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Message-ID: <f48463f1-ce64-08e6-0d37-614b76edcdd0@microchip.com>
Date: Fri, 10 Jun 2022 09:06:28 +0000
From: <Claudiu.Beznea@...rochip.com>
To: <Kavyasree.Kotagiri@...rochip.com>
CC: <devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <UNGLinuxDriver@...rochip.com>,
<krzysztof.kozlowski+dt@...aro.org>, <Nicolas.Ferre@...rochip.com>,
<alexandre.belloni@...tlin.com>
Subject: Re: [PATCH v2 3/3] mfd: atmel-flexcom: Add support for lan966x
flexcom chip-select configuration
On 09.06.2022 16:34, Kavyasree Kotagiri - I30978 wrote:
>
>>>>>> LAN966x SoC have 5 flexcoms. Each flexcom has 2 chip-selects.
>>>>>> For each chip select of each flexcom there is a configuration
>>>>>> register FLEXCOM_SHARED[0-4]:SS_MASK[0-1]. The width of
>>>>>> configuration register is 21 because there are 21 shared pins
>>>>>> on each of which the chip select can be mapped. Each bit of the
>>>>>> register represents a different FLEXCOM_SHARED pin.
>>>>>> Signed-off-by: Kavyasree Kotagiri <kavyasree.kotagiri@...rochip.com>
>>>>>> ---
>>>>>> v1 -> v2:
>>>>>> - use GENMASK for mask, macros for maximum allowed values.
>>>>>> - use u32 values for flexcom chipselects instead of strings.
>>>>>> - disable clock in case of errors.
>>>>>> drivers/mfd/atmel-flexcom.c | 93
>>>>> ++++++++++++++++++++++++++++++++++++-
>>>>>> 1 file changed, 92 insertions(+), 1 deletion(-)
>>>>>> diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
>>>>>> index 33caa4fba6af..ac700a85b46f 100644
>>>>>> --- a/drivers/mfd/atmel-flexcom.c
>>>>>> +++ b/drivers/mfd/atmel-flexcom.c
>>>>>> @@ -28,15 +28,68 @@
>>>>>> #define FLEX_MR_OPMODE(opmode) (((opmode) <<
>>>>> FLEX_MR_OPMODE_OFFSET) & \
>>>>>> FLEX_MR_OPMODE_MASK)
>>>>>> +/* LAN966x flexcom shared register offsets */
>>>>>> +#define FLEX_SHRD_SS_MASK_0 0x0
>>>>>> +#define FLEX_SHRD_SS_MASK_1 0x4
>>>>>> +#define FLEX_SHRD_PIN_MAX 20
>>>>>> +#define FLEX_CS_MAX 1
>>>>>> +#define FLEX_SHRD_MASK GENMASK(20, 0)
>>>>>> +
>>>>>> +struct atmel_flex_caps {
>>>>>> + bool has_flx_cs;
>>>>>> +};
>>>>>> +
>>>>>> struct atmel_flexcom {
>>>>>> void __iomem *base;
>>>>>> + void __iomem *flexcom_shared_base;
>>>>>> u32 opmode;
>>>>>> struct clk *clk;
>>>>>> };
>>>>>> +static int atmel_flexcom_lan966x_cs_config(struct platform_device
>>> *pdev)
>>>>>> +{
>>>>>> + struct atmel_flexcom *ddata = dev_get_drvdata(&pdev->dev);
>>>>>> + struct device_node *np = pdev->dev.of_node;
>>>>>> + u32 flx_shrd_pins[2], flx_cs[2], val;
>>>>>> + int err, i, count;
>>>>>> +
>>>>>> + count = of_property_count_u32_elems(np, "microchip,flx-shrd-
>>>>> pins");
>>>>>> + if (count <= 0 || count > 2) {
>>>>>> + dev_err(&pdev->dev, "Invalid %s property (%d)\n", "flx-shrd-
>>>>> pins",
>>>>>> + count);
>>>>>> + return -EINVAL;
>>>>>> + }
>>>>>> +
>>>>>> + err = of_property_read_u32_array(np, "microchip,flx-shrd-pins",
>>>>> flx_shrd_pins, count);
>>>>>> + if (err)
>>>>>> + return err;
>>>>>> +
>>>>>> + err = of_property_read_u32_array(np, "microchip,flx-cs", flx_cs,
>>>>> count);
>>>>>> + if (err)
>>>>>> + return err;
>>>>>> +
>>>>>> + for (i = 0; i < count; i++) {
>>>>>> + if (flx_shrd_pins[i] > FLEX_SHRD_PIN_MAX)
>>>>>> + return -EINVAL;
>>>>>> +
>>>>>> + if (flx_cs[i] > FLEX_CS_MAX)
>>>>>> + return -EINVAL;
>>>>>> +
>>>>>> + val = ~(1 << flx_shrd_pins[i]) & FLEX_SHRD_MASK;
>>>>>> +
>>>>>> + if (flx_cs[i] == 0)
>>>>>> + writel(val, ddata->flexcom_shared_base +
>>>>> FLEX_SHRD_SS_MASK_0);
>>>>>> + else
>>>>>> + writel(val, ddata->flexcom_shared_base +
>>>>> FLEX_SHRD_SS_MASK_1);
>>>>> There is still an open question on this topic from previous version.
>>>> https://lore.kernel.org/linux-arm-
>>> kernel/PH0PR11MB48724DE09A50D67F1EA9FBE092D89@...PR11MB4872.n
>>> amprd11.prod.outlook.com/
>>> "previous version" meant for me this the one at [1]... Another point that
>>> the versioning of this series is bad.
