Re: [PATCH 3/7] ARM: OMAP: Add command line option for I2C bus speed

[Tony Lindgren <tony@atomide.com>]

* Tony Lindgren <tony@atomide.com> [090304 13:51]:
> From: Jarkko Nikula <jarkko.nikula@nokia.com>
> 
> This patch adds a new command line option "i2c_bus=bus_id,clkrate" into
> I2C bus registration helper. Purpose of the option is to override the
> default board specific bus speed which is supplied by the
> omap_register_i2c_bus.
> 
> The default bus speed is typically set to speed of slowest I2C chip on the
> bus and overriding allow to use some experimental configurations or updated
> chip versions without any kernel modifications.

Jarkko, this should also be in Documentation/kernel-parameters.txt. Can
you please reply with a patch for that, and I'll fold it into this
patch?

Also, maybe it should be called omap_i2c_bus instead of i2c_bus?

Regards,

Tony
 
> Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>  arch/arm/plat-omap/i2c.c |   54 +++++++++++++++++++++++++++++++++++++---------
>  1 files changed, 44 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
> index 3e95954..aa70e43 100644
> --- a/arch/arm/plat-omap/i2c.c
> +++ b/arch/arm/plat-omap/i2c.c
> @@ -119,6 +119,46 @@ static void __init omap_i2c_mux_pins(int bus)
>  	omap_cfg_reg(scl);
>  }
>  
> +static int __init omap_i2c_nr_ports(void)
> +{
> +	int ports = 0;
> +
> +	if (cpu_class_is_omap1())
> +		ports = 1;
> +	else if (cpu_is_omap24xx())
> +		ports = 2;
> +	else if (cpu_is_omap34xx())
> +		ports = 3;
> +
> +	return ports;
> +}
> +
> +/**
> + * omap_i2c_bus_setup - Process command line options for the I2C bus speed
> + * @str: String of options
> + *
> + * This function allow to override the default I2C bus speed for given I2C
> + * bus with a command line option.
> + *
> + * Format: i2c_bus=bus_id,clkrate (in kHz)
> + *
> + * Returns 1 on success, 0 otherwise.
> + */
> +static int __init omap_i2c_bus_setup(char *str)
> +{
> +	int ports;
> +	int ints[3];
> +
> +	ports = omap_i2c_nr_ports();
> +	get_options(str, 3, ints);
> +	if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
> +		return 0;
> +	i2c_rate[ints[1] - 1] = ints[2];
> +
> +	return 1;
> +}
> +__setup("i2c_bus=", omap_i2c_bus_setup);
> +
>  /**
>   * omap_register_i2c_bus - register I2C bus with device descriptors
>   * @bus_id: bus id counting from number 1
> @@ -132,19 +172,12 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
>  			  struct i2c_board_info const *info,
>  			  unsigned len)
>  {
> -	int ports, err;
> +	int err;
>  	struct platform_device *pdev;
>  	struct resource *res;
>  	resource_size_t base, irq;
>  
> -	if (cpu_class_is_omap1())
> -		ports = 1;
> -	else if (cpu_is_omap24xx())
> -		ports = 2;
> -	else if (cpu_is_omap34xx())
> -		ports = 3;
> -
> -	BUG_ON(bus_id < 1 || bus_id > ports);
> +	BUG_ON(bus_id < 1 || bus_id > omap_i2c_nr_ports());
>  
>  	if (info) {
>  		err = i2c_register_board_info(bus_id, info, len);
> @@ -153,7 +186,8 @@ int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
>  	}
>  
>  	pdev = &omap_i2c_devices[bus_id - 1];
> -	*(u32 *)pdev->dev.platform_data = clkrate;
> +	if (i2c_rate[bus_id - 1] == 0)
> +		i2c_rate[bus_id - 1] = clkrate;
>  
>  	if (bus_id == 1) {
>  		res = pdev->resource;
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-omap" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html