On 08/10/2024 16:43, Théo Lebrun wrote:
> Hello Krzysztof,
>
> On Tue Oct 8, 2024 at 3:39 PM CEST, Krzysztof Kozlowski wrote:
>> On Tue, Oct 08, 2024 at 12:29:41PM +0200, Théo Lebrun wrote:
>>> Add EyeQ6H support to the nmk-i2c AMBA driver. It shares the same quirk
>>> as EyeQ5: the memory bus only supports 32-bit accesses. Avoid writeb()
>>> and readb() by reusing the same `priv->has_32b_bus` flag.
>>>
>>> It does NOT need to write speed-mode specific value into a register;
>>> therefore it does not depend on the mobileye,olb DT property.
>>>
>>> Refactoring is done using is_eyeq5 and is_eyeq6h boolean local
>>> variables. Sort variables in reverse christmas tree to try and
>>> introduce some logic into the ordering.
>>>
>>> Signed-off-by: Théo Lebrun <theo.lebrun@xxxxxxxxxxx>
>>> ---
>>> drivers/i2c/busses/i2c-nomadik.c | 22 +++++++++++-----------
>>> 1 file changed, 11 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
>>> index ad0f02acdb1215a1c04729f97bb14a4d93f88456..ea511d3a58073eaedb63850026e05b59427a69c6 100644
>>> --- a/drivers/i2c/busses/i2c-nomadik.c
>>> +++ b/drivers/i2c/busses/i2c-nomadik.c
>>> @@ -6,10 +6,10 @@
>>> * I2C master mode controller driver, used in Nomadik 8815
>>> * and Ux500 platforms.
>>> *
>>> - * The Mobileye EyeQ5 platform is also supported; it uses
>>> + * The Mobileye EyeQ5 and EyeQ6H platforms are also supported; they use
>>> * the same Ux500/DB8500 IP block with two quirks:
>>> * - The memory bus only supports 32-bit accesses.
>>> - * - A register must be configured for the I2C speed mode;
>>> + * - (only EyeQ5) A register must be configured for the I2C speed mode;
>>> * it is located in a shared register region called OLB.
>>> *
>>> * Author: Srinidhi Kasagar <srinidhi.kasagar@xxxxxxxxxxxxxx>
>>> @@ -1046,8 +1046,6 @@ static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)
>>> struct regmap *olb;
>>> unsigned int id;
>>>
>>> - priv->has_32b_bus = true;
>>> -
>>> olb = syscon_regmap_lookup_by_phandle_args(np, "mobileye,olb", 1, &id);
>>> if (IS_ERR(olb))
>>> return PTR_ERR(olb);
>>> @@ -1070,13 +1068,15 @@ static int nmk_i2c_eyeq5_probe(struct nmk_i2c_dev *priv)
>>>
>>> static int nmk_i2c_probe(struct amba_device *adev, const struct amba_id *id)
>>> {
>>> - int ret = 0;
>>> - struct nmk_i2c_dev *priv;
>>> - struct device_node *np = adev->dev.of_node;
>>> - struct device *dev = &adev->dev;
>>> - struct i2c_adapter *adap;
>>> struct i2c_vendor_data *vendor = id->data;
>>> + struct device_node *np = adev->dev.of_node;
>>> + bool is_eyeq6h = of_device_is_compatible(np, "mobileye,eyeq6h-i2c");
>>> + bool is_eyeq5 = of_device_is_compatible(np, "mobileye,eyeq5-i2c");
>>
>> You should use match data, not add compatibles in the middle of code.
>> That's preferred, scallable pattern. What you added here last time does
>> not scale and above change is a proof for that.
>
> I would have used match data if the driver struct had a .of_match_table
> field. `struct amba_driver` does not. Are you recommending the approach
> below?
>
> I don't see how it brings much to the driver but I do get the scaling
> issue as the number of support compatibles increases. This is a fear
> based on what *could* happen in the future though.
You still have adev->dev.of_node, which you can use for matching in
probe. See for example of_match_device() (and add a note so people will
not convert it to device_get_match_data() blindly).
Best regards,
Krzysztof
