xref: /linux/drivers/input/serio/xilinx_ps2.c (revision 3e51108c72e8adbcf3180ed40527a2a9d2d0123b)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Xilinx XPS PS/2 device driver
4  *
5  * (c) 2005 MontaVista Software, Inc.
6  * (c) 2008 Xilinx, Inc.
7  */
8 
9 
10 #include <linux/module.h>
11 #include <linux/serio.h>
12 #include <linux/interrupt.h>
13 #include <linux/errno.h>
14 #include <linux/slab.h>
15 #include <linux/list.h>
16 #include <linux/io.h>
17 #include <linux/mod_devicetable.h>
18 #include <linux/of_address.h>
19 #include <linux/of_irq.h>
20 #include <linux/platform_device.h>
21 
22 #define DRIVER_NAME		"xilinx_ps2"
23 
24 /* Register offsets for the xps2 device */
25 #define XPS2_SRST_OFFSET	0x00000000 /* Software Reset register */
26 #define XPS2_STATUS_OFFSET	0x00000004 /* Status register */
27 #define XPS2_RX_DATA_OFFSET	0x00000008 /* Receive Data register */
28 #define XPS2_TX_DATA_OFFSET	0x0000000C /* Transmit Data register */
29 #define XPS2_GIER_OFFSET	0x0000002C /* Global Interrupt Enable reg */
30 #define XPS2_IPISR_OFFSET	0x00000030 /* Interrupt Status register */
31 #define XPS2_IPIER_OFFSET	0x00000038 /* Interrupt Enable register */
32 
33 /* Reset Register Bit Definitions */
34 #define XPS2_SRST_RESET		0x0000000A /* Software Reset  */
35 
36 /* Status Register Bit Positions */
37 #define XPS2_STATUS_RX_FULL	0x00000001 /* Receive Full  */
38 #define XPS2_STATUS_TX_FULL	0x00000002 /* Transmit Full  */
39 
40 /*
41  * Bit definitions for ISR/IER registers. Both the registers have the same bit
42  * definitions and are only defined once.
43  */
44 #define XPS2_IPIXR_WDT_TOUT	0x00000001 /* Watchdog Timeout Interrupt */
45 #define XPS2_IPIXR_TX_NOACK	0x00000002 /* Transmit No ACK Interrupt */
46 #define XPS2_IPIXR_TX_ACK	0x00000004 /* Transmit ACK (Data) Interrupt */
47 #define XPS2_IPIXR_RX_OVF	0x00000008 /* Receive Overflow Interrupt */
48 #define XPS2_IPIXR_RX_ERR	0x00000010 /* Receive Error Interrupt */
49 #define XPS2_IPIXR_RX_FULL	0x00000020 /* Receive Data Interrupt */
50 
51 /* Mask for all the Transmit Interrupts */
52 #define XPS2_IPIXR_TX_ALL	(XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
53 
54 /* Mask for all the Receive Interrupts */
55 #define XPS2_IPIXR_RX_ALL	(XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR |  \
56 				 XPS2_IPIXR_RX_FULL)
57 
58 /* Mask for all the Interrupts */
59 #define XPS2_IPIXR_ALL		(XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL |  \
60 				 XPS2_IPIXR_WDT_TOUT)
61 
62 /* Global Interrupt Enable mask */
63 #define XPS2_GIER_GIE_MASK	0x80000000
64 
65 struct xps2data {
66 	int irq;
67 	spinlock_t lock;
68 	void __iomem *base_address;	/* virt. address of control registers */
69 	unsigned int flags;
70 	struct serio *serio;		/* serio */
71 	struct device *dev;
72 };
73 
74 /************************************/
75 /* XPS PS/2 data transmission calls */
76 /************************************/
77 
78 /**
79  * xps2_recv() - attempts to receive a byte from the PS/2 port.
80  * @drvdata:	pointer to ps2 device private data structure
81  * @byte:	address where the read data will be copied
82  *
83  * If there is any data available in the PS/2 receiver, this functions reads
84  * the data, otherwise it returns error.
