1#include <linux/module.h>
2#include <linux/kernel.h>
3#include <linux/init.h>
4#include <linux/gpio.h>
5#include <linux/spi/spi.h>
6#include <linux/delay.h>
7
8#include "fbtft.h"
9
10#define DRVNAME		"fb_ssd1351"
11#define WIDTH		128
12#define HEIGHT		128
13#define GAMMA_NUM	1
14#define GAMMA_LEN	63
15#define DEFAULT_GAMMA	"0 2 2 2 2 2 2 2 " \
16			"2 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" \
23
24static void register_onboard_backlight(struct fbtft_par *par);
25
26static int init_display(struct fbtft_par *par)
27{
28	fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
29
30	if (par->pdata
31		&& par->pdata->display.backlight == FBTFT_ONBOARD_BACKLIGHT) {
32		/* module uses onboard GPIO for panel power */
33		par->fbtftops.register_backlight = register_onboard_backlight;
34	}
35
36	par->fbtftops.reset(par);
37
38	write_reg(par, 0xfd, 0x12); /* Command Lock */
39	write_reg(par, 0xfd, 0xb1); /* Command Lock */
40	write_reg(par, 0xae); /* Display Off */
41	write_reg(par, 0xb3, 0xf1); /* Front Clock Div */
42	write_reg(par, 0xca, 0x7f); /* Set Mux Ratio */
43	write_reg(par, 0x15, 0x00, 0x7f); /* Set Column Address */
44	write_reg(par, 0x75, 0x00, 0x7f); /* Set Row Address */
45	write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
46	write_reg(par, 0xa2, 0x00); /* Set Display Offset */
47	write_reg(par, 0xb5, 0x00); /* Set GPIO */
48	write_reg(par, 0xab, 0x01); /* Set Function Selection */
49	write_reg(par, 0xb1, 0x32); /* Set Phase Length */
50	write_reg(par, 0xb4, 0xa0, 0xb5, 0x55); /* Set Segment Low Voltage */
51	write_reg(par, 0xbb, 0x17); /* Set Precharge Voltage */
52	write_reg(par, 0xbe, 0x05); /* Set VComH Voltage */
53	write_reg(par, 0xc1, 0xc8, 0x80, 0xc8); /* Set Contrast */
54	write_reg(par, 0xc7, 0x0f); /* Set Master Contrast */
55	write_reg(par, 0xb6, 0x01); /* Set Second Precharge Period */
56	write_reg(par, 0xa6); /* Set Display Mode Reset */
57	write_reg(par, 0xaf); /* Set Sleep Mode Display On */
58
59	return 0;
60}
61
62static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
63{
64	fbtft_par_dbg(DEBUG_SET_ADDR_WIN, par,
65		"%s(xs=%d, ys=%d, xe=%d, ye=%d)\n", __func__, xs, ys, xe, ye);
66
67	write_reg(par, 0x15, xs, xe);
68	write_reg(par, 0x75, ys, ye);
69	write_reg(par, 0x5c);
70}
71
72static int set_var(struct fbtft_par *par)
73{
74	unsigned remap;
75
76	fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
77
78	if (par->fbtftops.init_display != init_display) {
79		/* don't risk messing up register A0h */
80		fbtft_par_dbg(DEBUG_INIT_DISPLAY, par,
81			"%s: skipping since custom init_display() is used\n",
82			__func__);
83		return 0;
84	}
85
86	remap = 0x60 | (par->bgr << 2); /* Set Colour Depth */
87
88	switch (par->info->var.rotate) {
89	case 0:
90		write_reg(par, 0xA0, remap | 0x00 | 1<<4);
91		break;
92	case 270:
93		write_reg(par, 0xA0, remap | 0x03 | 1<<4);
94		break;
95	case 180:
96		write_reg(par, 0xA0, remap | 0x02);
97		break;
98	case 90:
99		write_reg(par, 0xA0, remap | 0x01);
100		break;
101	}
102
103	return 0;
104}
105
106/*
107	Grayscale Lookup Table
108	GS1 - GS63
109	The driver Gamma curve contains the relative values between the entries
110	in the Lookup table.
111
112	From datasheet:
113	8.8 Gray Scale Decoder
114
115		there are total 180 Gamma Settings (Setting 0 to Setting 180)
116		available for the Gray Scale table.
