xref: /linux/drivers/input/serio/xilinx_ps2.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1 /*
2  * Xilinx XPS PS/2 device driver
3  *
4  * (c) 2005 MontaVista Software, Inc.
5  * (c) 2008 Xilinx, Inc.
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License as published by the
9  * Free Software Foundation; either version 2 of the License, or (at your
10  * option) any later version.
11  *
12  * You should have received a copy of the GNU General Public License along
13  * with this program; if not, write to the Free Software Foundation, Inc.,
14  * 675 Mass Ave, Cambridge, MA 02139, USA.
15  */
16 
17 
18 #include <linux/module.h>
19 #include <linux/serio.h>
20 #include <linux/interrupt.h>
21 #include <linux/errno.h>
22 #include <linux/slab.h>
23 #include <linux/list.h>
24 #include <linux/io.h>
25 #include <linux/of_address.h>
26 #include <linux/of_device.h>
27 #include <linux/of_irq.h>
28 #include <linux/of_platform.h>
29 
30 #define DRIVER_NAME		"xilinx_ps2"
31 
32 /* Register offsets for the xps2 device */
33 #define XPS2_SRST_OFFSET	0x00000000 /* Software Reset register */
34 #define XPS2_STATUS_OFFSET	0x00000004 /* Status register */
35 #define XPS2_RX_DATA_OFFSET	0x00000008 /* Receive Data register */
36 #define XPS2_TX_DATA_OFFSET	0x0000000C /* Transmit Data register */
37 #define XPS2_GIER_OFFSET	0x0000002C /* Global Interrupt Enable reg */
38 #define XPS2_IPISR_OFFSET	0x00000030 /* Interrupt Status register */
39 #define XPS2_IPIER_OFFSET	0x00000038 /* Interrupt Enable register */
40 
41 /* Reset Register Bit Definitions */
42 #define XPS2_SRST_RESET		0x0000000A /* Software Reset  */
43 
44 /* Status Register Bit Positions */
45 #define XPS2_STATUS_RX_FULL	0x00000001 /* Receive Full  */
46 #define XPS2_STATUS_TX_FULL	0x00000002 /* Transmit Full  */
47 
48 /* Bit definitions for ISR/IER registers. Both the registers have the same bit
49  * definitions and are only defined once. */
50 #define XPS2_IPIXR_WDT_TOUT	0x00000001 /* Watchdog Timeout Interrupt */
51 #define XPS2_IPIXR_TX_NOACK	0x00000002 /* Transmit No ACK Interrupt */
52 #define XPS2_IPIXR_TX_ACK	0x00000004 /* Transmit ACK (Data) Interrupt */
53 #define XPS2_IPIXR_RX_OVF	0x00000008 /* Receive Overflow Interrupt */
54 #define XPS2_IPIXR_RX_ERR	0x00000010 /* Receive Error Interrupt */
55 #define XPS2_IPIXR_RX_FULL	0x00000020 /* Receive Data Interrupt */
56 
57 /* Mask for all the Transmit Interrupts */
58 #define XPS2_IPIXR_TX_ALL	(XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
59 
60 /* Mask for all the Receive Interrupts */
61 #define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
62 				 XPS2_IPIXR_RX_FULL)
63 
64 /* Mask for all the Interrupts */
65 #define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
66 				 XPS2_IPIXR_WDT_TOUT)
67 
68 /* Global Interrupt Enable mask */
69 #define XPS2_GIER_GIE_MASK	0x80000000
70 
71 struct xps2data {
72 	int irq;
73 	spinlock_t lock;
74 	void __iomem *base_address;	/* virt. address of control registers */
75 	unsigned int flags;
76 	struct serio *serio;		/* serio */
77 	struct device *dev;
78 };
79 
80 /************************************/
81 /* XPS PS/2 data transmission calls */
82 /************************************/
83 
84 /**
85  * xps2_recv() - attempts to receive a byte from the PS/2 port.
86  * @drvdata:	pointer to ps2 device private data structure
87  * @byte:	address where the read data will be copied
88  *
89  * If there is any data available in the PS/2 receiver, this functions reads
90  * the data, otherwise it returns error.
