1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
4  */
5 #ifndef _LINUX_SERDEV_H
6 #define _LINUX_SERDEV_H
7 
8 #include <linux/types.h>
9 #include <linux/device.h>
10 #include <linux/termios.h>
11 #include <linux/delay.h>
12 
13 struct serdev_controller;
14 struct serdev_device;
15 
16 /*
17  * serdev device structures
18  */
19 
20 /**
21  * struct serdev_device_ops - Callback operations for a serdev device
22  * @receive_buf:	Function called with data received from device;
23  *			returns number of bytes accepted; may sleep.
24  * @write_wakeup:	Function called when ready to transmit more data; must
25  *			not sleep.
26  */
27 struct serdev_device_ops {
28 	int (*receive_buf)(struct serdev_device *, const unsigned char *, size_t);
29 	void (*write_wakeup)(struct serdev_device *);
30 };
31 
32 /**
33  * struct serdev_device - Basic representation of an serdev device
34  * @dev:	Driver model representation of the device.
35  * @nr:		Device number on serdev bus.
36  * @ctrl:	serdev controller managing this device.
37  * @ops:	Device operations.
38  * @write_comp	Completion used by serdev_device_write() internally
39  * @write_lock	Lock to serialize access when writing data
40  */
41 struct serdev_device {
42 	struct device dev;
43 	int nr;
44 	struct serdev_controller *ctrl;
45 	const struct serdev_device_ops *ops;
46 	struct completion write_comp;
47 	struct mutex write_lock;
48 };
49 
to_serdev_device(struct device * d)50 static inline struct serdev_device *to_serdev_device(struct device *d)
51 {
52 	return container_of(d, struct serdev_device, dev);
53 }
54 
55 /**
56  * struct serdev_device_driver - serdev slave device driver
57  * @driver:	serdev device drivers should initialize name field of this
58  *		structure.
59  * @probe:	binds this driver to a serdev device.
60  * @remove:	unbinds this driver from the serdev device.
61  */
62 struct serdev_device_driver {
63 	struct device_driver driver;
64 	int	(*probe)(struct serdev_device *);
65 	void	(*remove)(struct serdev_device *);
66 };
67 
to_serdev_device_driver(struct device_driver * d)68 static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
69 {
70 	return container_of(d, struct serdev_device_driver, driver);
71 }
72 
73 enum serdev_parity {
74 	SERDEV_PARITY_NONE,
75 	SERDEV_PARITY_EVEN,
76 	SERDEV_PARITY_ODD,
77 };
78 
79 /*
80  * serdev controller structures
81  */
82 struct serdev_controller_ops {
83 	int (*write_buf)(struct serdev_controller *, const unsigned char *, size_t);
84 	void (*write_flush)(struct serdev_controller *);
85 	int (*write_room)(struct serdev_controller *);
86 	int (*open)(struct serdev_controller *);
87 	void (*close)(struct serdev_controller *);
88 	void (*set_flow_control)(struct serdev_controller *, bool);
89 	int (*set_parity)(struct serdev_controller *, enum serdev_parity);
90 	unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
91 	void (*wait_until_sent)(struct serdev_controller *, long);
92 	int (*get_tiocm)(struct serdev_controller *);
93 	int (*set_tiocm)(struct serdev_controller *, unsigned int, unsigned int);
94 };
95 
96 /**
97  * struct serdev_controller - interface to the serdev controller
98  * @dev:	Driver model representation of the device.
99  * @nr:		number identifier for this controller/bus.
100  * @serdev:	Pointer to slave device for this controller.
101  * @ops:	Controller operations.
102  */
103 struct serdev_controller {
104 	struct device		dev;
105 	unsigned int		nr;
106 	struct serdev_device	*serdev;
107 	const struct serdev_controller_ops *ops;
108 };
109 
to_serdev_controller(struct device * d)110 static inline struct serdev_controller *to_serdev_controller(struct device *d)
111 {
112 	return container_of(d, struct serdev_controller, dev);
113 }
114 
serdev_device_get_drvdata(const struct serdev_device * serdev)115 static inline void *serdev_device_get_drvdata(const struct serdev_device *serdev)
116 {
117 	return dev_get_drvdata(&serdev->dev);
118 }
119 
serdev_device_set_drvdata(struct serdev_device * serdev,void * data)120 static inline void serdev_device_set_drvdata(struct serdev_device *serdev, void *data)
121 {
122 	dev_set_drvdata(&serdev->dev, data);
123 }
124 
125 /**
126  * serdev_device_put() - decrement serdev device refcount
127  * @serdev	serdev device.