85  */
xps2_recv(struct xps2data * drvdata,u8 * byte)86 static int xps2_recv(struct xps2data *drvdata, u8 *byte)
87 {
88 	u32 sr;
89 	int status = -1;
90 
91 	/* If there is data available in the PS/2 receiver, read it */
92 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
93 	if (sr & XPS2_STATUS_RX_FULL) {
94 		*byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
95 		status = 0;
96 	}
97 
98 	return status;
99 }
100 
101 /*********************/
102 /* Interrupt handler */
103 /*********************/
xps2_interrupt(int irq,void * dev_id)104 static irqreturn_t xps2_interrupt(int irq, void *dev_id)
105 {
106 	struct xps2data *drvdata = dev_id;
107 	u32 intr_sr;
108 	u8 c;
109 	int status;
110 
111 	/* Get the PS/2 interrupts and clear them */
112 	intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
113 	out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
114 
115 	/* Check which interrupt is active */
116 	if (intr_sr & XPS2_IPIXR_RX_OVF)
117 		dev_warn(drvdata->dev, "receive overrun error\n");
118 
119 	if (intr_sr & XPS2_IPIXR_RX_ERR)
120 		drvdata->flags |= SERIO_PARITY;
121 
122 	if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
123 		drvdata->flags |= SERIO_TIMEOUT;
124 
125 	if (intr_sr & XPS2_IPIXR_RX_FULL) {
126 		status = xps2_recv(drvdata, &c);
127 
128 		/* Error, if a byte is not received */
129 		if (status) {
130 			dev_err(drvdata->dev,
131 				"wrong rcvd byte count (%d)\n", status);
132 		} else {
133 			serio_interrupt(drvdata->serio, c, drvdata->flags);
134 			drvdata->flags = 0;
135 		}
136 	}
137 
138 	return IRQ_HANDLED;
139 }
140 
141 /*******************/
142 /* serio callbacks */
143 /*******************/
144 
145 /**
146  * sxps2_write() - sends a byte out through the PS/2 port.
147  * @pserio:	pointer to the serio structure of the PS/2 port
148  * @c:		data that needs to be written to the PS/2 port
149  *
150  * This function checks if the PS/2 transmitter is empty and sends a byte.
151  * Otherwise it returns error. Transmission fails only when nothing is connected
152  * to the PS/2 port. Thats why, we do not try to resend the data in case of a
153  * failure.
154  */
sxps2_write(struct serio * pserio,unsigned char c)155 static int sxps2_write(struct serio *pserio, unsigned char c)
156 {
157 	struct xps2data *drvdata = pserio->port_data;
158 	u32 sr;
159 
160 	guard(spinlock_irqsave)(&drvdata->lock);
161 
162 	/* If the PS/2 transmitter is empty send a byte of data */
163 	sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
164 	if (sr & XPS2_STATUS_TX_FULL)
165 		return -EAGAIN;
166 
167 	out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
168 	return 0;
169 }
170 
171 /**
172  * sxps2_open() - called when a port is opened by the higher layer.
173  * @pserio:	pointer to the serio structure of the PS/2 device
174  *
175  * This function requests irq and enables interrupts for the PS/2 device.
176  */
sxps2_open(struct serio * pserio)177 static int sxps2_open(struct serio *pserio)
178 {
179 	struct xps2data *drvdata = pserio->port_data;
180 	int error;
181 	u8 c;
182 
183 	error = request_irq(drvdata->irq, &xps2_interrupt, 0,
184 				DRIVER_NAME, drvdata);
185 	if (error) {
186 		dev_err(drvdata->dev,
187 			"Couldn't allocate interrupt %d\n", drvdata->irq);
188 		return error;
189 	}
190 
191 	/* start reception by enabling the interrupts */
192 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
193 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
194 	(void)xps2_recv(drvdata, &c);
195 
196 	return 0;		/* success */
197 }
198 
199 /**
200  * sxps2_close() - frees the interrupt.
201  * @pserio:	pointer to the serio structure of the PS/2 device
202  *
203  * This function frees the irq and disables interrupts for the PS/2 device.
204  */
sxps2_close(struct serio * pserio)205 static void sxps2_close(struct serio *pserio)
206 {
207 	struct xps2data *drvdata = pserio->port_data;
208 
209 	/* Disable the PS2 interrupts */
210 	out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
211 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
212 	free_irq(drvdata->irq, drvdata);
213 }
214 
215 /**
216  * xps2_of_probe - probe method for the PS/2 device.
217  * @ofdev:	pointer to OF device structure
218  *
219  * This function probes the PS/2 device in the device tree.
220  * It initializes the driver data structure and the hardware.
221  * It returns 0, if the driver is bound to the PS/2 device, or a negative
222  * value if there is an error.