91  */
92 static int xps2_recv(struct xps2data *drvdata, u8 *byte)
93 {
94 	u32 sr;
95 	int status = -1;
96 
97 	/* If there is data available in the PS/2 receiver, read it */
98 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
99 	if (sr & XPS2_STATUS_RX_FULL) {
100 		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
101 		status = 0;
102 	}
103 
104 	return status;
105 }
106 
107 /*********************/
108 /* Interrupt handler */
109 /*********************/
110 static irqreturn_t xps2_interrupt(int irq, void *dev_id)
111 {
112 	struct xps2data *drvdata = dev_id;
113 	u32 intr_sr;
114 	u8 c;
115 	int status;
116 
117 	/* Get the PS/2 interrupts and clear them */
118 	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
119 	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
120 
121 	/* Check which interrupt is active */
122 	if (intr_sr & XPS2_IPIXR_RX_OVF)
123 		dev_warn(drvdata->dev, "receive overrun error\n");
124 
125 	if (intr_sr & XPS2_IPIXR_RX_ERR)
126 		drvdata->flags |= SERIO_PARITY;
127 
128 	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
129 		drvdata->flags |= SERIO_TIMEOUT;
130 
131 	if (intr_sr & XPS2_IPIXR_RX_FULL) {
132 		status = xps2_recv(drvdata, &c);
133 
134 		/* Error, if a byte is not received */
135 		if (status) {
136 			dev_err(drvdata->dev,
137 				"wrong rcvd byte count (%d)\n", status);
138 		} else {
139 			serio_interrupt(drvdata->serio, c, drvdata->flags);
140 			drvdata->flags = 0;
141 		}
142 	}
143 
144 	return IRQ_HANDLED;
145 }
146 
147 /*******************/
148 /* serio callbacks */
149 /*******************/
150 
151 /**
152  * sxps2_write() - sends a byte out through the PS/2 port.
153  * @pserio:	pointer to the serio structure of the PS/2 port
154  * @c:		data that needs to be written to the PS/2 port
155  *
156  * This function checks if the PS/2 transmitter is empty and sends a byte.
157  * Otherwise it returns error. Transmission fails only when nothing is connected
158  * to the PS/2 port. Thats why, we do not try to resend the data in case of a
159  * failure.
160  */
161 static int sxps2_write(struct serio *pserio, unsigned char c)
162 {
163 	struct xps2data *drvdata = pserio->port_data;
164 	unsigned long flags;
165 	u32 sr;
166 	int status = -1;
167 
168 	spin_lock_irqsave(&drvdata->lock, flags);
169 
170 	/* If the PS/2 transmitter is empty send a byte of data */
171 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
172 	if (!(sr & XPS2_STATUS_TX_FULL)) {
173 		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
174 		status = 0;
175 	}
176 
177 	spin_unlock_irqrestore(&drvdata->lock, flags);
178 
179 	return status;
180 }
181 
182 /**
183  * sxps2_open() - called when a port is opened by the higher layer.
184  * @pserio:	pointer to the serio structure of the PS/2 device
185  *
186  * This function requests irq and enables interrupts for the PS/2 device.
187  */
188 static int sxps2_open(struct serio *pserio)
189 {
190 	struct xps2data *drvdata = pserio->port_data;
191 	int error;
192 	u8 c;
193 
194 	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
195 				DRIVER_NAME, drvdata);
196 	if (error) {
197 		dev_err(drvdata->dev,
198 			"Couldn't allocate interrupt %d\n", drvdata->irq);
199 		return error;
200 	}
201 
202 	/* start reception by enabling the interrupts */
203 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
204 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
205 	(void)xps2_recv(drvdata, &c);
206 
207 	return 0;		/* success */
208 }
209 
210 /**
211  * sxps2_close() - frees the interrupt.
212  * @pserio:	pointer to the serio structure of the PS/2 device
213  *
214  * This function frees the irq and disables interrupts for the PS/2 device.
215  */
216 static void sxps2_close(struct serio *pserio)
217 {
218 	struct xps2data *drvdata = pserio->port_data;
219 
220 	/* Disable the PS2 interrupts */
221 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
222 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
223 	free_irq(drvdata->irq, drvdata);
224 }
225 
226 /**
227  * xps2_of_probe - probe method for the PS/2 device.
228  * @of_dev:	pointer to OF device structure
229  * @match:	pointer to the structure used for matching a device
230  *
231  * This function probes the PS/2 device in the device tree.
232  * It initializes the driver data structure and the hardware.
233  * It returns 0, if the driver is bound to the PS/2 device, or a negative
234  * value if there is an error.
