xref: /openbmc/linux/drivers/input/serio/xilinx_ps2.c (revision 612a462a)
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 /*
49  * Bit definitions for ISR/IER registers. Both the registers have the same bit
50  * definitions and are only defined once.
51  */
52 #define XPS2_IPIXR_WDT_TOUT	0x00000001 /* Watchdog Timeout Interrupt */
53 #define XPS2_IPIXR_TX_NOACK	0x00000002 /* Transmit No ACK Interrupt */
54 #define XPS2_IPIXR_TX_ACK	0x00000004 /* Transmit ACK (Data) Interrupt */
55 #define XPS2_IPIXR_RX_OVF	0x00000008 /* Receive Overflow Interrupt */
56 #define XPS2_IPIXR_RX_ERR	0x00000010 /* Receive Error Interrupt */
57 #define XPS2_IPIXR_RX_FULL	0x00000020 /* Receive Data Interrupt */
58 
59 /* Mask for all the Transmit Interrupts */
60 #define XPS2_IPIXR_TX_ALL	(XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
61 
62 /* Mask for all the Receive Interrupts */
63 #define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
64 				 XPS2_IPIXR_RX_FULL)
65 
66 /* Mask for all the Interrupts */
67 #define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
68 				 XPS2_IPIXR_WDT_TOUT)
69 
70 /* Global Interrupt Enable mask */
71 #define XPS2_GIER_GIE_MASK	0x80000000
72 
73 struct xps2data {
74 	int irq;
75 	spinlock_t lock;
76 	void __iomem *base_address;	/* virt. address of control registers */
77 	unsigned int flags;
78 	struct serio *serio;		/* serio */
79 	struct device *dev;
80 };
81 
82 /************************************/
83 /* XPS PS/2 data transmission calls */
84 /************************************/
85 
86 /**
87  * xps2_recv() - attempts to receive a byte from the PS/2 port.
88  * @drvdata:	pointer to ps2 device private data structure
89  * @byte:	address where the read data will be copied
90  *
91  * If there is any data available in the PS/2 receiver, this functions reads
92  * the data, otherwise it returns error.
93  */
94 static int xps2_recv(struct xps2data *drvdata, u8 *byte)
95 {
96 	u32 sr;
97 	int status = -1;
98 
99 	/* If there is data available in the PS/2 receiver, read it */
100 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
101 	if (sr & XPS2_STATUS_RX_FULL) {
102 		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
103 		status = 0;
104 	}
105 
106 	return status;
107 }
108 
109 /*********************/
110 /* Interrupt handler */
111 /*********************/
112 static irqreturn_t xps2_interrupt(int irq, void *dev_id)
113 {
114 	struct xps2data *drvdata = dev_id;
115 	u32 intr_sr;
116 	u8 c;
117 	int status;
118 
119 	/* Get the PS/2 interrupts and clear them */
120 	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
121 	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
122 
123 	/* Check which interrupt is active */
124 	if (intr_sr & XPS2_IPIXR_RX_OVF)
125 		dev_warn(drvdata->dev, "receive overrun error\n");
126 
127 	if (intr_sr & XPS2_IPIXR_RX_ERR)
128 		drvdata->flags |= SERIO_PARITY;
129 
130 	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
131 		drvdata->flags |= SERIO_TIMEOUT;
132 
133 	if (intr_sr & XPS2_IPIXR_RX_FULL) {
134 		status = xps2_recv(drvdata, &c);
135 
136 		/* Error, if a byte is not received */
137 		if (status) {
138 			dev_err(drvdata->dev,
139 				"wrong rcvd byte count (%d)\n", status);
140 		} else {
141 			serio_interrupt(drvdata->serio, c, drvdata->flags);
142 			drvdata->flags = 0;
143 		}
144 	}
145 
146 	return IRQ_HANDLED;
147 }
148 
149 /*******************/
150 /* serio callbacks */
151 /*******************/
152 
153 /**
154  * sxps2_write() - sends a byte out through the PS/2 port.
155  * @pserio:	pointer to the serio structure of the PS/2 port
156  * @c:		data that needs to be written to the PS/2 port
157  *
158  * This function checks if the PS/2 transmitter is empty and sends a byte.
159  * Otherwise it returns error. Transmission fails only when nothing is connected
160  * to the PS/2 port. Thats why, we do not try to resend the data in case of a
161  * failure.
162  */
163 static int sxps2_write(struct serio *pserio, unsigned char c)
164 {
165 	struct xps2data *drvdata = pserio->port_data;
166 	unsigned long flags;
167 	u32 sr;
168 	int status = -1;
169 
170 	spin_lock_irqsave(&drvdata->lock, flags);
171 
172 	/* If the PS/2 transmitter is empty send a byte of data */
173 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
174 	if (!(sr & XPS2_STATUS_TX_FULL)) {
175 		out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
176 		status = 0;
177 	}
178 
179 	spin_unlock_irqrestore(&drvdata->lock, flags);
180 
181 	return status;
182 }
183 
184 /**
185  * sxps2_open() - called when a port is opened by the higher layer.
186  * @pserio:	pointer to the serio structure of the PS/2 device
187  *
188  * This function requests irq and enables interrupts for the PS/2 device.
189  */
190 static int sxps2_open(struct serio *pserio)
191 {
192 	struct xps2data *drvdata = pserio->port_data;
193 	int error;
194 	u8 c;
195 
196 	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
197 				DRIVER_NAME, drvdata);
198 	if (error) {
199 		dev_err(drvdata->dev,
200 			"Couldn't allocate interrupt %d\n", drvdata->irq);
201 		return error;
202 	}
203 
204 	/* start reception by enabling the interrupts */
205 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
206 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
207 	(void)xps2_recv(drvdata, &c);
208 
209 	return 0;		/* success */
210 }
211 
212 /**
213  * sxps2_close() - frees the interrupt.
