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2c36c90f AK |
1 | /* |
2 | * Dell AIO Serial Backlight Driver | |
3 | * | |
4 | * Copyright (C) 2017 AceLan Kao <acelan.kao@canonical.com> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | */ | |
17 | ||
18 | #include <linux/kernel.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/acpi.h> | |
21 | #include <linux/serial_8250.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/backlight.h> | |
695f4adb | 24 | #include <linux/dmi.h> |
2c36c90f AK |
25 | #include <acpi/video.h> |
26 | ||
27 | #include "dell-uart-backlight.h" | |
28 | ||
29 | struct dell_uart_backlight { | |
30 | struct device *dev; | |
31 | struct backlight_device *dell_uart_bd; | |
32 | struct mutex brightness_mutex; | |
33 | int line; | |
34 | int bl_power; | |
35 | }; | |
36 | struct uart_8250_port *serial8250_get_port(int line); | |
37 | static struct tty_struct *tty; | |
38 | static struct file *ftty; | |
39 | ||
40 | unsigned int (*io_serial_in)(struct uart_port *p, int offset); | |
41 | int (*uart_write)(struct tty_struct *tty, const unsigned char *buf, int count); | |
42 | int (*uart_chars_in_buffer)(struct tty_struct *tty); | |
43 | ||
3ae4a11c AK |
44 | static bool force; |
45 | module_param(force, bool, 0444); | |
46 | MODULE_PARM_DESC(force, "load the driver regardless of the scalar status"); | |
47 | ||
2c36c90f AK |
48 | static struct dell_uart_bl_cmd uart_cmd[] = { |
49 | /* | |
50 | * Get Firmware Version: Tool uses this command to get firmware version. | |
51 | * Command: 0x6A 0x06 0x8F (Length:3 Type: 0x0A, Cmd:6 Checksum:0x8F) | |
52 | * Return data: 0x0D 0x06 Data checksum (Length:13,Cmd:0x06, | |
53 | * Data :F/W version(APRILIA=APR27-VXXX,PHINE=PHI23-VXXX), | |
54 | * checksum:SUM(Length and Cmd and Data)xor 0xFF . | |
55 | */ | |
56 | [DELL_UART_GET_FIRMWARE_VER] = { | |
57 | .cmd = {0x6A, 0x06, 0x8F}, | |
58 | .tx_len = 3, | |
59 | }, | |
42f03ced AK |
60 | /* |
61 | * Get Scalar Status: Tool uses this command to check if scalar IC controls brightness. | |
62 | * Command: 0x6A 0x1F 0x8F (Length:3 Type: 0x0A, Cmd:0x1F Checksum:0x76) | |
63 | * Return data: 0x04 0x1F Data checksum | |
64 | * (Data = 0: scalar cannot adjust brightness, Data = 1: scalar can adjust brightness) | |
65 | */ | |
66 | [DELL_UART_GET_SCALAR] = { | |
67 | .cmd = {0x6A,0x1F,0x76}, | |
68 | .ret = {0x04,0x1F,0x00,0x00}, | |
69 | .tx_len = 3, | |
70 | .rx_len = 4, | |
71 | }, | |
2c36c90f AK |
72 | /* |
73 | * Get Brightness level: Application uses this command for scaler to | |
74 | * get brightness. | |
75 | * Command: 0x6A 0x0C 0x89 | |
76 | * (Length:3 Type: 0x0A, Cmd:0x0C, Checksum:0x89) | |
77 | * Return data: 0x04 0x0C Data checksum | |
78 | * (Length:4 Cmd: 0x0C Data: brightness level | |
79 | * checksum: SUM(Length and Cmd and Data)xor 0xFF) | |
80 | * brightness level which ranges from 0~100. | |
81 | */ | |
82 | [DELL_UART_GET_BRIGHTNESS] = { | |
83 | .cmd = {0x6A, 0x0C, 0x89}, | |
84 | .ret = {0x04, 0x0C, 0x00, 0x00}, | |
85 | .tx_len = 3, | |
86 | .rx_len = 4, | |
87 | }, | |
88 | /* Set Brightness level: Application uses this command for scaler to | |
89 | * set brightness. | |
90 | * Command: 0x8A 0x0B Byte2 Checksum (Length:4 Type: 0x0A, Cmd:0x0B) | |
91 | * where Byte2 is the brightness level which ranges from 0~100. | |
92 | * Return data: 0x03 0x0B 0xF1(Length:3,Cmd:B,checksum:0xF1) | |
93 | * Scaler must send the 3bytes ack within 1 second when success, | |
94 | * other value if error | |
95 | */ | |
96 | [DELL_UART_SET_BRIGHTNESS] = { | |
97 | .cmd = {0x8A, 0x0B, 0x0, 0x0}, | |
98 | .ret = {0x03, 0x0B, 0xF1}, | |
99 | .tx_len = 4, | |
100 | .rx_len = 3, | |
101 | }, | |
102 | /* | |
103 | * Screen ON/OFF Control: Application uses this command to control | |
