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path: root/drivers/tty/serial/serial_mctrl_gpio.c
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Diffstat (limited to 'drivers/tty/serial/serial_mctrl_gpio.c')
-rw-r--r--drivers/tty/serial/serial_mctrl_gpio.c143
1 files changed, 143 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 000000000000..bf9560ffe3f4
--- /dev/null
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -0,0 +1,143 @@
+/*
+ * 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/gpio/consumer.h>
+#include <uapi/asm-generic/termios.h>
+
+#include "serial_mctrl_gpio.h"
+
+struct mctrl_gpios {
+ struct gpio_desc *gpio[UART_GPIO_MAX];
+};
+
+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, },
+ { "out1", TIOCM_OUT1, true, },
+ { "out2", TIOCM_OUT2, true, },
+};
+
+void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
+{
+ enum mctrl_gpio_idx i;
+
+ if (IS_ERR_OR_NULL(gpios))
+ return;
+
+ for (i = 0; i < UART_GPIO_MAX; i++)
+ if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
+ mctrl_gpios_desc[i].dir_out)
+ gpiod_set_value(gpios->gpio[i],
+ !!(mctrl & mctrl_gpios_desc[i].mctrl));
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_set);
+
+struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
+ enum mctrl_gpio_idx gidx)
+{
+ if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx]))
+ return gpios->gpio[gidx];
+ else
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
+
+unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
+{
+ enum mctrl_gpio_idx i;
+
+ /*
+ * return it unchanged if the structure is not allocated
+ */
+ if (IS_ERR_OR_NULL(gpios))
+ return *mctrl;
+
+ for (i = 0; i < UART_GPIO_MAX; i++) {
+ if (!IS_ERR_OR_NULL(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);
+
+struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
+{
+ struct mctrl_gpios *gpios;
+ enum mctrl_gpio_idx i;
+ int err;
+
+ gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
+ if (!gpios)
+ return ERR_PTR(-ENOMEM);
+
+ for (i = 0; i < UART_GPIO_MAX; i++) {
+ gpios->gpio[i] = devm_gpiod_get_index(dev,
+ mctrl_gpios_desc[i].name,
+ idx);
+
+ /*
+ * The GPIOs are maybe not all filled,
+ * this is not an error.
+ */
+ if (IS_ERR_OR_NULL(gpios->gpio[i]))
+ continue;
+
+ if (mctrl_gpios_desc[i].dir_out)
+ err = gpiod_direction_output(gpios->gpio[i], 0);
+ else
+ err = gpiod_direction_input(gpios->gpio[i]);
+ if (err) {
+ dev_dbg(dev, "Unable to set direction for %s GPIO",
+ mctrl_gpios_desc[i].name);
+ devm_gpiod_put(dev, gpios->gpio[i]);
+ gpios->gpio[i] = NULL;
+ }
+ }
+
+ 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 (IS_ERR_OR_NULL(gpios))
+ return;
+
+ for (i = 0; i < UART_GPIO_MAX; i++)
+ if (!IS_ERR_OR_NULL(gpios->gpio[i]))
+ devm_gpiod_put(dev, gpios->gpio[i]);
+ devm_kfree(dev, gpios);
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_free);