223  */
xps2_of_probe(struct platform_device * ofdev)224 static int xps2_of_probe(struct platform_device *ofdev)
225 {
226 	struct resource r_mem; /* IO mem resources */
227 	struct xps2data *drvdata;
228 	struct serio *serio;
229 	struct device *dev = &ofdev->dev;
230 	resource_size_t remap_size, phys_addr;
231 	unsigned int irq;
232 	int error;
233 
234 	dev_info(dev, "Device Tree Probing \'%pOFn\'\n", dev->of_node);
235 
236 	/* Get iospace for the device */
237 	error = of_address_to_resource(dev->of_node, 0, &r_mem);
238 	if (error) {
239 		dev_err(dev, "invalid address\n");
240 		return error;
241 	}
242 
243 	/* Get IRQ for the device */
244 	irq = irq_of_parse_and_map(dev->of_node, 0);
245 	if (!irq) {
246 		dev_err(dev, "no IRQ found\n");
247 		return -ENODEV;
248 	}
249 
250 	drvdata = kzalloc(sizeof(*drvdata), GFP_KERNEL);
251 	serio = kzalloc(sizeof(*serio), GFP_KERNEL);
252 	if (!drvdata || !serio) {
253 		error = -ENOMEM;
254 		goto failed1;
255 	}
256 
257 	spin_lock_init(&drvdata->lock);
258 	drvdata->irq = irq;
259 	drvdata->serio = serio;
260 	drvdata->dev = dev;
261 
262 	phys_addr = r_mem.start;
263 	remap_size = resource_size(&r_mem);
264 	if (!request_mem_region(phys_addr, remap_size, DRIVER_NAME)) {
265 		dev_err(dev, "Couldn't lock memory region at 0x%08llX\n",
266 			(unsigned long long)phys_addr);
267 		error = -EBUSY;
268 		goto failed1;
269 	}
270 
271 	/* Fill in configuration data and add them to the list */
272 	drvdata->base_address = ioremap(phys_addr, remap_size);
273 	if (drvdata->base_address == NULL) {
274 		dev_err(dev, "Couldn't ioremap memory at 0x%08llX\n",
275 			(unsigned long long)phys_addr);
276 		error = -EFAULT;
277 		goto failed2;
278 	}
279 
280 	/* Disable all the interrupts, just in case */
281 	out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
282 
283 	/*
284 	 * Reset the PS2 device and abort any current transaction,
285 	 * to make sure we have the PS2 in a good state.
286 	 */
287 	out_be32(drvdata->base_address + XPS2_SRST_OFFSET, XPS2_SRST_RESET);
288 
289 	dev_info(dev, "Xilinx PS2 at 0x%08llX mapped to 0x%p, irq=%d\n",
290 		 (unsigned long long)phys_addr, drvdata->base_address,
291 		 drvdata->irq);
292 
293 	serio->id.type = SERIO_8042;
294 	serio->write = sxps2_write;
295 	serio->open = sxps2_open;
296 	serio->close = sxps2_close;
297 	serio->port_data = drvdata;
298 	serio->dev.parent = dev;
299 	snprintf(serio->name, sizeof(serio->name),
300 		 "Xilinx XPS PS/2 at %08llX", (unsigned long long)phys_addr);
301 	snprintf(serio->phys, sizeof(serio->phys),
302 		 "xilinxps2/serio at %08llX", (unsigned long long)phys_addr);
303 
304 	serio_register_port(serio);
305 
306 	platform_set_drvdata(ofdev, drvdata);
307 	return 0;		/* success */
308 
309 failed2:
310 	release_mem_region(phys_addr, remap_size);
311 failed1:
312 	kfree(serio);
313 	kfree(drvdata);
314 
315 	return error;
316 }
317 
318 /**
319  * xps2_of_remove - unbinds the driver from the PS/2 device.
320  * @of_dev:	pointer to OF device structure
321  *
322  * This function is called if a device is physically removed from the system or
323  * if the driver module is being unloaded. It frees any resources allocated to
324  * the device.
325  */
xps2_of_remove(struct platform_device * of_dev)326 static void xps2_of_remove(struct platform_device *of_dev)
327 {
328 	struct xps2data *drvdata = platform_get_drvdata(of_dev);
329 	struct resource r_mem; /* IO mem resources */
330 
331 	serio_unregister_port(drvdata->serio);
332 	iounmap(drvdata->base_address);
333 
334 	/* Get iospace of the device */
335 	if (of_address_to_resource(of_dev->dev.of_node, 0, &r_mem))
336 		dev_err(drvdata->dev, "invalid address\n");
337 	else
338 		release_mem_region(r_mem.start, resource_size(&r_mem));
339 
340 	kfree(drvdata);
341 }
342 
343 /* Match table for of_platform binding */
344 static const struct of_device_id xps2_of_match[] = {
345 	{ .compatible = "xlnx,xps-ps2-1.00.a", },
346 	{ /* end of list */ },
347 };
348 MODULE_DEVICE_TABLE(of, xps2_of_match);
349 
350 static struct platform_driver xps2_of_driver = {
351 	.driver = {
352 		.name = DRIVER_NAME,
353 		.of_match_table = xps2_of_match,
354 	},
355 	.probe		= xps2_of_probe,
356 	.remove		= xps2_of_remove,
357 };
358 module_platform_driver(xps2_of_driver);
359 
360 MODULE_AUTHOR("Xilinx, Inc.");
361 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
362 MODULE_LICENSE("GPL");
363 
364