117
118		The gray scale is defined in incremental way, with reference
119		to the length of previous table entry:
120			Setting of GS1 has to be >= 0
121			Setting of GS2 has to be > Setting of GS1 +1
122			Setting of GS3 has to be > Setting of GS2 +1
123			:
124			Setting of GS63 has to be > Setting of GS62 +1
125
126
127*/
128static int set_gamma(struct fbtft_par *par, unsigned long *curves)
129{
130	unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
131	int i, acc = 0;
132
133	fbtft_par_dbg(DEBUG_INIT_DISPLAY, par, "%s()\n", __func__);
134
135	for (i = 0; i < 63; i++) {
136		if (i > 0 && curves[i] < 2) {
137			dev_err(par->info->device,
138				"Illegal value in Grayscale Lookup Table at index %d. " \
139				"Must be greater than 1\n", i);
140			return -EINVAL;
141		}
142		acc += curves[i];
143		tmp[i] = acc;
144		if (acc > 180) {
145			dev_err(par->info->device,
146				"Illegal value(s) in Grayscale Lookup Table. " \
147				"At index=%d, the accumulated value has exceeded 180\n", i);
148			return -EINVAL;
149		}
150	}
151
152	write_reg(par, 0xB8,
153	tmp[0], tmp[1], tmp[2], tmp[3], tmp[4], tmp[5], tmp[6], tmp[7],
154	tmp[8], tmp[9], tmp[10], tmp[11], tmp[12], tmp[13], tmp[14], tmp[15],
155	tmp[16], tmp[17], tmp[18], tmp[19], tmp[20], tmp[21], tmp[22], tmp[23],
156	tmp[24], tmp[25], tmp[26], tmp[27], tmp[28], tmp[29], tmp[30], tmp[31],
157	tmp[32], tmp[33], tmp[34], tmp[35], tmp[36], tmp[37], tmp[38], tmp[39],
158	tmp[40], tmp[41], tmp[42], tmp[43], tmp[44], tmp[45], tmp[46], tmp[47],
159	tmp[48], tmp[49], tmp[50], tmp[51], tmp[52], tmp[53], tmp[54], tmp[55],
160	tmp[56], tmp[57], tmp[58], tmp[59], tmp[60], tmp[61], tmp[62]);
161
162	return 0;
163}
164
165static int blank(struct fbtft_par *par, bool on)
166{
167	fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",
168		__func__, on ? "true" : "false");
169	if (on)
170		write_reg(par, 0xAE);
171	else
172		write_reg(par, 0xAF);
173	return 0;
174}
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		.init_display = init_display,
186		.set_addr_win = set_addr_win,
187		.set_var = set_var,
188		.set_gamma = set_gamma,
189		.blank = blank,
190	},
191};
192
193#ifdef CONFIG_FB_BACKLIGHT
194static int update_onboard_backlight(struct backlight_device *bd)
195{
196	struct fbtft_par *par = bl_get_data(bd);
197	bool on;
198
199	fbtft_par_dbg(DEBUG_BACKLIGHT, par,
200		"%s: power=%d, fb_blank=%d\n",
201		__func__, bd->props.power, bd->props.fb_blank);
202
203	on = (bd->props.power == FB_BLANK_UNBLANK)
204		&& (bd->props.fb_blank == FB_BLANK_UNBLANK);
205	/* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
206	write_reg(par, 0xB5, on ? 0x03 : 0x02);
207
208	return 0;
209}
210
211static void register_onboard_backlight(struct fbtft_par *par)
212{
213	struct backlight_device *bd;
214	struct backlight_properties bl_props = { 0, };
215	struct backlight_ops *bl_ops;
216
217	fbtft_par_dbg(DEBUG_BACKLIGHT, par, "%s()\n", __func__);
218
219	bl_ops = devm_kzalloc(par->info->device, sizeof(struct backlight_ops),
220				GFP_KERNEL);
221	if (!bl_ops)
222		return;
223
224	bl_ops->update_status = update_onboard_backlight;
225	bl_props.type = BACKLIGHT_RAW;
226	bl_props.power = FB_BLANK_POWERDOWN;
227
228	bd = backlight_device_register(dev_driver_string(par->info->device),
229				par->info->device, par, bl_ops, &bl_props);
230	if (IS_ERR(bd)) {
231		dev_err(par->info->device,
232			"cannot register backlight device (%ld)\n",
233			PTR_ERR(bd));
234		return;
235	}
236	par->info->bl_dev = bd;
237
238	if (!par->fbtftops.unregister_backlight)
239		par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
240}
241#else
242static void register_onboard_backlight(struct fbtft_par *par) { };
243#endif
244
245
246FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display);
247
248MODULE_ALIAS("spi:" DRVNAME);
249MODULE_ALIAS("platform:" DRVNAME);
250MODULE_ALIAS("spi:ssd1351");
251MODULE_ALIAS("platform:ssd1351");
252
253MODULE_DESCRIPTION("SSD1351 OLED Driver");
254MODULE_AUTHOR("James Davies");
255MODULE_LICENSE("GPL");
256