diff mbox series

iio: si1133: read 24 signed integer for measurement

Message ID 20200207160740.29508-1-maxime.roussinbelanger@gmail.com (mailing list archive)
State New, archived
Headers show
Series iio: si1133: read 24 signed integer for measurement | expand

Commit Message

Maxime Roussin-Bélanger Feb. 7, 2020, 4:07 p.m. UTC
The chip is configured in 24 bit mode. The values read from it must
always be treated as is. This fixes the issue by replacing the previous
16 bits value by a 24 bits buffer.

This changes affects the value output by previous version of the driver,
since the least significant byte was missing. The upper half of 16
bit values previously output are now the upper half of a 24 bit value.

Co-authored-by: Guillaume Champagne <champagne.guillaume.c@gmail.com>
Signed-off-by: Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com>
---
 drivers/iio/light/si1133.c | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

Comments

Jonathan Cameron Feb. 14, 2020, 2:22 p.m. UTC | #1
On Fri,  7 Feb 2020 11:07:40 -0500
Maxime Roussin-Bélanger         <maxime.roussinbelanger@gmail.com> wrote:

> The chip is configured in 24 bit mode. The values read from it must
> always be treated as is. This fixes the issue by replacing the previous
> 16 bits value by a 24 bits buffer.
> 
> This changes affects the value output by previous version of the driver,
> since the least significant byte was missing. The upper half of 16
> bit values previously output are now the upper half of a 24 bit value.
> 
> Co-authored-by: Guillaume Champagne <champagne.guillaume.c@gmail.com>
> Signed-off-by: Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com>
Patch looks fine, so question is whether we treat this as an enhancement,
or a fix? If it's a fix please provide a suitable fixes tag.

Thanks,

Jonathan

> ---
>  drivers/iio/light/si1133.c | 37 ++++++++++++++++++++++++-------------
>  1 file changed, 24 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/iio/light/si1133.c b/drivers/iio/light/si1133.c
> index 777b1a0848c9..509af982e185 100644
> --- a/drivers/iio/light/si1133.c
> +++ b/drivers/iio/light/si1133.c
> @@ -102,6 +102,9 @@
>  #define SI1133_INPUT_FRACTION_LOW	15
>  #define SI1133_LUX_OUTPUT_FRACTION	12
>  #define SI1133_LUX_BUFFER_SIZE		9
> +#define SI1133_MEASURE_BUFFER_SIZE	3
> +
> +#define SI1133_SIGN_BIT_INDEX 23
>  
>  static const int si1133_scale_available[] = {
>  	1, 2, 4, 8, 16, 32, 64, 128};
> @@ -234,13 +237,13 @@ static const struct si1133_lux_coeff lux_coeff = {
>  	}
>  };
>  
> -static int si1133_calculate_polynomial_inner(u32 input, u8 fraction, u16 mag,
> +static int si1133_calculate_polynomial_inner(s32 input, u8 fraction, u16 mag,
>  					     s8 shift)
>  {
>  	return ((input << fraction) / mag) << shift;
>  }
>  
> -static int si1133_calculate_output(u32 x, u32 y, u8 x_order, u8 y_order,
> +static int si1133_calculate_output(s32 x, s32 y, u8 x_order, u8 y_order,
>  				   u8 input_fraction, s8 sign,
>  				   const struct si1133_coeff *coeffs)
>  {
> @@ -276,7 +279,7 @@ static int si1133_calculate_output(u32 x, u32 y, u8 x_order, u8 y_order,
>   * The algorithm is from:
>   * https://siliconlabs.github.io/Gecko_SDK_Doc/efm32zg/html/si1133_8c_source.html#l00716
>   */
> -static int si1133_calc_polynomial(u32 x, u32 y, u8 input_fraction, u8 num_coeff,
> +static int si1133_calc_polynomial(s32 x, s32 y, u8 input_fraction, u8 num_coeff,
>  				  const struct si1133_coeff *coeffs)
>  {
>  	u8 x_order, y_order;
> @@ -614,23 +617,24 @@ static int si1133_measure(struct si1133_data *data,
>  {
>  	int err;
>  
> -	__be16 resp;
> +	u8 buffer[SI1133_MEASURE_BUFFER_SIZE];
>  
>  	err = si1133_set_adcmux(data, 0, chan->channel);
>  	if (err)
>  		return err;
>  
>  	/* Deactivate lux measurements if they were active */
>  	err = si1133_set_chlist(data, BIT(0));
>  	if (err)
>  		return err;
>  
> -	err = si1133_bulk_read(data, SI1133_REG_HOSTOUT(0), sizeof(resp),
> -			       (u8 *)&resp);
> +	err = si1133_bulk_read(data, SI1133_REG_HOSTOUT(0), sizeof(buffer),
> +			       buffer);
>  	if (err)
>  		return err;
>  
> -	*val = be16_to_cpu(resp);
> +	*val = sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
> +			     SI1133_SIGN_BIT_INDEX);
>  
>  	return err;
>  }
> @@ -704,9 +708,9 @@ static int si1133_get_lux(struct si1133_data *data, int *val)
>  {
>  	int err;
>  	int lux;
> -	u32 high_vis;
> -	u32 low_vis;
> -	u32 ir;
> +	s32 high_vis;
> +	s32 low_vis;
> +	s32 ir;
>  	u8 buffer[SI1133_LUX_BUFFER_SIZE];
>  
>  	/* Activate lux channels */
> @@ -719,9 +723,16 @@ static int si1133_get_lux(struct si1133_data *data, int *val)
>  	if (err)
>  		return err;
>  
> -	high_vis = (buffer[0] << 16) | (buffer[1] << 8) | buffer[2];
> -	low_vis = (buffer[3] << 16) | (buffer[4] << 8) | buffer[5];
> -	ir = (buffer[6] << 16) | (buffer[7] << 8) | buffer[8];
> +	high_vis =
> +		sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
> +			      SI1133_SIGN_BIT_INDEX);
> +
> +	low_vis =
> +		sign_extend32((buffer[3] << 16) | (buffer[4] << 8) | buffer[5],
> +			      SI1133_SIGN_BIT_INDEX);
> +
> +	ir = sign_extend32((buffer[6] << 16) | (buffer[7] << 8) | buffer[8],
> +			   SI1133_SIGN_BIT_INDEX);
>  
>  	if (high_vis > SI1133_ADC_THRESHOLD || ir > SI1133_ADC_THRESHOLD)
>  		lux = si1133_calc_polynomial(high_vis, ir,
Jonathan Cameron Feb. 14, 2020, 3:53 p.m. UTC | #2
On Fri, 14 Feb 2020 10:27:45 -0500
Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com> wrote:

