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SubjectRe: [PATCH v2 3/3] mfd: atmel-flexcom: Add support for lan966x flexcom chip-select configuration
Date
On 08.06.2022 11:20, 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@microchip.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@PH0PR11MB4872.namprd11.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@microchip.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.
>
>>> + }
>>> +
>>> + 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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