389 lines
8.7 KiB
C
389 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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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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#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 <linux/property.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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enum gpiod_flags flags;
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} mctrl_gpios_desc[UART_GPIO_MAX] = {
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{ "cts", TIOCM_CTS, GPIOD_IN, },
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{ "dsr", TIOCM_DSR, GPIOD_IN, },
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{ "dcd", TIOCM_CD, GPIOD_IN, },
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{ "rng", TIOCM_RNG, GPIOD_IN, },
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{ "rts", TIOCM_RTS, GPIOD_OUT_LOW, },
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{ "dtr", TIOCM_DTR, GPIOD_OUT_LOW, },
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};
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static bool mctrl_gpio_flags_is_dir_out(unsigned int idx)
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{
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return mctrl_gpios_desc[idx].flags & GPIOD_FLAGS_BIT_DIR_OUT;
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}
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/**
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* mctrl_gpio_set - set gpios according to mctrl state
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* @gpios: gpios to set
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* @mctrl: state to set
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*
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* Set the gpios according to the mctrl state.
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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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DECLARE_BITMAP(values, 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_gpio_flags_is_dir_out(i)) {
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desc_array[count] = gpios->gpio[i];
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__assign_bit(count, values,
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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, NULL, values);
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_set);
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/**
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* mctrl_gpio_to_gpiod - obtain gpio_desc of modem line index
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* @gpios: gpios to look into
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* @gidx: index of the modem line
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* Returns: the gpio_desc structure associated to the modem line index
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*/
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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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if (gpios == NULL)
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return NULL;
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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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/**
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* mctrl_gpio_get - update mctrl with the gpios values.
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* @gpios: gpios to get the info from
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* @mctrl: mctrl to set
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* Returns: modified mctrl (the same value as in @mctrl)
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*
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* Update mctrl with the gpios values.
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*/
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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_gpio_flags_is_dir_out(i)) {
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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_gpio_flags_is_dir_out(i)) {
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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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char *gpio_str;
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bool present;
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/* Check if GPIO property exists and continue if not */
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gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",
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mctrl_gpios_desc[i].name);
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if (!gpio_str)
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continue;
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present = device_property_present(dev, gpio_str);
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kfree(gpio_str);
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if (!present)
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continue;
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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,
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mctrl_gpios_desc[i].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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/**
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* mctrl_gpio_init - initialize uart gpios
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* @port: port to initialize gpios for
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* @idx: index of the gpio in the @port's device
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*
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* This will get the {cts,rts,...}-gpios from device tree if they are present
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* and request them, set direction etc, and return an allocated structure.
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* `devm_*` functions are used, so there's no need to call mctrl_gpio_free().
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* As this sets up the irq handling, make sure to not handle changes to the
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* gpio input lines in your driver, too.
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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_gpio_flags_is_dir_out(i))
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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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/**
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* mctrl_gpio_free - explicitly free uart gpios
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* @dev: uart port's device
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* @gpios: gpios structure to be freed
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*
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* This will free the requested gpios in mctrl_gpio_init(). As `devm_*`
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* functions are used, there's generally no need to call this function.
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*/
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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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/**
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* mctrl_gpio_enable_ms - enable irqs and handling of changes to the ms lines
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* @gpios: gpios to enable
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*/
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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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/**
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* mctrl_gpio_disable_ms - disable irqs and handling of changes to the ms lines
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* @gpios: gpios to disable
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*/
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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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void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (!gpios)
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return;
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if (!gpios->mctrl_on)
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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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continue;
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enable_irq_wake(gpios->irq[i]);
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}
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_enable_irq_wake);
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void mctrl_gpio_disable_irq_wake(struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (!gpios)
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return;
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if (!gpios->mctrl_on)
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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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continue;
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disable_irq_wake(gpios->irq[i]);
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}
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_disable_irq_wake);
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MODULE_LICENSE("GPL");
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