xref: /openbmc/linux/drivers/parisc/led.c (revision 789e527a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *	Chassis LCD/LED driver for HP-PARISC workstations
4  *
5  *	(c) Copyright 2000 Red Hat Software
6  *	(c) Copyright 2000 Helge Deller <hdeller@redhat.com>
7  *	(c) Copyright 2001 Randolph Chung <tausq@debian.org>
8  *	(c) Copyright 2000-2023 Helge Deller <deller@gmx.de>
9  *
10  *	The control of the LEDs and LCDs on PARISC machines has to be done
11  *	completely in software.
12  *
13  *	The LEDs can be configured at runtime in /sys/class/leds/
14  */
15 
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/types.h>
19 #include <linux/ioport.h>
20 #include <linux/utsname.h>
21 #include <linux/capability.h>
22 #include <linux/delay.h>
23 #include <linux/reboot.h>
24 #include <linux/uaccess.h>
25 #include <linux/leds.h>
26 #include <linux/platform_device.h>
27 
28 #include <asm/io.h>
29 #include <asm/processor.h>
30 #include <asm/hardware.h>
31 #include <asm/param.h>		/* HZ */
32 #include <asm/led.h>
33 #include <asm/pdc.h>
34 
35 #define LED_HAS_LCD 1
36 #define LED_HAS_LED 2
37 
38 static unsigned char led_type;		/* bitmask of LED_HAS_XXX */
39 static unsigned char lastleds;		/* LED state from most recent update */
40 static unsigned char lcd_new_text;
41 static unsigned char lcd_text[20];
42 static unsigned char lcd_text_default[20];
43 static unsigned char lcd_no_led_support; /* KittyHawk doesn't support LED on its LCD */
44 
45 struct lcd_block {
46 	unsigned char command;	/* stores the command byte      */
47 	unsigned char on;	/* value for turning LED on     */
48 	unsigned char off;	/* value for turning LED off    */
49 };
50 
51 /* Structure returned by PDC_RETURN_CHASSIS_INFO */
52 /* NOTE: we use unsigned long:16 two times, since the following member
53    lcd_cmd_reg_addr needs to be 64bit aligned on 64bit PA2.0-machines */
54 struct pdc_chassis_lcd_info_ret_block {
55 	unsigned long model:16;		/* DISPLAY_MODEL_XXXX */
56 	unsigned long lcd_width:16;	/* width of the LCD in chars (DISPLAY_MODEL_LCD only) */
57 	unsigned long lcd_cmd_reg_addr;	/* ptr to LCD cmd-register & data ptr for LED */
58 	unsigned long lcd_data_reg_addr; /* ptr to LCD data-register (LCD only) */
59 	unsigned int min_cmd_delay;	/* delay in uS after cmd-write (LCD only) */
60 	unsigned char reset_cmd1;	/* command #1 for writing LCD string (LCD only) */
61 	unsigned char reset_cmd2;	/* command #2 for writing LCD string (LCD only) */
62 	unsigned char act_enable;	/* 0 = no activity (LCD only) */
63 	struct lcd_block heartbeat;
64 	struct lcd_block disk_io;
65 	struct lcd_block lan_rcv;
66 	struct lcd_block lan_tx;
67 	char _pad;
68 };
69 
70 
71 /* LCD_CMD and LCD_DATA for KittyHawk machines */
72 #define KITTYHAWK_LCD_CMD  F_EXTEND(0xf0190000UL)
73 #define KITTYHAWK_LCD_DATA (KITTYHAWK_LCD_CMD + 1)
74 
75 /* lcd_info is pre-initialized to the values needed to program KittyHawk LCD's
76  * HP seems to have used Sharp/Hitachi HD44780 LCDs most of the time. */
77 static struct pdc_chassis_lcd_info_ret_block
78 lcd_info __attribute__((aligned(8)))  =
79 {
80 	.model =		DISPLAY_MODEL_NONE,
81 	.lcd_width =		16,
82 	.lcd_cmd_reg_addr =	KITTYHAWK_LCD_CMD,
83 	.lcd_data_reg_addr =	KITTYHAWK_LCD_DATA,
84 	.min_cmd_delay =	80,
85 	.reset_cmd1 =		0x80,
86 	.reset_cmd2 =		0xc0,
87 };
88 
89 /* direct access to some of the lcd_info variables */
90 #define LCD_CMD_REG	lcd_info.lcd_cmd_reg_addr
