summaryrefslogtreecommitdiff
path: root/drivers/input/serio/xilinx_ps2.c
blob: 8298e1f68234df7cbd33afbc4d452595155530c0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
/*
 * Xilinx XPS PS/2 device driver
 *
 * (c) 2005 MontaVista Software, Inc.
 * (c) 2008 Xilinx, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 675 Mass Ave, Cambridge, MA 02139, USA.
 */


#include <linux/module.h>
#include <linux/serio.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/io.h>

#include <linux/of_device.h>
#include <linux/of_platform.h>

#define DRIVER_NAME		"xilinx_ps2"

/* Register offsets for the xps2 device */
#define XPS2_SRST_OFFSET	0x00000000 /* Software Reset register */
#define XPS2_STATUS_OFFSET	0x00000004 /* Status register */
#define XPS2_RX_DATA_OFFSET	0x00000008 /* Receive Data register */
#define XPS2_TX_DATA_OFFSET	0x0000000C /* Transmit Data register */
#define XPS2_GIER_OFFSET	0x0000002C /* Global Interrupt Enable reg */
#define XPS2_IPISR_OFFSET	0x00000030 /* Interrupt Status register */
#define XPS2_IPIER_OFFSET	0x00000038 /* Interrupt Enable register */

/* Reset Register Bit Definitions */
#define XPS2_SRST_RESET		0x0000000A /* Software Reset  */

/* Status Register Bit Positions */
#define XPS2_STATUS_RX_FULL	0x00000001 /* Receive Full  */
#define XPS2_STATUS_TX_FULL	0x00000002 /* Transmit Full  */

/* Bit definitions for ISR/IER registers. Both the registers have the same bit
 * definitions and are only defined once. */
#define XPS2_IPIXR_WDT_TOUT	0x00000001 /* Watchdog Timeout Interrupt */
#define XPS2_IPIXR_TX_NOACK	0x00000002 /* Transmit No ACK Interrupt */
#define XPS2_IPIXR_TX_ACK	0x00000004 /* Transmit ACK (Data) Interrupt */
#define XPS2_IPIXR_RX_OVF	0x00000008 /* Receive Overflow Interrupt */
#define XPS2_IPIXR_RX_ERR	0x00000010 /* Receive Error Interrupt */
#define XPS2_IPIXR_RX_FULL	0x00000020 /* Receive Data Interrupt */

/* Mask for all the Transmit Interrupts */
#define XPS2_IPIXR_TX_ALL	(XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)

/* Mask for all the Receive Interrupts */
#define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
				 XPS2_IPIXR_RX_FULL)

/* Mask for all the Interrupts */
#define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
				 XPS2_IPIXR_WDT_TOUT)

/* Global Interrupt Enable mask */
#define XPS2_GIER_GIE_MASK	0x80000000

struct xps2data {
	int irq;
	spinlock_t lock;
	void __iomem *base_address;	/* virt. address of control registers */
	unsigned int flags;
	struct serio serio;		/* serio */
};

/************************************/
/* XPS PS/2 data transmission calls */
/************************************/

/**
 * xps2_recv() - attempts to receive a byte from the PS/2 port.
 * @drvdata:	pointer to ps2 device private data structure
 * @byte:	address where the read data will be copied
 *
 * If there is any data available in the PS/2 receiver, this functions reads
 * the data, otherwise it returns error.
 */
static int xps2_recv(struct xps2data *drvdata, u8 *byte)
{
	u32 sr;
	int status = -1;

	/* If there is data available in the PS/2 receiver, read it */
	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
	if (sr & XPS2_STATUS_RX_FULL) {
		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
		status = 0;
	}

	return status;
}

/*********************/
/* Interrupt handler */
/*********************/
static irqreturn_t xps2_interrupt(int irq, void *dev_id)
{
	struct xps2data *drvdata = dev_id;
	u32 intr_sr;
	u8 c;
	int status;

	/* Get the PS/2 interrupts and clear them */
	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);

	/* Check which interrupt is active */
	if (intr_sr & XPS2_IPIXR_RX_OVF)
		dev_warn(drvdata->serio.dev.parent, "receive overrun error\n");

	if (intr_sr & XPS2_IPIXR_RX_ERR)
		drvdata->flags |= SERIO_PARITY;

	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
		drvdata->flags |= SERIO_TIMEOUT;

	if (intr_sr & XPS2_IPIXR_RX_FULL) {
		status = xps2_recv(drvdata, &c);

		/* Error, if a byte is not received */
		if (status) {
			dev_err(drvdata->serio.dev.parent,
				"wrong rcvd byte count (%d)\n", status);
		} else {
			serio_interrupt(&drvdata->serio, c, drvdata->flags);
			drvdata->flags = 0;
		}
	}

	return IRQ_HANDLED;
}

/*******************/
/* serio callbacks */
/*******************/

/**
 * sxps2_write() - sends a byte out through the PS/2 port.
 * @pserio:	pointer to the serio structure of the PS/2 port
 * @c:		data that needs to be written to the PS/2 port
 *
 * This function checks if the PS/2 transmitter is empty and sends a byte.
 * Otherwise it returns error. Transmission fails only when nothing is connected
 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
 * failure.
 */
static int sxps2_write(struct serio *pserio, unsigned char c)
{
	struct xps2data *drvdata = pserio->port_data;
	unsigned long flags;
	u32 sr;
	int status = -1;

	spin_lock_irqsave(&drvdata->lock, flags);