128  */
serdev_device_put(struct serdev_device * serdev)129 static inline void serdev_device_put(struct serdev_device *serdev)
130 {
131 	if (serdev)
132 		put_device(&serdev->dev);
133 }
134 
serdev_device_set_client_ops(struct serdev_device * serdev,const struct serdev_device_ops * ops)135 static inline void serdev_device_set_client_ops(struct serdev_device *serdev,
136 					      const struct serdev_device_ops *ops)
137 {
138 	serdev->ops = ops;
139 }
140 
141 static inline
serdev_controller_get_drvdata(const struct serdev_controller * ctrl)142 void *serdev_controller_get_drvdata(const struct serdev_controller *ctrl)
143 {
144 	return ctrl ? dev_get_drvdata(&ctrl->dev) : NULL;
145 }
146 
serdev_controller_set_drvdata(struct serdev_controller * ctrl,void * data)147 static inline void serdev_controller_set_drvdata(struct serdev_controller *ctrl,
148 					       void *data)
149 {
150 	dev_set_drvdata(&ctrl->dev, data);
151 }
152 
153 /**
154  * serdev_controller_put() - decrement controller refcount
155  * @ctrl	serdev controller.
156  */
serdev_controller_put(struct serdev_controller * ctrl)157 static inline void serdev_controller_put(struct serdev_controller *ctrl)
158 {
159 	if (ctrl)
160 		put_device(&ctrl->dev);
161 }
162 
163 struct serdev_device *serdev_device_alloc(struct serdev_controller *);
164 int serdev_device_add(struct serdev_device *);
165 void serdev_device_remove(struct serdev_device *);
166 
167 struct serdev_controller *serdev_controller_alloc(struct device *, size_t);
168 int serdev_controller_add(struct serdev_controller *);
169 void serdev_controller_remove(struct serdev_controller *);
170 
serdev_controller_write_wakeup(struct serdev_controller * ctrl)171 static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl)
172 {
173 	struct serdev_device *serdev = ctrl->serdev;
174 
175 	if (!serdev || !serdev->ops->write_wakeup)
176 		return;
177 
178 	serdev->ops->write_wakeup(serdev);
179 }
180 
serdev_controller_receive_buf(struct serdev_controller * ctrl,const unsigned char * data,size_t count)181 static inline int serdev_controller_receive_buf(struct serdev_controller *ctrl,
182 					      const unsigned char *data,
183 					      size_t count)
184 {
185 	struct serdev_device *serdev = ctrl->serdev;
186 
187 	if (!serdev || !serdev->ops->receive_buf)
188 		return 0;
189 
190 	return serdev->ops->receive_buf(serdev, data, count);
191 }
192 
193 #if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
194 
195 int serdev_device_open(struct serdev_device *);
196 void serdev_device_close(struct serdev_device *);
197 int devm_serdev_device_open(struct device *, struct serdev_device *);
198 unsigned int serdev_device_set_baudrate(struct serdev_device *, unsigned int);
199 void serdev_device_set_flow_control(struct serdev_device *, bool);
200 int serdev_device_write_buf(struct serdev_device *, const unsigned char *, size_t);
201 void serdev_device_wait_until_sent(struct serdev_device *, long);
202 int serdev_device_get_tiocm(struct serdev_device *);
203 int serdev_device_set_tiocm(struct serdev_device *, int, int);
204 void serdev_device_write_wakeup(struct serdev_device *);
205 int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, long);
206 void serdev_device_write_flush(struct serdev_device *);
207 int serdev_device_write_room(struct serdev_device *);
208 
209 /*
210  * serdev device driver functions
211  */
212 int __serdev_device_driver_register(struct serdev_device_driver *, struct module *);
213 #define serdev_device_driver_register(sdrv) \
214 	__serdev_device_driver_register(sdrv, THIS_MODULE)
215 
216 /**
217  * serdev_device_driver_unregister() - unregister an serdev client driver
218  * @sdrv:	the driver to unregister
219  */
serdev_device_driver_unregister(struct serdev_device_driver * sdrv)220 static inline void serdev_device_driver_unregister(struct serdev_device_driver *sdrv)
221 {
222 	if (sdrv)
223 		driver_unregister(&sdrv->driver);
224 }
225 
226 #define module_serdev_device_driver(__serdev_device_driver) \
227 	module_driver(__serdev_device_driver, serdev_device_driver_register, \
228 			serdev_device_driver_unregister)
229 
230 #else
231 
serdev_device_open(struct serdev_device * sdev)232 static inline int serdev_device_open(struct serdev_device *sdev)
233 {
234 	return -ENODEV;
235 }
serdev_device_close(struct serdev_device * sdev)236 static inline void serdev_device_close(struct serdev_device *sdev) {}
