1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Helpers for controlling modem lines via GPIO
4  *
5  * Copyright (C) 2014 Paratronic S.A.
6  */
7 
8 #ifndef __SERIAL_MCTRL_GPIO__
9 #define __SERIAL_MCTRL_GPIO__
10 
11 #include <linux/err.h>
12 #include <linux/device.h>
13 #include <linux/gpio/consumer.h>
14 
15 struct uart_port;
16 
17 enum mctrl_gpio_idx {
18 	UART_GPIO_CTS,
19 	UART_GPIO_DSR,
20 	UART_GPIO_DCD,
21 	UART_GPIO_RNG,
22 	UART_GPIO_RI = UART_GPIO_RNG,
23 	UART_GPIO_RTS,
24 	UART_GPIO_DTR,
25 	UART_GPIO_MAX,
26 };
27 
28 /*
29  * Opaque descriptor for modem lines controlled by GPIOs
30  */
31 struct mctrl_gpios;
32 
33 #ifdef CONFIG_GPIOLIB
34 
35 /*
36  * Set state of the modem control output lines via GPIOs.
37  */
38 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
39 
40 /*
41  * Get state of the modem control input lines from GPIOs.
42  * The mctrl flags are updated and returned.
43  */
44 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
45 
46 /*
47  * Get state of the modem control output lines from GPIOs.
48  * The mctrl flags are updated and returned.
49  */
50 unsigned int
51 mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl);
52 
53 /*
54  * Returns the associated struct gpio_desc to the modem line gidx
55  */
56 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
57 				      enum mctrl_gpio_idx gidx);
58 
59 /*
60  * Request and set direction of modem control line GPIOs and set up irq
61  * handling.
62  * devm_* functions are used, so there's no need to call mctrl_gpio_free().
63  * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
64  * allocation error.
65  */
66 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx);
67 
68 /*
69  * Request and set direction of modem control line GPIOs.
70  * devm_* functions are used, so there's no need to call mctrl_gpio_free().
71  * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
72  * allocation error.
73  */
74 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev,
75 					   unsigned int idx);
76 
77 /*
78  * Free the mctrl_gpios structure.
79  * Normally, this function will not be called, as the GPIOs will
80  * be disposed of by the resource management code.
81  */
82 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
83 
84 /*
85  * Enable gpio interrupts to report status line changes.
86  */
87 void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
88 
89 /*
90  * Disable gpio interrupts to report status line changes.
91  */
92 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
93 
94 #else /* GPIOLIB */
95 
96 static inline
97 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
98 {
99 }
100 
101 static inline
102 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
103 {
104 	return *mctrl;
105 }
106 
107 static inline unsigned int
108 mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
109 {
110 	return *mctrl;
111 }
112 
113 static inline
114 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
115 				      enum mctrl_gpio_idx gidx)
116 {
117 	return ERR_PTR(-ENOSYS);
118 }
119 
120 static inline
121 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
122 {
123 	return ERR_PTR(-ENOSYS);
124 }
125 
126 static inline
127 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
128 {
129 	return ERR_PTR(-ENOSYS);
130 }
131 
132 static inline
133 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
134 {
135 }
136 
137 static inline void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
138 {
139 }
140 
141 static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
142 {
143 }
144 
145 #endif /* GPIOLIB */
146 
147 #endif
148