>>> The question was the following:
>>> "I may miss something but I don't see here the approach you introduced in
>>> [1]:
>>> + err = mux_control_select(flx_mux, args.args[0]);
>>> + if (!err) {
>>> + mux_control_deselect(flx_mux);
>>> "
>>> As I had in mind that you said you need mux_control_deselect() because
>>> your
>>> serial remain blocked otherwise (but I don't find that in the comments of
>>> [1]). And I don't see something similar to mux_control_deselect() being
>>> called in this patch.
>>> [1]
>>> https://lore.kernel.org/linux-arm-kernel/5f9fcc33-cc0f-c404-cf7f-
>>> cb73f60154ff@...rochip.com/
>>>> As part of comments from Peter Rosin - Instead of using mux driver, This
>>> patch is introducing
>>>> new dt-properties in atmel-flexom driver itlself to configure Flexcom
>>> shared registers.
>>>> Based on the chip-select(0 or 1) to be mapped to flexcom shared pin, write
>>> to the
>>>> respective register.
>>>> If you still have any questions, please comment.
>> https://lore.kernel.org/linux-arm-kernel/PH0PR11MB48724DE09A50D67F1EA9FBE092D89@PH0PR11MB4872.namprd11.prod.outlook.com/
>> To avoid confusion, I stopped continuing with above patch versioning(mux driver approach).
>> I started new patch series in which I am configuring FLEXCOM_SHARED[0-4]:SS_MASK[0-1]
>> registers in atmel-flexcom.c driver using new DT-properties, mux driver approach is no more followed
>> as suggested by Peter Rosin:
>> "
>>> If you are content with just programming a fixed set of values to
>>> a couple of registers depending on how the board is wired, some
>>> extra DT property on some node related to the flexcom seems like
>>> a better fit than a mux driver.
>> Based on your inputs, I planned to send a new patch with new DT properties
>> introduced in atmel-flexcom.c driver rather than mux driver.
>>
>> Thanks,
>> Kavya
>> "
>>
>> Thanks,
>> Kavya
>
> Hi Claudiu,
>
> Please let me know if you still have any comments. If not, I will send my v3 with clk_disable_unprepare moved to goto and some minor fixes(irq flags) in dt-bindings.
I got it now after the talk we had on internal chat. Please go with v3.
Thank you,
Claudiu Beznea
>
>>>>>> + }
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> static int atmel_flexcom_probe(struct platform_device *pdev)
>>>>>> {
>>>>>> struct device_node *np = pdev->dev.of_node;
>>>>>> + const struct atmel_flex_caps *caps;
>>>>>> struct resource *res;
>>>>>> struct atmel_flexcom *ddata;
>>>>>> int err;
>>>>>> @@ -76,13 +129,51 @@ static int atmel_flexcom_probe(struct
>>>>> platform_device *pdev)
>>>>>> */
>>>>>> writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base +
>>>>> FLEX_MR);
>>>>>> + caps = of_device_get_match_data(&pdev->dev);
>>>>>> + if (!caps) {
>>>>>> + dev_err(&pdev->dev, "Could not retrieve flexcom caps\n");
>>>>>> + clk_disable_unprepare(ddata->clk);
>>>>> Could you keep a common path to disable the clock? A goto label
>>> something
>>>>> like this:
>>>>> ret = -EINVAL;
>>>>> got clk_disable_unprepare;
>>>>>> + return -EINVAL;
>>>>>> + }
>>>>>> +
>>>>>> + if (caps->has_flx_cs) {
>>>>>> + ddata->flexcom_shared_base =
>>>>> devm_platform_get_and_ioremap_resource(pdev, 1, NULL);
>>>>>> + if (IS_ERR(ddata->flexcom_shared_base)) {
>>>>>> + clk_disable_unprepare(ddata->clk);
>>>>>> + return dev_err_probe(&pdev->dev,
>>>>>> + PTR_ERR(ddata-
>>>>>> flexcom_shared_base),
>>>>>> + "failed to get flexcom shared base
>>>>> address\n");
>>>>> ret = dev_err_probe(...);
>>>>> goto clk_disable_unprepare;
>>>>>> + }
>>>>>> +
>>>>>> + err = atmel_flexcom_lan966x_cs_config(pdev);
>>>>>> + if (err) {
>>>>>> + clk_disable_unprepare(ddata->clk);
>>>>>> + return err;
>>>>> goto clk_disable_unprepare;
>>>>>> + }
>>>>>> + }
>>>>>> +
>>>>> clk_unprepare:
>>>>>> clk_disable_unprepare(ddata->clk);
>>>>> if (ret)
>>>>> return ret;
>>>>>> return devm_of_platform_populate(&pdev->dev);
>>>>>> }
>>>>>> +static const struct atmel_flex_caps atmel_flexcom_caps = {};
>>>>>> +
>>>>>> +static const struct atmel_flex_caps lan966x_flexcom_caps = {
>>>>>> + .has_flx_cs = true,
>>>>>> +};
>>>>>> +
>>>>>> static const struct of_device_id atmel_flexcom_of_match[] = {
>>>>>> - { .compatible = "atmel,sama5d2-flexcom" },
>>>>>> + {
>>>>>> + .compatible = "atmel,sama5d2-flexcom",
>>>>>> + .data = &atmel_flexcom_caps,
>>>>>> + },
>>>>>> +
>>>>>> + {
>>>>>> + .compatible = "microchip,lan966x-flexcom",
>>>>>> + .data = &lan966x_flexcom_caps,
>>>>>> + },
>>>>>> +
>>>>>> { /* sentinel */ }
>>>>>> };
>>>>>> MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
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