1 // SPDX-License-Identifier: GPL-2.0+
3 * Helpers for controlling modem lines via GPIO
5 * Copyright (C) 2014 Paratronic S.A.
9 #include <linux/device.h>
10 #include <linux/irq.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/termios.h>
13 #include <linux/serial_core.h>
14 #include <linux/module.h>
15 #include <linux/property.h>
17 #include "serial_mctrl_gpio.h"
20 struct uart_port *port;
21 struct gpio_desc *gpio[UART_GPIO_MAX];
22 int irq[UART_GPIO_MAX];
23 unsigned int mctrl_prev;
31 } mctrl_gpios_desc[UART_GPIO_MAX] = {
32 { "cts", TIOCM_CTS, false, },
33 { "dsr", TIOCM_DSR, false, },
34 { "dcd", TIOCM_CD, false, },
35 { "rng", TIOCM_RNG, false, },
36 { "rts", TIOCM_RTS, true, },
37 { "dtr", TIOCM_DTR, true, },
40 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
42 enum mctrl_gpio_idx i;
43 struct gpio_desc *desc_array[UART_GPIO_MAX];
44 DECLARE_BITMAP(values, UART_GPIO_MAX);
45 unsigned int count = 0;
50 for (i = 0; i < UART_GPIO_MAX; i++)
51 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
52 desc_array[count] = gpios->gpio[i];
53 __assign_bit(count, values,
54 mctrl & mctrl_gpios_desc[i].mctrl);
57 gpiod_set_array_value(count, desc_array, NULL, values);
59 EXPORT_SYMBOL_GPL(mctrl_gpio_set);
61 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
62 enum mctrl_gpio_idx gidx)
64 return gpios->gpio[gidx];
66 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
68 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
70 enum mctrl_gpio_idx i;
75 for (i = 0; i < UART_GPIO_MAX; i++) {
76 if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
77 if (gpiod_get_value(gpios->gpio[i]))
78 *mctrl |= mctrl_gpios_desc[i].mctrl;
80 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
86 EXPORT_SYMBOL_GPL(mctrl_gpio_get);
89 mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
91 enum mctrl_gpio_idx i;
96 for (i = 0; i < UART_GPIO_MAX; i++) {
97 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
98 if (gpiod_get_value(gpios->gpio[i]))
99 *mctrl |= mctrl_gpios_desc[i].mctrl;
101 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
107 EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);
109 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
111 struct mctrl_gpios *gpios;
112 enum mctrl_gpio_idx i;
114 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
116 return ERR_PTR(-ENOMEM);
118 for (i = 0; i < UART_GPIO_MAX; i++) {
119 enum gpiod_flags flags;
123 /* Check if GPIO property exists and continue if not */
124 gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",
125 mctrl_gpios_desc[i].name);
129 present = device_property_present(dev, gpio_str);
134 if (mctrl_gpios_desc[i].dir_out)
135 flags = GPIOD_OUT_LOW;
140 devm_gpiod_get_index_optional(dev,
141 mctrl_gpios_desc[i].name,
144 if (IS_ERR(gpios->gpio[i]))
145 return ERR_CAST(gpios->gpio[i]);
150 EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
152 #define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
153 static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
155 struct mctrl_gpios *gpios = context;
156 struct uart_port *port = gpios->port;
157 u32 mctrl = gpios->mctrl_prev;
161 mctrl_gpio_get(gpios, &mctrl);
163 spin_lock_irqsave(&port->lock, flags);
165 mctrl_diff = mctrl ^ gpios->mctrl_prev;
166 gpios->mctrl_prev = mctrl;
168 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
169 if ((mctrl_diff & mctrl) & TIOCM_RI)
172 if ((mctrl_diff & mctrl) & TIOCM_DSR)
175 if (mctrl_diff & TIOCM_CD)
176 uart_handle_dcd_change(port, mctrl & TIOCM_CD);
178 if (mctrl_diff & TIOCM_CTS)
179 uart_handle_cts_change(port, mctrl & TIOCM_CTS);
181 wake_up_interruptible(&port->state->port.delta_msr_wait);
184 spin_unlock_irqrestore(&port->lock, flags);
189 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
191 struct mctrl_gpios *gpios;
192 enum mctrl_gpio_idx i;
194 gpios = mctrl_gpio_init_noauto(port->dev, idx);
200 for (i = 0; i < UART_GPIO_MAX; ++i) {
203 if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
206 ret = gpiod_to_irq(gpios->gpio[i]);
209 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
210 mctrl_gpios_desc[i].name, idx, ret);
215 /* irqs should only be enabled in .enable_ms */
216 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
218 ret = devm_request_irq(port->dev, gpios->irq[i],
219 mctrl_gpio_irq_handle,
220 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
223 /* alternatively implement polling */
225 "failed to request irq for %s (idx=%d, err=%d)\n",
226 mctrl_gpios_desc[i].name, idx, ret);
233 EXPORT_SYMBOL_GPL(mctrl_gpio_init);
235 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
237 enum mctrl_gpio_idx i;
242 for (i = 0; i < UART_GPIO_MAX; i++) {
244 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
247 devm_gpiod_put(dev, gpios->gpio[i]);
249 devm_kfree(dev, gpios);
251 EXPORT_SYMBOL_GPL(mctrl_gpio_free);
253 void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
255 enum mctrl_gpio_idx i;
260 /* .enable_ms may be called multiple times */
264 gpios->mctrl_on = true;
266 /* get initial status of modem lines GPIOs */
267 mctrl_gpio_get(gpios, &gpios->mctrl_prev);
269 for (i = 0; i < UART_GPIO_MAX; ++i) {
273 enable_irq(gpios->irq[i]);
276 EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
278 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
280 enum mctrl_gpio_idx i;
285 if (!gpios->mctrl_on)
288 gpios->mctrl_on = false;
290 for (i = 0; i < UART_GPIO_MAX; ++i) {
294 disable_irq(gpios->irq[i]);
297 EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
299 MODULE_LICENSE("GPL");