1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Power control for Samsung LTV350QV Quarter VGA LCD Panel
4  *
5  * Copyright (C) 2006, 2007 Atmel Corporation
6  */
7 #include <linux/delay.h>
8 #include <linux/err.h>
9 #include <linux/fb.h>
10 #include <linux/init.h>
11 #include <linux/lcd.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/spi/spi.h>
15 
16 #include "ltv350qv.h"
17 
18 #define POWER_IS_ON(pwr)	((pwr) <= FB_BLANK_NORMAL)
19 
20 struct ltv350qv {
21 	struct spi_device	*spi;
22 	u8			*buffer;
23 	int			power;
24 	struct lcd_device	*ld;
25 };
26 
27 /*
28  * The power-on and power-off sequences are taken from the
29  * LTV350QV-F04 data sheet from Samsung. The register definitions are
30  * taken from the S6F2002 command list also from Samsung.
31  *
32  * There's still some voodoo going on here, but it's a lot better than
33  * in the first incarnation of the driver where all we had was the raw
34  * numbers from the initialization sequence.
35  */
ltv350qv_write_reg(struct ltv350qv * lcd,u8 reg,u16 val)36 static int ltv350qv_write_reg(struct ltv350qv *lcd, u8 reg, u16 val)
37 {
38 	struct spi_message msg;
39 	struct spi_transfer index_xfer = {
40 		.len		= 3,
41 		.cs_change	= 1,
42 	};
43 	struct spi_transfer value_xfer = {
44 		.len		= 3,
45 	};
46 
47 	spi_message_init(&msg);
48 
49 	/* register index */
50 	lcd->buffer[0] = LTV_OPC_INDEX;
51 	lcd->buffer[1] = 0x00;
52 	lcd->buffer[2] = reg & 0x7f;
53 	index_xfer.tx_buf = lcd->buffer;
54 	spi_message_add_tail(&index_xfer, &msg);
55 
56 	/* register value */
57 	lcd->buffer[4] = LTV_OPC_DATA;
58 	lcd->buffer[5] = val >> 8;
59 	lcd->buffer[6] = val;
60 	value_xfer.tx_buf = lcd->buffer + 4;
61 	spi_message_add_tail(&value_xfer, &msg);
62 
63 	return spi_sync(lcd->spi, &msg);
64 }
65 
66 /* The comments are taken straight from the data sheet */
ltv350qv_power_on(struct ltv350qv * lcd)67 static int ltv350qv_power_on(struct ltv350qv *lcd)
68 {
69 	int ret;
70 
71 	/* Power On Reset Display off State */
72 	if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 0x0000))
73 		goto err;
74 	usleep_range(15000, 16000);
75 
76 	/* Power Setting Function 1 */
77 	if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE))
78 		goto err;
79 	if (ltv350qv_write_reg(lcd, LTV_PWRCTL2, LTV_VCOML_ENABLE))
80 		goto err_power1;
81 
82 	/* Power Setting Function 2 */
83 	if (ltv350qv_write_reg(lcd, LTV_PWRCTL1,
84 			       LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
85 			       | LTV_SUPPLY_CURRENT(5)))
86 		goto err_power2;
87 
88 	msleep(55);
89 
90 	/* Instruction Setting */
91 	ret = ltv350qv_write_reg(lcd, LTV_IFCTL,
92 				 LTV_NMD | LTV_REV | LTV_NL(0x1d));
93 	ret |= ltv350qv_write_reg(lcd, LTV_DATACTL,
94 				  LTV_DS_SAME | LTV_CHS_480
95 				  | LTV_DF_RGB | LTV_RGB_BGR);
96 	ret |= ltv350qv_write_reg(lcd, LTV_ENTRY_MODE,
97 				  LTV_VSPL_ACTIVE_LOW
98 				  | LTV_HSPL_ACTIVE_LOW
99 				  | LTV_DPL_SAMPLE_RISING
100 				  | LTV_EPL_ACTIVE_LOW
101 				  | LTV_SS_RIGHT_TO_LEFT);
102 	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL1, LTV_CLW(3));
103 	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
104 				  LTV_NW_INV_1LINE | LTV_FWI(3));
105 	ret |= ltv350qv_write_reg(lcd, LTV_VBP, 0x000a);
106 	ret |= ltv350qv_write_reg(lcd, LTV_HBP, 0x0021);
107 	ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0));
108 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), 0x0103);
109 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), 0x0301);
110 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), 0x1f0f);
111 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), 0x1f0f);
112 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), 0x0707);
113 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), 0x0307);
114 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), 0x0707);
115 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), 0x0000);
116 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), 0x0004);
117 	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), 0x0000);
118 	if (ret)
119 		goto err_settings;
120 
121 	/* Wait more than 2 frames */
122 	msleep(20);
123 
124 	/* Display On Sequence */
125 	ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
126 				 LTV_VCOM_DISABLE | LTV_VCOMOUT_ENABLE
127 				 | LTV_POWER_ON | LTV_DRIVE_CURRENT(5)
128 				 | LTV_SUPPLY_CURRENT(5));
129 	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
130 				  LTV_NW_INV_1LINE | LTV_DSC | LTV_FWI(3));
131 	if (ret)
132 		goto err_disp_on;
133 
134 	/* Display should now be ON. Phew. */
135 	return 0;
136 
137 err_disp_on:
138 	/*
139 	 * Try to recover. Error handling probably isn't very useful
140 	 * at this point, just make a best effort to switch the panel
141 	 * off.
