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Linux/drivers/input/serio/xilinx_ps2.c

  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 

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