Hello,
On Fri, Feb 06, 2015 at 05:55:32PM +0100, Janusz Uzycki wrote:
> 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>
For the git history this commit log is too verbose. The diff between v2
and v3 at least could be dropped.
I'd write something like:
serial: mctrl-gpio: Add irq handling
The actions required when modem status line inputs change don't need to
be duplicated in each driver using mctrl-gpio so add the respective
support to the mctrl-gpio core.
This adds a few new helper function and allows to remove some
boilerplate from the drivers currently using mctrl-gpio.
I think this patch still breaks bisectibilty, doesn't it? That means the
API changes and its users must be updated in a single patch.
> 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;
This function needs to hold port->lock, right? This should be
documented.
> + 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;
This should return IRQ_NONE if mctrl_diff is 0, doesn't it?
> +}
> +
> +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;
I'd expect drivers using mctrl-gpio to error out if mctrl_gpio_init_dt
fails. Also mctrl_gpio_init_dt never returns NULL, so IMHO this check
can be dropped. (There are more places in mctrl-gpio that should be
fixed accordingly.
> + 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]);
The function name isn't interesting here. Please drop it. Now that the
irqs are requested with IRQ_NOAUTOEN is there a reason not to use
devm_request_irq?
> + 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;
see above
> +
> + 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;
ditto
> +
> + /* 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;
>
> +
drop this
> #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;
The gpiolib stubs return -ENOSYS in this case. Maybe this should be done
here, too?
> +}
> +
> +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));
If gpiod_get_optional was used to get the handles, we could drop this
ugly IS_ERR_OR_NULL here, too.
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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