[PATCH] i2c: rcar_i2c: Enable configuring SCL rise and fall times

[Adam Ford]

On Tue, Aug 24, 2021 at 9:10 AM Adam Ford <aford173 at gmail.com> wrote:
>
> The Linux i2c driver supports i2c-scl-rising-time-ns,
> and i2c-scl-falling-time-ns, but U-Boot uses hard-coded values
> for these values.
>
> Update the calculation by fetching them from the device tree if
> present and use the previous values as the default if they are
> missing.
>
> Signed-off-by: Adam Ford <aford173 at gmail.com>
>
Do I have the right people in copy?  I was hoping to get some feedback
on this.  My boards use the i2c-scl-rising-time-ns to help properly
set the i2c clocking.

thanks
adam

> diff --git a/drivers/i2c/rcar_i2c.c b/drivers/i2c/rcar_i2c.c
> index 14bb6603d5..d9ece5e3a8 100644
> --- a/drivers/i2c/rcar_i2c.c
> +++ b/drivers/i2c/rcar_i2c.c
> @@ -64,6 +64,8 @@ enum rcar_i2c_type {
>  struct rcar_i2c_priv {
>         void __iomem            *base;
>         struct clk              clk;
> +       u32                     fall_ns;
> +       u32                     rise_ns;
>         u32                     intdelay;
>         u32                     icccr;
>         enum rcar_i2c_type      type;
> @@ -278,7 +280,7 @@ static int rcar_i2c_set_speed(struct udevice *dev, uint bus_freq_hz)
>          *  = F[sum * ick / 1000000000]
>          *  = F[(ick / 1000000) * sum / 1000]
>          */
> -       sum = 35 + 200 + priv->intdelay;
> +       sum = priv->fall_ns + priv->rise_ns + priv->intdelay;
>         round = (ick + 500000) / 1000000 * sum;
>         round = (round + 500) / 1000;
>
> @@ -323,6 +325,10 @@ static int rcar_i2c_probe(struct udevice *dev)
>         int ret;
>
>         priv->base = dev_read_addr_ptr(dev);
> +       priv->rise_ns = dev_read_u32_default(dev,
> +                                            "i2c-scl-rising-time-ns", 200);
> +       priv->fall_ns = dev_read_u32_default(dev,
> +                                            "i2c-scl-falling-time-ns", 35);
>         priv->intdelay = dev_read_u32_default(dev,
>                                               "i2c-scl-internal-delay-ns", 5);
>         priv->type = dev_get_driver_data(dev);
> --
> 2.25.1
>