Re: [PATCH 8/9] rtc-pcf2123: use sysfs groups

[Joshua Clayton <stillcompiling@gmail.com>]

On Wed, 25 Nov 2015 00:31:01 +0100
Alexandre Belloni <alexandre.belloni@free-electrons.com> wrote:

> Hi,
> 
> This is okay but I'm not actually sure about the usefulness of that
> interface. The driver is exactly here to abstract access to the
> registers. Limit it to registers that are not used by the driver?
> Also, It would probably better live in debugfs rather than in sysfs.
> 

I agree completely... can I do that? Can I just move them to debugfs or
remove them?
I ask because these sysfs register files are in mainline already, and
I know removing user facing kernel features is usually frowned on.

> On 04/11/2015 at 07:36:39 -0800, Joshua Clayton wrote :
> > Switch from manually creating all the sysfs attributes to
> > defining them mostly in the canonical way.
> > We are adding them to an spi driver, so we must still add and remove
> > the group manually, but everythig else is done by The Book(tm) .
> > 
> > Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
> > ---
> >  drivers/rtc/rtc-pcf2123.c | 118
> > +++++++++++++++++++++------------------------- 1 file changed, 55
> > insertions(+), 63 deletions(-)
> > 
> > diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
> > index 6701e6d..d494638 100644
> > --- a/drivers/rtc/rtc-pcf2123.c
> > +++ b/drivers/rtc/rtc-pcf2123.c
> > @@ -84,16 +84,6 @@
> >  
> >  static struct spi_driver pcf2123_driver;
> >  
> > -struct pcf2123_sysfs_reg {
> > -	struct device_attribute attr;
> > -	char name[2];
> > -};
> > -
> > -struct pcf2123_plat_data {
> > -	struct rtc_device *rtc;
> > -	struct pcf2123_sysfs_reg regs[16];
> > -};
> > -
> >  /*
> >   * Causes a 30 nanosecond delay to ensure that the PCF2123 chip
> > select
> >   * is released properly after an SPI write.  This function should
> > be @@ -146,17 +136,11 @@ static int pcf2123_write_reg(struct device
> > *dev, u8 reg, u8 val) static ssize_t pcf2123_show(struct device
> > *dev, struct device_attribute *attr, char *buffer)
> >  {
> > -	struct pcf2123_sysfs_reg *r;
> >  	u8 rxbuf[1];
> >  	unsigned long reg;
> >  	int ret;
> >  
> > -	r = container_of(attr, struct pcf2123_sysfs_reg, attr);
> > -
> > -	ret = kstrtoul(r->name, 16, &reg);
> > -	if (ret)
> > -		return ret;
> > -
> > +	reg = hex_to_bin(attr->attr.name[0]);
> >  	ret = pcf2123_read(dev, reg, rxbuf, 1);
> >  	if (ret < 0)
> >  		return -EIO;
> > @@ -166,25 +150,19 @@ static ssize_t pcf2123_show(struct device
> > *dev, struct device_attribute *attr, 
> >  static ssize_t pcf2123_store(struct device *dev, struct
> > device_attribute *attr, const char *buffer, size_t count) {
> > -	struct pcf2123_sysfs_reg *r;
> >  	unsigned long reg;
> >  	unsigned long val;
> > -
> >  	int ret;
> >  
> > -	r = container_of(attr, struct pcf2123_sysfs_reg, attr);
> > -
> > -	ret = kstrtoul(r->name, 16, &reg);
> > -	if (ret)
> > -		return ret;
> > -
> >  	ret = kstrtoul(buffer, 0, &val);
> >  	if (ret)
> >  		return ret;
> >  
> > +	reg = hex_to_bin(attr->attr.name[0]);
> >  	pcf2123_write_reg(dev, reg, val);
> >  	if (ret < 0)
> >  		return -EIO;
> > +
> >  	return count;
> >  }
> >  
> > @@ -326,17 +304,56 @@ static const struct rtc_class_ops
> > pcf2123_rtc_ops = { .set_time	= pcf2123_rtc_set_time,
> >  };
> >  
> > +static DEVICE_ATTR(0, S_IRUGO | S_IWUSR, pcf2123_show,
> > pcf2123_store); +static DEVICE_ATTR(1, S_IRUGO | S_IWUSR,
> > pcf2123_show, pcf2123_store); +static DEVICE_ATTR(2, S_IRUGO |
> > S_IWUSR, pcf2123_show, pcf2123_store); +static DEVICE_ATTR(3,
> > S_IRUGO | S_IWUSR, pcf2123_show, pcf2123_store); +static
