Re: [PATCH 1/7] staging:iio:ade7854: Rework I2C write function

[Rodrigo Siqueira]

Hi,

I will fixes all of these things here and in the other patches and send a
v2.

Thanks for the review.

On 03/15, Dan Carpenter wrote:
> On Wed, Mar 14, 2018 at 03:10:18PM -0300, Rodrigo Siqueira wrote:
> > The write operation using I2C has many code duplications and four
> > different interfaces per data size. This patch introduces a single
> > function that centralizes the main tasks.
> > 
> > The central function inserted by this patch can easily replace all the
> > four functions related to the data size. However, this patch does not
> > remove any code signature for keeping the meter module work and make
> > easier to review this patch.
> > 
> > Signed-off-by: Rodrigo Siqueira <rodrigosiqueiramelo@xxxxxxxxx>
> > ---
> >  drivers/staging/iio/meter/ade7854-i2c.c | 89 +++++++++++++++++++--------------
> >  drivers/staging/iio/meter/ade7854.h     |  7 +++
> >  2 files changed, 58 insertions(+), 38 deletions(-)
> > 
> > diff --git a/drivers/staging/iio/meter/ade7854-i2c.c b/drivers/staging/iio/meter/ade7854-i2c.c
> > index 317e4f0d8176..03133a05eae4 100644
> > --- a/drivers/staging/iio/meter/ade7854-i2c.c
> > +++ b/drivers/staging/iio/meter/ade7854-i2c.c
> > @@ -15,41 +15,74 @@
> >  #include <linux/iio/iio.h>
> >  #include "ade7854.h"
> >  
> > -static int ade7854_i2c_write_reg_8(struct device *dev,
> > -				   u16 reg_address,
> > -				   u8 val)
> > +static int ade7854_i2c_write_reg(struct device *dev,
> > +				 u16 reg_address,
> > +				 u32 val,
> > +				 enum data_size type)
> 
> 
> The data size should just be the number of bytes and not an enum.
> 1 means 1 byte / 8 bits.
> 2 means 2 bytes / 16 bits.
> 3 means 3 bytes / 24 bits.
> etc.
> 
> >  {
> >  	int ret;
> > +	int count;
> >  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> >  	struct ade7854_state *st = iio_priv(indio_dev);
> >  
> >  	mutex_lock(&st->buf_lock);
> >  	st->tx[0] = (reg_address >> 8) & 0xFF;
> >  	st->tx[1] = reg_address & 0xFF;
> > -	st->tx[2] = val;
> >  
> > -	ret = i2c_master_send(st->i2c, st->tx, 3);
> > +	switch (type) {
> > +	case DATA_SIZE_8_BITS:
> > +		st->tx[2] = val & 0xFF;
> > +		count = 3;
> > +		break;
> > +	case DATA_SIZE_16_BITS:
> > +		st->tx[2] = (val >> 8) & 0xFF;
> > +		st->tx[3] = val & 0xFF;
> > +		count = 4;
> > +		break;
> > +	case DATA_SIZE_24_BITS:
> > +		st->tx[2] = (val >> 16) & 0xFF;
> > +		st->tx[3] = (val >> 8) & 0xFF;
> > +		st->tx[4] = val & 0xFF;
> > +		count = 5;
> > +		break;
> > +	case DATA_SIZE_32_BITS:
> > +		st->tx[2] = (val >> 24) & 0xFF;
> > +		st->tx[3] = (val >> 16) & 0xFF;
> > +		st->tx[4] = (val >> 8) & 0xFF;
> > +		st->tx[5] = val & 0xFF;
> > +		count = 6;
> > +		break;
> > +	default:
> > +		ret = -EINVAL;
> > +		goto error_i2c_write_unlock;
> > +	}
> > +
> > +	ret = i2c_master_send(st->i2c, st->tx, count);
> > +
> > +error_i2c_write_unlock:
> 
