[PATCH 0/2] iio: Implement and utilize register structures for

[PATCH 0/2] iio: Implement and utilize register structures for

[William Breathitt Gray]

The STX104 and CIO-DAC drivers were updated to use I/O memory accessor
calls such as ioread8()/iowrite8() in previous patch series [1]. This
patch series is a continuation of the effort to improve the code
readability and reduce magic numbers by implementing and utilizing named
register data structures.

[1] https://lore.kernel.org/all/cover.1652201921.git.william.gray@linaro.org/

William Breathitt Gray (2):
  iio: adc: stx104: Implement and utilize register structures
  iio: dac: cio-dac: Implement and utilize register structures

 drivers/iio/adc/stx104.c  | 70 ++++++++++++++++++++++++++-------------
 drivers/iio/dac/cio-dac.c | 24 +++++++++-----
 2 files changed, 63 insertions(+), 31 deletions(-)


base-commit: 7fa61f7dba74f6c5baf9f02b760924692acdd282
-- 
2.36.1

[PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[William Breathitt Gray]

Reduce magic numbers and improve code readability by implementing and
utilizing named register data structures.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
 drivers/iio/adc/stx104.c | 70 +++++++++++++++++++++++++++-------------
 1 file changed, 47 insertions(+), 23 deletions(-)

diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c
index 7552351bfed9..7656b363e281 100644
--- a/drivers/iio/adc/stx104.c
+++ b/drivers/iio/adc/stx104.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/spinlock.h>
+#include <linux/types.h>
 
 #define STX104_OUT_CHAN(chan) {				\
 	.type = IIO_VOLTAGE,				\
@@ -44,14 +45,36 @@ static unsigned int num_stx104;
 module_param_hw_array(base, uint, ioport, &num_stx104, 0);
 MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
 
+/**
+ * struct stx104_reg - device register structure
+ * @ad:		ADC Data
+ * @achan:	ADC Channel
+ * @dio:	Digital I/O
+ * @dac:	DAC Channels
+ * @cir_asr:	Clear Interrupts and ADC Status
+ * @acr:	ADC Control
+ * @pccr_fsh:	Pacer Clock Control and FIFO Status MSB
+ * @acfg:	ADC Configuration
+ */
+struct stx104_reg {
+	u16 ad;
+	u8 achan;
+	u8 dio;
+	u16 dac[2];
+	u8 cir_asr;
+	u8 acr;
+	u8 pccr_fsh;
+	u8 acfg;
+};
+
 /**
  * struct stx104_iio - IIO device private data structure
  * @chan_out_states:	channels' output states
- * @base:		base port address of the IIO device
+ * @reg:		I/O address offset for the device registers
  */
 struct stx104_iio {
 	unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
-	void __iomem *base;
+	struct stx104_reg __iomem *reg;
 };
 
 /**
@@ -64,7 +87,7 @@ struct stx104_iio {
 struct stx104_gpio {
 	struct gpio_chip chip;
 	spinlock_t lock;
-	void __iomem *base;
+	u8 __iomem *base;
 	unsigned int out_state;
 };
 
@@ -72,6 +95,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
 {
 	struct stx104_iio *const priv = iio_priv(indio_dev);
+	struct stx104_reg __iomem *const reg = priv->reg;
 	unsigned int adc_config;
 	int adbu;
 	int gain;
@@ -79,7 +103,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
 	switch (mask) {
 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		/* get gain configuration */
-		adc_config = ioread8(priv->base + 11);
+		adc_config = ioread8(&reg->acfg);
 		gain = adc_config & 0x3;
 
 		*val = 1 << gain;
@@ -91,24 +115,24 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
 		}
 
 		/* select ADC channel */
-		iowrite8(chan->channel | (chan->channel << 4), priv->base + 2);
+		iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
 
 		/* trigger ADC sample capture and wait for completion */
-		iowrite8(0, priv->base);
-		while (ioread8(priv->base + 8) & BIT(7));
+		iowrite8(0, &reg->ad);
+		while (ioread8(&reg->cir_asr) & BIT(7));
 
