Re: [PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Peter Hurley <peter@hurleysoftware.com>]

Hi Richard,

On 05/13/2014 02:20 PM, Richard Genoud wrote:
> Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.
> 
> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---
>  drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 122 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 43ca659..3fceae0 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -45,6 +45,7 @@
>  #include <linux/gpio.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/err.h>
> +#include <linux/irq.h>
>  
>  #include <asm/io.h>
>  #include <asm/ioctls.h>
> @@ -167,7 +168,9 @@ struct atmel_uart_port {
>  
>  	struct serial_rs485	rs485;		/* rs485 settings */
>  	struct mctrl_gpios	*gpios;
> +	int			gpio_irq[UART_GPIO_MAX];
>  	unsigned int		tx_done_mask;
> +	bool			ms_irq_enabled;
>  	bool			is_usart;	/* usart or uart */
>  	struct timer_list	uart_timer;	/* uart timer */
>  	int (*prepare_rx)(struct uart_port *port);
> @@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
>   */
>  static void atmel_enable_ms(struct uart_port *port)
>  {
> -	UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
> -			| ATMEL_US_DCDIC | ATMEL_US_CTSIC);
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	uint32_t ier = 0;
> +
> +	/*
> +	 * Interrupt should not be enabled twice
> +	 */
> +	if (atmel_port->ms_irq_enabled)
> +		return;
> +
> +	atmel_port->ms_irq_enabled = true;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
> +	else
> +		ier |= ATMEL_US_CTSIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
> +	else
> +		ier |= ATMEL_US_DSRIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
> +	else
> +		ier |= ATMEL_US_RIIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
> +	else
> +		ier |= ATMEL_US_DCDIC;

Where are these gpio irqs disabled if !UART_ENABLE_MS()?


> +
> +	UART_PUT_IER(port, ier);
>  }
>  
>  /*
> @@ -1079,11 +1112,31 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
>  static irqreturn_t atmel_interrupt(int irq, void *dev_id)
>  {
>  	struct uart_port *port = dev_id;
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>  	unsigned int status, pending, pass_counter = 0;
> +	bool gpio_handled = false;
>  
>  	do {
>  		status = atmel_get_lines_status(port);
>  		pending = status & UART_GET_IMR(port);
> +		if (!gpio_handled) {
> +			/*
> +			 * Dealing with GPIO interrupt
> +			 */
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_CTS])
> +				pending |= ATMEL_US_CTSIC;
> +
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_DSR])
> +				pending |= ATMEL_US_DSRIC;
> +
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_RI])
> +				pending |= ATMEL_US_RIIC;
> +
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_DCD])
> +				pending |= ATMEL_US_DCDIC;
> +
> +			gpio_handled = true;
> +		}
>  		if (!pending)
>  			break;
>  
> @@ -1563,6 +1616,45 @@ static void atmel_get_ip_name(struct uart_port *port)
>  	}
>  }
>  
> +static void atmel_free_gpio_irq(struct uart_port *port)
> +{
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	enum mctrl_gpio_idx i;
> +
> +	for (i = 0; i < UART_GPIO_MAX; i++)
> +		if (atmel_port->gpio_irq[i] >= 0)
> +			free_irq(atmel_port->gpio_irq[i], port);
> +}
> +
> +static int atmel_request_gpio_irq(struct uart_port *port)
> +{
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	int *irq = atmel_port->gpio_irq;
> +	enum mctrl_gpio_idx i;
> +	int err = 0;
> +
> +	for (i = 0; (i < UART_GPIO_MAX) && !err; i++) {
> +		if (irq[i] < 0)
> +			continue;
> +
> +		irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
> +		err = request_irq(irq[i], atmel_interrupt, IRQ_TYPE_EDGE_BOTH,
> +				  "atmel_serial", port);
> +		if (err)
> +			dev_err(port->dev, "atmel_startup - Can't get %d irq\n",
> +				irq[i]);
> +	}
> +
> +	/*
> +	 * If something went wrong, rollback.
> +	 */
> +	while (err && (--i >= 0))
> +		if (irq[i] >= 0)
> +			free_irq(irq[i], port);
> +
> +	return err;
> +}
> +
>  /*
>   * Perform initialization and enable port for reception
>   */
> @@ -1579,6 +1671,7 @@ static int atmel_startup(struct uart_port *port)
>  	 * handle an unexpected interrupt
>  	 */
>  	UART_PUT_IDR(port, -1);
> +	atmel_port->ms_irq_enabled = false;
>  
>  	/*
>  	 * Allocate the IRQ
> @@ -1591,6 +1684,13 @@ static int atmel_startup(struct uart_port *port)
>  	}
>  
>  	/*
> +	 * Get the GPIO lines IRQ
> +	 */
> +	retval = atmel_request_gpio_irq(port);
> +	if (retval)
> +		goto free_irq;
> +
> +	/*
>  	 * Initialize DMA (if necessary)
>  	 */
>  	atmel_init_property(atmel_port, pdev);
> @@ -1654,6 +1754,11 @@ static int atmel_startup(struct uart_port *port)
>  	}
>  
>  	return 0;
> +
> +free_irq:
> +	free_irq(port->irq, port);
> +
> +	return retval;
>  }
>  
>  /*
> @@ -1701,9 +1806,12 @@ static void atmel_shutdown(struct uart_port *port)
>  	atmel_port->rx_ring.tail = 0;
>  
>  	/*
> -	 * Free the interrupt
> +	 * Free the interrupts
>  	 */
>  	free_irq(port->irq, port);
> +	atmel_free_gpio_irq(port);
> +
> +	atmel_port->ms_irq_enabled = false;
>  }
>  
>  /*
> @@ -2366,10 +2474,21 @@ static int atmel_serial_resume(struct platform_device *pdev)
>  
>  static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev)
>  {
> +	enum mctrl_gpio_idx i;
> +	struct gpio_desc *gpiod;
> +
>  	p->gpios = mctrl_gpio_init(dev, 0);
>  	if (IS_ERR_OR_NULL(p->gpios))
>  		return -1;
>  
> +	for (i = 0; i < UART_GPIO_MAX; i++) {
> +		gpiod = mctrl_gpio_to_gpiod(p->gpios, i);
> +		if (gpiod && (gpiod_get_direction(gpiod) == GPIOF_DIR_IN))
> +			p->gpio_irq[i] = gpiod_to_irq(gpiod);
> +		else
> +			p->gpio_irq[i] = -EINVAL;
> +	}
> +
>  	return 0;
>  }
>  
>