2 * Helpers for controlling modem lines via GPIO
4 * Copyright (C) 2014 Paratronic S.A.
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.
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.
17 #include <linux/err.h>
18 #include <linux/device.h>
19 #include <linux/irq.h>
20 #include <linux/gpio/consumer.h>
21 #include <linux/termios.h>
22 #include <linux/serial_core.h>
24 #include "serial_mctrl_gpio.h"
27 struct uart_port *port;
28 struct gpio_desc *gpio[UART_GPIO_MAX];
29 int irq[UART_GPIO_MAX];
30 unsigned int mctrl_prev;
38 } mctrl_gpios_desc[UART_GPIO_MAX] = {
39 { "cts", TIOCM_CTS, false, },
40 { "dsr", TIOCM_DSR, false, },
41 { "dcd", TIOCM_CD, false, },
42 { "rng", TIOCM_RNG, false, },
43 { "rts", TIOCM_RTS, true, },
44 { "dtr", TIOCM_DTR, true, },
45 { "out1", TIOCM_OUT1, true, },
46 { "out2", TIOCM_OUT2, true, },
49 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
51 enum mctrl_gpio_idx i;
52 struct gpio_desc *desc_array[UART_GPIO_MAX];
53 int value_array[UART_GPIO_MAX];
54 unsigned int count = 0;
56 for (i = 0; i < UART_GPIO_MAX; i++)
57 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
58 desc_array[count] = gpios->gpio[i];
59 value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
62 gpiod_set_array_value(count, desc_array, value_array);
64 EXPORT_SYMBOL_GPL(mctrl_gpio_set);
66 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
67 enum mctrl_gpio_idx gidx)
69 return gpios->gpio[gidx];
71 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
73 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
75 enum mctrl_gpio_idx i;
77 for (i = 0; i < UART_GPIO_MAX; i++) {
78 if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
79 if (gpiod_get_value(gpios->gpio[i]))
80 *mctrl |= mctrl_gpios_desc[i].mctrl;
82 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
88 EXPORT_SYMBOL_GPL(mctrl_gpio_get);
90 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
92 struct mctrl_gpios *gpios;
93 enum mctrl_gpio_idx i;
95 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
97 return ERR_PTR(-ENOMEM);
99 for (i = 0; i < UART_GPIO_MAX; i++) {
100 enum gpiod_flags flags;
102 if (mctrl_gpios_desc[i].dir_out)
103 flags = GPIOD_OUT_LOW;
108 devm_gpiod_get_index_optional(dev,
109 mctrl_gpios_desc[i].name,
112 if (IS_ERR(gpios->gpio[i]))
113 return ERR_CAST(gpios->gpio[i]);
118 EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
120 #define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
121 static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
123 struct mctrl_gpios *gpios = context;
124 struct uart_port *port = gpios->port;
125 u32 mctrl = gpios->mctrl_prev;
128 mctrl_gpio_get(gpios, &mctrl);
130 mctrl_diff = mctrl ^ gpios->mctrl_prev;
131 gpios->mctrl_prev = mctrl;
133 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
134 if ((mctrl_diff & mctrl) & TIOCM_RI)
137 if ((mctrl_diff & mctrl) & TIOCM_DSR)
140 if (mctrl_diff & TIOCM_CD)
141 uart_handle_dcd_change(port, mctrl & TIOCM_CD);
143 if (mctrl_diff & TIOCM_CTS)
144 uart_handle_cts_change(port, mctrl & TIOCM_CTS);
146 wake_up_interruptible(&port->state->port.delta_msr_wait);
152 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
154 struct mctrl_gpios *gpios;
155 enum mctrl_gpio_idx i;
157 gpios = mctrl_gpio_init_noauto(port->dev, idx);
163 for (i = 0; i < UART_GPIO_MAX; ++i) {
166 if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
169 ret = gpiod_to_irq(gpios->gpio[i]);
172 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
173 mctrl_gpios_desc[i].name, idx, ret);
178 /* irqs should only be enabled in .enable_ms */
179 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
181 ret = devm_request_irq(port->dev, gpios->irq[i],
182 mctrl_gpio_irq_handle,
183 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
186 /* alternatively implement polling */
188 "failed to request irq for %s (idx=%d, err=%d)\n",
189 mctrl_gpios_desc[i].name, idx, ret);
197 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
199 enum mctrl_gpio_idx i;
201 for (i = 0; i < UART_GPIO_MAX; i++) {
203 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
206 devm_gpiod_put(dev, gpios->gpio[i]);
208 devm_kfree(dev, gpios);
210 EXPORT_SYMBOL_GPL(mctrl_gpio_free);
212 void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
214 enum mctrl_gpio_idx i;
216 /* .enable_ms may be called multiple times */
220 gpios->mctrl_on = true;
222 /* get initial status of modem lines GPIOs */
223 mctrl_gpio_get(gpios, &gpios->mctrl_prev);
225 for (i = 0; i < UART_GPIO_MAX; ++i) {
229 enable_irq(gpios->irq[i]);
232 EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
234 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
236 enum mctrl_gpio_idx i;
238 if (!gpios->mctrl_on)
241 gpios->mctrl_on = false;
243 for (i = 0; i < UART_GPIO_MAX; ++i) {
247 disable_irq(gpios->irq[i]);