91 #define LCD_DATA_REG	lcd_info.lcd_data_reg_addr
92 #define LED_DATA_REG	lcd_info.lcd_cmd_reg_addr	/* LASI & ASP only */
93 
94 /* ptr to LCD/LED-specific function */
95 static void (*led_func_ptr) (unsigned char);
96 
97 
lcd_print_now(void)98 static void lcd_print_now(void)
99 {
100 	int i;
101 	char *str = lcd_text;
102 
103 	if (lcd_info.model != DISPLAY_MODEL_LCD)
104 		return;
105 
106 	if (!lcd_new_text)
107 		return;
108 	lcd_new_text = 0;
109 
110 	/* Set LCD Cursor to 1st character */
111 	gsc_writeb(lcd_info.reset_cmd1, LCD_CMD_REG);
112 	udelay(lcd_info.min_cmd_delay);
113 
114 	/* Print the string */
115 	for (i = 0; i < lcd_info.lcd_width; i++) {
116 		gsc_writeb(*str ? *str++ : ' ', LCD_DATA_REG);
117 		udelay(lcd_info.min_cmd_delay);
118 	}
119 }
120 
121 /**
122  *	lcd_print()
123  *
124  *	@str: string to show on the LCD. If NULL, print current string again.
125  *
126  *	Displays the given string on the LCD-Display of newer machines.
127  */
lcd_print(const char * str)128 void lcd_print(const char *str)
129 {
130 	/* copy display string to buffer for procfs */
131 	if (str)
132 		strscpy(lcd_text, str, sizeof(lcd_text));
133 	lcd_new_text = 1;
134 
135 	/* print now if LCD without any LEDs */
136 	if (led_type == LED_HAS_LCD)
137 		lcd_print_now();
138 }
139 
140 #define	LED_DATA	0x01	/* data to shift (0:on 1:off) */
141 #define	LED_STROBE	0x02	/* strobe to clock data */
142 
143 /**
144  *	led_ASP_driver() - LED driver for the ASP controller chip
145  *
146  *	@leds: bitmap representing the LED status
147  */
led_ASP_driver(unsigned char leds)148 static void led_ASP_driver(unsigned char leds)
149 {
150 	int i;
151 
152 	leds = ~leds;
153 	for (i = 0; i < 8; i++) {
154 		unsigned char value;
155 		value = (leds & 0x80) >> 7;
156 		gsc_writeb( value,		 LED_DATA_REG );
157 		gsc_writeb( value | LED_STROBE,	 LED_DATA_REG );
158 		leds <<= 1;
159 	}
160 }
161 
162 /**
163  *	led_LASI_driver() - LED driver for the LASI controller chip
164  *
165  *	@leds: bitmap representing the LED status
166  */
led_LASI_driver(unsigned char leds)167 static void led_LASI_driver(unsigned char leds)
168 {
169 	leds = ~leds;
170 	gsc_writeb( leds, LED_DATA_REG );
171 }
172 
173 /**
174  *	led_LCD_driver() - LED & LCD driver for LCD chips
175  *
176  *	@leds: bitmap representing the LED status
177  */
led_LCD_driver(unsigned char leds)178 static void led_LCD_driver(unsigned char leds)
179 {
180 	static const unsigned char mask[4] = {
181 		LED_HEARTBEAT, LED_DISK_IO,
182 		LED_LAN_RCV, LED_LAN_TX };
183 
184 	static struct lcd_block * const blockp[4] = {
185 		&lcd_info.heartbeat,
186 		&lcd_info.disk_io,
187 		&lcd_info.lan_rcv,
188 		&lcd_info.lan_tx
189 	};
190 	static unsigned char latest_leds;
191 	int i;
192 
193 	for (i = 0; i < 4; ++i) {
194 		if ((leds & mask[i]) == (latest_leds & mask[i]))
195 			continue;
196 
197 		gsc_writeb( blockp[i]->command, LCD_CMD_REG );
198 		udelay(lcd_info.min_cmd_delay);
199 
200 		gsc_writeb( leds & mask[i] ? blockp[i]->on :
201 				blockp[i]->off, LCD_DATA_REG );
202 		udelay(lcd_info.min_cmd_delay);
203 	}
204 	latest_leds = leds;
205 
206 	lcd_print_now();
207 }
208 
209 
210 /**
211  *	lcd_system_halt()
212  *
213  *	@nb: pointer to the notifier_block structure
214  *	@event: the event (SYS_RESTART, SYS_HALT or SYS_POWER_OFF)
215  *	@buf: pointer to a buffer (not used)
216  *
217  *	Called by the reboot notifier chain at shutdown. Stops all
218  *	LED/LCD activities.
