1// SPDX-License-Identifier: GPL-2.0
2/* -*- linux-c -*-
3 * Cypress USB Thermometer driver
4 *
5 * Copyright (c) 2004 Erik Rigtorp <erkki@linux.nu> <erik@rigtorp.com>
6 *
7 * This driver works with Elektor magazine USB Interface as published in
8 * issue #291. It should also work with the original starter kit/demo board
9 * from Cypress.
10 */
11
12
13#include <linux/kernel.h>
14#include <linux/errno.h>
15#include <linux/slab.h>
16#include <linux/module.h>
17#include <linux/usb.h>
18
19#define DRIVER_AUTHOR "Erik Rigtorp"
20#define DRIVER_DESC "Cypress USB Thermometer driver"
21
22#define USB_SKEL_VENDOR_ID	0x04b4
23#define USB_SKEL_PRODUCT_ID	0x0002
24
25static const struct usb_device_id id_table[] = {
26	{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
27	{ }
28};
29MODULE_DEVICE_TABLE (usb, id_table);
30
31/* Structure to hold all of our device specific stuff */
32struct usb_cytherm {
33	struct usb_device    *udev;	 /* save off the usb device pointer */
34	struct usb_interface *interface; /* the interface for this device */
35	int brightness;
36};
37
38
39/* Vendor requests */
40/* They all operate on one byte at a time */
41#define PING       0x00
42#define READ_ROM   0x01 /* Reads form ROM, value = address */
43#define READ_RAM   0x02 /* Reads form RAM, value = address */
44#define WRITE_RAM  0x03 /* Write to RAM, value = address, index = data */
45#define READ_PORT  0x04 /* Reads from port, value = address */
46#define WRITE_PORT 0x05 /* Write to port, value = address, index = data */
47
48
49/* Send a vendor command to device */
50static int vendor_command(struct usb_device *dev, unsigned char request,
51			  unsigned char value, unsigned char index,
52			  void *buf, int size)
53{
54	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
55			       request,
56			       USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_OTHER,
57			       value,
58			       index, buf, size,
59			       USB_CTRL_GET_TIMEOUT);
60}
61
62
63
64#define BRIGHTNESS 0x2c     /* RAM location for brightness value */
65#define BRIGHTNESS_SEM 0x2b /* RAM location for brightness semaphore */
66
67static ssize_t brightness_show(struct device *dev, struct device_attribute *attr, char *buf)
68{
69	struct usb_interface *intf = to_usb_interface(dev);
70	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
71
72	return sprintf(buf, "%i", cytherm->brightness);
73}
74
75static ssize_t brightness_store(struct device *dev, struct device_attribute *attr, const char *buf,
76			      size_t count)
77{
78	struct usb_interface *intf = to_usb_interface(dev);
79	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
80
81	unsigned char *buffer;
82	int retval;
83
84	buffer = kmalloc(8, GFP_KERNEL);
85	if (!buffer)
86		return 0;
87
88	cytherm->brightness = simple_strtoul(buf, NULL, 10);
89
90	if (cytherm->brightness > 0xFF)
91		cytherm->brightness = 0xFF;
92	else if (cytherm->brightness < 0)
93		cytherm->brightness = 0;
94
95	/* Set brightness */
96	retval = vendor_command(cytherm->udev, WRITE_RAM, BRIGHTNESS,
97				cytherm->brightness, buffer, 8);
98	if (retval)
99		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
100	/* Inform µC that we have changed the brightness setting */
101	retval = vendor_command(cytherm->udev, WRITE_RAM, BRIGHTNESS_SEM,
102				0x01, buffer, 8);
103	if (retval)
104		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
105
106	kfree(buffer);
107
108	return count;
109}
110static DEVICE_ATTR_RW(brightness);
111
112
113#define TEMP 0x33 /* RAM location for temperature */
114#define SIGN 0x34 /* RAM location for temperature sign */
115
116static ssize_t temp_show(struct device *dev, struct device_attribute *attr, char *buf)
117{
118
119	struct usb_interface *intf = to_usb_interface(dev);
120	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
121
122	int retval;
123	unsigned char *buffer;
124
125	int temp, sign;
126
127	buffer = kmalloc(8, GFP_KERNEL);
128	if (!buffer)
129		return 0;
130
131	/* read temperature */
132	retval = vendor_command(cytherm->udev, READ_RAM, TEMP, 0, buffer, 8);
133	if (retval)
134		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
135	temp = buffer[1];
136
137	/* read sign */
138	retval = vendor_command(cytherm->udev, READ_RAM, SIGN, 0, buffer, 8);
139	if (retval)
140		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
141	sign = buffer[1];
142
143	kfree(buffer);
144
145	return sprintf(buf, "%c%i.%i", sign ? '-' : '+', temp >> 1,
146		       5*(temp - ((temp >> 1) << 1)));
147}
148static DEVICE_ATTR_RO(temp);
149
150
151#define BUTTON 0x7a
152
153static ssize_t button_show(struct device *dev, struct device_attribute *attr, char *buf)
154{
155
156	struct usb_interface *intf = to_usb_interface(dev);
