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 struct uart_port;
26 
27 enum mctrl_gpio_idx {
28 	UART_GPIO_CTS,
29 	UART_GPIO_DSR,
30 	UART_GPIO_DCD,
31 	UART_GPIO_RNG,
32 	UART_GPIO_RI = UART_GPIO_RNG,
33 	UART_GPIO_RTS,
34 	UART_GPIO_DTR,
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 input 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  * Get state of the modem control output lines from GPIOs.
58  * The mctrl flags are updated and returned.
59  */
60 unsigned int
61 mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl);
62 
63 /*
64  * Returns the associated struct gpio_desc to the modem line gidx
65  */
66 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
67 				      enum mctrl_gpio_idx gidx);
68 
69 /*
70  * Request and set direction of modem control line GPIOs and set up irq
71  * handling.
72  * devm_* functions are used, so there's no need to call mctrl_gpio_free().
73  * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
74  * allocation error.
75  */
76 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx);
77 
78 /*
79  * Request and set direction of modem control line GPIOs.
80  * devm_* functions are used, so there's no need to call mctrl_gpio_free().
81  * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
82  * allocation error.
83  */
84 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev,
85 					   unsigned int idx);
86 
87 /*
88  * Free the mctrl_gpios structure.
89  * Normally, this function will not be called, as the GPIOs will
90  * be disposed of by the resource management code.
91  */
92 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
93 
94 /*
95  * Enable gpio interrupts to report status line changes.
96  */
97 void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
98 
99 /*
100  * Disable gpio interrupts to report status line changes.
101  */
102 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
103 
104 #else /* GPIOLIB */
105 
106 static inline
107 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
108 {
109 }
110 
111 static inline
112 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
113 {
114 	return *mctrl;
115 }
116 
117 static inline unsigned int
118 mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
119 {
120 	return *mctrl;
121 }
122 
123 static inline
124 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
125 				      enum mctrl_gpio_idx gidx)
126 {
127 	return ERR_PTR(-ENOSYS);
128 }
129 
130 static inline
131 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
132 {
133 	return ERR_PTR(-ENOSYS);
134 }
135 
136 static inline
137 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
138 {
139 	return ERR_PTR(-ENOSYS);
140 }
141 
142 static inline
143 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
144 {
145 }
146 
147 static inline void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
148 {
149 }
150 
151 static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
152 {
153 }
154 
155 #endif /* GPIOLIB */
156 
157 #endif
158