Re: [PATCH v3 11/12] mfd: bd9571mwv: Make the driver more generic

[Vaittinen, Matti]

On Wed, 2020-12-16 at 10:25 +0200, Matti Vaittinen wrote:
> On Wed, 2020-12-16 at 16:37 +0900, Yoshihiro Shimoda wrote:
> > From: Khiem Nguyen <khiem.nguyen.xt@xxxxxxxxxxx>
> > 
> > Since the driver supports BD9571MWV PMIC only,
> > this patch makes the functions and data structure become more
> > generic
> > so that it can support other PMIC variants as well.
> > 
> > Signed-off-by: Khiem Nguyen <khiem.nguyen.xt@xxxxxxxxxxx>
> > [shimoda: rebase and refactor]
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> 
> Reviewed-by: Matti Vaittinen <matti.vaittinen@xxxxxxxxxxxxxxxxx>
> 
> > ---
> >  drivers/mfd/bd9571mwv.c       | 95 +++++++++++++++++++++++++++----
> > ------------
> >  include/linux/mfd/bd9571mwv.h | 18 ++------
> >  2 files changed, 63 insertions(+), 50 deletions(-)
> > 
> > diff --git a/drivers/mfd/bd9571mwv.c b/drivers/mfd/bd9571mwv.c
> > index 49e968e..ccf1a60 100644
> > --- a/drivers/mfd/bd9571mwv.c
> > +++ b/drivers/mfd/bd9571mwv.c
> > @@ -3,6 +3,7 @@
> >   * ROHM BD9571MWV-M MFD driver
> >   *
> >   * Copyright (C) 2017 Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
> > + * Copyright (C) 2020 Renesas Electronics Corporation
> >   *
> >   * Based on the TPS65086 driver
> >   */
> > @@ -14,6 +15,19 @@
> >  
> >  #include <linux/mfd/bd9571mwv.h>
> >  
> > +/**
> > + * struct bd957x_data - internal data for the bd957x driver
> > + *
> > + * Internal data to distinguish bd957x variants
> > + */
> > +struct bd957x_data {
> > +	char *part_name;
> > +	const struct regmap_config *regmap_config;
> > +	const struct regmap_irq_chip *irq_chip;
> > +	const struct mfd_cell *cells;
> > +	int num_cells;
> > +};
> > +
> 
> I do like the way you placed the variant data in owns structs. Well
> thought.
> 
> >  static const struct mfd_cell bd9571mwv_cells[] = {
> >  	{ .name = "bd9571mwv-regulator", },
> >  	{ .name = "bd9571mwv-gpio", },
> > @@ -102,13 +116,21 @@ static struct regmap_irq_chip
> > bd9571mwv_irq_chip = {
> >  	.num_irqs	= ARRAY_SIZE(bd9571mwv_irqs),
> >  };
> >  
> > -static int bd9571mwv_identify(struct bd9571mwv *bd)
> > +static const struct bd957x_data bd9571mwv_data = {
> > +	.part_name = BD9571MWV_PART_NAME,
> > +	.regmap_config = &bd9571mwv_regmap_config,
> > +	.irq_chip = &bd9571mwv_irq_chip,
> > +	.cells = bd9571mwv_cells,
> > +	.num_cells = ARRAY_SIZE(bd9571mwv_cells),
> > +};
> > +
> > +static int bd9571mwv_identify(struct device *dev, struct regmap
> > *regmap,
> > +			      const char *part_name)
> >  {
> > -	struct device *dev = bd->dev;
> >  	unsigned int value;
> >  	int ret;
> >  
> > -	ret = regmap_read(bd->regmap, BD9571MWV_VENDOR_CODE, &value);
> > +	ret = regmap_read(regmap, BD9571MWV_VENDOR_CODE, &value);
> >  	if (ret) {
> >  		dev_err(dev, "Failed to read vendor code register
> > (ret=%i)\n",
> >  			ret);
> > @@ -121,27 +143,20 @@ static int bd9571mwv_identify(struct
> > bd9571mwv
> > *bd)
> >  		return -EINVAL;
> >  	}
> >  
> > -	ret = regmap_read(bd->regmap, BD9571MWV_PRODUCT_CODE, &value);
> > +	ret = regmap_read(regmap, BD9571MWV_PRODUCT_CODE, &value);
> >  	if (ret) {
> >  		dev_err(dev, "Failed to read product code register
> > (ret=%i)\n",
> >  			ret);
> >  		return ret;
> >  	}
> > -
> > -	if (value != BD9571MWV_PRODUCT_CODE_VAL) {
> > -		dev_err(dev, "Invalid product code ID %02x (expected
> > %02x)\n",
> > -			value, BD9571MWV_PRODUCT_CODE_VAL);
> > -		return -EINVAL;
> > -	}
> > -
> > -	ret = regmap_read(bd->regmap, BD9571MWV_PRODUCT_REVISION,
> > &value);
> > +	ret = regmap_read(regmap, BD9571MWV_PRODUCT_REVISION, &value);
> >  	if (ret) {
> >  		dev_err(dev, "Failed to read revision register
> > (ret=%i)\n",
> >  			ret);
> >  		return ret;
> >  	}
> >  
> > -	dev_info(dev, "Device: BD9571MWV rev. %d\n", value & 0xff);
> > +	dev_info(dev, "Device: %s rev. %d\n", part_name, value & 0xff);
> >  
> >  	return 0;
> >  }
> > @@ -149,38 +164,48 @@ static int bd9571mwv_identify(struct
> > bd9571mwv
> > *bd)
> >  static int bd9571mwv_probe(struct i2c_client *client,
> >  			  const struct i2c_device_id *ids)
> >  {
> > -	struct bd9571mwv *bd;
> > -	int ret;
> > -
> > -	bd = devm_kzalloc(&client->dev, sizeof(*bd), GFP_KERNEL);
> > -	if (!bd)
> > -		return -ENOMEM;
> > -
> > -	i2c_set_clientdata(client, bd);
> > -	bd->dev = &client->dev;
> > -	bd->irq = client->irq;
> > +	const struct bd957x_data *data;
> > +	struct device *dev = &client->dev;
> > +	struct regmap *regmap;
> > +	struct regmap_irq_chip_data *irq_data;
> > +	int ret, irq = client->irq;
> > +
> > +	/* Read the PMIC product code */
> > +	ret = i2c_smbus_read_byte_data(client, BD9571MWV_PRODUCT_CODE);
> 
> Having to use the i2c_smbus_read_byte_data for a device which is
> going
> to be used with regmap slightly bugs me. But as you want to do the
> runtime probing, then this access must be done prior regmap
> registration - so I can't think of a better way. :(

I just noticed that reading the product code is something one would
expect the bd9571mwv_identify() be doing. Now when you do read product
code already here, the additional value brought by bd9571mwv_identify()
is quite small. If you ever re-spin this, please consider if
bd9571mwv_identify() is actually usefull or if product code reading
should be done in that function - or if the usefull checks (if any)
from the identify() could be inlined here :)

Best Regards
    Matti Vaittinen