219  */
lcd_system_halt(struct notifier_block * nb,unsigned long event,void * buf)220 static int lcd_system_halt(struct notifier_block *nb, unsigned long event, void *buf)
221 {
222 	const char *txt;
223 
224 	switch (event) {
225 	case SYS_RESTART:	txt = "SYSTEM RESTART";
226 				break;
227 	case SYS_HALT:		txt = "SYSTEM HALT";
228 				break;
229 	case SYS_POWER_OFF:	txt = "SYSTEM POWER OFF";
230 				break;
231 	default:		return NOTIFY_DONE;
232 	}
233 
234 	lcd_print(txt);
235 
236 	return NOTIFY_OK;
237 }
238 
239 static struct notifier_block lcd_system_halt_notifier = {
240 	.notifier_call = lcd_system_halt,
241 };
242 
243 static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness);
244 
245 struct hppa_led {
246 	struct led_classdev	led_cdev;
247 	unsigned char		led_bit;
248 };
249 #define to_hppa_led(d) container_of(d, struct hppa_led, led_cdev)
250 
251 typedef void (*set_handler)(struct led_classdev *, enum led_brightness);
252 struct led_type {
253 	const char	*name;
254 	set_handler	handler;
255 	const char	*default_trigger;
256 };
257 
258 #define NUM_LEDS_PER_BOARD	8
259 struct hppa_drvdata {
260 	struct hppa_led	leds[NUM_LEDS_PER_BOARD];
261 };
262 
set_led(struct led_classdev * led_cdev,enum led_brightness brightness)263 static void set_led(struct led_classdev *led_cdev, enum led_brightness brightness)
264 {
265 	struct hppa_led *p = to_hppa_led(led_cdev);
266 	unsigned char led_bit = p->led_bit;
267 
268 	if (brightness == LED_OFF)
269 		lastleds &= ~led_bit;
270 	else
271 		lastleds |= led_bit;
272 
273 	if (led_func_ptr)
274 		led_func_ptr(lastleds);
275 }
276 
277 
hppa_led_generic_probe(struct platform_device * pdev,struct led_type * types)278 static int hppa_led_generic_probe(struct platform_device *pdev,
279 				  struct led_type *types)
280 {
281 	struct hppa_drvdata *p;
282 	int i, err;
283 
284 	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
285 	if (!p)
286 		return -ENOMEM;
287 
288 	for (i = 0; i < NUM_LEDS_PER_BOARD; i++) {
289 		struct led_classdev *lp = &p->leds[i].led_cdev;
290 
291 		p->leds[i].led_bit = BIT(i);
292 		lp->name = types[i].name;
293 		lp->brightness = LED_FULL;
294 		lp->brightness_set = types[i].handler;
295 		lp->default_trigger = types[i].default_trigger;
296 		err = led_classdev_register(&pdev->dev, lp);
297 		if (err) {
298 			dev_err(&pdev->dev, "Could not register %s LED\n",
299 			       lp->name);
300 			for (i--; i >= 0; i--)
301 				led_classdev_unregister(&p->leds[i].led_cdev);
302 			return err;
303 		}
304 	}
305 
306 	platform_set_drvdata(pdev, p);
307 
308 	return 0;
309 }
310 
platform_led_remove(struct platform_device * pdev)311 static int platform_led_remove(struct platform_device *pdev)
312 {
313 	struct hppa_drvdata *p = platform_get_drvdata(pdev);
314 	int i;
315 
316 	for (i = 0; i < NUM_LEDS_PER_BOARD; i++)
317 		led_classdev_unregister(&p->leds[i].led_cdev);
318 
319 	return 0;
320 }
321 
322 static struct led_type mainboard_led_types[NUM_LEDS_PER_BOARD] = {
323 	{
324 		.name		= "platform-lan-tx",
325 		.handler	= set_led,
326 		.default_trigger = "tx",
327 	},
328 	{
329 		.name		= "platform-lan-rx",
330 		.handler	= set_led,
331 		.default_trigger = "rx",
332 	},
333 	{
334 		.name		= "platform-disk",
335 		.handler	= set_led,
336 		.default_trigger = "disk-activity",
337 	},
