// 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 <linux/property.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; enum gpiod_flags flags; } mctrl_gpios_desc[UART_GPIO_MAX] = { { "cts", TIOCM_CTS, GPIOD_IN, }, { "dsr", TIOCM_DSR, GPIOD_IN, }, { "dcd", TIOCM_CD, GPIOD_IN, }, { "rng", TIOCM_RNG, GPIOD_IN, }, { "rts", TIOCM_RTS, GPIOD_OUT_LOW, }, { "dtr", TIOCM_DTR, GPIOD_OUT_LOW, }, }; static bool mctrl_gpio_flags_is_dir_out(unsigned int idx) { return mctrl_gpios_desc[idx].flags & GPIOD_FLAGS_BIT_DIR_OUT; } 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_gpio_flags_is_dir_out(i)) { desc_array[count] = gpios->gpio[i]; __assign_bit(count, values, mctrl & mctrl_gpios_desc[i].mctrl); count++; } gpiod_set_array_value(count, desc_array, NULL, values); } EXPORT_SYMBOL_GPL(mctrl_gpio_set); struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, enum mctrl_gpio_idx gidx) { if (gpios == NULL) return NULL; 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_gpio_flags_is_dir_out(i)) { 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_gpio_flags_is_dir_out(i)) { 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++) { char *gpio_str; bool present; /* Check if GPIO property exists and continue if not */ gpio_str = kasprintf(GFP_KERNEL, "%s-gpios", mctrl_gpios_desc[i].name); if (!gpio_str) continue; present = device_property_present(dev, gpio_str); kfree(gpio_str); if (!present) continue; gpios->gpio[i] = devm_gpiod_get_index_optional(dev, mctrl_gpios_desc[i].name, idx, mctrl_gpios_desc[i].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_gpio_flags_is_dir_out(i)) 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");