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

[Laurent Pinchart]

On Monday 26 May 2008 11:58, Laurent Pinchart wrote:
> 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 ?

Sorry to bother everybody again, but I'd like this patch to go in 2.6.27. Is 
there any pending issue ? Platforms without GPIO support shouldn't be 
affected and get_mctrl()/set_mctrl() behaviour is backward compatible for 
existing platforms.

> > Signed-off-by: Laurent Pinchart <laurentp at 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 at 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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