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#include <linux/err.h>
19#include <linux/device.h>
20#include <linux/gpio/consumer.h>
21#include <linux/termios.h>
22
23#include "serial_mctrl_gpio.h"
24
25struct mctrl_gpios {
26	struct gpio_desc *gpio[UART_GPIO_MAX];
27};
28
29static const struct {
30	const char *name;
31	unsigned int mctrl;
32	bool dir_out;
33} mctrl_gpios_desc[UART_GPIO_MAX] = {
34	{ "cts", TIOCM_CTS, false, },
35	{ "dsr", TIOCM_DSR, false, },
36	{ "dcd", TIOCM_CD, false, },
37	{ "rng", TIOCM_RNG, false, },
38	{ "rts", TIOCM_RTS, true, },
39	{ "dtr", TIOCM_DTR, true, },
40	{ "out1", TIOCM_OUT1, true, },
41	{ "out2", TIOCM_OUT2, true, },
42};
43
44void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
45{
46	enum mctrl_gpio_idx i;
47	struct gpio_desc *desc_array[UART_GPIO_MAX];
48	int value_array[UART_GPIO_MAX];
49	unsigned int count = 0;
50
51	for (i = 0; i < UART_GPIO_MAX; i++)
52		if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
53		    mctrl_gpios_desc[i].dir_out) {
54			desc_array[count] = gpios->gpio[i];
55			value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
56			count++;
57		}
58	gpiod_set_array(count, desc_array, value_array);
59}
60EXPORT_SYMBOL_GPL(mctrl_gpio_set);
61
62struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
63				      enum mctrl_gpio_idx gidx)
64{
65	return gpios->gpio[gidx];
66}
67EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
68
69unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
70{
71	enum mctrl_gpio_idx i;
72
73	for (i = 0; i < UART_GPIO_MAX; i++) {
74		if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
75			if (gpiod_get_value(gpios->gpio[i]))
76				*mctrl |= mctrl_gpios_desc[i].mctrl;
77			else
78				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
79		}
80	}
81
82	return *mctrl;
83}
84EXPORT_SYMBOL_GPL(mctrl_gpio_get);
85
86struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
87{
88	struct mctrl_gpios *gpios;
89	enum mctrl_gpio_idx i;
90
91	gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
92	if (!gpios)
93		return ERR_PTR(-ENOMEM);
94
95	for (i = 0; i < UART_GPIO_MAX; i++) {
96		enum gpiod_flags flags;
97
98		if (mctrl_gpios_desc[i].dir_out)
99			flags = GPIOD_OUT_LOW;
100		else
101			flags = GPIOD_IN;
102
103		gpios->gpio[i] =
104			devm_gpiod_get_index_optional(dev,
105						      mctrl_gpios_desc[i].name,
106						      idx, flags);
107
108		if (IS_ERR(gpios->gpio[i]))
109			return ERR_CAST(gpios->gpio[i]);
110	}
111
112	return gpios;
113}
114EXPORT_SYMBOL_GPL(mctrl_gpio_init);
115
116void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
117{
118	enum mctrl_gpio_idx i;
119
120	for (i = 0; i < UART_GPIO_MAX; i++)
121		if (!IS_ERR_OR_NULL(gpios->gpio[i]))
122			devm_gpiod_put(dev, gpios->gpio[i]);
123	devm_kfree(dev, gpios);
124}
125EXPORT_SYMBOL_GPL(mctrl_gpio_free);
126