> On Fri, Feb 14, 2020 at 9:22 AM Jonathan Cameron <jic23@kernel.org> wrote:
> >
> > On Fri,  7 Feb 2020 11:07:40 -0500
> > Maxime Roussin-Bélanger         <maxime.roussinbelanger@gmail.com> wrote:
> >  
> > > The chip is configured in 24 bit mode. The values read from it must
> > > always be treated as is. This fixes the issue by replacing the previous
> > > 16 bits value by a 24 bits buffer.
> > >
> > > This changes affects the value output by previous version of the driver,
> > > since the least significant byte was missing. The upper half of 16
> > > bit values previously output are now the upper half of a 24 bit value.
> > >
> > > Co-authored-by: Guillaume Champagne <champagne.guillaume.c@gmail.com>
> > > Signed-off-by: Maxime Roussin-Bélanger <maxime.roussinbelanger@gmail.com  
> >
> > Patch looks fine, so question is whether we treat this as an enhancement,
> > or a fix? If it's a fix please provide a suitable fixes tag.  
> 
> I'm not 100% of what fixes tag mean, but I assume it's something like
> 
> Tested-By: SomeoneTestedIt <TheDudeEmail@gmail.com>
Nope it identifies the point at which the issue was originally introduced.

See  Documentation/process/submitting-patches.rst

Jonathan

> 
> Am I correct?
> 
> Thanks,
> Max.
> 
> >
> > Thanks,
> >
> > Jonathan
> >  
> > > ---
> > >  drivers/iio/light/si1133.c | 37 ++++++++++++++++++++++++-------------
> > >  1 file changed, 24 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/drivers/iio/light/si1133.c b/drivers/iio/light/si1133.c
> > > index 777b1a0848c9..509af982e185 100644
> > > --- a/drivers/iio/light/si1133.c
> > > +++ b/drivers/iio/light/si1133.c
> > > @@ -102,6 +102,9 @@
> > >  #define SI1133_INPUT_FRACTION_LOW    15
> > >  #define SI1133_LUX_OUTPUT_FRACTION   12
> > >  #define SI1133_LUX_BUFFER_SIZE               9
> > > +#define SI1133_MEASURE_BUFFER_SIZE   3
> > > +
> > > +#define SI1133_SIGN_BIT_INDEX 23
> > >
> > >  static const int si1133_scale_available[] = {
> > >       1, 2, 4, 8, 16, 32, 64, 128};
> > > @@ -234,13 +237,13 @@ static const struct si1133_lux_coeff lux_coeff = {
> > >       }
> > >  };
> > >
> > > -static int si1133_calculate_polynomial_inner(u32 input, u8 fraction,  
> u16 mag,
> > > +static int si1133_calculate_polynomial_inner(s32 input, u8 fraction,  
> u16 mag,
> > >                                            s8 shift)
> > >  {
> > >       return ((input << fraction) / mag) << shift;
> > >  }
> > >
> > > -static int si1133_calculate_output(u32 x, u32 y, u8 x_order, u8  
> y_order,
> > > +static int si1133_calculate_output(s32 x, s32 y, u8 x_order, u8  
> y_order,
> > >                                  u8 input_fraction, s8 sign,
> > >                                  const struct si1133_coeff *coeffs)
> > >  {
> > > @@ -276,7 +279,7 @@ static int si1133_calculate_output(u32 x, u32 y, u8  
> x_order, u8 y_order,
