A driver using mctrl_gpio called gpiod_get_direction() to check if gpio is input line. However .get_direction callback is not available for all platforms. The patch allows to avoid the function. The patch introduces the following helpers: - mctrl_gpio_request_irqs - mctrl_gpio_free_irqs - mctrl_gpio_enable_ms - mctrl_gpio_disable_ms They allow to: - simplify drivers which use mctrl_gpio - hide irq table in mctrl_gpio - use default irq handler for gpios - better separate code for gpio modem lines from uart's code In addition mctrl_gpio_init() has been renamed to mctrl_gpio_init_dt() to focus DT usage. Also mctrl_gpio_init_dt() initializes irq table for gpios now and passes struct uart_port into struct mctrl_gpios. This resulted in changed mctrl_gpio_init_dt() parameter. It also requires port->dev is set before the function is called. There were also fixed: - irq = 0 means invalid/unused (-EINVAL no more used) - mctrl_gpio_request_irqs() doesn't use negative enum value if request_irq() failed. The mctrl_gpio_is_gpio() inline function is under discussion and likely it can replace exported mctrl_gpio_to_gpiod() function. Signed-off-by: Janusz Uzycki <j.uzycki@xxxxxxxxxxxxxx> --- The patch requires to update the drivers which use mctrl_gpio: - atmel_serial - mxs-auart - clps711x Please test it again on the platforms above. Compile tests (next-20150204) and a test on mxs (i.mx28) hardware were done only. Changes since RFC v2: - fixed mctrl_gpio_request_irqs(): just calling mctrl_gpio_free_irqs() on failure was wrong idea because free_irq() would be called for not requested irqs yet and kernel/irq/manage.c: free_irq(): __free_irq(): WARN: "Trying to free already-free IRQ %d" would appear - fixed mctrl_gpio_is_gpio() inline function: 1. allow to compile when CONFIG_GPIOLIB is not defined (inline is not broken, reported by Richard Genoud), 2. now a serial driver also can be a module (exported function used), 3. gpios can be NULL (protected in mctrl_gpio_to_gpiod()) It calls mctrl_gpio_to_gpiod() which likely can be removed and replaced by simpler mctrl_gpio_is_gpio() - IRQ_NOAUTOEN setting and request_irq() atomic issue commented in the code (thanks to Uwe Kleine-König) despite other drivers do the same - removed (clean up) useless comment "return -ENOTSUP" from mctrl_gpio_request_irqs() inline function, it shouldn't return any error if serial_mctrl_gpio.h is just a stub, ie. CONFIG_GPIOLIB not defined - fixed mctrl_gpio_request_irqs(), mctrl_gpio_free_irqs(), mctrl_gpio_enable_ms(), mctrl_gpio_disable_ms: if "gpios" is NULL just return without any error. Serial drivers don't fail on probe(), just warns, if mctrl_gpio_init_dt() returns NULL or an error. - updated the documentation on mctrl_ helpers: Documentation/serial/driver --- Documentation/serial/driver | 22 +++++- drivers/tty/serial/serial_mctrl_gpio.c | 132 ++++++++++++++++++++++++++++++++- drivers/tty/serial/serial_mctrl_gpio.h | 61 ++++++++++++++- 3 files changed, 209 insertions(+), 6 deletions(-) diff --git a/Documentation/serial/driver b/Documentation/serial/driver index c415b0e..7a0811c 100644 --- a/Documentation/serial/driver +++ b/Documentation/serial/driver @@ -439,7 +439,7 @@ 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_dt(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 @@ -453,8 +453,28 @@ mctrl_gpio_free(dev, gpios): mctrl_gpio_to_gpiod(gpios, gidx) This returns the gpio structure associated to the modem line index. +mctrl_gpio_is_gpio(gpios, gidx) + This returns true if the given modem line index is initialized and + handled by mtrl_gpio, ie. the line is a gpio line. + 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. + +mctrl_gpio_request_irqs(gpios) + This requests an interrupt of each input gpio line. The interupts + are set disabled and triggered on both edges. + It returns an error code or zero if success. + +mctrl_gpio_free_irqs(gpios) + This will free the requested interrupts of gpio lines. + +mctrl_gpio_enable_ms(gpios) + This enables modem status interrupts assigned to gpio lines. + It should be called by enable_ms() of an uart driver. + +mctrl_gpio_disable_ms(gpios) + This disables modem status interrupts assigned to gpio lines. + It should be called by disable_ms() of an uart driver. diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c index a38596c..7c43d15 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.c +++ b/drivers/tty/serial/serial_mctrl_gpio.c @@ -19,11 +19,15 @@ #include <linux/device.h> #include <linux/gpio/consumer.h> #include <linux/termios.h> +#include <linux/irq.