Re: [PATCH] powerpc: Modem control lines support for the cpm_uart driver

[Laurent Pinchart <laurentp@cse-semaphore.com>]

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On Wednesday 16 April 2008 11:10, Laurent Pinchart wrote:
> This patch replaces the get_mctrl/set_mctrl stubs with modem control line
> read/write access through the GPIO lib.
> 
> Available modem control lines are described in the device tree using GPIO
> bindings.

Any show stopper on this patch ? Could it get into powerpc-next ?

> Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
> ---
>  Documentation/powerpc/booting-without-of.txt |   10 ++++++
>  drivers/serial/cpm_uart/cpm_uart.h           |   10 ++++++
>  drivers/serial/cpm_uart/cpm_uart_core.c      |   40 ++++++++++++++++++++++++--
>  3 files changed, 57 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
> index 1e5572a..012f231 100644
> --- a/Documentation/powerpc/booting-without-of.txt
> +++ b/Documentation/powerpc/booting-without-of.txt
> @@ -1976,6 +1976,14 @@ platforms are moved over to use the flattened-device-tree model.
>     - fsl,cpm2-scc-uart
>     - fsl,qe-uart
>  
> +   Modem control lines connected to GPIO controllers are listed in the
> +   gpios property as described in section VIII.1 in the following order:
> +
> +   CTS, RTS, DCD, DSR, DTR, and RI.
> +
> +   The gpios property is optional and can be left out when control lines are
> +   not used.
> +
>     Example:
>  
>  	serial@11a00 {
> @@ -1987,6 +1995,8 @@ platforms are moved over to use the flattened-device-tree model.
>  		interrupt-parent = <&PIC>;
>  		fsl,cpm-brg = <1>;
>  		fsl,cpm-command = <00800000>;
> +		gpios = <&gpio_c 15 0
> +			 &gpio_d 29 0>;
>  	};
>  
>     iii) Network
> diff --git a/drivers/serial/cpm_uart/cpm_uart.h b/drivers/serial/cpm_uart/cpm_uart.h
> index 0cc39f8..d0c55e2 100644
> --- a/drivers/serial/cpm_uart/cpm_uart.h
> +++ b/drivers/serial/cpm_uart/cpm_uart.h
> @@ -50,6 +50,15 @@
>  
>  #define SCC_WAIT_CLOSING 100
>  
> +#define GPIO_CTS	0
> +#define GPIO_RTS	1
> +#define GPIO_DCD	2
> +#define GPIO_DSR	3
> +#define GPIO_DTR	4
> +#define GPIO_RI		5
> +
> +#define NUM_GPIOS	(GPIO_RI+1)
> +
>  struct uart_cpm_port {
>  	struct uart_port	port;
>  	u16			rx_nrfifos;
> @@ -82,6 +91,7 @@ struct uart_cpm_port {
>  	int 			wait_closing;
>  	/* value to combine with opcode to form cpm command */
>  	u32			command;
> +	int			gpios[NUM_GPIOS];
>  };
>  
>  #ifndef CONFIG_PPC_CPM_NEW_BINDING
> diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
> index 7a704ff..0f08071 100644
> --- a/drivers/serial/cpm_uart/cpm_uart_core.c
> +++ b/drivers/serial/cpm_uart/cpm_uart_core.c
> @@ -42,6 +42,8 @@
>  #include <linux/bootmem.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/fs_uart_pd.h>
> +#include <linux/gpio.h>
> +#include <linux/of_gpio.h>
>  
>  #include <asm/io.h>
>  #include <asm/irq.h>
> @@ -152,13 +154,41 @@ static unsigned int cpm_uart_tx_empty(struct uart_port *port)
>  
>  static void cpm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
>  {
> -	/* Whee. Do nothing. */
> +	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
> +
> +	if (pinfo->gpios[GPIO_RTS] >= 0)
> +		gpio_set_value(pinfo->gpios[GPIO_RTS], !(mctrl & TIOCM_RTS));
> +
> +	if (pinfo->gpios[GPIO_DTR] >= 0)
> +		gpio_set_value(pinfo->gpios[GPIO_DTR], !(mctrl & TIOCM_DTR));
>  }
>  
>  static unsigned int cpm_uart_get_mctrl(struct uart_port *port)
>  {
> -	/* Whee. Do nothing. */
> -	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
> +	struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
> +	unsigned int mctrl = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
> +
> +	if (pinfo->gpios[GPIO_CTS] >= 0) {
> +		if (gpio_get_value(pinfo->gpios[GPIO_CTS]))
> +			mctrl &= ~TIOCM_CTS;
> +	}
> +
> +	if (pinfo->gpios[GPIO_DSR] >= 0) {
> +		if (gpio_get_value(pinfo->gpios[GPIO_DSR]))
> +			mctrl &= ~TIOCM_DSR;
> +	}
> +
> +	if (pinfo->gpios[GPIO_DCD] >= 0) {
> +		if (gpio_get_value(pinfo->gpios[GPIO_DCD]))
> +			mctrl &= ~TIOCM_CAR;
> +	}
> +
> +	if (pinfo->gpios[GPIO_RI] >= 0) {
> +		if (!gpio_get_value(pinfo->gpios[GPIO_RI]))
> +			mctrl |= TIOCM_RNG;
> +	}
> +
> +	return mctrl;
>  }
>  
>  /*
> @@ -959,6 +989,7 @@ static int cpm_uart_init_port(struct device_node *np,
>  	void __iomem *mem, *pram;
>  	int len;
>  	int ret;
> +	int i;
>  
>  	data = of_get_property(np, "fsl,cpm-brg", &len);
>  	if (!data || len != 4) {
> @@ -1017,6 +1048,9 @@ static int cpm_uart_init_port(struct device_node *np,
>  		goto out_pram;
>  	}
>  
> +	for (i = 0; i < NUM_GPIOS; i++)
> +		pinfo->gpios[i] = of_get_gpio(np, i);
> +
>  	return cpm_uart_request_port(&pinfo->port);
>  
>  out_pram:
> -- 
> 1.5.0
> 
> 

-- 
Laurent Pinchart
CSE Semaphore Belgium

Chaussee de Bruxelles, 732A
B-1410 Waterloo
Belgium

T +32 (2) 387 42 59
F +32 (2) 387 42 75

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