-		*val = ioread16(priv->base);
+		*val = ioread16(&reg->ad);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
 		/* get ADC bipolar/unipolar configuration */
-		adc_config = ioread8(priv->base + 11);
+		adc_config = ioread8(&reg->acfg);
 		adbu = !(adc_config & BIT(2));
 
 		*val = -32768 * adbu;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		/* get ADC bipolar/unipolar and gain configuration */
-		adc_config = ioread8(priv->base + 11);
+		adc_config = ioread8(&reg->acfg);
 		adbu = !(adc_config & BIT(2));
 		gain = adc_config & 0x3;
 
@@ -130,16 +154,16 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
 		/* Only four gain states (x1, x2, x4, x8) */
 		switch (val) {
 		case 1:
-			iowrite8(0, priv->base + 11);
+			iowrite8(0, &priv->reg->acfg);
 			break;
 		case 2:
-			iowrite8(1, priv->base + 11);
+			iowrite8(1, &priv->reg->acfg);
 			break;
 		case 4:
-			iowrite8(2, priv->base + 11);
+			iowrite8(2, &priv->reg->acfg);
 			break;
 		case 8:
-			iowrite8(3, priv->base + 11);
+			iowrite8(3, &priv->reg->acfg);
 			break;
 		default:
 			return -EINVAL;
@@ -153,7 +177,7 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
 				return -EINVAL;
 
 			priv->chan_out_states[chan->channel] = val;
-			iowrite16(val, priv->base + 4 + 2 * chan->channel);
+			iowrite16(val, priv->reg->dac + chan->channel);
 
 			return 0;
 		}
@@ -307,15 +331,15 @@ static int stx104_probe(struct device *dev, unsigned int id)
 	}
 
 	priv = iio_priv(indio_dev);
-	priv->base = devm_ioport_map(dev, base[id], STX104_EXTENT);
-	if (!priv->base)
+	priv->reg = devm_ioport_map(dev, base[id], STX104_EXTENT);
+	if (!priv->reg)
 		return -ENOMEM;
 
 	indio_dev->info = &stx104_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
 	/* determine if differential inputs */
-	if (ioread8(priv->base + 8) & BIT(5)) {
+	if (ioread8(&priv->reg->cir_asr) & BIT(5)) {
 		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
 		indio_dev->channels = stx104_channels_diff;
 	} else {
@@ -326,14 +350,14 @@ static int stx104_probe(struct device *dev, unsigned int id)
 	indio_dev->name = dev_name(dev);
 
 	/* configure device for software trigger operation */
-	iowrite8(0, priv->base + 9);
+	iowrite8(0, &priv->reg->acr);
 
 	/* initialize gain setting to x1 */
-	iowrite8(0, priv->base + 11);
+	iowrite8(0, &priv->reg->acfg);
 
 	/* initialize DAC output to 0V */
-	iowrite16(0, priv->base + 4);
-	iowrite16(0, priv->base + 6);
+	iowrite16(0, &priv->reg->dac[0]);
+	iowrite16(0, &priv->reg->dac[1]);
 
 	stx104gpio->chip.label = dev_name(dev);
 	stx104gpio->chip.parent = dev;
@@ -348,7 +372,7 @@ static int stx104_probe(struct device *dev, unsigned int id)
 	stx104gpio->chip.get_multiple = stx104_gpio_get_multiple;
 	stx104gpio->chip.set = stx104_gpio_set;
 	stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
-	stx104gpio->base = priv->base + 3;
+	stx104gpio->base = &priv->reg->dio;
 	stx104gpio->out_state = 0x0;
 
 	spin_lock_init(&stx104gpio->lock);
-- 
2.36.1

[PATCH 2/2] iio: dac: cio-dac: Implement and utilize register structures

[William Breathitt Gray]

Reduce magic numbers and improve code readability by implementing and
utilizing named register data structures.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
 drivers/iio/dac/cio-dac.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
index 8080984dcb03..7860450ceaf3 100644
--- a/drivers/iio/dac/cio-dac.c
+++ b/drivers/iio/dac/cio-dac.c
@@ -16,6 +16,7 @@
 #include <linux/isa.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/types.h>
 