104 | * screen ON or OFF. | |
105 | * Command: 0x8A 0x0E Byte2 Checksum (Length:4 Type: 0x0A, Cmd:0x0E) | |
106 | * where | |
107 | * Byte2=0 to turn OFF the screen. | |
108 | * Byte2=1 to turn ON the screen | |
109 | * Other value of Byte2 is reserved and invalid. | |
110 | * Return data: 0x03 0x0E 0xEE(Length:3,Cmd:E,checksum:0xEE) | |
111 | */ | |
112 | [DELL_UART_SET_BACKLIGHT_POWER] = { | |
113 | .cmd = {0x8A, 0x0E, 0x00, 0x0}, | |
114 | .ret = {0x03, 0x0E, 0xEE}, | |
115 | .tx_len = 4, | |
116 | .rx_len = 3, | |
117 | }, | |
118 | }; | |
119 | ||
695f4adb AK |
120 | static const struct dmi_system_id dell_uart_backlight_alpha_platform[] __initconst = { |
121 | { | |
122 | .ident = "Dell Inspiron 7777 AIO", | |
123 | .matches = { | |
124 | DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), | |
125 | DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7777 AIO"), | |
126 | }, | |
127 | }, | |
128 | { | |
129 | .ident = "Dell Inspiron 5477 AIO", | |
130 | .matches = { | |
131 | DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), | |
132 | DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 5477 AIO"), | |
133 | }, | |
134 | }, | |
135 | { | |
136 | .ident = "Dell OptiPlex 7769 AIO", | |
137 | .matches = { | |
138 | DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), | |
139 | DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 7769 AIO"), | |
140 | }, | |
141 | }, | |
142 | { | |
143 | .ident = "Dell OptiPlex 5260 AIO", | |
144 | .matches = { | |
145 | DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."), | |
146 | DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex 5260 AIO"), | |
147 | }, | |
148 | }, | |
149 | { } | |
150 | }; | |
151 | ||
2c36c90f AK |
152 | static int dell_uart_write(struct uart_8250_port *up, __u8 *buf, int len) |
153 | { | |
154 | int actual = 0; | |
155 | struct uart_port *port = &up->port; | |
156 | ||
157 | tty_port_tty_wakeup(&port->state->port); | |
158 | tty = tty_port_tty_get(&port->state->port); | |
159 | actual = uart_write(tty, buf, len); | |
160 | while (uart_chars_in_buffer(tty)) | |
161 | udelay(10); | |
162 | ||
163 | return actual; | |
164 | } | |
165 | ||
166 | static int dell_uart_read(struct uart_8250_port *up, __u8 *buf, int len) | |
167 | { | |
168 | int i, retry; | |
169 | unsigned long flags; | |
170 | ||
171 | spin_lock_irqsave(&up->port.lock, flags); | |
172 | for (i = 0; i < len; i++) { | |
173 | retry = 10; | |
174 | while (!(io_serial_in(&up->port, UART_LSR) & UART_LSR_DR)) { | |
175 | if (--retry == 0) | |
176 | break; | |
177 | mdelay(20); | |
178 | } | |
179 | ||
180 | if (retry == 0) | |
181 | break; | |
182 | buf[i] = io_serial_in(&up->port, UART_RX); | |
183 | } | |
184 | spin_unlock_irqrestore(&up->port.lock, flags); | |
185 | ||
186 | return i; | |
187 | } | |
188 | ||
189 | static void dell_uart_dump_cmd(const char *func, const char *prefix, | |
190 | const char *cmd, int len) | |
191 | { | |
192 | char buf[80]; | |
193 | ||
194 | snprintf(buf, 80, "dell_uart_backlight:%s:%s", func, prefix); | |
195 | if (len != 0) | |
196 | print_hex_dump_debug(buf, DUMP_PREFIX_NONE, | |
197 | 16, 1, cmd, len, false); | |
198 | else | |
199 | pr_debug("dell_uart_backlight:%s:%sNULL\n", func, prefix); | |
200 | ||
201 | } | |
202 | ||
203 | /* | |
204 | * checksum: SUM(Length and Cmd and Data)xor 0xFF) | |
205 | */ | |
206 | static unsigned char dell_uart_checksum(unsigned char *buf, int len) | |
207 | { | |
208 | unsigned char val = 0; | |
209 | ||
210 | while (len-- > 0) | |
211 | val += buf[len]; | |
212 | ||
213 | return val ^ 0xff; | |
214 | } | |
215 | ||
216 | /* | |
217 | * There is no command to get backlight power status, | |
218 | * so we set the backlight power to "on" while initializing, | |