214  * @pserio:	pointer to the serio structure of the PS/2 device
215  *
216  * This function frees the irq and disables interrupts for the PS/2 device.
217  */
218 static void sxps2_close(struct serio *pserio)
219 {
220 	struct xps2data *drvdata = pserio->port_data;
221 
222 	/* Disable the PS2 interrupts */
223 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
224 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
225 	free_irq(drvdata->irq, drvdata);
226 }
227 
228 /**
229  * xps2_of_probe - probe method for the PS/2 device.
230  * @of_dev:	pointer to OF device structure
231  * @match:	pointer to the structure used for matching a device
232  *
233  * This function probes the PS/2 device in the device tree.
234  * It initializes the driver data structure and the hardware.
235  * It returns 0, if the driver is bound to the PS/2 device, or a negative
236  * value if there is an error.
237  */
238 static int xps2_of_probe(struct platform_device *ofdev)
239 {
240 	struct resource r_mem; /* IO mem resources */
241 	struct xps2data *drvdata;
242 	struct serio *serio;
243 	struct device *dev = &ofdev->dev;
244 	resource_size_t remap_size, phys_addr;
245 	unsigned int irq;
246 	int error;
247 
248 	dev_info(dev, "Device Tree Probing \'%s\'\n", dev->of_node->name);
249 
250 	/* Get iospace for the device */
251 	error = of_address_to_resource(dev->of_node, 0, &r_mem);
252 	if (error) {
253 		dev_err(dev, "invalid address\n");
254 		return error;
255 	}
256 
257 	/* Get IRQ for the device */
258 	irq = irq_of_parse_and_map(dev->of_node, 0);
259 	if (!irq) {
260 		dev_err(dev, "no IRQ found\n");
261 		return -ENODEV;
262 	}
263 
264 	drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
265 	serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
266 	if (!drvdata || !serio) {
267 		error = -ENOMEM;
268 		goto failed1;
269 	}
270 
271 	spin_lock_init(&drvdata->lock);
272 	drvdata->irq = irq;
273 	drvdata->serio = serio;
274 	drvdata->dev = dev;
275 
276 	phys_addr = r_mem.start;
277 	remap_size = resource_size(&r_mem);
278 	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
279 		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
280 			(unsigned long long)phys_addr);
281 		error = -EBUSY;
282 		goto failed1;
283 	}
284 
285 	/* Fill in configuration data and add them to the list */
286 	drvdata->base_address = ioremap(phys_addr, remap_size);
287 	if (drvdata->base_address == NULL) {
288 		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
289 			(unsigned long long)phys_addr);
290 		error = -EFAULT;
291 		goto failed2;
292 	}
293 
294 	/* Disable all the interrupts, just in case */
295 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
296 
297 	/*
298 	 * Reset the PS2 device and abort any current transaction,
299 	 * to make sure we have the PS2 in a good state.
300 	 */
301 	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
302 
303 	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
304 		 (unsigned long long)phys_addr, drvdata->base_address,
305 		 drvdata->irq);
306 
307 	serio->id.type = SERIO_8042;
308 	serio->write = sxps2_write;
309 	serio->open = sxps2_open;
310 	serio->close = sxps2_close;
311 	serio->port_data = drvdata;
312 	serio->dev.parent = dev;
313 	snprintf(serio->name, sizeof(serio->name),
314 		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
315 	snprintf(serio->phys, sizeof(serio->phys),
316 		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
317 
318 	serio_register_port(serio);
319 
320 	platform_set_drvdata(ofdev, drvdata);
321 	return 0;		/* success */
322 
323 failed2:
324 	release_mem_region(phys_addr, remap_size);
325 failed1:
326 	kfree(serio);
327 	kfree(drvdata);
328 
329 	return error;
330 }
331 
332 /**
333  * xps2_of_remove - unbinds the driver from the PS/2 device.
334  * @of_dev:	pointer to OF device structure
335  *
336  * This function is called if a device is physically removed from the system or
337  * if the driver module is being unloaded. It frees any resources allocated to
338  * the device.
339  */
340 static int xps2_of_remove(struct platform_device *of_dev)
341 {
342 	struct xps2data *drvdata = platform_get_drvdata(of_dev);
343 	struct resource r_mem; /* IO mem resources */
344 
345 	serio_unregister_port(drvdata->serio);
346 	iounmap(drvdata->base_address);
347 
348 	/* Get iospace of the device */
349 	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
350 		dev_err(drvdata->dev, "invalid address\n");
351 	else
352 		release_mem_region(r_mem.start, resource_size(&r_mem));
353 
354 	kfree(drvdata);
355 
356 	return 0;
357 }
358 
359 /* Match table for of_platform binding */
360 static const struct of_device_id xps2_of_match[] = {
361 	{ .compatible = "xlnx,xps-ps2-1.00.a", },
362 	{ /* end of list */ },
363 };
364 MODULE_DEVICE_TABLE(of, xps2_of_match);
365 
366 static struct platform_driver xps2_of_driver = {
367 	.driver = {
368 		.name = DRIVER_NAME,
369 		.of_match_table = xps2_of_match,
370 	},
371 	.probe		= xps2_of_probe,
372 	.remove		= xps2_of_remove,
373 };
374 module_platform_driver(xps2_of_driver);
375 
376 MODULE_AUTHOR("Xilinx, Inc.");
377 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
378 MODULE_LICENSE("GPL");
379 
380