Re: [i2c] [RFC] PXA3xx: Add support for power i2c bus

[Ben Dooks <ben-linux@fluff.org>]

On Thu, Aug 14, 2008 at 02:38:09PM +0300, Mike Rapoport wrote:
> Russell King - ARM Linux wrote:
> > On Thu, Aug 14, 2008 at 11:55:07AM +0300, Mike Rapoport wrote:
> >> diff --git a/arch/arm/mach-pxa/generic.h b/arch/arm/mach-pxa/generic.h
> >> index 041c048..13a786d 100644
> >> --- a/arch/arm/mach-pxa/generic.h
> >> +++ b/arch/arm/mach-pxa/generic.h
> >> @@ -9,9 +9,10 @@
> >>   * published by the Free Software Foundation.
> >>   */
> >>
> >> -typedef int (*set_wake_t)(unsigned int, unsigned int);
> >> +typedef int (*set_wake_t) (unsigned int, unsigned int);
> > 
> > Undoes perfectly good formatting.
> > 
> >> @@ -982,10 +992,13 @@ static int i2c_pxa_probe(struct platform_device *dev)
> >>  	snprintf(i2c->adap.name, sizeof(i2c->adap.name), "pxa_i2c-i2c.%u",
> >>  		 i2c->adap.nr);
> >>
> >> -	i2c->clk = clk_get(&dev->dev, "I2CCLK");
> >> -	if (IS_ERR(i2c->clk)) {
> >> -		ret = PTR_ERR(i2c->clk);
> >> -		goto eclk;
> >> +	/* PXA3xx has power I2C clock always on */
> >> +	if (!(cpu_is_pxa3xx() && i2c->adap.nr == 1)) {
> >> +		i2c->clk = clk_get(&dev->dev, "I2CCLK");
> >> +		if (IS_ERR(i2c->clk)) {
> >> +			ret = PTR_ERR(i2c->clk);
> >> +			goto eclk;
> >> +		}
> > 
> > Umm, no.  It would be far better to provide a dummy clock rather than
> > mess drivers up with this and lots of other conditional stuff.
> 
> Would that be better?
> 
> Signed-off-by: Mike Rapoport <mike@compulab.co.il>
> 
>  arch/arm/mach-pxa/devices.h          |    1 +
>  arch/arm/mach-pxa/include/mach/i2c.h |    6 ++++-
>  arch/arm/mach-pxa/pxa27x.c           |    2 +-
>  arch/arm/mach-pxa/pxa3xx.c           |   45 ++++++++++++++++++++++++++++++++++
>  drivers/i2c/busses/i2c-pxa.c         |   20 +++++++++++----
>  5 files changed, 67 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm/mach-pxa/devices.h b/arch/arm/mach-pxa/devices.h
> index 887c738..bb04af4 100644
> --- a/arch/arm/mach-pxa/devices.h
> +++ b/arch/arm/mach-pxa/devices.h
> @@ -32,5 +32,6 @@ extern struct platform_device pxa27x_device_pwm0;
>  extern struct platform_device pxa27x_device_pwm1;
> 
>  extern struct platform_device pxa3xx_device_nand;
> +extern struct platform_device pxa3xx_device_i2c_power;
> 
>  void __init pxa_register_device(struct platform_device *dev, void *data);
> diff --git a/arch/arm/mach-pxa/include/mach/i2c.h b/arch/arm/mach-pxa/include/mach/i2c.h
> index 80596b0..897e717 100644
> --- a/arch/arm/mach-pxa/include/mach/i2c.h
> +++ b/arch/arm/mach-pxa/include/mach/i2c.h
> @@ -71,7 +71,11 @@ struct i2c_pxa_platform_data {
>  extern void pxa_set_i2c_info(struct i2c_pxa_platform_data *info);
> 
>  #ifdef CONFIG_PXA27x
> -extern void pxa_set_i2c_power_info(struct i2c_pxa_platform_data *info);
> +extern void pxa27x_set_i2c_power_info(struct i2c_pxa_platform_data *info);
> +#endif
> +
> +#ifdef CONFIG_PXA3xx
> +extern void pxa3xx_set_i2c_power_info(struct i2c_pxa_platform_data *info);
>  #endif
> 
>  #endif
> diff --git a/arch/arm/mach-pxa/pxa27x.c b/arch/arm/mach-pxa/pxa27x.c
> index f9f6a9c..c33cf6a 100644
> --- a/arch/arm/mach-pxa/pxa27x.c
> +++ b/arch/arm/mach-pxa/pxa27x.c
> @@ -349,7 +349,7 @@ struct platform_device pxa27x_device_i2c_power = {
>  	.num_resources	= ARRAY_SIZE(i2c_power_resources),
>  };
> 
> -void __init pxa_set_i2c_power_info(struct i2c_pxa_platform_data *info)
> +void __init pxa27x_set_i2c_power_info(struct i2c_pxa_platform_data *info)
>  {
>  	local_irq_disable();
>  	PCFR |= PCFR_PI2CEN;
> diff --git a/arch/arm/mach-pxa/pxa3xx.c b/arch/arm/mach-pxa/pxa3xx.c
> index 03cbc38..b3cd5d0 100644
> --- a/arch/arm/mach-pxa/pxa3xx.c
> +++ b/arch/arm/mach-pxa/pxa3xx.c
> @@ -203,6 +203,19 @@ static const struct clkops clk_pout_ops = {
