ssd1289.c
Andy Shevchenko ec03c21043 staging: fbtft: Rectify GPIO handling
The infamous commit c440eee1a7 ("Staging: staging: fbtft: Switch to
the GPIO descriptor interface") broke GPIO handling completely.
It has already four commits to rectify and it seems not enough.
In order to fix the mess here we:

  1) Set default to "inactive" for all requested pins

  2) Fix CS#, RD#, and WR# pins polarity since it's active low
     and GPIO descriptor interface takes it into consideration
     from the Device Tree or ACPI

  3) Consolidate chip activation (CS# assertion) under default
     ->reset() callback

To summarize the expectations about polarity for GPIOs:

   RD#			Low
   WR#			Low
   CS#			Low
   RESET#		Low
   DC or RS		High
   RW			High
   Data	0 .. 15		High

See also Adafruit learning course [1] for the example of the schematics.

While at it, drop unneeded NULL checks, since GPIO API is tolerant to that.

[1]: https://learn.adafruit.com/adafruit-2-8-and-3-2-color-tft-touchscreen-breakout-v2/downloads

Fixes: 92e3e88488 ("Staging: fbtft: Fix GPIO handling")
Fixes: b918d1c270 ("Staging: fbtft: Fix reset assertion when using gpio descriptor")
Fixes: dbc4f989c8 ("Staging: fbtft: Fix probing of gpio descriptor")
Fixes: c440eee1a7 ("Staging: fbtft: Switch to the gpio descriptor interface")
Cc: Jan Sebastian Götte <linux@jaseg.net>
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-10 11:19:39 +02:00

