summaryrefslogtreecommitdiff
path: root/drivers/tty/serial/serial_mctrl_gpio.c
blob: 7d9d2c7b6c3973e47d6ab703961f2481c8e21760 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
// SPDX-License-Identifier: GPL-2.0+
/*
 * Helpers for controlling modem lines via GPIO
 *
 * Copyright (C) 2014 Paratronic S.A.
 */

#include <linux/err.h>
#include <linux/device.h>
#include <linux/irq.h>
#include <linux/gpio/consumer.h>
#include <linux/termios.h>
#include <linux/serial_core.h>
#include <linux/module.h>

#include "serial_mctrl_gpio.h"

struct mctrl_gpios {
	struct uart_port *port;
	struct gpio_desc *gpio[UART_GPIO_MAX];
	int irq[UART_GPIO_MAX];
	unsigned int mctrl_prev;
	bool mctrl_on;
};

static const struct {
	const char *name;
	unsigned int mctrl;
	bool dir_out;
} mctrl_gpios_desc[UART_GPIO_MAX] = {
	{ "cts", TIOCM_CTS, false, },
	{ "dsr", TIOCM_DSR, false, },
	{ "dcd", TIOCM_CD, false, },
	{ "rng", TIOCM_RNG, false, },
	{ "rts", TIOCM_RTS, true, },
	{ "dtr", TIOCM_DTR, true, },
};

void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
{
	enum mctrl_gpio_idx i;
	struct gpio_desc *desc_array[UART_GPIO_MAX];
	DECLARE_BITMAP(values, UART_GPIO_MAX);
	unsigned int count = 0;

	if (gpios == NULL)
		return;

	for (i = 0; i < UART_GPIO_MAX; i++)
		if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
			desc_array[count] = gpios->gpio[i];
			__assign_bit(count, values,
				     mctrl & mctrl_gpios_desc[i].mctrl);
			count++;
		}
	gpiod_set_array_value(count, desc_array, values);
}
EXPORT_SYMBOL_GPL(mctrl_gpio_set);

struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
				      enum mctrl_gpio_idx gidx)
{
	return gpios->gpio[gidx];
}
EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);

unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return *mctrl;

	for (i = 0; i < UART_GPIO_MAX; i++) {
		if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
			if (gpiod_get_value(gpios->gpio[i]))
				*mctrl |= mctrl_gpios_desc[i].mctrl;
			else
				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
		}
	}

	return *mctrl;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_get);

unsigned int
mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return *mctrl;

	for (i = 0; i < UART_GPIO_MAX; i++) {
		if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
			if (gpiod_get_value(gpios->gpio[i]))
				*mctrl |= mctrl_gpios_desc[i].mctrl;
			else
				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
		}
	}

	return *mctrl;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);

struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
{
	struct mctrl_gpios *gpios;
	enum mctrl_gpio_idx i;

	gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
	if (!gpios)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < UART_GPIO_MAX; i++) {
		enum gpiod_flags flags;

		if (mctrl_gpios_desc[i].dir_out)
			flags = GPIOD_OUT_LOW;
		else
			flags = GPIOD_IN;

		gpios->gpio[i] =
			devm_gpiod_get_index_optional(dev,
						      mctrl_gpios_desc[i].name,
						      idx, flags);

		if (IS_ERR(gpios->gpio[i]))
			return ERR_CAST(gpios->gpio[i]);
	}

	return gpios;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);

#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
{
	struct mctrl_gpios *gpios = context;
	struct uart_port *port = gpios->port;
	u32 mctrl = gpios->mctrl_prev;
	u32 mctrl_diff;
	unsigned long flags;

	mctrl_gpio_get(gpios, &mctrl);

	spin_lock_irqsave(&port->lock, flags);

	mctrl_diff = mctrl ^ gpios->mctrl_prev;
	gpios->mctrl_prev = mctrl;

	if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
		if ((mctrl_diff & mctrl) & TIOCM_RI)
			port->icount.rng++;

		if ((mctrl_diff & mctrl) & TIOCM_DSR)
			port->icount.dsr++;

		if (mctrl_diff & TIOCM_CD)
			uart_handle_dcd_change(port, mctrl & TIOCM_CD);

		if (mctrl_diff & TIOCM_CTS)
			uart_handle_cts_change(port, mctrl & TIOCM_CTS);

		wake_up_interruptible(&port->state->port.delta_msr_wait);
	}

	spin_unlock_irqrestore(&port->lock, flags);

	return IRQ_HANDLED;
}

struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
{
	struct mctrl_gpios *gpios;
	enum mctrl_gpio_idx i;

	gpios = mctrl_gpio_init_noauto(port->dev, idx);
	if (IS_ERR(gpios))
		return gpios;

	gpios->port = port;

	for (i = 0; i < UART_GPIO_MAX; ++i) {
		int ret;

		if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
			continue;

		ret = gpiod_to_irq(gpios->gpio[i]);
		if (ret <= 0) {
			dev_err(port->dev,
				"failed to find corresponding irq for %s (idx=%d, err=%d)\n",
				mctrl_gpios_desc[i].name, idx, ret);
			return ERR_PTR(ret);
		}
		gpios->irq[i] = ret;

		/* irqs should only be enabled in .enable_ms */
		irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);

		ret = devm_request_irq(port->dev, gpios->irq[i],
				       mctrl_gpio_irq_handle,
				       IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
				       gpios);
		if (ret) {
			/* alternatively implement polling */
			dev_err(port->dev,
				"failed to request irq for %s (idx=%d, err=%d)\n",
				mctrl_gpios_desc[i].name, idx, ret);
			return ERR_PTR(ret);
		}
	}

	return gpios;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_init);

void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return;

	for (i = 0; i < UART_GPIO_MAX; i++) {
		if (gpios->irq[i])
			devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);

		if (gpios->gpio[i])
			devm_gpiod_put(dev, gpios->gpio[i]);
	}
	devm_kfree(dev, gpios);
}
EXPORT_SYMBOL_GPL(mctrl_gpio_free);

void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return;

	/* .enable_ms may be called multiple times */
	if (gpios->mctrl_on)
		return;

	gpios->mctrl_on = true;

	/* get initial status of modem lines GPIOs */
	mctrl_gpio_get(gpios, &gpios->mctrl_prev);

	for (i = 0; i < UART_GPIO_MAX; ++i) {
		if (!gpios->irq[i])
			continue;

		enable_irq(gpios->irq[i]);
	}
}
EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);

void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return;

	if (!gpios->mctrl_on)
		return;

	gpios->mctrl_on = false;

	for (i = 0; i < UART_GPIO_MAX; ++i) {
		if (!gpios->irq[i])
			continue;

		disable_irq(gpios->irq[i]);
	}
}
EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);

MODULE_LICENSE("GPL");