1 /*
2  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 and
6  * only version 2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13 #ifndef _LINUX_SERDEV_H
14 #define _LINUX_SERDEV_H
15 
16 #include <linux/types.h>
17 #include <linux/device.h>
18 #include <linux/termios.h>
19 #include <linux/delay.h>
20 
21 struct serdev_controller;
22 struct serdev_device;
23 
24 /*
25  * serdev device structures
26  */
27 
28 /**
29  * struct serdev_device_ops - Callback operations for a serdev device
30  * @receive_buf:	Function called with data received from device;
31  *			returns number of bytes accepted; may sleep.
32  * @write_wakeup:	Function called when ready to transmit more data; must
33  *			not sleep.
34  */
35 struct serdev_device_ops {
36 	int (*receive_buf)(struct serdev_device *, const unsigned char *, size_t);
37 	void (*write_wakeup)(struct serdev_device *);
38 };
39 
40 /**
41  * struct serdev_device - Basic representation of an serdev device
42  * @dev:	Driver model representation of the device.
43  * @nr:		Device number on serdev bus.
44  * @ctrl:	serdev controller managing this device.
45  * @ops:	Device operations.
46  * @write_comp	Completion used by serdev_device_write() internally
47  * @write_lock	Lock to serialize access when writing data
48  */
49 struct serdev_device {
50 	struct device dev;
51 	int nr;
52 	struct serdev_controller *ctrl;
53 	const struct serdev_device_ops *ops;
54 	struct completion write_comp;
55 	struct mutex write_lock;
56 };
57 
to_serdev_device(struct device * d)58 static inline struct serdev_device *to_serdev_device(struct device *d)
59 {
60 	return container_of(d, struct serdev_device, dev);
61 }
62 
63 /**
64  * struct serdev_device_driver - serdev slave device driver
65  * @driver:	serdev device drivers should initialize name field of this
66  *		structure.
67  * @probe:	binds this driver to a serdev device.
68  * @remove:	unbinds this driver from the serdev device.
69  */
70 struct serdev_device_driver {
71 	struct device_driver driver;
72 	int	(*probe)(struct serdev_device *);
73 	void	(*remove)(struct serdev_device *);
74 };
75 
to_serdev_device_driver(struct device_driver * d)76 static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
77 {
78 	return container_of(d, struct serdev_device_driver, driver);
79 }
80 
81 enum serdev_parity {
82 	SERDEV_PARITY_NONE,
83 	SERDEV_PARITY_EVEN,
84 	SERDEV_PARITY_ODD,
85 };
86 
87 /*
88  * serdev controller structures
89  */
90 struct serdev_controller_ops {
91 	int (*write_buf)(struct serdev_controller *, const unsigned char *, size_t);
92 	void (*write_flush)(struct serdev_controller *);
93 	int (*write_room)(struct serdev_controller *);
94 	int (*open)(struct serdev_controller *);
95 	void (*close)(struct serdev_controller *);
96 	void (*set_flow_control)(struct serdev_controller *, bool);
97 	int (*set_parity)(struct serdev_controller *, enum serdev_parity);
98 	unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
99 	void (*wait_until_sent)(struct serdev_controller *, long);
100 	int (*get_tiocm)(struct serdev_controller *);
101 	int (*set_tiocm)(struct serdev_controller *, unsigned int, unsigned int);
102 };
103 
104 /**
105  * struct serdev_controller - interface to the serdev controller
106  * @dev:	Driver model representation of the device.
107  * @nr:		number identifier for this controller/bus.
108  * @serdev:	Pointer to slave device for this controller.
109  * @ops:	Controller operations.
110  */
111 struct serdev_controller {
112 	struct device		dev;
113 	unsigned int		nr;
114 	struct serdev_device	*serdev;
115 	const struct serdev_controller_ops *ops;
116 };
117 
to_serdev_controller(struct device * d)118 static inline struct serdev_controller *to_serdev_controller(struct device *d)
119 {
120 	return container_of(d, struct serdev_controller, dev);
121 }
122 
serdev_device_get_drvdata(const struct serdev_device * serdev)123 static inline void *serdev_device_get_drvdata(const struct serdev_device *serdev)
124 {
125 	return dev_get_drvdata(&serdev->dev);
126 }
127 
serdev_device_set_drvdata(struct serdev_device * serdev,void * data)128 static inline void serdev_device_set_drvdata(struct serdev_device *serdev, void *data)
129 {
130 	dev_set_drvdata(&serdev->dev, data);
131 }
132 
133 /**
134  * serdev_device_put() - decrement serdev device refcount
135  * @serdev	serdev device.