 #define CIO_DAC_NUM_CHAN 16
 
@@ -34,14 +35,22 @@ static unsigned int num_cio_dac;
 module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
 MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
 
+/**
+ * struct cio_dac_reg - device register structure
+ * @da:	D/A data
+ */
+struct cio_dac_reg {
+	u16 da[CIO_DAC_NUM_CHAN];
+};
+
 /**
  * struct cio_dac_iio - IIO device private data structure
  * @chan_out_states:	channels' output states
- * @base:		base port address of the IIO device
+ * @reg:		I/O address offset for the device registers
  */
 struct cio_dac_iio {
 	int chan_out_states[CIO_DAC_NUM_CHAN];
-	void __iomem *base;
+	struct cio_dac_reg __iomem *reg;
 };
 
 static int cio_dac_read_raw(struct iio_dev *indio_dev,
@@ -61,7 +70,6 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int val, int val2, long mask)
 {
 	struct cio_dac_iio *const priv = iio_priv(indio_dev);
-	const unsigned int chan_addr_offset = 2 * chan->channel;
 
 	if (mask != IIO_CHAN_INFO_RAW)
 		return -EINVAL;
@@ -71,7 +79,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
 		return -EINVAL;
 
 	priv->chan_out_states[chan->channel] = val;
-	iowrite16(val, priv->base + chan_addr_offset);
+	iowrite16(val, priv->reg->da + chan->channel);
 
 	return 0;
 }
@@ -106,8 +114,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
 	}
 
 	priv = iio_priv(indio_dev);
-	priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
-	if (!priv->base)
+	priv->reg = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
+	if (!priv->reg)
 		return -ENOMEM;
 
 	indio_dev->info = &cio_dac_info;
@@ -117,8 +125,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
 	indio_dev->name = dev_name(dev);
 
 	/* initialize DAC outputs to 0V */
-	for (i = 0; i < 32; i += 2)
-		iowrite16(0, priv->base + i);
+	for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
+		iowrite16(0, priv->reg->da + i);
 
 	return devm_iio_device_register(dev, indio_dev);
 }
-- 
2.36.1

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[Jonathan Cameron]

On Mon,  6 Jun 2022 10:15:17 -0400
William Breathitt Gray <william.gray@linaro.org> wrote:

> Reduce magic numbers and improve code readability by implementing and
> utilizing named register data structures.
> 
> Signed-off-by: William Breathitt Gray <william.gray@linaro.org>

A few comments inline, but looks fine to me otherwise.

