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
20struct 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 */
36static 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(m: &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(t: &index_xfer, m: &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(t: &value_xfer, m: &msg);
62
63 return spi_sync(spi: lcd->spi, message: &msg);
64}
65
66/* The comments are taken straight from the data sheet */
67static 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, val: 0x0000))
73 goto err;
74 usleep_range(min: 15000, max: 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(msecs: 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, val: 0x000a);
106 ret |= ltv350qv_write_reg(lcd, LTV_HBP, val: 0x0021);
107 ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0));
108 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), val: 0x0103);
109 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), val: 0x0301);
110 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), val: 0x1f0f);
111 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), val: 0x1f0f);
112 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), val: 0x0707);
113 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), val: 0x0307);
114 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), val: 0x0707);
115 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), val: 0x0000);
116 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), val: 0x0004);
117 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), val: 0x0000);
118 if (ret)
119 goto err_settings;
120
121 /* Wait more than 2 frames */
122 msleep(msecs: 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
137err_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));
148err_settings:
149err_power2:
150err_power1:
151 ltv350qv_write_reg(lcd, LTV_PWRCTL2, val: 0x0000);
152 usleep_range(min: 1000, max: 1100);
153err:
154 ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
155 return -EIO;
156}
157
158static 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, val: 0x0000);
172
173 /* Wait at least 1 ms */
174 usleep_range(min: 1000, max: 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
191static 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
206static int ltv350qv_set_power(struct lcd_device *ld, int power)
207{
208 struct ltv350qv *lcd = lcd_get_data(ld_dev: ld);
209
210 return ltv350qv_power(lcd, power);
211}
212
213static int ltv350qv_get_power(struct lcd_device *ld)
214{
215 struct ltv350qv *lcd = lcd_get_data(ld_dev: ld);
216
217 return lcd->power;
218}
219
220static struct lcd_ops ltv_ops = {
221 .get_power = ltv350qv_get_power,
222 .set_power = ltv350qv_set_power,
223};
224
225static 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(dev: &spi->dev, size: 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(dev: &spi->dev, size: 8, GFP_KERNEL);
238 if (!lcd->buffer)
239 return -ENOMEM;
240
241 ld = devm_lcd_device_register(dev: &spi->dev, name: "ltv350qv", parent: &spi->dev, devdata: lcd,
242 ops: &ltv_ops);
243 if (IS_ERR(ptr: ld))
244 return PTR_ERR(ptr: ld);
245
246 lcd->ld = ld;
247
248 ret = ltv350qv_power(lcd, power: FB_BLANK_UNBLANK);
249 if (ret)
250 return ret;
251
252 spi_set_drvdata(spi, data: lcd);
253
254 return 0;
255}
256
257static void ltv350qv_remove(struct spi_device *spi)
258{
259 struct ltv350qv *lcd = spi_get_drvdata(spi);
260
261 ltv350qv_power(lcd, power: FB_BLANK_POWERDOWN);
262}
263
264#ifdef CONFIG_PM_SLEEP
265static int ltv350qv_suspend(struct device *dev)
266{
267 struct ltv350qv *lcd = dev_get_drvdata(dev);
268
269 return ltv350qv_power(lcd, power: FB_BLANK_POWERDOWN);
270}
271
272static int ltv350qv_resume(struct device *dev)
273{
274 struct ltv350qv *lcd = dev_get_drvdata(dev);
275
276 return ltv350qv_power(lcd, power: FB_BLANK_UNBLANK);
277}
278#endif
279
280static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume);
281
282/* Power down all displays on reboot, poweroff or halt */
283static void ltv350qv_shutdown(struct spi_device *spi)
284{
285 struct ltv350qv *lcd = spi_get_drvdata(spi);
286
287 ltv350qv_power(lcd, power: FB_BLANK_POWERDOWN);
288}
289
290static 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
301module_spi_driver(ltv350qv_driver);
302
303MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
304MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
305MODULE_LICENSE("GPL");
306MODULE_ALIAS("spi:ltv350qv");
307

source code of linux/drivers/video/backlight/ltv350qv.c