linux-kernel - Re: [PATCH v3] mfd: Add support for Merrifield Basin Cove PMIC

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Message-ID: <20190626092601.GH9224@smile.fi.intel.com>
Date:   Wed, 26 Jun 2019 12:26:01 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] mfd: Add support for Merrifield Basin Cove PMIC

On Mon, Jun 24, 2019 at 05:13:48PM +0100, Lee Jones wrote:
> On Wed, 12 Jun 2019, Andy Shevchenko wrote:
> 
> > Add an MFD driver for Intel Merrifield Basin Cove PMIC.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
> > - updated copyright year to be 2019
> > - rebased on top of latest vanilla rc
> > 
> >  drivers/mfd/Kconfig                      |  11 ++
> >  drivers/mfd/Makefile                     |   1 +
> >  drivers/mfd/intel_soc_pmic_mrfld.c       | 157 +++++++++++++++++++++++
> >  include/linux/mfd/intel_soc_pmic_mrfld.h |  81 ++++++++++++
> >  4 files changed, 250 insertions(+)
> >  create mode 100644 drivers/mfd/intel_soc_pmic_mrfld.c
> >  create mode 100644 include/linux/mfd/intel_soc_pmic_mrfld.h
> 
> [...]
> 
> > +static int bcove_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct intel_soc_pmic *pmic;
> > +	unsigned int i;
> > +	int ret;
> > +
> > +	pmic = devm_kzalloc(dev, sizeof(*pmic), GFP_KERNEL);
> > +	if (!pmic)
> > +		return -ENOMEM;
> > +
> > +	platform_set_drvdata(pdev, pmic);
> > +	pmic->dev = &pdev->dev;
> > +
> > +	pmic->regmap = devm_regmap_init(dev, NULL, pmic, &bcove_regmap_config);
> > +	if (IS_ERR(pmic->regmap))
> > +		return PTR_ERR(pmic->regmap);
> > +
> > +	for (i = 0; i < ARRAY_SIZE(irq_level2_resources); i++) {
> > +		ret = platform_get_irq(pdev, i);
> 
> If you already know the order, define the children's device IDs in the
> parent's shared header ('intel_soc_pmic_mrfld.h'?) and retreive them
> like:
> 
>   platform_get_irq(pdev->parent, <SUITABLE_DEFINED_ID>);
> 
> Then you can skip all of this platform device -> platform device hoop
> jumping.

The idea of MFD is to get children to be parent agnostic
(at least to some extent). What you are proposing here
seems like disadvantage from MFD philosophy. No?


-- 
With Best Regards,
Andy Shevchenko