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

[Heiko Schocher]

Hello Adam,

On 20.09.21 14:21, Adam Ford wrote:
> 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.

No, I think all fine, for me the patch is okay, so:

Reviewed-by: Heiko Schocher <hs at denx.de>

Ah, I see, in patchwork the patch is assigned to Marek... added Marek
to cc.

@Marek: Is it okay for you, if I pickup the patch, when new u-boot
version is out? Else you can pick it up.

Thanks!

bye,
Heiko
> 
> 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
>>

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