aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/staging/fbtft/fb_ssd1351.c
blob: b8d55aa8c5c7572b0097fb50f65fdacd0d9a2e0c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
// SPDX-License-Identifier: GPL-2.0
#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 */
		fbtft_par_dbg(DEBUG_INIT_DISPLAY, par,
			      "%s: skipping since custom init_display() is used\n",
			       __func__);
		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, fb_blank=%d\n",
		      __func__, bd->props.power, bd->props.fb_blank);

	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 = FB_BLANK_POWERDOWN;

	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");