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SubjectRe: [PATCH] mfd: qcom-spmi-pmic: Add support for more chips versions
On 11/6/2014 12:54 AM, Ivan T. Ivanov wrote:
> On Wed, 2014-11-05 at 17:36 -0800, Bjorn Andersson wrote:
>> On Wed, Nov 5, 2014 at 10:31 AM, Ivan T. Ivanov <iivanov@mm-sol.com> wrote:
>>> On Wed, 2014-11-05 at 10:11 -0800, Bjorn Andersson wrote:
>>>> On Tue, Nov 4, 2014 at 5:33 AM, Ivan T. Ivanov <iivanov@mm-sol.com>
>>>> wrote:
>>>> [..]
>>>>> @@ -28,11 +144,27 @@ static int pmic_spmi_probe(struct spmi_device
>>>>> *sdev)
>>>>> {
>>>>> struct device_node *root = sdev->dev.of_node;
>>>>> struct regmap *regmap;
>>>>> + struct property *prop;
>>>>> + int major, minor, ret;
>>>>> + char *name, compatible[32];
>>>>>
>>>>> regmap = devm_regmap_init_spmi_ext(sdev,
>>>>> &spmi_regmap_config);
Hi Ivan, I have a general question about this driver/layer.
Since the driver is using regmap, why does it need to be
qcom-*spmi*-pmic ? could we drop the spmi part?
regmap's point is abstraction of the bus technology, and indeed some
PMICs use i2c.

>>>>> if (IS_ERR(regmap))
>>>>> return PTR_ERR(regmap);
>>>>>
>>>>> + ret = pmic_spmi_read_revid(regmap, &name, &major, &minor);
>>>>> + if (!ret) {
>>>>> + snprintf(compatible, ARRAY_SIZE(compatible),
>>>>> "qcom,%s-v%d.%d",
>>>>> + name, major, minor);
>>>>> + prop = kzalloc(sizeof(*prop), GFP_KERNEL);
>>>>> + if (prop) {
>>>>> + prop->name = kstrdup("compatible",
>>>>> GFP_KERNEL);
>>>>> + prop->value = kstrdup(compatible,
>>>>> GFP_KERNEL);
>>>>> + prop->length = strlen(prop->value);
>>>>> + of_update_property(root, prop);
>>>>> + }
>>>>> + }
>>>>> +
>>>> Why would you do this?
>>>> What benefit does it give to patch the of_node to have a more
>>>> specific
>>>> compatible?
>>> Some of the child device drivers have to know PMIC chip revision.
>>>
>> So your plan is to have a strstr(parent->compatible, "-v2") there?
> Actually also PMIC subtype (pm8841, pm8226...) is also required, so
> the plan is to have something like this:
>
> {
> static const struct of_device_id pmic_match_table[] = {
> { .compatible = "qcom,pm8941-v1.0" },
> { .compatible = "qcom,pm8841-v0.0" },
> { }
>
> };
>
> const struct of_device_id *match;
>
> match = of_match_device(pmic_match_table, pdev->dev.parent);
> if (match) {
> dev_info(&pdev->dev, "%s chip detected\n", match->compatible);
> }
> }
>
>> Could you be a little bit more elaborate on what you're trying to do
>> and which child devices that might be?
> For example ADC drivers are required temperature compensation based
> on PMIC variant and chip manufacturer.
>
> This patch have one issue, at least :-). Using of_update_property will prevent
> driver to be build as module. which, I think, is coming from the fact the
> on first load it will modify device compatible property and will be impossible
> driver to match device id again. Still thinking how to overcome this.
>
> Regards,
> Ivan
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--
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project



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