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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/tty/serial/serial_mctrl_gpio.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/tty/serial/serial_mctrl_gpio.c')
-rw-r--r--drivers/tty/serial/serial_mctrl_gpio.c388
1 files changed, 388 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
new file mode 100644
index 0000000000..7d5aaa8d42
--- /dev/null
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -0,0 +1,388 @@
+// 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;
+}
+
+/**
+ * mctrl_gpio_set - set gpios according to mctrl state
+ * @gpios: gpios to set
+ * @mctrl: state to set
+ *
+ * Set the gpios according to the mctrl state.
+ */
+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);
+
+/**
+ * mctrl_gpio_to_gpiod - obtain gpio_desc of modem line index
+ * @gpios: gpios to look into
+ * @gidx: index of the modem line
+ * Returns: the gpio_desc structure associated to the modem line index
+ */
+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);
+
+/**
+ * mctrl_gpio_get - update mctrl with the gpios values.
+ * @gpios: gpios to get the info from
+ * @mctrl: mctrl to set
+ * Returns: modified mctrl (the same value as in @mctrl)
+ *
+ * Update mctrl with the gpios values.
+ */
+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;
+}
+
+/**
+ * mctrl_gpio_init - initialize uart gpios
+ * @port: port to initialize gpios for
+ * @idx: index of the gpio in the @port's device
+ *
+ * This will get the {cts,rts,...}-gpios from device tree if they are present
+ * and request them, set direction etc, and return an allocated structure.
+ * `devm_*` functions are used, so there's no need to call mctrl_gpio_free().
+ * As this sets up the irq handling, make sure to not handle changes to the
+ * gpio input lines in your driver, too.
+ */
+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);
+
+/**
+ * mctrl_gpio_free - explicitly free uart gpios
+ * @dev: uart port's device
+ * @gpios: gpios structure to be freed
+ *
+ * This will free the requested gpios in mctrl_gpio_init(). As `devm_*`
+ * functions are used, there's generally no need to call this function.
+ */
+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);
+
+/**
+ * mctrl_gpio_enable_ms - enable irqs and handling of changes to the ms lines
+ * @gpios: gpios to enable
+ */
+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);
+
+/**
+ * mctrl_gpio_disable_ms - disable irqs and handling of changes to the ms lines
+ * @gpios: gpios to disable
+ */
+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);
+
+void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios)
+{
+ enum mctrl_gpio_idx i;
+
+ if (!gpios)
+ return;
+
+ if (!gpios->mctrl_on)
+ return;
+
+ for (i = 0; i < UART_GPIO_MAX; ++i) {
+ if (!gpios->irq[i])
+ continue;
+
+ enable_irq_wake(gpios->irq[i]);
+ }
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_enable_irq_wake);
+
+void mctrl_gpio_disable_irq_wake(struct mctrl_gpios *gpios)
+{
+ enum mctrl_gpio_idx i;
+
+ if (!gpios)
+ return;
+
+ if (!gpios->mctrl_on)
+ return;
+
+ for (i = 0; i < UART_GPIO_MAX; ++i) {
+ if (!gpios->irq[i])
+ continue;
+
+ disable_irq_wake(gpios->irq[i]);
+ }
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_disable_irq_wake);
+
+MODULE_LICENSE("GPL");