// SPDX-License-Identifier: GPL-2.0
#include <linux/backlight.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spi/spi.h>
#include <linux/delay.h>
#include "fbtft.h"
#define DRVNAME "fb_ssd1351"
#define WIDTH 128
#define HEIGHT 128
#define GAMMA_NUM 1
#define GAMMA_LEN 63
#define DEFAULT_GAMMA "0 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2 2 " \
"2 2 2 2 2 2 2" \
static void register_onboard_backlight(struct fbtft_par *par);
static int init_display(struct fbtft_par *par)
{
if (par->pdata &&
par->pdata->display.backlight == FBTFT_ONBOARD_BACKLIGHT) {
/* module uses onboard GPIO for panel power */
par->fbtftops.register_backlight = register_onboard_backlight;
}
par->fbtftops.reset(par);
write_reg(par, 0xfd, 0x12); /* Command Lock */
write_reg(par, 0xfd, 0xb1); /* Command Lock */
write_reg(par, 0xae); /* Display Off */
write_reg(par, 0xb3, 0xf1); /* Front Clock Div */
write_reg(par, 0xca, 0x7f); /* Set Mux Ratio */
write_reg(par, 0x15, 0x00, 0x7f); /* Set Column Address */
write_reg(par, 0x75, 0x00, 0x7f); /* Set Row Address */
write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
write_reg(par, 0xa2, 0x00); /* Set Display Offset */
write_reg(par, 0xb5, 0x00); /* Set GPIO */
write_reg(par, 0xab, 0x01); /* Set Function Selection */
write_reg(par, 0xb1, 0x32); /* Set Phase Length */
write_reg(par, 0xb4, 0xa0, 0xb5, 0x55); /* Set Segment Low Voltage */
write_reg(par, 0xbb, 0x17); /* Set Precharge Voltage */
write_reg(par, 0xbe, 0x05); /* Set VComH Voltage */
write_reg(par, 0xc1, 0xc8, 0x80, 0xc8); /* Set Contrast */
write_reg(par, 0xc7, 0x0f); /* Set Master Contrast */
write_reg(par, 0xb6, 0x01); /* Set Second Precharge Period */
write_reg(par, 0xa6); /* Set Display Mode Reset */
write_reg(par, 0xaf); /* Set Sleep Mode Display On */
return 0;
}
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
write_reg(par, 0x15, xs, xe);
write_reg(par, 0x75, ys, ye);
write_reg(par, 0x5c);
}
static int set_var(struct fbtft_par *par)
{
unsigned int remap;
if (par->fbtftops.init_display != init_display) {
/* don't risk messing up register A0h */
return 0;
}
remap = 0x60 | (par->bgr << 2); /* Set Colour Depth */
switch (par->info->var.rotate) {
case 0:
write_reg(par, 0xA0, remap | 0x00 | BIT(4));
break;
case 270:
write_reg(par, 0xA0, remap | 0x03 | BIT(4));
break;
case 180:
write_reg(par, 0xA0, remap | 0x02);
break;
case 90:
write_reg(par, 0xA0, remap | 0x01);
break;
}
return 0;
}
/*
* 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 : %d. Must be greater than 1\n",
i, curves[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 : %d, the accumulated value has exceeded 180\n",
i, acc);
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)
{
fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
__func__, on ? "true" : "false");
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 = {
.init_display = init_display,
.set_addr_win = set_addr_win,
.set_var = set_var,
.set_gamma = set_gamma,
.blank = blank,
},
};
static int update_onboard_backlight(struct backlight_device *bd)
{
struct fbtft_par *par = bl_get_data(bd);
bool on;
fbtft_par_dbg(DEBUG_BACKLIGHT, par, "%s: power=%d\n", __func__, bd->props.power);
on = !backlight_is_blank(bd);
/* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
write_reg(par, 0xB5, on ? 0x03 : 0x02);
return 0;
}
static const struct backlight_ops bl_ops = {
.update_status = update_onboard_backlight,
};
static void register_onboard_backlight(struct fbtft_par *par)
{
struct backlight_device *bd;
struct backlight_properties bl_props = { 0, };
bl_props.type = BACKLIGHT_RAW;
bl_props.power = BACKLIGHT_POWER_OFF;
bd = backlight_device_register(dev_driver_string(par->info->device),
par->info->device, par, &bl_ops,
&bl_props);
if (IS_ERR(bd)) {
dev_err(par->info->device,
"cannot register backlight device (%ld)\n",
PTR_ERR(bd));
return;
}
par->info->bl_dev = bd;
if (!par->fbtftops.unregister_backlight)
par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
}
FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display);
MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:ssd1351");
MODULE_ALIAS("platform:ssd1351");
MODULE_DESCRIPTION("SSD1351 OLED Driver");
MODULE_AUTHOR("James Davies");
MODULE_LICENSE("GPL");
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