xref: /openbmc/linux/drivers/input/serio/sa1111ps2.c (revision 2a598d0b) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/drivers/input/serio/sa1111ps2.c
4  *
5  *  Copyright (C) 2002 Russell King
6  */
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/input.h>
10 #include <linux/serio.h>
11 #include <linux/errno.h>
12 #include <linux/interrupt.h>
13 #include <linux/ioport.h>
14 #include <linux/delay.h>
15 #include <linux/device.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 
19 #include <asm/io.h>
20 
21 #include <asm/hardware/sa1111.h>
22 
23 #define PS2CR		0x0000
24 #define PS2STAT		0x0004
25 #define PS2DATA		0x0008
26 #define PS2CLKDIV	0x000c
27 #define PS2PRECNT	0x0010
28 
29 #define PS2CR_ENA	0x08
30 #define PS2CR_FKD	0x02
31 #define PS2CR_FKC	0x01
32 
33 #define PS2STAT_STP	0x0100
34 #define PS2STAT_TXE	0x0080
35 #define PS2STAT_TXB	0x0040
36 #define PS2STAT_RXF	0x0020
37 #define PS2STAT_RXB	0x0010
38 #define PS2STAT_ENA	0x0008
39 #define PS2STAT_RXP	0x0004
40 #define PS2STAT_KBD	0x0002
41 #define PS2STAT_KBC	0x0001
42 
43 struct ps2if {
44 	struct serio		*io;
45 	struct sa1111_dev	*dev;
46 	void __iomem		*base;
47 	int			rx_irq;
48 	int			tx_irq;
49 	unsigned int		open;
50 	spinlock_t		lock;
51 	unsigned int		head;
52 	unsigned int		tail;
53 	unsigned char		buf[4];
54 };
55 
56 /*
57  * Read all bytes waiting in the PS2 port.  There should be
58  * at the most one, but we loop for safety.  If there was a
59  * framing error, we have to manually clear the status.
60  */
61 static irqreturn_t ps2_rxint(int irq, void *dev_id)
62 {
63 	struct ps2if *ps2if = dev_id;
64 	unsigned int scancode, flag, status;
65 
66 	status = readl_relaxed(ps2if->base + PS2STAT);
67 	while (status & PS2STAT_RXF) {
68 		if (status & PS2STAT_STP)
69 			writel_relaxed(PS2STAT_STP, ps2if->base + PS2STAT);
70 
71 		flag = (status & PS2STAT_STP ? SERIO_FRAME : 0) |
72 		       (status & PS2STAT_RXP ? 0 : SERIO_PARITY);
73 
74 		scancode = readl_relaxed(ps2if->base + PS2DATA) & 0xff;
75 
76 		if (hweight8(scancode) & 1)
77 			flag ^= SERIO_PARITY;
78 
79 		serio_interrupt(ps2if->io, scancode, flag);
80 
81 		status = readl_relaxed(ps2if->base + PS2STAT);
82         }
83 
84         return IRQ_HANDLED;
85 }
86 
87 /*
88  * Completion of ps2 write
89  */
90 static irqreturn_t ps2_txint(int irq, void *dev_id)
91 {
92 	struct ps2if *ps2if = dev_id;
93 	unsigned int status;
94 
95 	spin_lock(&ps2if->lock);
96 	status = readl_relaxed(ps2if->base + PS2STAT);
97 	if (ps2if->head == ps2if->tail) {
98 		disable_irq_nosync(irq);
99 		/* done */
100 	} else if (status & PS2STAT_TXE) {
101 		writel_relaxed(ps2if->buf[ps2if->tail], ps2if->base + PS2DATA);
102 		ps2if->tail = (ps2if->tail + 1) & (sizeof(ps2if->buf) - 1);
103 	}
104 	spin_unlock(&ps2if->lock);
105 
106 	return IRQ_HANDLED;
107 }
108 
109 /*
110  * Write a byte to the PS2 port.  We have to wait for the
111  * port to indicate that the transmitter is empty.
112  */
113 static int ps2_write(struct serio *io, unsigned char val)
114 {
115 	struct ps2if *ps2if = io->port_data;
116 	unsigned long flags;
117 	unsigned int head;
118 
119 	spin_lock_irqsave(&ps2if->lock, flags);
120 
121 	/*
122 	 * If the TX register is empty, we can go straight out.