142 	 */
143 	ltv350qv_write_reg(lcd, LTV_PWRCTL1,
144 			   LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
145 			   | LTV_SUPPLY_CURRENT(5));
146 	ltv350qv_write_reg(lcd, LTV_GATECTL2,
147 			   LTV_NW_INV_1LINE | LTV_FWI(3));
148 err_settings:
149 err_power2:
150 err_power1:
151 	ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
152 	usleep_range(1000, 1100);
153 err:
154 	ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
155 	return -EIO;
156 }
157 
ltv350qv_power_off(struct ltv350qv * lcd)158 static int ltv350qv_power_off(struct ltv350qv *lcd)
159 {
160 	int ret;
161 
162 	/* Display Off Sequence */
163 	ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
164 				 LTV_VCOM_DISABLE
165 				 | LTV_DRIVE_CURRENT(5)
166 				 | LTV_SUPPLY_CURRENT(5));
167 	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
168 				  LTV_NW_INV_1LINE | LTV_FWI(3));
169 
170 	/* Power down setting 1 */
171 	ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
172 
173 	/* Wait at least 1 ms */
174 	usleep_range(1000, 1100);
175 
176 	/* Power down setting 2 */
177 	ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
178 
179 	/*
180 	 * No point in trying to recover here. If we can't switch the
181 	 * panel off, what are we supposed to do other than inform the
182 	 * user about the failure?
183 	 */
184 	if (ret)
185 		return -EIO;
186 
187 	/* Display power should now be OFF */
188 	return 0;
189 }
190 
ltv350qv_power(struct ltv350qv * lcd,int power)191 static int ltv350qv_power(struct ltv350qv *lcd, int power)
192 {
193 	int ret = 0;
194 
195 	if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
196 		ret = ltv350qv_power_on(lcd);
197 	else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
198 		ret = ltv350qv_power_off(lcd);
199 
200 	if (!ret)
201 		lcd->power = power;
202 
203 	return ret;
204 }
205 
ltv350qv_set_power(struct lcd_device * ld,int power)206 static int ltv350qv_set_power(struct lcd_device *ld, int power)
207 {
208 	struct ltv350qv *lcd = lcd_get_data(ld);
209 
210 	return ltv350qv_power(lcd, power);
211 }
212 
ltv350qv_get_power(struct lcd_device * ld)213 static int ltv350qv_get_power(struct lcd_device *ld)
214 {
215 	struct ltv350qv *lcd = lcd_get_data(ld);
216 
217 	return lcd->power;
218 }
219 
220 static struct lcd_ops ltv_ops = {
221 	.get_power	= ltv350qv_get_power,
222 	.set_power	= ltv350qv_set_power,
223 };
224 
ltv350qv_probe(struct spi_device * spi)225 static int ltv350qv_probe(struct spi_device *spi)
226 {
227 	struct ltv350qv *lcd;
228 	struct lcd_device *ld;
229 	int ret;
230 
231 	lcd = devm_kzalloc(&spi->dev, sizeof(struct ltv350qv), GFP_KERNEL);
232 	if (!lcd)
233 		return -ENOMEM;
234 
235 	lcd->spi = spi;
236 	lcd->power = FB_BLANK_POWERDOWN;
237 	lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL);
238 	if (!lcd->buffer)
239 		return -ENOMEM;
240 
241 	ld = devm_lcd_device_register(&spi->dev, "ltv350qv", &spi->dev, lcd,
242 					&ltv_ops);
243 	if (IS_ERR(ld))
244 		return PTR_ERR(ld);
245 
246 	lcd->ld = ld;
247 
248 	ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
249 	if (ret)
250 		return ret;
251 
252 	spi_set_drvdata(spi, lcd);
253 
254 	return 0;
255 }
256 
ltv350qv_remove(struct spi_device * spi)257 static void ltv350qv_remove(struct spi_device *spi)
258 {
259 	struct ltv350qv *lcd = spi_get_drvdata(spi);
260 
261 	ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
262 }
263 
264 #ifdef CONFIG_PM_SLEEP
ltv350qv_suspend(struct device * dev)265 static int ltv350qv_suspend(struct device *dev)
266 {
267 	struct ltv350qv *lcd = dev_get_drvdata(dev);
268 
269 	return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
270 }
271 
ltv350qv_resume(struct device * dev)272 static int ltv350qv_resume(struct device *dev)
273 {
274 	struct ltv350qv *lcd = dev_get_drvdata(dev);
275 
276 	return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
277 }
278 #endif
279 
280 static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume);
281 
282 /* Power down all displays on reboot, poweroff or halt */
ltv350qv_shutdown(struct spi_device * spi)283 static void ltv350qv_shutdown(struct spi_device *spi)
284 {
285 	struct ltv350qv *lcd = spi_get_drvdata(spi);
286 
287 	ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
288 }
289 
290 static struct spi_driver ltv350qv_driver = {
291 	.driver = {
292 		.name		= "ltv350qv",
293 		.pm		= &ltv350qv_pm_ops,
294 	},
295 
296 	.probe		= ltv350qv_probe,
297 	.remove		= ltv350qv_remove,
298 	.shutdown	= ltv350qv_shutdown,
299 };
300 
301 module_spi_driver(ltv350qv_driver);
302 
303 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
304 MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
305 MODULE_LICENSE("GPL");
306 MODULE_ALIAS("spi:ltv350qv");
307