Jonathan

> ---
>  drivers/iio/adc/stx104.c | 70 +++++++++++++++++++++++++++-------------
>  1 file changed, 47 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c
> index 7552351bfed9..7656b363e281 100644
> --- a/drivers/iio/adc/stx104.c
> +++ b/drivers/iio/adc/stx104.c
> @@ -16,6 +16,7 @@
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/spinlock.h>
> +#include <linux/types.h>
>  
>  #define STX104_OUT_CHAN(chan) {				\
>  	.type = IIO_VOLTAGE,				\
> @@ -44,14 +45,36 @@ static unsigned int num_stx104;
>  module_param_hw_array(base, uint, ioport, &num_stx104, 0);
>  MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
>  
> +/**
> + * struct stx104_reg - device register structure
> + * @ad:		ADC Data
> + * @achan:	ADC Channel
> + * @dio:	Digital I/O
> + * @dac:	DAC Channels
> + * @cir_asr:	Clear Interrupts and ADC Status
> + * @acr:	ADC Control
> + * @pccr_fsh:	Pacer Clock Control and FIFO Status MSB
> + * @acfg:	ADC Configuration
> + */
> +struct stx104_reg {
> +	u16 ad;
> +	u8 achan;
> +	u8 dio;
> +	u16 dac[2];
> +	u8 cir_asr;
> +	u8 acr;
> +	u8 pccr_fsh;
> +	u8 acfg;
> +};
> +
>  /**
>   * struct stx104_iio - IIO device private data structure
>   * @chan_out_states:	channels' output states
> - * @base:		base port address of the IIO device
> + * @reg:		I/O address offset for the device registers
>   */
>  struct stx104_iio {
>  	unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
> -	void __iomem *base;
> +	struct stx104_reg __iomem *reg;
>  };
>  
>  /**
> @@ -64,7 +87,7 @@ struct stx104_iio {
>  struct stx104_gpio {
>  	struct gpio_chip chip;
>  	spinlock_t lock;
> -	void __iomem *base;
> +	u8 __iomem *base;
>  	unsigned int out_state;
>  };
>  
> @@ -72,6 +95,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
>  	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
>  {
>  	struct stx104_iio *const priv = iio_priv(indio_dev);
> +	struct stx104_reg __iomem *const reg = priv->reg;
>  	unsigned int adc_config;
>  	int adbu;
>  	int gain;
> @@ -79,7 +103,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
>  	switch (mask) {
>  	case IIO_CHAN_INFO_HARDWAREGAIN:
>  		/* get gain configuration */
> -		adc_config = ioread8(priv->base + 11);
> +		adc_config = ioread8(&reg->acfg);
>  		gain = adc_config & 0x3;
>  
>  		*val = 1 << gain;
> @@ -91,24 +115,24 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
>  		}
>  
>  		/* select ADC channel */
> -		iowrite8(chan->channel | (chan->channel << 4), priv->base + 2);
> +		iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
>  
>  		/* trigger ADC sample capture and wait for completion */
> -		iowrite8(0, priv->base);
> -		while (ioread8(priv->base + 8) & BIT(7));
> +		iowrite8(0, &reg->ad);

Curious - 8 bit write to a 16 bit address?  Maybe worth a comment
on why.

> +		while (ioread8(&reg->cir_asr) & BIT(7));
>  
> -		*val = ioread16(priv->base);
> +		*val = ioread16(&reg->ad);
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_OFFSET:
>  		/* get ADC bipolar/unipolar configuration */
> -		adc_config = ioread8(priv->base + 11);
> +		adc_config = ioread8(&reg->acfg);
>  		adbu = !(adc_config & BIT(2));
>  
>  		*val = -32768 * adbu;
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_SCALE:
>  		/* get ADC bipolar/unipolar and gain configuration */
> -		adc_config = ioread8(priv->base + 11);
> +		adc_config = ioread8(&reg->acfg);
>  		adbu = !(adc_config & BIT(2));
>  		gain = adc_config & 0x3;
>  
> @@ -130,16 +154,16 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
>  		/* Only four gain states (x1, x2, x4, x8) */
>  		switch (val) {
>  		case 1:
> -			iowrite8(0, priv->base + 11);
> +			iowrite8(0, &priv->reg->acfg);
>  			break;
>  		case 2:
> -			iowrite8(1, priv->base + 11);
> +			iowrite8(1, &priv->reg->acfg);
>  			break;
>  		case 4:
> -			iowrite8(2, priv->base + 11);
> +			iowrite8(2, &priv->reg->acfg);
>  			break;
>  		case 8:
> -			iowrite8(3, priv->base + 11);
> +			iowrite8(3, &priv->reg->acfg);
>  			break;
>  		default:
>  			return -EINVAL;
> @@ -153,7 +177,7 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
>  				return -EINVAL;
>  
>  			priv->chan_out_states[chan->channel] = val;
> -			iowrite16(val, priv->base + 4 + 2 * chan->channel);
> +			iowrite16(val, priv->reg->dac + chan->channel);
Perhaps for consistency with below go with
&priv->reg->dac[chan->channels];