> > >   * The algorithm is from:
> > >   *  
> https://siliconlabs.github.io/Gecko_SDK_Doc/efm32zg/html/si1133_8c_source.html#l00716
> > >   */
> > > -static int si1133_calc_polynomial(u32 x, u32 y, u8 input_fraction, u8  
> num_coeff,
> > > +static int si1133_calc_polynomial(s32 x, s32 y, u8 input_fraction, u8  
> num_coeff,
> > >                                 const struct si1133_coeff *coeffs)
> > >  {
> > >       u8 x_order, y_order;
> > > @@ -614,23 +617,24 @@ static int si1133_measure(struct si1133_data  
> *data,
> > >  {
> > >       int err;
> > >
> > > -     __be16 resp;
> > > +     u8 buffer[SI1133_MEASURE_BUFFER_SIZE];
> > >
> > >       err = si1133_set_adcmux(data, 0, chan->channel);
> > >       if (err)
> > >               return err;
> > >
> > >       /* Deactivate lux measurements if they were active */
> > >       err = si1133_set_chlist(data, BIT(0));
> > >       if (err)
> > >               return err;
> > >
> > > -     err = si1133_bulk_read(data, SI1133_REG_HOSTOUT(0), sizeof(resp),
> > > -                            (u8 *)&resp);
> > > +     err = si1133_bulk_read(data, SI1133_REG_HOSTOUT(0),  
> sizeof(buffer),
> > > +                            buffer);
> > >       if (err)
> > >               return err;
> > >
> > > -     *val = be16_to_cpu(resp);
> > > +     *val = sign_extend32((buffer[0] << 16) | (buffer[1] << 8) |  
> buffer[2],
> > > +                          SI1133_SIGN_BIT_INDEX);
> > >
> > >       return err;
> > >  }
> > > @@ -704,9 +708,9 @@ static int si1133_get_lux(struct si1133_data *data,  
> int *val)
> > >  {
> > >       int err;
> > >       int lux;
> > > -     u32 high_vis;
> > > -     u32 low_vis;
> > > -     u32 ir;
> > > +     s32 high_vis;
> > > +     s32 low_vis;
> > > +     s32 ir;
> > >       u8 buffer[SI1133_LUX_BUFFER_SIZE];
> > >
> > >       /* Activate lux channels */
> > > @@ -719,9 +723,16 @@ static int si1133_get_lux(struct si1133_data  
> *data, int *val)
> > >       if (err)
> > >               return err;
> > >
> > > -     high_vis = (buffer[0] << 16) | (buffer[1] << 8) | buffer[2];
> > > -     low_vis = (buffer[3] << 16) | (buffer[4] << 8) | buffer[5];
> > > -     ir = (buffer[6] << 16) | (buffer[7] << 8) | buffer[8];
> > > +     high_vis =
> > > +             sign_extend32((buffer[0] << 16) | (buffer[1] << 8) |  
> buffer[2],
> > > +                           SI1133_SIGN_BIT_INDEX);
> > > +
> > > +     low_vis =
> > > +             sign_extend32((buffer[3] << 16) | (buffer[4] << 8) |  
> buffer[5],
> > > +                           SI1133_SIGN_BIT_INDEX);
> > > +
> > > +     ir = sign_extend32((buffer[6] << 16) | (buffer[7] << 8) |  
> buffer[8],
> > > +                        SI1133_SIGN_BIT_INDEX);
> > >
> > >       if (high_vis > SI1133_ADC_THRESHOLD || ir > SI1133_ADC_THRESHOLD)
> > >               lux = si1133_calc_polynomial(high_vis, ir,
diff mbox series