219 | * and then track and report its status by bl_power variable | |
220 | */ | |
221 | static inline int dell_uart_get_bl_power(struct dell_uart_backlight *dell_pdata) | |
222 | { | |
223 | return dell_pdata->bl_power; | |
224 | } | |
225 | ||
226 | static int dell_uart_set_bl_power(struct backlight_device *bd, int power) | |
227 | { | |
228 | struct dell_uart_bl_cmd *bl_cmd = | |
229 | &uart_cmd[DELL_UART_SET_BACKLIGHT_POWER]; | |
230 | struct dell_uart_backlight *dell_pdata = bl_get_data(bd); | |
231 | struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line); | |
232 | int rx_len; | |
233 | ||
234 | if (power != FB_BLANK_POWERDOWN) | |
235 | power = FB_BLANK_UNBLANK; | |
236 | ||
237 | bl_cmd->cmd[2] = power ? 0 : 1; | |
238 | bl_cmd->cmd[3] = dell_uart_checksum(bl_cmd->cmd, bl_cmd->tx_len - 1); | |
239 | ||
240 | dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len); | |
241 | ||
242 | if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) { | |
243 | pr_debug("Failed to get mutex_lock"); | |
244 | return 0; | |
245 | } | |
246 | ||
247 | dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len); | |
248 | rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len); | |
249 | ||
250 | mutex_unlock(&dell_pdata->brightness_mutex); | |
251 | ||
252 | dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len); | |
253 | ||
254 | bd->props.power = power; | |
255 | dell_pdata->bl_power = power; | |
256 | ||
257 | return 0; | |
258 | } | |
259 | ||
260 | static int dell_uart_get_brightness(struct backlight_device *bd) | |
261 | { | |
262 | struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_GET_BRIGHTNESS]; | |
263 | struct dell_uart_backlight *dell_pdata = bl_get_data(bd); | |
264 | struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line); | |
265 | int rx_len, brightness = 0; | |
266 | ||
267 | dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len); | |
268 | ||
269 | if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) { | |
270 | pr_debug("Failed to get mutex_lock"); | |
271 | return 0; | |
272 | } | |
273 | ||
274 | dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len); | |
275 | rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len); | |
276 | ||
277 | mutex_unlock(&dell_pdata->brightness_mutex); | |
278 | ||
279 | dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len); | |
280 | ||
281 | brightness = (unsigned int)bl_cmd->ret[2]; | |
282 | ||
283 | return brightness; | |
284 | } | |
285 | ||
286 | static int dell_uart_update_status(struct backlight_device *bd) | |
287 | { | |
288 | struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_SET_BRIGHTNESS]; | |
289 | struct dell_uart_backlight *dell_pdata = bl_get_data(bd); | |
290 | struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line); | |
291 | int rx_len; | |
292 | ||
293 | bl_cmd->cmd[2] = bd->props.brightness; | |
294 | bl_cmd->cmd[3] = dell_uart_checksum(bl_cmd->cmd, bl_cmd->tx_len - 1); | |
295 | ||
296 | dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len); | |
297 | ||
298 | if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) { | |
299 | pr_debug("Failed to get mutex_lock"); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len); | |
304 | rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len); | |
305 | ||
306 | mutex_unlock(&dell_pdata->brightness_mutex); | |
307 | ||
308 | dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len); | |
309 | ||
310 | if (bd->props.power != dell_uart_get_bl_power(dell_pdata)) | |
311 | dell_uart_set_bl_power(bd, bd->props.power); | |
312 | ||
313 | return 0; | |
314 | } | |
315 | ||
316 | static int dell_uart_get_scalar_status(struct dell_uart_backlight *dell_pdata) | |
317 | { | |
318 | struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_GET_SCALAR]; | |