157	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
158
159	int retval;
160	unsigned char *buffer;
161
162	buffer = kmalloc(8, GFP_KERNEL);
163	if (!buffer)
164		return 0;
165
166	/* check button */
167	retval = vendor_command(cytherm->udev, READ_RAM, BUTTON, 0, buffer, 8);
168	if (retval)
169		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
170
171	retval = buffer[1];
172
173	kfree(buffer);
174
175	if (retval)
176		return sprintf(buf, "1");
177	else
178		return sprintf(buf, "0");
179}
180static DEVICE_ATTR_RO(button);
181
182
183static ssize_t port0_show(struct device *dev, struct device_attribute *attr, char *buf)
184{
185	struct usb_interface *intf = to_usb_interface(dev);
186	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
187
188	int retval;
189	unsigned char *buffer;
190
191	buffer = kmalloc(8, GFP_KERNEL);
192	if (!buffer)
193		return 0;
194
195	retval = vendor_command(cytherm->udev, READ_PORT, 0, 0, buffer, 8);
196	if (retval)
197		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
198
199	retval = buffer[1];
200
201	kfree(buffer);
202
203	return sprintf(buf, "%d", retval);
204}
205
206
207static ssize_t port0_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
208{
209	struct usb_interface *intf = to_usb_interface(dev);
210	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
211
212	unsigned char *buffer;
213	int retval;
214	int tmp;
215
216	buffer = kmalloc(8, GFP_KERNEL);
217	if (!buffer)
218		return 0;
219
220	tmp = simple_strtoul(buf, NULL, 10);
221
222	if (tmp > 0xFF)
223		tmp = 0xFF;
224	else if (tmp < 0)
225		tmp = 0;
226
227	retval = vendor_command(cytherm->udev, WRITE_PORT, 0,
228				tmp, buffer, 8);
229	if (retval)
230		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
231
232	kfree(buffer);
233
234	return count;
235}
236static DEVICE_ATTR_RW(port0);
237
238static ssize_t port1_show(struct device *dev, struct device_attribute *attr, char *buf)
239{
240	struct usb_interface *intf = to_usb_interface(dev);
241	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
242
243	int retval;
244	unsigned char *buffer;
245
246	buffer = kmalloc(8, GFP_KERNEL);
247	if (!buffer)
248		return 0;
249
250	retval = vendor_command(cytherm->udev, READ_PORT, 1, 0, buffer, 8);
251	if (retval)
252		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
253
254	retval = buffer[1];
255
256	kfree(buffer);
257
258	return sprintf(buf, "%d", retval);
259}
260
261
262static ssize_t port1_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
263{
264	struct usb_interface *intf = to_usb_interface(dev);
265	struct usb_cytherm *cytherm = usb_get_intfdata(intf);
266
267	unsigned char *buffer;
268	int retval;
269	int tmp;
270
271	buffer = kmalloc(8, GFP_KERNEL);
272	if (!buffer)
273		return 0;
274
275	tmp = simple_strtoul(buf, NULL, 10);
276
277	if (tmp > 0xFF)
278		tmp = 0xFF;
279	else if (tmp < 0)
280		tmp = 0;
281
282	retval = vendor_command(cytherm->udev, WRITE_PORT, 1,
283				tmp, buffer, 8);
284	if (retval)
285		dev_dbg(&cytherm->udev->dev, "retval = %d\n", retval);
286
287	kfree(buffer);
288
289	return count;
290}
291static DEVICE_ATTR_RW(port1);
292
293static struct attribute *cytherm_attrs[] = {
294	&dev_attr_brightness.attr,
295	&dev_attr_temp.attr,
296	&dev_attr_button.attr,
297	&dev_attr_port0.attr,
298	&dev_attr_port1.attr,
299	NULL,
300};
301ATTRIBUTE_GROUPS(cytherm);
302
303static int cytherm_probe(struct usb_interface *interface,
304			 const struct usb_device_id *id)
305{
306	struct usb_device *udev = interface_to_usbdev(interface);
307	struct usb_cytherm *dev;
308	int retval = -ENOMEM;
309
310	dev = kzalloc(sizeof(struct usb_cytherm), GFP_KERNEL);
311	if (!dev)
312		goto error_mem;
313
314	dev->udev = usb_get_dev(udev);
315
316	usb_set_intfdata(interface, dev);
317
318	dev->brightness = 0xFF;
319
320	dev_info(&interface->dev,
321		  "Cypress thermometer device now attached\n");
322	return 0;
323
324error_mem:
325	return retval;
326}
327
328static void cytherm_disconnect(struct usb_interface *interface)
329{
330	struct usb_cytherm *dev;
331
332	dev = usb_get_intfdata(interface);
333
334	/* first remove the files, then NULL the pointer */
335	usb_set_intfdata(interface, NULL);
336
337	usb_put_dev(dev->udev);
338
339	kfree(dev);
340
341	dev_info(&interface->dev, "Cypress thermometer now disconnected\n");
342}
343
344/* usb specific object needed to register this driver with the usb subsystem */
345static struct usb_driver cytherm_driver = {
346	.name =		"cytherm",
347	.probe =	cytherm_probe,
348	.disconnect =	cytherm_disconnect,
349	.id_table =	id_table,
350	.dev_groups =	cytherm_groups,
351};
352
353module_usb_driver(cytherm_driver);
354
355MODULE_AUTHOR(DRIVER_AUTHOR);
356MODULE_DESCRIPTION(DRIVER_DESC);
357MODULE_LICENSE("GPL");
358