> These labels are sort of long.  And what does the "i2c_write" really
> mean?  It should be obvious that we're not jumping to a different
> function.
> 
> Just "unlock:" is OK as a label name.
> 
> >  	mutex_unlock(&st->buf_lock);
> >  
> >  	return ret;
> >  }
> >  
> > +static int ade7854_i2c_write_reg_8(struct device *dev,
> > +				   u16 reg_address,
> > +				   u8 val)
> > +{
> > +	int ret;
> > +
> > +	ret = ade7854_i2c_write_reg(dev, reg_address, val, DATA_SIZE_8_BITS);
> > +
> > +	return ret;
> > +}
> 
> Just do it like this:
> 
> static int ade7854_i2c_write_reg_8(struct device *dev, u16 reg_address, u8 val)
> {
> 	return ade7854_i2c_write_reg(dev, reg_address, val, DATA_SIZE_8_BITS);
> }
> 
> 
> 
> > +
> >  static int ade7854_i2c_write_reg_16(struct device *dev,
> >  				    u16 reg_address,
> >  				    u16 val)
> >  {
> >  	int ret;
> > -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > -	struct ade7854_state *st = iio_priv(indio_dev);
> >  
> > -	mutex_lock(&st->buf_lock);
> > -	st->tx[0] = (reg_address >> 8) & 0xFF;
> > -	st->tx[1] = reg_address & 0xFF;
> > -	st->tx[2] = (val >> 8) & 0xFF;
> > -	st->tx[3] = val & 0xFF;
> > -
> > -	ret = i2c_master_send(st->i2c, st->tx, 4);
> > -	mutex_unlock(&st->buf_lock);
> > +	ret = ade7854_i2c_write_reg(dev, reg_address, val, DATA_SIZE_16_BITS);
> >  
> >  	return ret;
> 
> Again:
> 
> 	return ade7854_i2c_write_reg(dev, reg_address, val, DATA_SIZE_16_BITS);
> 
> 
> 
> >  }
> > @@ -59,18 +92,8 @@ static int ade7854_i2c_write_reg_24(struct device *dev,
> >  				    u32 val)
> >  {
> >  	int ret;
> > -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > -	struct ade7854_state *st = iio_priv(indio_dev);
> >  
> > -	mutex_lock(&st->buf_lock);
> > -	st->tx[0] = (reg_address >> 8) & 0xFF;
> > -	st->tx[1] = reg_address & 0xFF;
> > -	st->tx[2] = (val >> 16) & 0xFF;
> > -	st->tx[3] = (val >> 8) & 0xFF;
> > -	st->tx[4] = val & 0xFF;
> > -
> > -	ret = i2c_master_send(st->i2c, st->tx, 5);
> > -	mutex_unlock(&st->buf_lock);
> > +	ret = ade7854_i2c_write_reg(dev, reg_address, val, DATA_SIZE_24_BITS);
> >  
> >  	return ret;
> 
> Same.
> 
> >  }
> > @@ -80,23 +103,13 @@ static int ade7854_i2c_write_reg_32(struct device *dev,
> >  				    u32 val)
> >  {
> >  	int ret;
> > -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > -	struct ade7854_state *st = iio_priv(indio_dev);
> > -
> > -	mutex_lock(&st->buf_lock);
> > -	st->tx[0] = (reg_address >> 8) & 0xFF;
> > -	st->tx[1] = reg_address & 0xFF;
> > -	st->tx[2] = (val >> 24) & 0xFF;
> > -	st->tx[3] = (val >> 16) & 0xFF;
> > -	st->tx[4] = (val >> 8) & 0xFF;
> > -	st->tx[5] = val & 0xFF;
> >  
> > -	ret = i2c_master_send(st->i2c, st->tx, 6);
> > -	mutex_unlock(&st->buf_lock);
> > +	ret = ade7854_i2c_write_reg(dev, reg_address, val, DATA_SIZE_32_BITS);
> >  
> >  	return ret;
> 
> Same.
> 
> >  }
> >  
> > +
> 
> Checkpatch.pl will complain about this second blank line.
> 
> regards,
> dan carpenter
>