338 	{
339 		.name		= "platform-heartbeat",
340 		.handler	= set_led,
341 		.default_trigger = "heartbeat",
342 	},
343 	{
344 		.name		= "platform-LED4",
345 		.handler	= set_led,
346 		.default_trigger = "panic",
347 	},
348 	{
349 		.name		= "platform-LED5",
350 		.handler	= set_led,
351 		.default_trigger = "panic",
352 	},
353 	{
354 		.name		= "platform-LED6",
355 		.handler	= set_led,
356 		.default_trigger = "panic",
357 	},
358 	{
359 		.name		= "platform-LED7",
360 		.handler	= set_led,
361 		.default_trigger = "panic",
362 	},
363 };
364 
platform_led_probe(struct platform_device * pdev)365 static int platform_led_probe(struct platform_device *pdev)
366 {
367 	return hppa_led_generic_probe(pdev, mainboard_led_types);
368 }
369 
370 MODULE_ALIAS("platform:platform-leds");
371 
372 static struct platform_driver hppa_mainboard_led_driver = {
373 	.probe		= platform_led_probe,
374 	.remove		= platform_led_remove,
375 	.driver		= {
376 		.name	= "platform-leds",
377 	},
378 };
379 
380 static struct platform_driver * const drivers[] = {
381 	&hppa_mainboard_led_driver,
382 };
383 
384 static struct platform_device platform_leds = {
385 	.name = "platform-leds",
386 };
387 
388 /**
389  *	register_led_driver()
390  *
391  *	@model: model type, one of the DISPLAY_MODEL_XXXX values
392  *	@cmd_reg: physical address of cmd register for the LED/LCD
393  *	@data_reg: physical address of data register for the LED/LCD
394  *
395  *	Registers a chassis LED or LCD which should be driven by this driver.
396  *	Only PDC-based, LASI- or ASP-style LEDs and LCDs are supported.
397  */
register_led_driver(int model,unsigned long cmd_reg,unsigned long data_reg)398 int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg)
399 {
400 	if (led_func_ptr || !data_reg)
401 		return 1;
402 
403 	/* No LEDs when running in QEMU */
404 	if (running_on_qemu)
405 		return 1;
406 
407 	lcd_info.model = model;		/* store the values */
408 	LCD_CMD_REG = (cmd_reg == LED_CMD_REG_NONE) ? 0 : cmd_reg;
409 
410 	switch (lcd_info.model) {
411 	case DISPLAY_MODEL_LCD:
412 		LCD_DATA_REG = data_reg;
413 		pr_info("led: LCD display at %#lx and %#lx\n",
414 			LCD_CMD_REG , LCD_DATA_REG);
415 		led_func_ptr = led_LCD_driver;
416 		if (lcd_no_led_support)
417 			led_type = LED_HAS_LCD;
418 		else
419 			led_type = LED_HAS_LCD | LED_HAS_LED;
420 		break;
421 
422 	case DISPLAY_MODEL_LASI:
423 		LED_DATA_REG = data_reg;
424 		led_func_ptr = led_LASI_driver;
425 		pr_info("led: LED display at %#lx\n", LED_DATA_REG);
426 		led_type = LED_HAS_LED;
427 		break;
428 
429 	case DISPLAY_MODEL_OLD_ASP:
430 		LED_DATA_REG = data_reg;
431 		led_func_ptr = led_ASP_driver;
432 		pr_info("led: LED (ASP-style) display at %#lx\n",
433 		    LED_DATA_REG);
434 		led_type = LED_HAS_LED;
435 		break;
436 
437 	default:
438 		pr_err("led: Unknown LCD/LED model type %d\n", lcd_info.model);
439 		return 1;
440 	}
441 
442 	platform_register_drivers(drivers, ARRAY_SIZE(drivers));
443 
444 	return register_reboot_notifier(&lcd_system_halt_notifier);
445 }
446 
447 /**
448  *	early_led_init()
449  *
450  *	early_led_init() is called early in the bootup-process and asks the
451  *	PDC for an usable chassis LCD or LED. If the PDC doesn't return any
452  *	info, then a LED might be detected by the LASI or ASP drivers later.
