diff options
| -rw-r--r-- | Documentation/serial/driver | 25 | ||||
| -rw-r--r-- | drivers/tty/serial/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/tty/serial/Makefile | 3 | ||||
| -rw-r--r-- | drivers/tty/serial/serial_mctrl_gpio.c | 143 | ||||
| -rw-r--r-- | drivers/tty/serial/serial_mctrl_gpio.h | 110 |
5 files changed, 284 insertions, 0 deletions
diff --git a/Documentation/serial/driver b/Documentation/serial/driver index c3a7689a90e6..3bba1aeb799c 100644 --- a/Documentation/serial/driver +++ b/Documentation/serial/driver @@ -429,3 +429,28 @@ thus: struct uart_port port; int my_stuff; }; + +Modem control lines via GPIO +---------------------------- + +Some helpers are provided in order to set/get modem control lines via GPIO. + +mctrl_gpio_init(dev, idx): + 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(). + +mctrl_gpio_free(dev, gpios): + This will free the requested gpios in mctrl_gpio_init(). + As devm_* function are used, there's generally no need to call + this function. + +mctrl_gpio_to_gpiod(gpios, gidx) + This returns the gpio structure associated to the modem line index. + +mctrl_gpio_set(gpios, mctrl): + This will sets the gpios according to the mctrl state. + +mctrl_gpio_get(gpios, mctrl): + This will update mctrl with the gpios values. diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index d88c058634ff..4bf6d220357b 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1553,4 +1553,7 @@ config SERIAL_MEN_Z135 endmenu +config SERIAL_MCTRL_GPIO + tristate + endif # TTY diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile index 712732b43917..0080cc362e09 100644 --- a/drivers/tty/serial/Makefile +++ b/drivers/tty/serial/Makefile @@ -92,3 +92,6 @@ obj-$(CONFIG_SERIAL_ARC) += arc_uart.o obj-$(CONFIG_SERIAL_RP2) += rp2.o obj-$(CONFIG_SERIAL_FSL_LPUART) += fsl_lpuart.o obj-$(CONFIG_SERIAL_MEN_Z135) += men_z135_uart.o + +# GPIOLIB helpers for modem control lines +obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o 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); diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h new file mode 100644 index 000000000000..400ba0494a17 --- /dev/null +++ b/drivers/tty/serial/serial_mctrl_gpio.h @@ -0,0 +1,110 @@ +/* + * 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. + * + */ + +#ifndef __SERIAL_MCTRL_GPIO__ +#define __SERIAL_MCTRL_GPIO__ + +#include <linux/err.h> +#include <linux/device.h> +#include <linux/gpio/consumer.h> + +enum mctrl_gpio_idx { + UART_GPIO_CTS, + UART_GPIO_DSR, + UART_GPIO_DCD, + UART_GPIO_RNG, + UART_GPIO_RI = UART_GPIO_RNG, + UART_GPIO_RTS, + UART_GPIO_DTR, + UART_GPIO_OUT1, + UART_GPIO_OUT2, + UART_GPIO_MAX, +}; + +/* + * Opaque descriptor for modem lines controlled by GPIOs + */ +struct mctrl_gpios; + +#ifdef CONFIG_GPIOLIB + +/* + * Set state of the modem control output lines via GPIOs. + */ +void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl); + +/* + * Get state of the modem control output lines from GPIOs. + * The mctrl flags are updated and returned. + */ +unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl); + +/* + * Returns the associated struct gpio_desc to the modem line gidx + */ +struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, + enum mctrl_gpio_idx gidx); + +/* + * Request and set direction of modem control lines GPIOs. + * devm_* functions are used, so there's no need to call mctrl_gpio_free(). + * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on + * allocation error. + */ +struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx); + +/* + * Free the mctrl_gpios structure. + * Normally, this function will not be called, as the GPIOs will + * be disposed of by the resource management code. + */ +void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios); + +#else /* GPIOLIB */ + +static inline +void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl) +{ +} + +static inline +unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl) +{ + return *mctrl; +} + +static inline +struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, + enum mctrl_gpio_idx gidx) +{ + return ERR_PTR(-ENOSYS); +} + +static inline +struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) +{ + return ERR_PTR(-ENOSYS); +} + +static inline +void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) +{ +} + +#endif /* GPIOLIB */ + +#endif |