235  */
236 static int xps2_of_probe(struct platform_device *ofdev)
237 {
238 	struct resource r_mem; /* IO mem resources */
239 	struct xps2data *drvdata;
240 	struct serio *serio;
241 	struct device *dev = &ofdev->dev;
242 	resource_size_t remap_size, phys_addr;
243 	unsigned int irq;
244 	int error;
245 
246 	dev_info(dev, "Device Tree Probing \'%s\'\n",
247 			ofdev->dev.of_node->name);
248 
249 	/* Get iospace for the device */
250 	error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
251 	if (error) {
252 		dev_err(dev, "invalid address\n");
253 		return error;
254 	}
255 
256 	/* Get IRQ for the device */
257 	irq = irq_of_parse_and_map(ofdev->dev.of_node, 0);
258 	if (!irq) {
259 		dev_err(dev, "no IRQ found\n");
260 		return -ENODEV;
261 	}
262 
263 	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
264 	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
265 	if (!drvdata || !serio) {
266 		error = -ENOMEM;
267 		goto failed1;
268 	}
269 
270 	spin_lock_init(&drvdata->lock);
271 	drvdata->irq = irq;
272 	drvdata->serio = serio;
273 	drvdata->dev = dev;
274 
275 	phys_addr = r_mem.start;
276 	remap_size = resource_size(&r_mem);
277 	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
278 		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
279 			(unsigned long long)phys_addr);
280 		error = -EBUSY;
281 		goto failed1;
282 	}
283 
284 	/* Fill in configuration data and add them to the list */
285 	drvdata->base_address = ioremap(phys_addr, remap_size);
286 	if (drvdata->base_address == NULL) {
287 		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
288 			(unsigned long long)phys_addr);
289 		error = -EFAULT;
290 		goto failed2;
291 	}
292 
293 	/* Disable all the interrupts, just in case */
294 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
295 
296 	/* Reset the PS2 device and abort any current transaction, to make sure
297 	 * we have the PS2 in a good state */
298 	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
299 
300 	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
301 		 (unsigned long long)phys_addr, drvdata->base_address,
302 		 drvdata->irq);
303 
304 	serio->id.type = SERIO_8042;
305 	serio->write = sxps2_write;
306 	serio->open = sxps2_open;
307 	serio->close = sxps2_close;
308 	serio->port_data = drvdata;
309 	serio->dev.parent = dev;
310 	snprintf(serio->name, sizeof(serio->name),
311 		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
312 	snprintf(serio->phys, sizeof(serio->phys),
313 		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
314 
315 	serio_register_port(serio);
316 
317 	platform_set_drvdata(ofdev, drvdata);
318 	return 0;		/* success */
319 
320 failed2:
321 	release_mem_region(phys_addr, remap_size);
322 failed1:
323 	kfree(serio);
324 	kfree(drvdata);
325 
326 	return error;
327 }
328 
329 /**
330  * xps2_of_remove - unbinds the driver from the PS/2 device.
331  * @of_dev:	pointer to OF device structure
332  *
333  * This function is called if a device is physically removed from the system or
334  * if the driver module is being unloaded. It frees any resources allocated to
335  * the device.
336  */
337 static int xps2_of_remove(struct platform_device *of_dev)
338 {
339 	struct xps2data *drvdata = platform_get_drvdata(of_dev);
340 	struct resource r_mem; /* IO mem resources */
341 
342 	serio_unregister_port(drvdata->serio);
343 	iounmap(drvdata->base_address);
344 
345 	/* Get iospace of the device */
346 	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
347 		dev_err(drvdata->dev, "invalid address\n");
348 	else
349 		release_mem_region(r_mem.start, resource_size(&r_mem));
350 
351 	kfree(drvdata);
352 
353 	return 0;
354 }
355 
356 /* Match table for of_platform binding */
357 static const struct of_device_id xps2_of_match[] = {
358 	{ .compatible = "xlnx,xps-ps2-1.00.a", },
359 	{ /* end of list */ },
360 };
361 MODULE_DEVICE_TABLE(of, xps2_of_match);
362 
363 static struct platform_driver xps2_of_driver = {
364 	.driver = {
365 		.name = DRIVER_NAME,
366 		.owner = THIS_MODULE,
367 		.of_match_table = xps2_of_match,
368 	},
369 	.probe		= xps2_of_probe,
370 	.remove		= xps2_of_remove,
371 };
372 module_platform_driver(xps2_of_driver);
373 
374 MODULE_AUTHOR("Xilinx, Inc.");
375 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
376 MODULE_LICENSE("GPL");
377 
378