[PATCH v3 04/10] i2c: meson: use i2c core for DT clock-frequency parsing

[Neil Armstrong]

On 03/11/2017 07:23 PM, Heiner Kallweit wrote:
> We don't have to parse the DT manually to retrieve the bus frequency
> and we don't have to maintain an own default for the bus frequency.
> Let the i2c core do this for us.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1 at gmail.com>
> Reviewed-by: Jerome Brunet <jbrunet at baylibre.com>
> ---
> v2:
> - added Reviewed-by
> v3:
> - changed order of patches
> ---
>  drivers/i2c/busses/i2c-meson.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
> index e597764e..ac0ac82d 100644
> --- a/drivers/i2c/busses/i2c-meson.c
> +++ b/drivers/i2c/busses/i2c-meson.c
> @@ -38,7 +38,6 @@
>  #define REG_CTRL_CLKDIV_MASK	((BIT(10) - 1) << REG_CTRL_CLKDIV_SHIFT)
>  
>  #define I2C_TIMEOUT_MS		500
> -#define DEFAULT_FREQ		100000
>  
>  enum {
>  	TOKEN_END = 0,
> @@ -387,15 +386,14 @@ static int meson_i2c_probe(struct platform_device *pdev)
>  	struct device_node *np = pdev->dev.of_node;
>  	struct meson_i2c *i2c;
>  	struct resource *mem;
> -	u32 freq;
> +	struct i2c_timings timings;
>  	int irq, ret = 0;
>  
>  	i2c = devm_kzalloc(&pdev->dev, sizeof(struct meson_i2c), GFP_KERNEL);
>  	if (!i2c)
>  		return -ENOMEM;
>  
> -	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", &freq))
> -		freq = DEFAULT_FREQ;
> +	i2c_parse_fw_timings(&pdev->dev, &timings, true);
>  
>  	i2c->dev = &pdev->dev;
>  	platform_set_drvdata(pdev, i2c);
> @@ -453,7 +451,7 @@ static int meson_i2c_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	meson_i2c_set_clk_div(i2c, freq);
> +	meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
>  
>  	return 0;
>  }
> 

Hi Heiner,

I'm sorry, but you should *really* update the dt-bindings.

The dt bindings are now strictly related to how the driver is implemented, or which
attributes are used, but how the device tree node should conform to.

In this particular case, in the recent addition of "standard" i2c attributes for
speed and timings, you should refer to this "i2c.txt" file to specify how the node
should conform.

And finally, this patch would be correct since the node will be supposed to conform
to the correct bindings.

Neil