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; }; static const struct { @@ -96,8 +100,9 @@ unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl) } EXPORT_SYMBOL_GPL(mctrl_gpio_get); -struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) +struct mctrl_gpios *mctrl_gpio_init_dt(struct uart_port *port, unsigned int idx) { + struct device *dev = port->dev; struct mctrl_gpios *gpios; enum mctrl_gpio_idx i; int err; @@ -106,6 +111,7 @@ struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) if (!gpios) return ERR_PTR(-ENOMEM); + gpios->port = port; for (i = 0; i < UART_GPIO_MAX; i++) { gpios->gpio[i] = devm_gpiod_get_index(dev, mctrl_gpios_desc[i].name, @@ -128,11 +134,13 @@ struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) devm_gpiod_put(dev, gpios->gpio[i]); gpios->gpio[i] = NULL; } + if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) + gpios->irq[i] = gpiod_to_irq(gpios->gpio[i]); } return gpios; } -EXPORT_SYMBOL_GPL(mctrl_gpio_init); +EXPORT_SYMBOL_GPL(mctrl_gpio_init_dt); void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) { @@ -147,3 +155,123 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) devm_kfree(dev, gpios); } EXPORT_SYMBOL_GPL(mctrl_gpio_free); + +/* + * Dealing with GPIO interrupt + */ +#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 & TIOCM_RI) + port->icount.rng++; + if (mctrl_diff & 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; +} + +int mctrl_gpio_request_irqs(struct mctrl_gpios *gpios) +{ + struct uart_port *port = gpios->port; + int *irq = gpios->irq; + enum mctrl_gpio_idx i; + int err = 0; + + /* When gpios is NULL just gpio irqs are also never set + * so return without any error */ + if (IS_ERR_OR_NULL(gpios)) + return err; + + for (i = 0; i < UART_GPIO_MAX; i++) { + if (irq[i] <= 0) + continue; + + /* + * FIXME IRQ_NOAUTOEN: + * This is not undone in the error path. To be fixed + * properly this needs to be set atomically together with + * request_irq. + */ + irq_set_status_flags(irq[i], IRQ_NOAUTOEN); + err = request_irq(irq[i], mctrl_gpio_irq_handle, + IRQ_TYPE_EDGE_BOTH, + dev_name(port->dev), gpios); + if (err) { + dev_err(port->dev, "%s: Can't get %d irq\n", + __func__, irq[i]); + break; + } + } + + /* + * If something went wrong, rollback avoiding + * negative enum values. + */ + while (err && i > 0) { + i--; + if (irq[i] > 0) + free_irq(irq[i], gpios); + } + + return err; +} +EXPORT_SYMBOL_GPL(mctrl_gpio_request_irqs); + +void mctrl_gpio_free_irqs(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 (gpios->irq[i] > 0) + free_irq(gpios->irq[i], gpios); +} +EXPORT_SYMBOL_GPL(mctrl_gpio_free_irqs); + +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios) +{ + enum mctrl_gpio_idx i; + + if (IS_ERR_OR_NULL(gpios)) + return; + + /* 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] > 0) + 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 (IS_ERR_OR_NULL(gpios)) + return; + + for (i = 0; i < UART_GPIO_MAX; i++) + if (gpios->irq[i] > 0) + disable_irq(gpios->irq[i]); +} +EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms); diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h index 400ba04..1f79be3 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.h +++ b/drivers/tty/serial/serial_mctrl_gpio.h @@ -21,6 +21,7 @@ #include <linux/err.h> #include <linux/device.h> #include <linux/gpio/consumer.h> +#include <linux/serial_core.h> enum mctrl_gpio_idx { UART_GPIO_CTS, @@ -40,6 +41,7 @@ enum mctrl_gpio_idx { */ struct mctrl_gpios; + #ifdef CONFIG_GPIOLIB /* @@ -60,12 +62,13 @@ 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. + * Request and set direction of modem control lines GPIOs. DT is used. + * Initialize irq table for 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); +struct mctrl_gpios *mctrl_gpio_init_dt(struct uart_port *port, unsigned int idx); /* * Free the mctrl_gpios structure. @@ -74,6 +77,28 @@ struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx); */ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios); +/* + * Request irqs for input lines GPIOs. The irqs are set disabled + * and triggered on both edges. + * Returns zero if OK, otherwise an error code. + */ +int mctrl_gpio_request_irqs(struct mctrl_gpios *gpios); + +/* + * Free irqs for input lines GPIOs. + */ +void mctrl_gpio_free_irqs(struct mctrl_gpios *gpios); + +/* + * Disable modem status interrupts assigned to GPIOs + */ +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios); + +/* + * Enable modem status interrupts assigned to GPIOs + */ +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios); + #else /* GPIOLIB */ static inline @@ -95,7 +120,7 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios, } static inline -struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx) +struct mctrl_gpios *mctrl_gpio_init_dt(struct uart_port *port, unsigned int idx) { return ERR_PTR(-ENOSYS); } @@ -105,6 +130,36 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios) { } +static inline +int mctrl_gpio_request_irqs(struct mctrl_gpios *gpios) +{ + return 0; +} + +static inline +void mctrl_gpio_free_irqs(struct mctrl_gpios *gpios) +{ +} + +static inline +void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios) +{ +} + +static inline +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios) +{ +} + #endif /* GPIOLIB */ +/* + * Return true if gidx is GPIO line, otherwise false. + */ +static inline +bool mctrl_gpio_is_gpio(struct mctrl_gpios *gpios, enum mctrl_gpio_idx gidx) +{ + return !IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(gpios, gidx)); +} + #endif -- 1.7.11.3 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html