319 | struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line); | |
320 | int rx_len; | |
ed491f25 | 321 | int status = 0, retry = 50; |
2c36c90f AK |
322 | |
323 | dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len); | |
324 | ||
325 | if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) { | |
326 | pr_debug("Failed to get mutex_lock"); | |
327 | return 0; | |
328 | } | |
329 | ||
330 | dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len); | |
7ea80b62 AK |
331 | do { |
332 | rx_len = dell_uart_read(uart, bl_cmd->ret, bl_cmd->rx_len); | |
333 | if (rx_len == 0) | |
334 | msleep(100); | |
335 | } while (rx_len == 0 && --retry); | |
2c36c90f AK |
336 | |
337 | mutex_unlock(&dell_pdata->brightness_mutex); | |
338 | ||
339 | dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len); | |
340 | ||
341 | if (rx_len == 4) | |
342 | status = (unsigned int)bl_cmd->ret[2]; | |
343 | ||
344 | return status; | |
345 | } | |
346 | ||
347 | static int dell_uart_show_firmware_ver(struct dell_uart_backlight *dell_pdata) | |
348 | { | |
349 | struct dell_uart_bl_cmd *bl_cmd = &uart_cmd[DELL_UART_GET_FIRMWARE_VER]; | |
350 | struct uart_8250_port *uart = serial8250_get_port(dell_pdata->line); | |
351 | int rx_len = 0, retry = 10; | |
352 | ||
353 | dell_uart_dump_cmd(__func__, "tx: ", bl_cmd->cmd, bl_cmd->tx_len); | |
354 | ||
355 | if (mutex_lock_killable(&dell_pdata->brightness_mutex) < 0) { | |
356 | pr_debug("Failed to get mutex_lock"); | |
357 | return -1; | |
358 | } | |
359 | ||
360 | dell_uart_write(uart, bl_cmd->cmd, bl_cmd->tx_len); | |
361 | while (retry-- > 0) { | |
362 | /* first byte is data length */ | |
363 | dell_uart_read(uart, bl_cmd->ret, 1); | |
364 | rx_len = (int)bl_cmd->ret[0]; | |
365 | if (bl_cmd->ret[0] > 80 || bl_cmd->ret[0] == 0) { | |
366 | pr_debug("Failed to get firmware version\n"); | |
367 | if (retry == 0) { | |
368 | mutex_unlock(&dell_pdata->brightness_mutex); | |
369 | return -1; | |
370 | } | |
371 | msleep(100); | |
372 | continue; | |
373 | } | |
374 | ||
375 | dell_uart_read(uart, bl_cmd->ret+1, rx_len-1); | |
376 | break; | |
377 | } | |
378 | mutex_unlock(&dell_pdata->brightness_mutex); | |
379 | ||
380 | dell_uart_dump_cmd(__func__, "rx: ", bl_cmd->ret, rx_len); | |
381 | ||
382 | pr_debug("Firmare str(%d)= %s\n", (int)bl_cmd->ret[0], bl_cmd->ret+2); | |
383 | return rx_len; | |
384 | } | |
385 | ||
386 | static const struct backlight_ops dell_uart_backlight_ops = { | |
387 | .get_brightness = dell_uart_get_brightness, | |
388 | .update_status = dell_uart_update_status, | |
389 | }; | |
390 | ||
391 | static int dell_uart_startup(struct dell_uart_backlight *dell_pdata) | |
392 | { | |
393 | struct uart_8250_port *uartp; | |
394 | struct uart_port *port; | |
395 | ||
396 | dell_pdata->line = 0; | |
397 | uartp = serial8250_get_port(dell_pdata->line); | |
398 | port = &uartp->port; | |
399 | tty = port->state->port.tty; | |
400 | io_serial_in = port->serial_in; | |
401 | uart_write = tty->driver->ops->write; | |
402 | uart_chars_in_buffer = tty->driver->ops->chars_in_buffer; | |
403 | ||
404 | return 0; | |
405 | } | |
406 | ||
407 | static int dell_uart_bl_add(struct acpi_device *dev) | |
408 | { | |
409 | struct dell_uart_backlight *dell_pdata; | |
410 | struct backlight_properties props; | |
411 | struct backlight_device *dell_uart_bd; | |
412 | ||
413 | dell_pdata = kzalloc(sizeof(struct dell_uart_backlight), GFP_KERNEL); | |
414 | if (!dell_pdata) { | |
415 | pr_debug("Failed to allocate memory for dell_uart_backlight\n"); | |
695f4adb | 416 | return -ENOMEM; |
2c36c90f AK |
417 | } |
418 | dell_pdata->dev = &dev->dev; | |
419 | dell_uart_startup(dell_pdata); | |
420 | dev->driver_data = dell_pdata; | |
421 | ||