179 lines
4.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* FB driver for the SSD1289 LCD Controller
*
* Copyright (C) 2013 Noralf Tronnes
*
* Init sequence taken from ITDB02_Graph16.cpp - (C)2010-2011 Henning Karlsen
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include "fbtft.h"
#define DRVNAME "fb_ssd1289"
#define WIDTH 240
#define HEIGHT 320
#define DEFAULT_GAMMA "02 03 2 5 7 7 4 2 4 2\n" \
"02 03 2 5 7 5 4 2 4 2"
static unsigned int reg11 = 0x6040;
module_param(reg11, uint, 0000);
MODULE_PARM_DESC(reg11, "Register 11h value");
static int init_display(struct fbtft_par *par)
{
par->fbtftops.reset(par);
write_reg(par, 0x00, 0x0001);
write_reg(par, 0x03, 0xA8A4);
write_reg(par, 0x0C, 0x0000);
write_reg(par, 0x0D, 0x080C);
write_reg(par, 0x0E, 0x2B00);
write_reg(par, 0x1E, 0x00B7);
write_reg(par, 0x01,
BIT(13) | (par->bgr << 11) | BIT(9) | (HEIGHT - 1));
write_reg(par, 0x02, 0x0600);
write_reg(par, 0x10, 0x0000);
write_reg(par, 0x05, 0x0000);
write_reg(par, 0x06, 0x0000);
write_reg(par, 0x16, 0xEF1C);
write_reg(par, 0x17, 0x0003);
write_reg(par, 0x07, 0x0233);
write_reg(par, 0x0B, 0x0000);
write_reg(par, 0x0F, 0x0000);
write_reg(par, 0x41, 0x0000);
write_reg(par, 0x42, 0x0000);
write_reg(par, 0x48, 0x0000);
write_reg(par, 0x49, 0x013F);
write_reg(par, 0x4A, 0x0000);
write_reg(par, 0x4B, 0x0000);
write_reg(par, 0x44, 0xEF00);
write_reg(par, 0x45, 0x0000);
write_reg(par, 0x46, 0x013F);
write_reg(par, 0x23, 0x0000);
write_reg(par, 0x24, 0x0000);
write_reg(par, 0x25, 0x8000);
write_reg(par, 0x4f, 0x0000);
write_reg(par, 0x4e, 0x0000);
write_reg(par, 0x22);
return 0;
}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
switch (par->info->var.rotate) {
/* R4Eh - Set GDDRAM X address counter */
/* R4Fh - Set GDDRAM Y address counter */
case 0:
write_reg(par, 0x4e, xs);
write_reg(par, 0x4f, ys);
break;
case 180:
write_reg(par, 0x4e, par->info->var.xres - 1 - xs);
write_reg(par, 0x4f, par->info->var.yres - 1 - ys);
break;
case 270:
write_reg(par, 0x4e, par->info->var.yres - 1 - ys);
write_reg(par, 0x4f, xs);
break;
case 90:
write_reg(par, 0x4e, ys);
write_reg(par, 0x4f, par->info->var.xres - 1 - xs);
break;
}
/* R22h - RAM data write */
write_reg(par, 0x22);
}
static int set_var(struct fbtft_par *par)
{
if (par->fbtftops.init_display != init_display) {
/* don't risk messing up register 11h */
fbtft_par_dbg(DEBUG_INIT_DISPLAY, par,
"%s: skipping since custom init_display() is used\n",
__func__);
return 0;
}
switch (par->info->var.rotate) {
case 0:
write_reg(par, 0x11, reg11 | 0x30);
break;
case 270:
write_reg(par, 0x11, reg11 | 0x28);
break;
case 180:
write_reg(par, 0x11, reg11 | 0x00);
break;
case 90:
write_reg(par, 0x11, reg11 | 0x18);
break;
}
return 0;
}
/*
* Gamma string format:
* VRP0 VRP1 PRP0 PRP1 PKP0 PKP1 PKP2 PKP3 PKP4 PKP5
* VRN0 VRN1 PRN0 PRN1 PKN0 PKN1 PKN2 PKN3 PKN4 PKN5
*/
#define CURVE(num, idx) curves[(num) * par->gamma.num_values + (idx)]
static int set_gamma(struct fbtft_par *par, u32 *curves)
{
static const unsigned long mask[] = {
0x1f, 0x1f, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
0x1f, 0x1f, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
};
int i, j;
/* apply mask */
for (i = 0; i < 2; i++)
for (j = 0; j < 10; j++)
CURVE(i, j) &= mask[i * par->gamma.num_values + j];
write_reg(par, 0x0030, CURVE(0, 5) << 8 | CURVE(0, 4));
write_reg(par, 0x0031, CURVE(0, 7) << 8 | CURVE(0, 6));
write_reg(par, 0x0032, CURVE(0, 9) << 8 | CURVE(0, 8));
write_reg(par, 0x0033, CURVE(0, 3) << 8 | CURVE(0, 2));
write_reg(par, 0x0034, CURVE(1, 5) << 8 | CURVE(1, 4));
write_reg(par, 0x0035, CURVE(1, 7) << 8 | CURVE(1, 6));
write_reg(par, 0x0036, CURVE(1, 9) << 8 | CURVE(1, 8));
write_reg(par, 0x0037, CURVE(1, 3) << 8 | CURVE(1, 2));
write_reg(par, 0x003A, CURVE(0, 1) << 8 | CURVE(0, 0));
write_reg(par, 0x003B, CURVE(1, 1) << 8 | CURVE(1, 0));
return 0;
}
#undef CURVE
static struct fbtft_display display = {
.regwidth = 16,
.width = WIDTH,
.height = HEIGHT,
.gamma_num = 2,
.gamma_len = 10,
.gamma = DEFAULT_GAMMA,
.fbtftops = {
.init_display = init_display,
.set_addr_win = set_addr_win,
.set_var = set_var,
.set_gamma = set_gamma,
},
};
FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1289", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:ssd1289");
MODULE_ALIAS("platform:ssd1289");
MODULE_DESCRIPTION("FB driver for the SSD1289 LCD Controller");
MODULE_AUTHOR("Noralf Tronnes");
MODULE_LICENSE("GPL");