123 	 */
124 	if (readl_relaxed(ps2if->base + PS2STAT) & PS2STAT_TXE) {
125 		writel_relaxed(val, ps2if->base + PS2DATA);
126 	} else {
127 		if (ps2if->head == ps2if->tail)
128 			enable_irq(ps2if->tx_irq);
129 		head = (ps2if->head + 1) & (sizeof(ps2if->buf) - 1);
130 		if (head != ps2if->tail) {
131 			ps2if->buf[ps2if->head] = val;
132 			ps2if->head = head;
133 		}
134 	}
135 
136 	spin_unlock_irqrestore(&ps2if->lock, flags);
137 	return 0;
138 }
139 
140 static int ps2_open(struct serio *io)
141 {
142 	struct ps2if *ps2if = io->port_data;
143 	int ret;
144 
145 	ret = sa1111_enable_device(ps2if->dev);
146 	if (ret)
147 		return ret;
148 
149 	ret = request_irq(ps2if->rx_irq, ps2_rxint, 0,
150 			  SA1111_DRIVER_NAME(ps2if->dev), ps2if);
151 	if (ret) {
152 		printk(KERN_ERR "sa1111ps2: could not allocate IRQ%d: %d\n",
153 			ps2if->rx_irq, ret);
154 		sa1111_disable_device(ps2if->dev);
155 		return ret;
156 	}
157 
158 	ret = request_irq(ps2if->tx_irq, ps2_txint, 0,
159 			  SA1111_DRIVER_NAME(ps2if->dev), ps2if);
160 	if (ret) {
161 		printk(KERN_ERR "sa1111ps2: could not allocate IRQ%d: %d\n",
162 			ps2if->tx_irq, ret);
163 		free_irq(ps2if->rx_irq, ps2if);
164 		sa1111_disable_device(ps2if->dev);
165 		return ret;
166 	}
167 
168 	ps2if->open = 1;
169 
170 	enable_irq_wake(ps2if->rx_irq);
171 
172 	writel_relaxed(PS2CR_ENA, ps2if->base + PS2CR);
173 	return 0;
174 }
175 
176 static void ps2_close(struct serio *io)
177 {
178 	struct ps2if *ps2if = io->port_data;
179 
180 	writel_relaxed(0, ps2if->base + PS2CR);
181 
182 	disable_irq_wake(ps2if->rx_irq);
183 
184 	ps2if->open = 0;
185 
186 	free_irq(ps2if->tx_irq, ps2if);
187 	free_irq(ps2if->rx_irq, ps2if);
188 
189 	sa1111_disable_device(ps2if->dev);
190 }
191 
192 /*
193  * Clear the input buffer.
194  */
195 static void ps2_clear_input(struct ps2if *ps2if)
196 {
197 	int maxread = 100;
198 
199 	while (maxread--) {
200 		if ((readl_relaxed(ps2if->base + PS2DATA) & 0xff) == 0xff)
201 			break;
202 	}
203 }
204 
205 static unsigned int ps2_test_one(struct ps2if *ps2if,
206 					   unsigned int mask)
207 {
208 	unsigned int val;
209 
210 	writel_relaxed(PS2CR_ENA | mask, ps2if->base + PS2CR);
211 
212 	udelay(10);
213 
214 	val = readl_relaxed(ps2if->base + PS2STAT);
215 	return val & (PS2STAT_KBC | PS2STAT_KBD);
216 }
217 
218 /*
219  * Test the keyboard interface.  We basically check to make sure that
220  * we can drive each line to the keyboard independently of each other.
221  */
222 static int ps2_test(struct ps2if *ps2if)
223 {
224 	unsigned int stat;
225 	int ret = 0;
226 
227 	stat = ps2_test_one(ps2if, PS2CR_FKC);
228 	if (stat != PS2STAT_KBD) {
229 		printk("PS/2 interface test failed[1]: %02x\n", stat);
230 		ret = -ENODEV;
231 	}
232 
233 	stat = ps2_test_one(ps2if, 0);
234 	if (stat != (PS2STAT_KBC | PS2STAT_KBD)) {
235 		printk("PS/2 interface test failed[2]: %02x\n", stat);
236 		ret = -ENODEV;
237 	}
238 
239 	stat = ps2_test_one(ps2if, PS2CR_FKD);
240 	if (stat != PS2STAT_KBC) {
241 		printk("PS/2 interface test failed[3]: %02x\n", stat);
242 		ret = -ENODEV;
243 	}
244 
245 	writel_relaxed(0, ps2if->base + PS2CR);
246 
247 	return ret;
248 }
249 
250 /*
251  * Add one device to this driver.