422 | mutex_init(&dell_pdata->brightness_mutex); | |
423 | ||
695f4adb AK |
424 | if (!force) { |
425 | if (dmi_check_system(dell_uart_backlight_alpha_platform)) { | |
426 | /* try another command to make sure there is no scalar IC */ | |
427 | if (dell_uart_show_firmware_ver(dell_pdata) <= 4) { | |
428 | pr_debug("Scalar is not in charge of brightness adjustment.\n"); | |
429 | kzfree(dell_pdata); | |
430 | return -ENODEV; | |
431 | } | |
432 | } | |
433 | else if (!dell_uart_get_scalar_status(dell_pdata)) { | |
434 | pr_debug("Scalar is not in charge of brightness adjustment.\n"); | |
435 | kzfree(dell_pdata); | |
436 | return -ENODEV; | |
437 | } | |
2c36c90f | 438 | } |
23552db7 | 439 | dell_uart_show_firmware_ver(dell_pdata); |
2c36c90f AK |
440 | |
441 | memset(&props, 0, sizeof(struct backlight_properties)); | |
442 | props.type = BACKLIGHT_PLATFORM; | |
443 | props.max_brightness = 100; | |
444 | ||
445 | dell_uart_bd = backlight_device_register("dell_uart_backlight", | |
446 | &dev->dev, | |
447 | dell_pdata, | |
448 | &dell_uart_backlight_ops, | |
449 | &props); | |
450 | if (IS_ERR(dell_uart_bd)) { | |
451 | kzfree(dell_pdata); | |
452 | pr_debug("Backlight registration failed\n"); | |
695f4adb | 453 | return PTR_ERR(dell_uart_bd); |
2c36c90f AK |
454 | } |
455 | ||
456 | dell_pdata->dell_uart_bd = dell_uart_bd; | |
457 | ||
458 | dell_uart_set_bl_power(dell_uart_bd, FB_BLANK_UNBLANK); | |
459 | dell_uart_bd->props.brightness = 100; | |
460 | backlight_update_status(dell_uart_bd); | |
461 | ||
462 | /* unregister acpi backlight interface */ | |
463 | acpi_video_set_dmi_backlight_type(acpi_backlight_vendor); | |
464 | ||
465 | return 0; | |
466 | } | |
467 | ||
468 | static int dell_uart_bl_remove(struct acpi_device *dev) | |
469 | { | |
470 | struct dell_uart_backlight *dell_pdata = dev->driver_data; | |
471 | ||
472 | backlight_device_unregister(dell_pdata->dell_uart_bd); | |
473 | kzfree(dell_pdata); | |
474 | ||
475 | return 0; | |
476 | } | |
477 | ||
478 | static int dell_uart_bl_suspend(struct device *dev) | |
479 | { | |
480 | filp_close(ftty, NULL); | |
481 | return 0; | |
482 | } | |
483 | ||
484 | static int dell_uart_bl_resume(struct device *dev) | |
485 | { | |
486 | ftty = filp_open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY, 0); | |
487 | return 0; | |
488 | } | |
489 | ||
490 | static SIMPLE_DEV_PM_OPS(dell_uart_bl_pm, dell_uart_bl_suspend, dell_uart_bl_resume); | |
491 | ||
492 | static const struct acpi_device_id dell_uart_bl_ids[] = { | |
493 | {"DELL0501", 0}, | |
494 | {"", 0}, | |
495 | }; | |
496 | ||
497 | static struct acpi_driver dell_uart_backlight_driver = { | |
498 | .name = "Dell AIO serial backlight", | |
499 | .ids = dell_uart_bl_ids, | |
500 | .ops = { | |
501 | .add = dell_uart_bl_add, | |
502 | .remove = dell_uart_bl_remove, | |
503 | }, | |
504 | .drv.pm = &dell_uart_bl_pm, | |
505 | }; | |
506 | ||
507 | static int __init dell_uart_bl_init(void) | |
508 | { | |
509 | ftty = filp_open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY, 0); | |
510 | if (IS_ERR(ftty)) { | |
511 | pr_debug("cannot open /dev/ttyS0\n"); | |
512 | return -EINVAL; | |
513 | } | |
514 | ||
515 | return acpi_bus_register_driver(&dell_uart_backlight_driver); | |
516 | } | |
517 | ||
518 | static void __exit dell_uart_bl_exit(void) | |
519 | { | |
520 | filp_close(ftty, NULL); | |
521 | ||
522 | acpi_bus_unregister_driver(&dell_uart_backlight_driver); | |
523 | } | |
524 | ||
525 | module_init(dell_uart_bl_init); | |
526 | module_exit(dell_uart_bl_exit); | |
527 | MODULE_DEVICE_TABLE(acpi, dell_uart_bl_ids); | |
528 | MODULE_DESCRIPTION("Dell AIO Serial Backlight module"); | |
529 | MODULE_AUTHOR("AceLan Kao <acelan.kao@canonical.com>"); | |
530 | MODULE_LICENSE("GPL"); |