294 lines
6.6 KiB
C
294 lines
6.6 KiB
C
/*
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* Helpers for controlling modem lines via GPIO
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*
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* Copyright (C) 2014 Paratronic S.A.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/irq.h>
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#include <linux/gpio/consumer.h>
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#include <linux/termios.h>
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#include <linux/serial_core.h>
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#include <linux/module.h>
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#include "serial_mctrl_gpio.h"
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struct mctrl_gpios {
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struct uart_port *port;
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struct gpio_desc *gpio[UART_GPIO_MAX];
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int irq[UART_GPIO_MAX];
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unsigned int mctrl_prev;
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bool mctrl_on;
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};
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static const struct {
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const char *name;
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unsigned int mctrl;
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bool dir_out;
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} mctrl_gpios_desc[UART_GPIO_MAX] = {
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{ "cts", TIOCM_CTS, false, },
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{ "dsr", TIOCM_DSR, false, },
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{ "dcd", TIOCM_CD, false, },
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{ "rng", TIOCM_RNG, false, },
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{ "rts", TIOCM_RTS, true, },
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{ "dtr", TIOCM_DTR, true, },
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};
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void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
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{
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enum mctrl_gpio_idx i;
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struct gpio_desc *desc_array[UART_GPIO_MAX];
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int value_array[UART_GPIO_MAX];
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unsigned int count = 0;
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if (gpios == NULL)
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return;
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for (i = 0; i < UART_GPIO_MAX; i++)
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if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
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desc_array[count] = gpios->gpio[i];
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value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
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count++;
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}
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gpiod_set_array_value(count, desc_array, value_array);
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_set);
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx)
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{
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return gpios->gpio[gidx];
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
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unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
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{
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enum mctrl_gpio_idx i;
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if (gpios == NULL)
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return *mctrl;
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for (i = 0; i < UART_GPIO_MAX; i++) {
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if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
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if (gpiod_get_value(gpios->gpio[i]))
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*mctrl |= mctrl_gpios_desc[i].mctrl;
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else
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*mctrl &= ~mctrl_gpios_desc[i].mctrl;
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}
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}
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return *mctrl;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_get);
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unsigned int
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mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
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{
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enum mctrl_gpio_idx i;
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if (gpios == NULL)
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return *mctrl;
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for (i = 0; i < UART_GPIO_MAX; i++) {
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if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
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if (gpiod_get_value(gpios->gpio[i]))
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*mctrl |= mctrl_gpios_desc[i].mctrl;
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else
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*mctrl &= ~mctrl_gpios_desc[i].mctrl;
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}
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}
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return *mctrl;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);
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struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
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{
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struct mctrl_gpios *gpios;
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enum mctrl_gpio_idx i;
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gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
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if (!gpios)
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return ERR_PTR(-ENOMEM);
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for (i = 0; i < UART_GPIO_MAX; i++) {
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enum gpiod_flags flags;
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if (mctrl_gpios_desc[i].dir_out)
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flags = GPIOD_OUT_LOW;
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else
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flags = GPIOD_IN;
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gpios->gpio[i] =
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devm_gpiod_get_index_optional(dev,
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mctrl_gpios_desc[i].name,
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idx, flags);
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if (IS_ERR(gpios->gpio[i]))
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return ERR_CAST(gpios->gpio[i]);
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}
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return gpios;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
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#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
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static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
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{
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struct mctrl_gpios *gpios = context;
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struct uart_port *port = gpios->port;
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u32 mctrl = gpios->mctrl_prev;
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u32 mctrl_diff;
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unsigned long flags;
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mctrl_gpio_get(gpios, &mctrl);
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spin_lock_irqsave(&port->lock, flags);
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mctrl_diff = mctrl ^ gpios->mctrl_prev;
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gpios->mctrl_prev = mctrl;
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if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
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if ((mctrl_diff & mctrl) & TIOCM_RI)
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port->icount.rng++;
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if ((mctrl_diff & mctrl) & TIOCM_DSR)
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port->icount.dsr++;
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if (mctrl_diff & TIOCM_CD)
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uart_handle_dcd_change(port, mctrl & TIOCM_CD);
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if (mctrl_diff & TIOCM_CTS)
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uart_handle_cts_change(port, mctrl & TIOCM_CTS);
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wake_up_interruptible(&port->state->port.delta_msr_wait);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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return IRQ_HANDLED;
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}
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struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
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{
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struct mctrl_gpios *gpios;
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enum mctrl_gpio_idx i;
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gpios = mctrl_gpio_init_noauto(port->dev, idx);
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if (IS_ERR(gpios))
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return gpios;
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gpios->port = port;
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for (i = 0; i < UART_GPIO_MAX; ++i) {
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int ret;
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if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
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continue;
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ret = gpiod_to_irq(gpios->gpio[i]);
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if (ret <= 0) {
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dev_err(port->dev,
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"failed to find corresponding irq for %s (idx=%d, err=%d)\n",
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mctrl_gpios_desc[i].name, idx, ret);
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return ERR_PTR(ret);
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}
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gpios->irq[i] = ret;
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/* irqs should only be enabled in .enable_ms */
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irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
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ret = devm_request_irq(port->dev, gpios->irq[i],
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mctrl_gpio_irq_handle,
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IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
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gpios);
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if (ret) {
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/* alternatively implement polling */
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dev_err(port->dev,
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"failed to request irq for %s (idx=%d, err=%d)\n",
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mctrl_gpios_desc[i].name, idx, ret);
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return ERR_PTR(ret);
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}
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}
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return gpios;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_init);
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (gpios == NULL)
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return;
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for (i = 0; i < UART_GPIO_MAX; i++) {
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if (gpios->irq[i])
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devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
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if (gpios->gpio[i])
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devm_gpiod_put(dev, gpios->gpio[i]);
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}
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devm_kfree(dev, gpios);
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_free);
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void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (gpios == NULL)
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return;
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/* .enable_ms may be called multiple times */
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if (gpios->mctrl_on)
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return;
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gpios->mctrl_on = true;
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/* get initial status of modem lines GPIOs */
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mctrl_gpio_get(gpios, &gpios->mctrl_prev);
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for (i = 0; i < UART_GPIO_MAX; ++i) {
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if (!gpios->irq[i])
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continue;
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enable_irq(gpios->irq[i]);
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}
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
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void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (gpios == NULL)
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return;
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if (!gpios->mctrl_on)
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return;
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gpios->mctrl_on = false;
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for (i = 0; i < UART_GPIO_MAX; ++i) {
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if (!gpios->irq[i])
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continue;
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disable_irq(gpios->irq[i]);
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}
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
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MODULE_LICENSE("GPL");
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