>  	.disable	= clk_pout_disable,
>  };
> 
> +static void clk_dummy_enable(struct clk *clk)
> +{
> +}
> +
> +static void clk_dummy_disable(struct clk *clk)
> +{
> +}
> +
> +static const struct clkops clk_dummy_ops = {
> +	.enable		= clk_dummy_enable,
> +	.disable	= clk_dummy_disable,
> +};
> +
>  static struct clk pxa3xx_clks[] = {
>  	{
>  		.name           = "CLK_POUT",
> @@ -211,6 +224,13 @@ static struct clk pxa3xx_clks[] = {
>  		.delay          = 70,
>  	},
> 
> +	/* Power I2C clock is always on */
> +	{
> +		.name		= "I2CCLK",
> +		.ops		= &clk_dummy_ops,
> +		.dev		= &pxa3xx_device_i2c_power.dev,
> +	},
> +
>  	PXA3xx_CK("LCDCLK",  LCD,    &clk_pxa3xx_hsio_ops, &pxa_device_fb.dev),
>  	PXA3xx_CK("CAMCLK",  CAMERA, &clk_pxa3xx_hsio_ops, NULL),
>  	PXA3xx_CK("AC97CLK", AC97,   &clk_pxa3xx_ac97_ops, NULL),
> @@ -509,6 +529,30 @@ void __init pxa3xx_init_irq(void)
>   * device registration specific to PXA3xx.
>   */
> 
> +static struct resource i2c_power_resources[] = {
> +	{
> +		.start  = 0x40f500c0,
> +		.end    = 0x40f500d3,
> +		.flags	= IORESOURCE_MEM,
> +	}, {
> +		.start	= IRQ_PWRI2C,
> +		.end	= IRQ_PWRI2C,
> +		.flags	= IORESOURCE_IRQ,
> +	},
> +};
> +
> +struct platform_device pxa3xx_device_i2c_power = {
> +	.name		= "pxa2xx-i2c",
> +	.id		= 1,
> +	.resource	= i2c_power_resources,
> +	.num_resources	= ARRAY_SIZE(i2c_power_resources),
> +};
> +
> +void __init pxa3xx_set_i2c_power_info(struct i2c_pxa_platform_data *info)
> +{
> +	pxa3xx_device_i2c_power.dev.platform_data = info;
> +}
> +
>  static struct platform_device *devices[] __initdata = {
>  /*	&pxa_device_udc,	The UDC driver is PXA25x only */
>  	&pxa_device_ffuart,
> @@ -522,6 +566,7 @@ static struct platform_device *devices[] __initdata = {
>  	&pxa3xx_device_ssp4,
>  	&pxa27x_device_pwm0,
>  	&pxa27x_device_pwm1,
> +	&pxa3xx_device_i2c_power,
>  };
> 
>  static struct sys_device pxa3xx_sysdev[] = {
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index 44d8384..981bb07 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -68,11 +68,21 @@ struct pxa_i2c {
>  	int			use_pio;
>  };
> 
> -#define _IBMR(i2c)	((i2c)->reg_base + 0)
> -#define _IDBR(i2c)	((i2c)->reg_base + 8)
> -#define _ICR(i2c)	((i2c)->reg_base + 0x10)
> -#define _ISR(i2c)	((i2c)->reg_base + 0x18)
> -#define _ISAR(i2c)	((i2c)->reg_base + 0x20)
> +#define _IBMR(i2c)	\
> +	((i2c)->reg_base + \
> +	 ((cpu_is_pxa3xx() && ((i2c)->adap.nr == 1)) ? 0x0 : 0x0))
> +#define _IDBR(i2c)	\
> +	((i2c)->reg_base + \
> +	 ((cpu_is_pxa3xx() && ((i2c)->adap.nr == 1)) ? 0x4 : 0x8))
> +#define _ICR(i2c)	\
> +	((i2c)->reg_base + \
> +	 ((cpu_is_pxa3xx() && ((i2c)->adap.nr == 1)) ? 0x8 : 0x10))
> +#define _ISR(i2c)	\
> +	((i2c)->reg_base + \
> +	 ((cpu_is_pxa3xx() && ((i2c)->adap.nr == 1)) ? 0xc : 0x18))
> +#define _ISAR(i2c)	\
> +	((i2c)->reg_base + \
> +	 ((cpu_is_pxa3xx() && ((i2c)->adap.nr == 1)) ? 0x10 : 0x20))

Not very nice, how about making the i2c structure have pointers
to each of the registers which can be setup at probe time. Or even
just have a multiplier in the structure, as these all look to be reg/2
in the case of pxa3xx and adap.nr == 1... 

Note, adap.nr shouldn't really be used to differentiate, use the
platform device number

+#define _IDBR(i2c)	((i2c)->reg_base + (0x4 << (i2c)->reg_shift))
+#define _ICR(i2c)	((i2c)->reg_base + (0x8 << (i2c)->reg_shift))
etc.

then do in the probe:

	i2c->reg_shift = (cpu_is_pxa3xx() && <is_power_i2c>) ? 0 : 1;

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

-------------------------------------------------------------------
List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel
FAQ:        http://www.arm.linux.org.uk/mailinglists/faq.php
Etiquette:  http://www.arm.linux.org.uk/mailinglists/etiquette.php