252  */
253 static int ps2_probe(struct sa1111_dev *dev)
254 {
255 	struct ps2if *ps2if;
256 	struct serio *serio;
257 	int ret;
258 
259 	ps2if = kzalloc(sizeof(struct ps2if), GFP_KERNEL);
260 	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
261 	if (!ps2if || !serio) {
262 		ret = -ENOMEM;
263 		goto free;
264 	}
265 
266 	serio->id.type		= SERIO_8042;
267 	serio->write		= ps2_write;
268 	serio->open		= ps2_open;
269 	serio->close		= ps2_close;
270 	strscpy(serio->name, dev_name(&dev->dev), sizeof(serio->name));
271 	strscpy(serio->phys, dev_name(&dev->dev), sizeof(serio->phys));
272 	serio->port_data	= ps2if;
273 	serio->dev.parent	= &dev->dev;
274 	ps2if->io		= serio;
275 	ps2if->dev		= dev;
276 	sa1111_set_drvdata(dev, ps2if);
277 
278 	spin_lock_init(&ps2if->lock);
279 
280 	ps2if->rx_irq = sa1111_get_irq(dev, 0);
281 	if (ps2if->rx_irq <= 0) {
282 		ret = ps2if->rx_irq ? : -ENXIO;
283 		goto free;
284 	}
285 
286 	ps2if->tx_irq = sa1111_get_irq(dev, 1);
287 	if (ps2if->tx_irq <= 0) {
288 		ret = ps2if->tx_irq ? : -ENXIO;
289 		goto free;
290 	}
291 
292 	/*
293 	 * Request the physical region for this PS2 port.
294 	 */
295 	if (!request_mem_region(dev->res.start,
296 				dev->res.end - dev->res.start + 1,
297 				SA1111_DRIVER_NAME(dev))) {
298 		ret = -EBUSY;
299 		goto free;
300 	}
301 
302 	/*
303 	 * Our parent device has already mapped the region.
304 	 */
305 	ps2if->base = dev->mapbase;
306 
307 	sa1111_enable_device(ps2if->dev);
308 
309 	/* Incoming clock is 8MHz */
310 	writel_relaxed(0, ps2if->base + PS2CLKDIV);
311 	writel_relaxed(127, ps2if->base + PS2PRECNT);
312 
313 	/*
314 	 * Flush any pending input.
315 	 */
316 	ps2_clear_input(ps2if);
317 
318 	/*
319 	 * Test the keyboard interface.
320 	 */
321 	ret = ps2_test(ps2if);
322 	if (ret)
323 		goto out;
324 
325 	/*
326 	 * Flush any pending input.
327 	 */
328 	ps2_clear_input(ps2if);
329 
330 	sa1111_disable_device(ps2if->dev);
331 	serio_register_port(ps2if->io);
332 	return 0;
333 
334  out:
335 	sa1111_disable_device(ps2if->dev);
336 	release_mem_region(dev->res.start, resource_size(&dev->res));
337  free:
338 	sa1111_set_drvdata(dev, NULL);
339 	kfree(ps2if);
340 	kfree(serio);
341 	return ret;
342 }
343 
344 /*
345  * Remove one device from this driver.
346  */
347 static void ps2_remove(struct sa1111_dev *dev)
348 {
349 	struct ps2if *ps2if = sa1111_get_drvdata(dev);
350 
351 	serio_unregister_port(ps2if->io);
352 	release_mem_region(dev->res.start, resource_size(&dev->res));
353 	sa1111_set_drvdata(dev, NULL);
354 
355 	kfree(ps2if);
356 }
357 
358 /*
359  * Our device driver structure
360  */
361 static struct sa1111_driver ps2_driver = {
362 	.drv = {
363 		.name	= "sa1111-ps2",
364 		.owner	= THIS_MODULE,
365 	},
366 	.devid		= SA1111_DEVID_PS2,
367 	.probe		= ps2_probe,
368 	.remove		= ps2_remove,
369 };
370 
371 static int __init ps2_init(void)
372 {
373 	return sa1111_driver_register(&ps2_driver);
374 }
375 
376 static void __exit ps2_exit(void)
377 {
378 	sa1111_driver_unregister(&ps2_driver);
379 }
380 
381 module_init(ps2_init);
382 module_exit(ps2_exit);
383 
384 MODULE_AUTHOR("Russell King <rmk@arm.linux.org.uk>");
385 MODULE_DESCRIPTION("SA1111 PS2 controller driver");
386 MODULE_LICENSE("GPL");
387