453  *	KittyHawk machines have often a buggy PDC, so that we explicitly check
454  *	for those machines here.
455  */
early_led_init(void)456 static int __init early_led_init(void)
457 {
458 	struct pdc_chassis_info chassis_info;
459 	int ret;
460 
461 	snprintf(lcd_text_default, sizeof(lcd_text_default),
462 		"Linux %s", init_utsname()->release);
463 	strcpy(lcd_text, lcd_text_default);
464 	lcd_new_text = 1;
465 
466 	/* Work around the buggy PDC of KittyHawk-machines */
467 	switch (CPU_HVERSION) {
468 	case 0x580:		/* KittyHawk DC2-100 (K100) */
469 	case 0x581:		/* KittyHawk DC3-120 (K210) */
470 	case 0x582:		/* KittyHawk DC3 100 (K400) */
471 	case 0x583:		/* KittyHawk DC3 120 (K410) */
472 	case 0x58B:		/* KittyHawk DC2 100 (K200) */
473 		pr_info("LCD on KittyHawk-Machine found.\n");
474 		lcd_info.model = DISPLAY_MODEL_LCD;
475 		/* KittyHawk has no LED support on its LCD, so skip LED detection */
476 		lcd_no_led_support = 1;
477 		goto found;	/* use the preinitialized values of lcd_info */
478 	}
479 
480 	/* initialize the struct, so that we can check for valid return values */
481 	chassis_info.actcnt = chassis_info.maxcnt = 0;
482 
483 	ret = pdc_chassis_info(&chassis_info, &lcd_info, sizeof(lcd_info));
484 	if (ret != PDC_OK) {
485 not_found:
486 		lcd_info.model = DISPLAY_MODEL_NONE;
487 		return 1;
488 	}
489 
490 	/* check the results. Some machines have a buggy PDC */
491 	if (chassis_info.actcnt <= 0 || chassis_info.actcnt != chassis_info.maxcnt)
492 		goto not_found;
493 
494 	switch (lcd_info.model) {
495 	case DISPLAY_MODEL_LCD:		/* LCD display */
496 		if (chassis_info.actcnt <
497 			offsetof(struct pdc_chassis_lcd_info_ret_block, _pad)-1)
498 			goto not_found;
499 		if (!lcd_info.act_enable) {
500 			/* PDC tells LCD should not be used. */
501 			goto not_found;
502 		}
503 		break;
504 
505 	case DISPLAY_MODEL_NONE:	/* no LED or LCD available */
506 		goto not_found;
507 
508 	case DISPLAY_MODEL_LASI:	/* Lasi style 8 bit LED display */
509 		if (chassis_info.actcnt != 8 && chassis_info.actcnt != 32)
510 			goto not_found;
511 		break;
512 
513 	default:
514 		pr_warn("PDC reported unknown LCD/LED model %d\n",
515 		       lcd_info.model);
516 		goto not_found;
517 	}
518 
519 found:
520 	/* register the LCD/LED driver */
521 	return register_led_driver(lcd_info.model, LCD_CMD_REG, LCD_DATA_REG);
522 }
523 arch_initcall(early_led_init);
524 
525 /**
526  *	register_led_regions()
527  *
528  *	Register_led_regions() registers the LCD/LED regions for /procfs.
529  *	At bootup - where the initialisation of the LCD/LED often happens
530  *	not all internal structures of request_region() are properly set up,
531  *	so that we delay the led-registration until after busdevices_init()
532  *	has been executed.
533  */
register_led_regions(void)534 static void __init register_led_regions(void)
535 {
536 	switch (lcd_info.model) {
537 	case DISPLAY_MODEL_LCD:
538 		request_mem_region((unsigned long)LCD_CMD_REG,  1, "lcd_cmd");
539 		request_mem_region((unsigned long)LCD_DATA_REG, 1, "lcd_data");
540 		break;
541 	case DISPLAY_MODEL_LASI:
542 	case DISPLAY_MODEL_OLD_ASP:
543 		request_mem_region((unsigned long)LED_DATA_REG, 1, "led_data");
544 		break;
545 	}
546 }
547 
startup_leds(void)548 static int __init startup_leds(void)
549 {
550 	if (platform_device_register(&platform_leds))
551                 printk(KERN_INFO "LED: failed to register LEDs\n");
552 	register_led_regions();
553 	return 0;
554 }
555 device_initcall(startup_leds);
556