> > DEVICE_ATTR(4, S_IRUGO | S_IWUSR, pcf2123_show, pcf2123_store);
> > +static DEVICE_ATTR(5, S_IRUGO | S_IWUSR, pcf2123_show,
> > pcf2123_store); +static DEVICE_ATTR(6, S_IRUGO | S_IWUSR,
> > pcf2123_show, pcf2123_store); +static DEVICE_ATTR(7, S_IRUGO |
> > S_IWUSR, pcf2123_show, pcf2123_store); +static DEVICE_ATTR(8,
> > S_IRUGO | S_IWUSR, pcf2123_show, pcf2123_store); +static
> > DEVICE_ATTR(9, S_IRUGO | S_IWUSR, pcf2123_show, pcf2123_store);
> > +static DEVICE_ATTR(a, S_IRUGO | S_IWUSR, pcf2123_show,
> > pcf2123_store); +static DEVICE_ATTR(b, S_IRUGO | S_IWUSR,
> > pcf2123_show, pcf2123_store); +static DEVICE_ATTR(c, S_IRUGO |
> > S_IWUSR, pcf2123_show, pcf2123_store); +static DEVICE_ATTR(d,
> > S_IRUGO | S_IWUSR, pcf2123_show, pcf2123_store); +static
> > DEVICE_ATTR(e, S_IRUGO | S_IWUSR, pcf2123_show, pcf2123_store);
> > +static DEVICE_ATTR(f, S_IRUGO | S_IWUSR, pcf2123_show,
> > pcf2123_store); + +static struct attribute *pcf2123_attrs[] = {
> > +	&dev_attr_0.attr,
> > +	&dev_attr_1.attr,
> > +	&dev_attr_2.attr,
> > +	&dev_attr_3.attr,
> > +	&dev_attr_4.attr,
> > +	&dev_attr_5.attr,
> > +	&dev_attr_6.attr,
> > +	&dev_attr_7.attr,
> > +	&dev_attr_8.attr,
> > +	&dev_attr_9.attr,
> > +	&dev_attr_a.attr,
> > +	&dev_attr_b.attr,
> > +	&dev_attr_c.attr,
> > +	&dev_attr_d.attr,
> > +	&dev_attr_e.attr,
> > +	&dev_attr_f.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group pcf2123_group = {
> > +	.attrs = pcf2123_attrs,
> > +};
> > +
> > +static const struct attribute_group *pcf2123_groups[] = {
> > +	&pcf2123_group,
> > +	NULL
> > +};
> > +
> >  static int pcf2123_probe(struct spi_device *spi)
> >  {
> >  	struct rtc_device *rtc;
> > -	struct pcf2123_plat_data *pdata;
> > -	int ret, i;
> > -
> > -	pdata = devm_kzalloc(&spi->dev, sizeof(struct
> > pcf2123_plat_data),
> > -				GFP_KERNEL);
> > -	if (!pdata)
> > -		return -ENOMEM;
> > -	spi->dev.platform_data = pdata;
> > +	int ret;
> >  
> >  	if (!pcf2123_time_valid(&spi->dev)) {
> >  		ret = pcf2123_reset(&spi->dev);
> > @@ -360,29 +377,13 @@ static int pcf2123_probe(struct spi_device
> > *spi) goto kfree_exit;
> >  	}
> >  
> > -	pdata->rtc = rtc;
> > -
> > -	for (i = 0; i < 16; i++) {
> > -		sysfs_attr_init(&pdata->regs[i].attr.attr);
> > -		sprintf(pdata->regs[i].name, "%1x", i);
> > -		pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
> > -		pdata->regs[i].attr.attr.name =
> > pdata->regs[i].name;
> > -		pdata->regs[i].attr.show = pcf2123_show;
> > -		pdata->regs[i].attr.store = pcf2123_store;
> > -		ret = device_create_file(&spi->dev,
> > &pdata->regs[i].attr);
> > -		if (ret) {
> > -			dev_err(&spi->dev, "Unable to create sysfs
> > %s\n",
> > -				pdata->regs[i].name);
> > -			goto sysfs_exit;
> > -		}
> > -	}
> > +	ret = sysfs_create_groups(&spi->dev.kobj, pcf2123_groups);
> > +	if (ret)
> > +		goto sysfs_exit;
> >  
> >  	return 0;
> > -
> >  sysfs_exit:
> > -	for (i--; i >= 0; i--)
> > -		device_remove_file(&spi->dev,
> > &pdata->regs[i].attr); -
> > +	sysfs_remove_groups(&spi->dev.kobj, pcf2123_groups);
> >  kfree_exit:
> >  	spi->dev.platform_data = NULL;
> >  	return ret;
> > @@ -390,16 +391,7 @@ kfree_exit:
> >  
> >  static int pcf2123_remove(struct spi_device *spi)
> >  {
> > -	struct pcf2123_plat_data *pdata =
> > dev_get_platdata(&spi->dev);
> > -	int i;
> > -
> > -	if (pdata) {
> > -		for (i = 0; i < 16; i++)
> > -			if (pdata->regs[i].name[0])
> > -				device_remove_file(&spi->dev,
> > -
> > &pdata->regs[i].attr);
> > -	}
> > -
> > +	sysfs_remove_groups(&spi->dev.kobj, pcf2123_groups);
> >  	return 0;
> >  }
> >  
> > -- 
> > 2.5.0
> > 
>