[linux-2.6-block.git] / drivers / tty / serial / serial_mctrl_gpio.c

/*
 * Helpers for controlling modem lines via GPIO
 *
 * Copyright (C) 2014 Paratronic S.A.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#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];
	int value_array[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];
			value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
			count++;
		}
	gpiod_set_array_value(count, desc_array, value_array);
}
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");
Commit	Line	Data
84130aac RG	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.
84130aac RG	15	*/
	16
	17	#include <linux/err.h>
	18	#include <linux/device.h>
ce59e48f	19	#include <linux/irq.h>
84130aac	20	#include <linux/gpio/consumer.h>
93b88774	21	#include <linux/termios.h>
ce59e48f	22	#include <linux/serial_core.h>
82a3f87f	23	#include <linux/module.h>
84130aac RG	24
	25	#include "serial_mctrl_gpio.h"
	26
	27	struct mctrl_gpios {
ce59e48f	28	struct uart_port *port;
84130aac	29	struct gpio_desc *gpio[UART_GPIO_MAX];
ce59e48f UKK	30	int irq[UART_GPIO_MAX];
	31	unsigned int mctrl_prev;
	32	bool mctrl_on;
84130aac RG	33	};
	34
	35	static const struct {
	36	const char *name;
	37	unsigned int mctrl;
	38	bool dir_out;
	39	} mctrl_gpios_desc[UART_GPIO_MAX] = {
	40	{ "cts", TIOCM_CTS, false, },
	41	{ "dsr", TIOCM_DSR, false, },
	42	{ "dcd", TIOCM_CD, false, },
	43	{ "rng", TIOCM_RNG, false, },
	44	{ "rts", TIOCM_RTS, true, },
	45	{ "dtr", TIOCM_DTR, true, },
84130aac RG	46	};
	47
	48	void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
	49	{
	50	enum mctrl_gpio_idx i;
834296a3 RI	51	struct gpio_desc *desc_array[UART_GPIO_MAX];
	52	int value_array[UART_GPIO_MAX];
	53	unsigned int count = 0;
84130aac	54
434be0ae YY	55	if (gpios == NULL)
	56	return;
	57
84130aac	58	for (i = 0; i < UART_GPIO_MAX; i++)
445df7ff	59	if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
834296a3 RI	60	desc_array[count] = gpios->gpio[i];
	61	value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
	62	count++;
	63	}
3fff99bc	64	gpiod_set_array_value(count, desc_array, value_array);
84130aac RG	65	}
	66	EXPORT_SYMBOL_GPL(mctrl_gpio_set);
	67
	68	struct gpio_desc mctrl_gpio_to_gpiod(struct mctrl_gpios gpios,
	69	enum mctrl_gpio_idx gidx)
	70	{
9e9f079c	71	return gpios->gpio[gidx];
84130aac RG	72	}
	73	EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
	74
	75	unsigned int mctrl_gpio_get(struct mctrl_gpios gpios, unsigned int mctrl)
	76	{
	77	enum mctrl_gpio_idx i;
	78
434be0ae YY	79	if (gpios == NULL)
	80	return *mctrl;
	81
84130aac	82	for (i = 0; i < UART_GPIO_MAX; i++) {
9e9f079c	83	if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
84130aac RG	84	if (gpiod_get_value(gpios->gpio[i]))
	85	*mctrl \|= mctrl_gpios_desc[i].mctrl;
	86	else
	87	*mctrl &= ~mctrl_gpios_desc[i].mctrl;
	88	}
	89	}
	90
	91	return *mctrl;
	92	}
	93	EXPORT_SYMBOL_GPL(mctrl_gpio_get);
	94
bf5cee68 YY	95	unsigned int
	96	mctrl_gpio_get_outputs(struct mctrl_gpios gpios, unsigned int mctrl)
	97	{
	98	enum mctrl_gpio_idx i;
	99
434be0ae YY	100	if (gpios == NULL)
	101	return *mctrl;
	102
bf5cee68 YY	103	for (i = 0; i < UART_GPIO_MAX; i++) {
	104	if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
	105	if (gpiod_get_value(gpios->gpio[i]))
	106	*mctrl \|= mctrl_gpios_desc[i].mctrl;
	107	else
	108	*mctrl &= ~mctrl_gpios_desc[i].mctrl;
	109	}
	110	}
	111
	112	return *mctrl;
	113	}
	114	EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);
	115
7d8c70d8	116	struct mctrl_gpios mctrl_gpio_init_noauto(struct device dev, unsigned int idx)
84130aac RG	117	{
	118	struct mctrl_gpios *gpios;
	119	enum mctrl_gpio_idx i;
84130aac RG	120
	121	gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
	122	if (!gpios)
	123	return ERR_PTR(-ENOMEM);
	124
	125	for (i = 0; i < UART_GPIO_MAX; i++) {
1d267ea6	126	enum gpiod_flags flags;
84130aac RG	127
84130aac RG	128	if (mctrl_gpios_desc[i].dir_out)
1d267ea6	129	flags = GPIOD_OUT_LOW;
84130aac	130	else
1d267ea6 UKK	131	flags = GPIOD_IN;
	132
	133	gpios->gpio[i] =
	134	devm_gpiod_get_index_optional(dev,
	135	mctrl_gpios_desc[i].name,
	136	idx, flags);
	137
	138	if (IS_ERR(gpios->gpio[i]))
13bc2bb9	139	return ERR_CAST(gpios->gpio[i]);
