2 * Xilinx XPS PS/2 device driver
4 * (c) 2005 MontaVista Software, Inc.
5 * (c) 2008 Xilinx, Inc.
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.
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.
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/init.h>
24 #include <linux/list.h>
26 #include <linux/of_address.h>
27 #include <linux/of_device.h>
28 #include <linux/of_irq.h>
29 #include <linux/of_platform.h>
31 #define DRIVER_NAME "xilinx_ps2"
33 /* Register offsets for the xps2 device */
34 #define XPS2_SRST_OFFSET 0x00000000 /* Software Reset register */
35 #define XPS2_STATUS_OFFSET 0x00000004 /* Status register */
36 #define XPS2_RX_DATA_OFFSET 0x00000008 /* Receive Data register */
37 #define XPS2_TX_DATA_OFFSET 0x0000000C /* Transmit Data register */
38 #define XPS2_GIER_OFFSET 0x0000002C /* Global Interrupt Enable reg */
39 #define XPS2_IPISR_OFFSET 0x00000030 /* Interrupt Status register */
40 #define XPS2_IPIER_OFFSET 0x00000038 /* Interrupt Enable register */
42 /* Reset Register Bit Definitions */
43 #define XPS2_SRST_RESET 0x0000000A /* Software Reset */
45 /* Status Register Bit Positions */
46 #define XPS2_STATUS_RX_FULL 0x00000001 /* Receive Full */
47 #define XPS2_STATUS_TX_FULL 0x00000002 /* Transmit Full */
49 /* Bit definitions for ISR/IER registers. Both the registers have the same bit
50 * definitions and are only defined once. */
51 #define XPS2_IPIXR_WDT_TOUT 0x00000001 /* Watchdog Timeout Interrupt */
52 #define XPS2_IPIXR_TX_NOACK 0x00000002 /* Transmit No ACK Interrupt */
53 #define XPS2_IPIXR_TX_ACK 0x00000004 /* Transmit ACK (Data) Interrupt */
54 #define XPS2_IPIXR_RX_OVF 0x00000008 /* Receive Overflow Interrupt */
55 #define XPS2_IPIXR_RX_ERR 0x00000010 /* Receive Error Interrupt */
56 #define XPS2_IPIXR_RX_FULL 0x00000020 /* Receive Data Interrupt */
58 /* Mask for all the Transmit Interrupts */
59 #define XPS2_IPIXR_TX_ALL (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_TX_ACK)
61 /* Mask for all the Receive Interrupts */
62 #define XPS2_IPIXR_RX_ALL (XPS2_IPIXR_RX_OVF | XPS2_IPIXR_RX_ERR | \
65 /* Mask for all the Interrupts */
66 #define XPS2_IPIXR_ALL (XPS2_IPIXR_TX_ALL | XPS2_IPIXR_RX_ALL | \
69 /* Global Interrupt Enable mask */
70 #define XPS2_GIER_GIE_MASK 0x80000000
75 void __iomem *base_address; /* virt. address of control registers */
77 struct serio *serio; /* serio */
81 /************************************/
82 /* XPS PS/2 data transmission calls */
83 /************************************/
86 * xps2_recv() - attempts to receive a byte from the PS/2 port.
87 * @drvdata: pointer to ps2 device private data structure
88 * @byte: address where the read data will be copied
90 * If there is any data available in the PS/2 receiver, this functions reads
91 * the data, otherwise it returns error.
93 static int xps2_recv(struct xps2data *drvdata, u8 *byte)
98 /* If there is data available in the PS/2 receiver, read it */
99 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
100 if (sr & XPS2_STATUS_RX_FULL) {
101 *byte = in_be32(drvdata->base_address + XPS2_RX_DATA_OFFSET);
108 /*********************/
109 /* Interrupt handler */
110 /*********************/
111 static irqreturn_t xps2_interrupt(int irq, void *dev_id)
113 struct xps2data *drvdata = dev_id;
118 /* Get the PS/2 interrupts and clear them */
119 intr_sr = in_be32(drvdata->base_address + XPS2_IPISR_OFFSET);
120 out_be32(drvdata->base_address + XPS2_IPISR_OFFSET, intr_sr);
122 /* Check which interrupt is active */
123 if (intr_sr & XPS2_IPIXR_RX_OVF)
124 dev_warn(drvdata->dev, "receive overrun error\n");
126 if (intr_sr & XPS2_IPIXR_RX_ERR)
127 drvdata->flags |= SERIO_PARITY;
129 if (intr_sr & (XPS2_IPIXR_TX_NOACK | XPS2_IPIXR_WDT_TOUT))
130 drvdata->flags |= SERIO_TIMEOUT;
132 if (intr_sr & XPS2_IPIXR_RX_FULL) {
133 status = xps2_recv(drvdata, &c);
135 /* Error, if a byte is not received */
137 dev_err(drvdata->dev,
138 "wrong rcvd byte count (%d)\n", status);
140 serio_interrupt(drvdata->serio, c, drvdata->flags);
148 /*******************/
149 /* serio callbacks */
150 /*******************/
153 * sxps2_write() - sends a byte out through the PS/2 port.