	/* If the PS/2 transmitter is empty send a byte of data */
	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
	if (!(sr & XPS2_STATUS_TX_FULL)) {
		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
		status = 0;
	}

	spin_unlock_irqrestore(&drvdata->lock, flags);

	return status;
}

/**
 * sxps2_open() - called when a port is opened by the higher layer.
 * @pserio:	pointer to the serio structure of the PS/2 device
 *
 * This function requests irq and enables interrupts for the PS/2 device.
 */
static int sxps2_open(struct serio *pserio)
{
	struct xps2data *drvdata = pserio->port_data;
	int error;
	u8 c;

	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
				DRIVER_NAME, drvdata);
	if (error) {
		dev_err(drvdata->serio.dev.parent,
			"Couldn't allocate interrupt %d\n", drvdata->irq);
		return error;
	}

	/* start reception by enabling the interrupts */
	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
	(void)xps2_recv(drvdata, &c);

	return 0;		/* success */
}

/**
 * sxps2_close() - frees the interrupt.
 * @pserio:	pointer to the serio structure of the PS/2 device
 *
 * This function frees the irq and disables interrupts for the PS/2 device.
 */
static void sxps2_close(struct serio *pserio)
{
	struct xps2data *drvdata = pserio->port_data;

	/* Disable the PS2 interrupts */
	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
	free_irq(drvdata->irq, drvdata);
}

/**
 * xps2_of_probe - probe method for the PS/2 device.
 * @of_dev:	pointer to OF device structure
 * @match:	pointer to the stucture used for matching a device
 *
 * This function probes the PS/2 device in the device tree.
 * It initializes the driver data structure and the hardware.
 * It returns 0, if the driver is bound to the PS/2 device, or a negative
 * value if there is an error.
 */
static int __devinit xps2_of_probe(struct of_device *ofdev,
				   const struct of_device_id *match)
{
	struct resource r_irq; /* Interrupt resources */
	struct resource r_mem; /* IO mem resources */
	struct xps2data *drvdata;
	struct serio *serio;
	struct device *dev = &ofdev->dev;
	resource_size_t remap_size, phys_addr;
	int error;

	dev_info(dev, "Device Tree Probing \'%s\'\n",
			ofdev->node->name);

	/* Get iospace for the device */
	error = of_address_to_resource(ofdev->node, 0, &r_mem);
	if (error) {
		dev_err(dev, "invalid address\n");
		return error;
	}

	/* Get IRQ for the device */
	if (of_irq_to_resource(ofdev->node, 0, &r_irq) == NO_IRQ) {
		dev_err(dev, "no IRQ found\n");
		return -ENODEV;
	}

	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
	if (!drvdata) {
		dev_err(dev, "Couldn't allocate device private record\n");
		return -ENOMEM;
	}

	dev_set_drvdata(dev, drvdata);

	spin_lock_init(&drvdata->lock);
	drvdata->irq = r_irq.start;

	phys_addr = r_mem.start;
	remap_size = resource_size(&r_mem);
	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
			(unsigned long long)phys_addr);
		error = -EBUSY;
		goto failed1;
	}

	/* Fill in configuration data and add them to the list */
	drvdata->base_address = ioremap(phys_addr, remap_size);
	if (drvdata->base_address == NULL) {
		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
			(unsigned long long)phys_addr);
		error = -EFAULT;
		goto failed2;
	}

	/* Disable all the interrupts, just in case */
	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);

	/* Reset the PS2 device and abort any current transaction, to make sure
	 * we have the PS2 in a good state */
	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);

	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
		 (unsigned long long)phys_addr, drvdata->base_address,
		 drvdata->irq);

	serio = &drvdata->serio;
	serio->id.type = SERIO_8042;
	serio->write = sxps2_write;
	serio->open = sxps2_open;
	serio->close = sxps2_close;
	serio->port_data = drvdata;
	serio->dev.parent = dev;
	snprintf(serio->name, sizeof(serio->name),
		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
	snprintf(serio->phys, sizeof(serio->phys),
		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);

	serio_register_port(serio);

	return 0;		/* success */

failed2:
	release_mem_region(phys_addr, remap_size);
failed1:
	kfree(drvdata);
	dev_set_drvdata(dev, NULL);

	return error;
}

/**
 * xps2_of_remove - unbinds the driver from the PS/2 device.
 * @of_dev:	pointer to OF device structure
 *
 * This function is called if a device is physically removed from the system or
 * if the driver module is being unloaded. It frees any resources allocated to
 * the device.
 */
static int __devexit xps2_of_remove(struct of_device *of_dev)
{
	struct device *dev = &of_dev->dev;
	struct xps2data *drvdata = dev_get_drvdata(dev);
	struct resource r_mem; /* IO mem resources */

	serio_unregister_port(&drvdata->serio);
	iounmap(drvdata->base_address);

	/* Get iospace of the device */
	if (of_address_to_resource(of_dev->node, 0, &r_mem))
		dev_err(dev, "invalid address\n");
	else
		release_mem_region(r_mem.start, resource_size(&r_mem));

	kfree(drvdata);

	dev_set_drvdata(dev, NULL);

	return 0;
}

/* Match table for of_platform binding */
static const struct of_device_id xps2_of_match[] __devinitconst = {
	{ .compatible = "xlnx,xps-ps2-1.00.a", },
	{ /* end of list */ },
};
MODULE_DEVICE_TABLE(of, xps2_of_match);

static struct of_platform_driver xps2_of_driver = {
	.name		= DRIVER_NAME,
	.match_table	= xps2_of_match,
	.probe		= xps2_of_probe,
	.remove		= __devexit_p(xps2_of_remove),
};

static int __init xps2_init(void)
{
	return of_register_platform_driver(&xps2_of_driver);
}

static void __exit xps2_cleanup(void)
{
	of_unregister_platform_driver(&xps2_of_driver);
}

module_init(xps2_init);
module_exit(xps2_cleanup);

MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
MODULE_LICENSE("GPL");