Patch

diff --git a/drivers/iio/light/si1133.c b/drivers/iio/light/si1133.c
index 777b1a0848c9..509af982e185 100644
--- a/drivers/iio/light/si1133.c
+++ b/drivers/iio/light/si1133.c
@@ -102,6 +102,9 @@ 
 #define SI1133_INPUT_FRACTION_LOW	15
 #define SI1133_LUX_OUTPUT_FRACTION	12
 #define SI1133_LUX_BUFFER_SIZE		9
+#define SI1133_MEASURE_BUFFER_SIZE	3
+
+#define SI1133_SIGN_BIT_INDEX 23
 
 static const int si1133_scale_available[] = {
 	1, 2, 4, 8, 16, 32, 64, 128};
@@ -234,13 +237,13 @@  static const struct si1133_lux_coeff lux_coeff = {
 	}
 };
 
-static int si1133_calculate_polynomial_inner(u32 input, u8 fraction, u16 mag,
+static int si1133_calculate_polynomial_inner(s32 input, u8 fraction, u16 mag,
 					     s8 shift)
 {
 	return ((input << fraction) / mag) << shift;
 }
 
-static int si1133_calculate_output(u32 x, u32 y, u8 x_order, u8 y_order,
+static int si1133_calculate_output(s32 x, s32 y, u8 x_order, u8 y_order,
 				   u8 input_fraction, s8 sign,
 				   const struct si1133_coeff *coeffs)
 {
@@ -276,7 +279,7 @@  static int si1133_calculate_output(u32 x, u32 y, u8 x_order, u8 y_order,
  * The algorithm is from:
  * https://siliconlabs.github.io/Gecko_SDK_Doc/efm32zg/html/si1133_8c_source.html#l00716
  */
-static int si1133_calc_polynomial(u32 x, u32 y, u8 input_fraction, u8 num_coeff,
+static int si1133_calc_polynomial(s32 x, s32 y, u8 input_fraction, u8 num_coeff,
 				  const struct si1133_coeff *coeffs)
 {
 	u8 x_order, y_order;
@@ -614,23 +617,24 @@  static int si1133_measure(struct si1133_data *data,
 {
 	int err;
 
-	__be16 resp;
+	u8 buffer[SI1133_MEASURE_BUFFER_SIZE];
 
 	err = si1133_set_adcmux(data, 0, chan->channel);
 	if (err)
 		return err;
 
 	/* Deactivate lux measurements if they were active */
 	err = si1133_set_chlist(data, BIT(0));
 	if (err)
 		return err;
 
-	err = si1133_bulk_read(data, SI1133_REG_HOSTOUT(0), sizeof(resp),
-			       (u8 *)&resp);
+	err = si1133_bulk_read(data, SI1133_REG_HOSTOUT(0), sizeof(buffer),
+			       buffer);
 	if (err)
 		return err;
 
-	*val = be16_to_cpu(resp);
+	*val = sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
+			     SI1133_SIGN_BIT_INDEX);
 
 	return err;
 }
@@ -704,9 +708,9 @@  static int si1133_get_lux(struct si1133_data *data, int *val)
 {
 	int err;
 	int lux;
-	u32 high_vis;
-	u32 low_vis;
-	u32 ir;
+	s32 high_vis;
+	s32 low_vis;
+	s32 ir;
 	u8 buffer[SI1133_LUX_BUFFER_SIZE];
 
 	/* Activate lux channels */
@@ -719,9 +723,16 @@  static int si1133_get_lux(struct si1133_data *data, int *val)
 	if (err)
 		return err;
 
-	high_vis = (buffer[0] << 16) | (buffer[1] << 8) | buffer[2];
-	low_vis = (buffer[3] << 16) | (buffer[4] << 8) | buffer[5];
-	ir = (buffer[6] << 16) | (buffer[7] << 8) | buffer[8];
+	high_vis =
+		sign_extend32((buffer[0] << 16) | (buffer[1] << 8) | buffer[2],
+			      SI1133_SIGN_BIT_INDEX);
+
+	low_vis =
+		sign_extend32((buffer[3] << 16) | (buffer[4] << 8) | buffer[5],
+			      SI1133_SIGN_BIT_INDEX);
+
+	ir = sign_extend32((buffer[6] << 16) | (buffer[7] << 8) | buffer[8],
+			   SI1133_SIGN_BIT_INDEX);
 
 	if (high_vis > SI1133_ADC_THRESHOLD || ir > SI1133_ADC_THRESHOLD)
 		lux = si1133_calc_polynomial(high_vis, ir,