diff options
| -rw-r--r-- | Documentation/serial/driver | 10 | ||||
| -rw-r--r-- | drivers/tty/serial/serial_mctrl_gpio.c | 129 | ||||
| -rw-r--r-- | drivers/tty/serial/serial_mctrl_gpio.h | 35 |
3 files changed, 171 insertions, 3 deletions
diff --git a/Documentation/serial/driver b/Documentation/serial/driver index c415b0ef4493..379468e12680 100644 --- a/Documentation/serial/driver +++ b/Documentation/serial/driver @@ -439,11 +439,13 @@ Modem control lines via GPIO Some helpers are provided in order to set/get modem control lines via GPIO. -mctrl_gpio_init(dev, idx): +mctrl_gpio_init(port, 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(). + As this sets up the irq handling make sure to not handle changes to the + gpio input lines in your driver, too. mctrl_gpio_free(dev, gpios): This will free the requested gpios in mctrl_gpio_init(). @@ -458,3 +460,9 @@ mctrl_gpio_set(gpios, mctrl): mctrl_gpio_get(gpios, mctrl): This will update mctrl with the gpios values. + +mctrl_gpio_enable_ms(gpios): + Enables irqs and handling of changes to the ms lines. + +mctrl_gpio_disable_ms(gpios): + Disables irqs and handling of changes to the ms lines. diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c index 1cdedd3bfb43..3eb57eb532f1 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.c +++ b/drivers/tty/serial/serial_mctrl_gpio.c @@ -12,18 +12,23 @@ * 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/irq.h> #include <linux/gpio/consumer.h> #include <linux/termios.h> +#include <linux/serial_core.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 { @@ -112,13 +117,133 @@ struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx) } 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; + + mctrl_gpio_get(gpios, &mctrl); + + 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); + } + + 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_gpios_desc[i].dir_out) + 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; +} + void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) { enum mctrl_gpio_idx i; - for (i = 0; i < UART_GPIO_MAX; i++) + 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; + + /* .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->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]); + } +} diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h index 6d046fcf744e..3c4ac9ae41f9 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.h +++ b/drivers/tty/serial/serial_mctrl_gpio.h @@ -22,6 +22,8 @@ #include <linux/device.h> #include <linux/gpio/consumer.h> +struct uart_port; + enum mctrl_gpio_idx { UART_GPIO_CTS, UART_GPIO_DSR, @@ -60,6 +62,15 @@ 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 and sets up irq + * handling. + * 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 uart_port *port, unsigned int idx); + +/* * 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 @@ -75,6 +86,16 @@ struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, */ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios); +/* + * Enable gpio interrupts to report status line changes. + */ +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios); + +/* + * Disable gpio interrupts to report status line changes. + */ +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios); + #else /* GPIOLIB */ static inline @@ -96,6 +117,12 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, } static inline +struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx) +{ + return ERR_PTR(-ENOSYS); +} + +static inline struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx) { return ERR_PTR(-ENOSYS); @@ -106,6 +133,14 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) { } +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios) +{ +} + +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios) +{ +} + #endif /* GPIOLIB */ #endif |