136  */
serdev_device_put(struct serdev_device * serdev)137 static inline void serdev_device_put(struct serdev_device *serdev)
138 {
139 	if (serdev)
140 		put_device(&serdev->dev);
141 }
142 
serdev_device_set_client_ops(struct serdev_device * serdev,const struct serdev_device_ops * ops)143 static inline void serdev_device_set_client_ops(struct serdev_device *serdev,
144 					      const struct serdev_device_ops *ops)
145 {
146 	serdev->ops = ops;
147 }
148 
149 static inline
serdev_controller_get_drvdata(const struct serdev_controller * ctrl)150 void *serdev_controller_get_drvdata(const struct serdev_controller *ctrl)
151 {
152 	return ctrl ? dev_get_drvdata(&ctrl->dev) : NULL;
153 }
154 
serdev_controller_set_drvdata(struct serdev_controller * ctrl,void * data)155 static inline void serdev_controller_set_drvdata(struct serdev_controller *ctrl,
156 					       void *data)
157 {
158 	dev_set_drvdata(&ctrl->dev, data);
159 }
160 
161 /**
162  * serdev_controller_put() - decrement controller refcount
163  * @ctrl	serdev controller.
164  */
serdev_controller_put(struct serdev_controller * ctrl)165 static inline void serdev_controller_put(struct serdev_controller *ctrl)
166 {
167 	if (ctrl)
168 		put_device(&ctrl->dev);
169 }
170 
171 struct serdev_device *serdev_device_alloc(struct serdev_controller *);
172 int serdev_device_add(struct serdev_device *);
173 void serdev_device_remove(struct serdev_device *);
174 
175 struct serdev_controller *serdev_controller_alloc(struct device *, size_t);
176 int serdev_controller_add(struct serdev_controller *);
177 void serdev_controller_remove(struct serdev_controller *);
178 
serdev_controller_write_wakeup(struct serdev_controller * ctrl)179 static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl)
180 {
181 	struct serdev_device *serdev = ctrl->serdev;
182 
183 	if (!serdev || !serdev->ops->write_wakeup)
184 		return;
185 
186 	serdev->ops->write_wakeup(serdev);
187 }
188 
serdev_controller_receive_buf(struct serdev_controller * ctrl,const unsigned char * data,size_t count)189 static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
190 					      const unsigned char *data,
191 					      size_t count)
192 {
193 	struct serdev_device *serdev = ctrl->serdev;
194 
195 	if (!serdev || !serdev->ops->receive_buf)
196 		return 0;
197 
198 	return serdev->ops->receive_buf(serdev, data, count);
199 }
200 
201 #if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
202 
203 int serdev_device_open(struct serdev_device *);
204 void serdev_device_close(struct serdev_device *);
205 int devm_serdev_device_open(struct device *, struct serdev_device *);
206 unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
207 void serdev_device_set_flow_control(struct serdev_device *, bool);
208 int serdev_device_write_buf(struct serdev_device *, const unsigned char *, size_t);
209 void serdev_device_wait_until_sent(struct serdev_device *, long);
210 int serdev_device_get_tiocm(struct serdev_device *);
211 int serdev_device_set_tiocm(struct serdev_device *, int, int);
212 void serdev_device_write_wakeup(struct serdev_device *);
213 int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, unsigned long);
214 void serdev_device_write_flush(struct serdev_device *);
215 int serdev_device_write_room(struct serdev_device *);
216 
217 /*
218  * serdev device driver functions
219  */
220 int __serdev_device_driver_register(struct serdev_device_driver *, struct module *);
221 #define serdev_device_driver_register(sdrv) \
222 	__serdev_device_driver_register(sdrv, THIS_MODULE)
223 
224 /**
225  * serdev_device_driver_unregister() - unregister an serdev client driver
226  * @sdrv:	the driver to unregister
227  */
serdev_device_driver_unregister(struct serdev_device_driver * sdrv)228 static inline void serdev_device_driver_unregister(struct serdev_device_driver *sdrv)
229 {
230 	if (sdrv)
231 		driver_unregister(&sdrv->driver);
232 }
233 
234 #define module_serdev_device_driver(__serdev_device_driver) \
235 	module_driver(__serdev_device_driver, serdev_device_driver_register, \
236 			serdev_device_driver_unregister)
237 
238 #else
239 
