1 /*
2  * Helpers for controlling modem lines via GPIO
3  *
4  * Copyright (C) 2014 Paratronic S.A.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  */
17 
18 #ifndef __SERIAL_MCTRL_GPIO__
19 #define __SERIAL_MCTRL_GPIO__
20 
21 #include <linux/err.h>
22 #include <linux/device.h>
23 #include <linux/gpio/consumer.h>
24 
25 enum mctrl_gpio_idx {
26 	UART_GPIO_CTS,
27 	UART_GPIO_DSR,
28 	UART_GPIO_DCD,
29 	UART_GPIO_RNG,
30 	UART_GPIO_RI = UART_GPIO_RNG,
31 	UART_GPIO_RTS,
32 	UART_GPIO_DTR,
33 	UART_GPIO_OUT1,
34 	UART_GPIO_OUT2,
35 	UART_GPIO_MAX,
36 };
37 
38 /*
39  * Opaque descriptor for modem lines controlled by GPIOs
40  */
41 struct mctrl_gpios;
42 
43 #ifdef CONFIG_GPIOLIB
44 
45 /*
46  * Set state of the modem control output lines via GPIOs.
47  */
48 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
49 
50 /*
51  * Get state of the modem control output lines from GPIOs.
52  * The mctrl flags are updated and returned.
53  */
54 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
55 
56 /*
57  * Returns the associated struct gpio_desc to the modem line gidx
58  */
59 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
60 				      enum mctrl_gpio_idx gidx);
61 
62 /*
63  * Request and set direction of modem control lines GPIOs.
64  * devm_* functions are used, so there's no need to call mctrl_gpio_free().
65  * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
66  * allocation error.
67  */
68 struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
69 
70 /*
71  * Free the mctrl_gpios structure.
72  * Normally, this function will not be called, as the GPIOs will
73  * be disposed of by the resource management code.
74  */
75 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
76 
77 #else /* GPIOLIB */
78 
79 static inline
80 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
81 {
82 }
83 
84 static inline
85 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
86 {
87 	return *mctrl;
88 }
89 
90 static inline
91 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
92 				      enum mctrl_gpio_idx gidx)
93 {
94 	return ERR_PTR(-ENOSYS);
95 }
96 
97 static inline
98 struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
99 {
100 	return ERR_PTR(-ENOSYS);
101 }
102 
103 static inline
104 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
105 {
106 }
107 
108 #endif /* GPIOLIB */
109 
110 #endif
111