84130aac RG	140	}
	141
	142	return gpios;
	143	}
7d8c70d8	144	EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
84130aac	145
ce59e48f UKK	146	#define MCTRL_ANY_DELTA (TIOCM_RI \| TIOCM_DSR \| TIOCM_CD \| TIOCM_CTS)
	147	static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
	148	{
	149	struct mctrl_gpios *gpios = context;
	150	struct uart_port *port = gpios->port;
	151	u32 mctrl = gpios->mctrl_prev;
	152	u32 mctrl_diff;
d11df618	153	unsigned long flags;
ce59e48f UKK	154
	155	mctrl_gpio_get(gpios, &mctrl);
	156
d11df618 YY	157	spin_lock_irqsave(&port->lock, flags);
d11df618 YY	158
ce59e48f UKK	159	mctrl_diff = mctrl ^ gpios->mctrl_prev;
	160	gpios->mctrl_prev = mctrl;
	161
	162	if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
	163	if ((mctrl_diff & mctrl) & TIOCM_RI)
	164	port->icount.rng++;
	165
	166	if ((mctrl_diff & mctrl) & TIOCM_DSR)
	167	port->icount.dsr++;
	168
	169	if (mctrl_diff & TIOCM_CD)
	170	uart_handle_dcd_change(port, mctrl & TIOCM_CD);
	171
	172	if (mctrl_diff & TIOCM_CTS)
	173	uart_handle_cts_change(port, mctrl & TIOCM_CTS);
	174
	175	wake_up_interruptible(&port->state->port.delta_msr_wait);
	176	}
	177
d11df618 YY	178	spin_unlock_irqrestore(&port->lock, flags);
d11df618 YY	179
ce59e48f UKK	180	return IRQ_HANDLED;
	181	}
	182
	183	struct mctrl_gpios mctrl_gpio_init(struct uart_port port, unsigned int idx)
	184	{
	185	struct mctrl_gpios *gpios;
	186	enum mctrl_gpio_idx i;
	187
	188	gpios = mctrl_gpio_init_noauto(port->dev, idx);
	189	if (IS_ERR(gpios))
	190	return gpios;
	191
	192	gpios->port = port;
	193
	194	for (i = 0; i < UART_GPIO_MAX; ++i) {
	195	int ret;
	196
	197	if (!gpios->gpio[i] \|\| mctrl_gpios_desc[i].dir_out)
	198	continue;
	199
	200	ret = gpiod_to_irq(gpios->gpio[i]);
	201	if (ret <= 0) {
	202	dev_err(port->dev,
	203	"failed to find corresponding irq for %s (idx=%d, err=%d)\n",
	204	mctrl_gpios_desc[i].name, idx, ret);
	205	return ERR_PTR(ret);
	206	}
	207	gpios->irq[i] = ret;
	208
	209	/* irqs should only be enabled in .enable_ms */
	210	irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
	211
	212	ret = devm_request_irq(port->dev, gpios->irq[i],
	213	mctrl_gpio_irq_handle,
	214	IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
	215	gpios);
	216	if (ret) {
	217	/* alternatively implement polling */
	218	dev_err(port->dev,
	219	"failed to request irq for %s (idx=%d, err=%d)\n",
	220	mctrl_gpios_desc[i].name, idx, ret);
	221	return ERR_PTR(ret);
	222	}
	223	}
	224
	225	return gpios;
	226	}
4f71a2e0	227	EXPORT_SYMBOL_GPL(mctrl_gpio_init);
ce59e48f	228
84130aac RG	229	void mctrl_gpio_free(struct device dev, struct mctrl_gpios gpios)
	230	{
	231	enum mctrl_gpio_idx i;
	232
434be0ae YY	233	if (gpios == NULL)
	234	return;
	235
ce59e48f UKK	236	for (i = 0; i < UART_GPIO_MAX; i++) {
	237	if (gpios->irq[i])
	238	devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
	239
445df7ff	240	if (gpios->gpio[i])
84130aac	241	devm_gpiod_put(dev, gpios->gpio[i]);
ce59e48f	242	}
84130aac RG	243	devm_kfree(dev, gpios);
	244	}
	245	EXPORT_SYMBOL_GPL(mctrl_gpio_free);
ce59e48f UKK	246
	247	void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
	248	{
	249	enum mctrl_gpio_idx i;
	250
434be0ae YY	251	if (gpios == NULL)
	252	return;
	253
ce59e48f UKK	254	/* .enable_ms may be called multiple times */
	255	if (gpios->mctrl_on)
	256	return;
	257
	258	gpios->mctrl_on = true;
	259
	260	/* get initial status of modem lines GPIOs */
	261	mctrl_gpio_get(gpios, &gpios->mctrl_prev);
	262
	263	for (i = 0; i < UART_GPIO_MAX; ++i) {
	264	if (!gpios->irq[i])
	265	continue;
	266
	267	enable_irq(gpios->irq[i]);
	268	}
	269	}
	270	EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
	271
	272	void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
	273	{
	274	enum mctrl_gpio_idx i;
	275
434be0ae YY	276	if (gpios == NULL)
	277	return;
	278
ce59e48f UKK	279	if (!gpios->mctrl_on)
	280	return;
	281
	282	gpios->mctrl_on = false;
	283
	284	for (i = 0; i < UART_GPIO_MAX; ++i) {
	285	if (!gpios->irq[i])
	286	continue;
	287
	288	disable_irq(gpios->irq[i]);
	289	}
	290	}
4f71a2e0	291	EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
82a3f87f RI	292
82a3f87f RI	293	MODULE_LICENSE("GPL");