154 * @pserio: pointer to the serio structure of the PS/2 port
155 * @c: data that needs to be written to the PS/2 port
157 * This function checks if the PS/2 transmitter is empty and sends a byte.
158 * Otherwise it returns error. Transmission fails only when nothing is connected
159 * to the PS/2 port. Thats why, we do not try to resend the data in case of a
162 static int sxps2_write(struct serio *pserio, unsigned char c)
164 struct xps2data *drvdata = pserio->port_data;
169 spin_lock_irqsave(&drvdata->lock, flags);
171 /* If the PS/2 transmitter is empty send a byte of data */
172 sr = in_be32(drvdata->base_address + XPS2_STATUS_OFFSET);
173 if (!(sr & XPS2_STATUS_TX_FULL)) {
174 out_be32(drvdata->base_address + XPS2_TX_DATA_OFFSET, c);
178 spin_unlock_irqrestore(&drvdata->lock, flags);
184 * sxps2_open() - called when a port is opened by the higher layer.
185 * @pserio: pointer to the serio structure of the PS/2 device
187 * This function requests irq and enables interrupts for the PS/2 device.
189 static int sxps2_open(struct serio *pserio)
191 struct xps2data *drvdata = pserio->port_data;
195 error = request_irq(drvdata->irq, &xps2_interrupt, 0,
196 DRIVER_NAME, drvdata);
198 dev_err(drvdata->dev,
199 "Couldn't allocate interrupt %d\n", drvdata->irq);
203 /* start reception by enabling the interrupts */
204 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, XPS2_GIER_GIE_MASK);
205 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, XPS2_IPIXR_RX_ALL);
206 (void)xps2_recv(drvdata, &c);
208 return 0; /* success */
212 * sxps2_close() - frees the interrupt.
213 * @pserio: pointer to the serio structure of the PS/2 device
215 * This function frees the irq and disables interrupts for the PS/2 device.
217 static void sxps2_close(struct serio *pserio)
219 struct xps2data *drvdata = pserio->port_data;
221 /* Disable the PS2 interrupts */
222 out_be32(drvdata->base_address + XPS2_GIER_OFFSET, 0x00);
223 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0x00);
224 free_irq(drvdata->irq, drvdata);
228 * xps2_of_probe - probe method for the PS/2 device.
229 * @of_dev: pointer to OF device structure
230 * @match: pointer to the structure used for matching a device
232 * This function probes the PS/2 device in the device tree.
233 * It initializes the driver data structure and the hardware.
234 * It returns 0, if the driver is bound to the PS/2 device, or a negative
235 * value if there is an error.
237 static int xps2_of_probe(struct platform_device *ofdev)
239 struct resource r_irq; /* Interrupt resources */
240 struct resource r_mem; /* IO mem resources */
241 struct xps2data *drvdata;
243 struct device *dev = &ofdev->dev;
244 resource_size_t remap_size, phys_addr;
247 dev_info(dev, "Device Tree Probing \'%s\'\n",
248 ofdev->dev.of_node->name);
250 /* Get iospace for the device */
251 error = of_address_to_resource(ofdev->dev.of_node, 0, &r_mem);
253 dev_err(dev, "invalid address\n");
257 /* Get IRQ for the device */
258 if (!of_irq_to_resource(ofdev->dev.of_node, 0, &r_irq)) {
259 dev_err(dev, "no IRQ found\n");
263 drvdata = kzalloc(sizeof(struct xps2data), GFP_KERNEL);
264 serio = kzalloc(sizeof(struct serio), GFP_KERNEL);
265 if (!drvdata || !serio) {
270 spin_lock_init(&drvdata->lock);
271 drvdata->irq = r_irq.start;
272 drvdata->serio = serio;
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);
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);
293 /* Disable all the interrupts, just in case */
294 out_be32(drvdata->base_address + XPS2_IPIER_OFFSET, 0);
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);
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,
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);
315 serio_register_port(serio);
317 platform_set_drvdata(ofdev, drvdata);
318 return 0; /* success */
321 release_mem_region(phys_addr, remap_size);
330 * xps2_of_remove - unbinds the driver from the PS/2 device.
331 * @of_dev: pointer to OF device structure
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
337 static int xps2_of_remove(struct platform_device *of_dev)
339 struct xps2data *drvdata = platform_get_drvdata(of_dev);
340 struct resource r_mem; /* IO mem resources */
342 serio_unregister_port(drvdata->serio);
343 iounmap(drvdata->base_address);
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");
349 release_mem_region(r_mem.start, resource_size(&r_mem));
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 */ },
361 MODULE_DEVICE_TABLE(of, xps2_of_match);
363 static struct platform_driver xps2_of_driver = {
366 .owner = THIS_MODULE,
367 .of_match_table = xps2_of_match,
369 .probe = xps2_of_probe,
370 .remove = xps2_of_remove,
372 module_platform_driver(xps2_of_driver);
374 MODULE_AUTHOR("Xilinx, Inc.");
375 MODULE_DESCRIPTION("Xilinx XPS PS/2 driver");
376 MODULE_LICENSE("GPL");