serdev_device_set_baudrate(struct serdev_device * sdev,unsigned int baudrate)237 static inline unsigned int serdev_device_set_baudrate(struct serdev_device *sdev, unsigned int baudrate)
238 {
239 	return 0;
240 }
serdev_device_set_flow_control(struct serdev_device * sdev,bool enable)241 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)242 static inline int serdev_device_write_buf(struct serdev_device *serdev,
243 					  const unsigned char *buf,
244 					  size_t count)
245 {
246 	return -ENODEV;
247 }
serdev_device_wait_until_sent(struct serdev_device * sdev,long timeout)248 static inline void serdev_device_wait_until_sent(struct serdev_device *sdev, long timeout) {}
serdev_device_get_tiocm(struct serdev_device * serdev)249 static inline int serdev_device_get_tiocm(struct serdev_device *serdev)
250 {
251 	return -ENOTSUPP;
252 }
serdev_device_set_tiocm(struct serdev_device * serdev,int set,int clear)253 static inline int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
254 {
255 	return -ENOTSUPP;
256 }
serdev_device_write(struct serdev_device * sdev,const unsigned char * buf,size_t count,unsigned long timeout)257 static inline int serdev_device_write(struct serdev_device *sdev, const unsigned char *buf,
258 				      size_t count, unsigned long timeout)
259 {
260 	return -ENODEV;
261 }
serdev_device_write_flush(struct serdev_device * sdev)262 static inline void serdev_device_write_flush(struct serdev_device *sdev) {}
serdev_device_write_room(struct serdev_device * sdev)263 static inline int serdev_device_write_room(struct serdev_device *sdev)
264 {
265 	return 0;
266 }
267 
268 #define serdev_device_driver_register(x)
269 #define serdev_device_driver_unregister(x)
270 
271 #endif /* CONFIG_SERIAL_DEV_BUS */
272 
serdev_device_get_cts(struct serdev_device * serdev)273 static inline bool serdev_device_get_cts(struct serdev_device *serdev)
274 {
275 	int status = serdev_device_get_tiocm(serdev);
276 	return !!(status & TIOCM_CTS);
277 }
278 
serdev_device_wait_for_cts(struct serdev_device * serdev,bool state,int timeout_ms)279 static inline int serdev_device_wait_for_cts(struct serdev_device *serdev, bool state, int timeout_ms)
280 {
281 	unsigned long timeout;
282 	bool signal;
283 
284 	timeout = jiffies + msecs_to_jiffies(timeout_ms);
285 	while (time_is_after_jiffies(timeout)) {
286 		signal = serdev_device_get_cts(serdev);
287 		if (signal == state)
288 			return 0;
289 		usleep_range(1000, 2000);
290 	}
291 
292 	return -ETIMEDOUT;
293 }
294 
serdev_device_set_rts(struct serdev_device * serdev,bool enable)295 static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enable)
296 {
297 	if (enable)
298 		return serdev_device_set_tiocm(serdev, TIOCM_RTS, 0);
299 	else
300 		return serdev_device_set_tiocm(serdev, 0, TIOCM_RTS);
301 }
302 
303 int serdev_device_set_parity(struct serdev_device *serdev,
304 			     enum serdev_parity parity);
305 
306 /*
307  * serdev hooks into TTY core
308  */
309 struct tty_port;
310 struct tty_driver;
311 
312 #ifdef CONFIG_SERIAL_DEV_CTRL_TTYPORT
313 struct device *serdev_tty_port_register(struct tty_port *port,
314 					struct device *parent,
315 					struct tty_driver *drv, int idx);
316 int serdev_tty_port_unregister(struct tty_port *port);
317 #else
serdev_tty_port_register(struct tty_port * port,struct device * parent,struct tty_driver * drv,int idx)318 static inline struct device *serdev_tty_port_register(struct tty_port *port,
319 					   struct device *parent,
320 					   struct tty_driver *drv, int idx)
321 {
322 	return ERR_PTR(-ENODEV);
323 }
serdev_tty_port_unregister(struct tty_port * port)324 static inline int serdev_tty_port_unregister(struct tty_port *port)
325 {
326 	return -ENODEV;
327 }
328 #endif /* CONFIG_SERIAL_DEV_CTRL_TTYPORT */
329 
330 struct acpi_resource;
331 struct acpi_resource_uart_serialbus;
332 
333 #ifdef CONFIG_ACPI
334 bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
335 				   struct acpi_resource_uart_serialbus **uart);
336 #else
serdev_acpi_get_uart_resource(struct acpi_resource * ares,struct acpi_resource_uart_serialbus ** uart)337 static inline bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
338 						 struct acpi_resource_uart_serialbus **uart)
339 {
340 	return false;
341 }
342 #endif /* CONFIG_ACPI */
343 
344 #endif /*_LINUX_SERDEV_H */
345