serdev_device_open(struct serdev_device * sdev)240 static inline int serdev_device_open(struct serdev_device *sdev)
241 {
242 	return -ENODEV;
243 }
serdev_device_close(struct serdev_device * sdev)244 static inline void serdev_device_close(struct serdev_device *sdev) {}
serdev_device_set_baudrate(struct serdev_device * sdev,unsigned int baudrate)245 static inline unsigned int serdev_device_set_baudrate(struct serdev_device *sdev, unsigned int baudrate)
246 {
247 	return 0;
248 }
serdev_device_set_flow_control(struct serdev_device * sdev,bool enable)249 static inline void serdev_device_set_flow_control(struct serdev_device *sdev, bool enable) {}
serdev_device_write_buf(struct serdev_device * serdev,const unsigned char * buf,size_t count)250 static inline int serdev_device_write_buf(struct serdev_device *serdev,
251 					  const unsigned char *buf,
252 					  size_t count)
253 {
254 	return -ENODEV;
255 }
serdev_device_wait_until_sent(struct serdev_device * sdev,long timeout)256 static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, long timeout) {}
serdev_device_get_tiocm(struct serdev_device * serdev)257 static inline int serdev_device_get_tiocm(struct serdev_device *serdev)
258 {
259 	return -ENOTSUPP;
260 }
serdev_device_set_tiocm(struct serdev_device * serdev,int set,int clear)261 static inline int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
262 {
263 	return -ENOTSUPP;
264 }
serdev_device_write(struct serdev_device * sdev,const unsigned char * buf,size_t count,unsigned long timeout)265 static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf,
266 				      size_t count, unsigned long timeout)
267 {
268 	return -ENODEV;
269 }
serdev_device_write_flush(struct serdev_device * sdev)270 static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
serdev_device_write_room(struct serdev_device * sdev)271 static inline int serdev_device_write_room(struct serdev_device *sdev)
272 {
273 	return 0;
274 }
275 
276 #define serdev_device_driver_register(x)
277 #define serdev_device_driver_unregister(x)
278 
279 #endif /* CONFIG_SERIAL_DEV_BUS */
280 
serdev_device_get_cts(struct serdev_device * serdev)281 static inline bool serdev_device_get_cts(struct serdev_device *serdev)
282 {
283 	int status = serdev_device_get_tiocm(serdev);
284 	return !!(status & TIOCM_CTS);
285 }
286 
serdev_device_wait_for_cts(struct serdev_device * serdev,bool state,int timeout_ms)287 static inline int serdev_device_wait_for_cts(struct serdev_device *serdev, bool state, int timeout_ms)
288 {
289 	unsigned long timeout;
290 	bool signal;
291 
292 	timeout = jiffies + msecs_to_jiffies(timeout_ms);
293 	while (time_is_after_jiffies(timeout)) {
294 		signal = serdev_device_get_cts(serdev);
295 		if (signal == state)
296 			return 0;
297 		usleep_range(1000, 2000);
298 	}
299 
300 	return -ETIMEDOUT;
301 }
302 
serdev_device_set_rts(struct serdev_device * serdev,bool enable)303 static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enable)
304 {
305 	if (enable)
306 		return serdev_device_set_tiocm(serdev, TIOCM_RTS, 0);
307 	else
308 		return serdev_device_set_tiocm(serdev, 0, TIOCM_RTS);
309 }
310 
311 int serdev_device_set_parity(struct serdev_device *serdev,
312 			     enum serdev_parity parity);
313 
314 /*
315  * serdev hooks into TTY core
316  */
317 struct tty_port;
318 struct tty_driver;
319 
320 #ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
321 struct device *serdev_tty_port_register(struct tty_port *port,
322 					struct device *parent,
323 					struct tty_driver *drv, int idx);
324 int serdev_tty_port_unregister(struct tty_port *port);
325 #else
serdev_tty_port_register(struct tty_port * port,struct device * parent,struct tty_driver * drv,int idx)326 static inline struct device *serdev_tty_port_register(struct tty_port *port,
327 					   struct device *parent,
328 					   struct tty_driver *drv, int idx)
329 {
330 	return ERR_PTR(-ENODEV);
331 }
serdev_tty_port_unregister(struct tty_port * port)332 static inline int serdev_tty_port_unregister(struct tty_port *port)
333 {
334 	return -ENODEV;
335 }
336 #endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
337 
338 #endif /*_LINUX_SERDEV_H */
339