>  
>  			return 0;
>  		}
> @@ -307,15 +331,15 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  	}
>  
>  	priv = iio_priv(indio_dev);
> -	priv->base = devm_ioport_map(dev, base[id], STX104_EXTENT);
> -	if (!priv->base)
> +	priv->reg = devm_ioport_map(dev, base[id], STX104_EXTENT);
> +	if (!priv->reg)
>  		return -ENOMEM;
>  
>  	indio_dev->info = &stx104_info;
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  
>  	/* determine if differential inputs */
> -	if (ioread8(priv->base + 8) & BIT(5)) {
> +	if (ioread8(&priv->reg->cir_asr) & BIT(5)) {
>  		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
>  		indio_dev->channels = stx104_channels_diff;
>  	} else {
> @@ -326,14 +350,14 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  	indio_dev->name = dev_name(dev);
>  
>  	/* configure device for software trigger operation */
> -	iowrite8(0, priv->base + 9);
> +	iowrite8(0, &priv->reg->acr);
>  
>  	/* initialize gain setting to x1 */
> -	iowrite8(0, priv->base + 11);
> +	iowrite8(0, &priv->reg->acfg);
>  
>  	/* initialize DAC output to 0V */
> -	iowrite16(0, priv->base + 4);
> -	iowrite16(0, priv->base + 6);
> +	iowrite16(0, &priv->reg->dac[0]);
> +	iowrite16(0, &priv->reg->dac[1]);
>  
>  	stx104gpio->chip.label = dev_name(dev);
>  	stx104gpio->chip.parent = dev;
> @@ -348,7 +372,7 @@ static int stx104_probe(struct device *dev, unsigned int id)
>  	stx104gpio->chip.get_multiple = stx104_gpio_get_multiple;
>  	stx104gpio->chip.set = stx104_gpio_set;
>  	stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
> -	stx104gpio->base = priv->base + 3;
> +	stx104gpio->base = &priv->reg->dio;
>  	stx104gpio->out_state = 0x0;
>  
>  	spin_lock_init(&stx104gpio->lock);

Re: [PATCH 2/2] iio: dac: cio-dac: Implement and utilize register structures

[Jonathan Cameron]

On Mon,  6 Jun 2022 10:15:18 -0400
William Breathitt Gray <william.gray@linaro.org> wrote:

> Reduce magic numbers and improve code readability by implementing and
> utilizing named register data structures.
> 
> Signed-off-by: William Breathitt Gray <william.gray@linaro.org>

I'm unconvinced this one really helps readability seeing
as you are only indexing a straight forward array.

Simply using u16 __iomem *
would provide the main cleanup which is avoiding the indexing
via * 2.

Thanks,

Jonathan


> ---
>  drivers/iio/dac/cio-dac.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
> index 8080984dcb03..7860450ceaf3 100644
> --- a/drivers/iio/dac/cio-dac.c
> +++ b/drivers/iio/dac/cio-dac.c
> @@ -16,6 +16,7 @@
>  #include <linux/isa.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
> +#include <linux/types.h>
>  
>  #define CIO_DAC_NUM_CHAN 16
>  
> @@ -34,14 +35,22 @@ static unsigned int num_cio_dac;
>  module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
>  MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
>  
> +/**
> + * struct cio_dac_reg - device register structure
> + * @da:	D/A data
> + */
> +struct cio_dac_reg {
> +	u16 da[CIO_DAC_NUM_CHAN];
> +};
> +
>  /**
>   * struct cio_dac_iio - IIO device private data structure
>   * @chan_out_states:	channels' output states
> - * @base:		base port address of the IIO device
> + * @reg:		I/O address offset for the device registers
>   */
>  struct cio_dac_iio {
>  	int chan_out_states[CIO_DAC_NUM_CHAN];
> -	void __iomem *base;
> +	struct cio_dac_reg __iomem *reg;
>  };
>  
>  static int cio_dac_read_raw(struct iio_dev *indio_dev,
> @@ -61,7 +70,6 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
>  	struct iio_chan_spec const *chan, int val, int val2, long mask)
>  {
>  	struct cio_dac_iio *const priv = iio_priv(indio_dev);
> -	const unsigned int chan_addr_offset = 2 * chan->channel;
>  
>  	if (mask != IIO_CHAN_INFO_RAW)
>  		return -EINVAL;
> @@ -71,7 +79,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
>  		return -EINVAL;
>  
>  	priv->chan_out_states[chan->channel] = val;
> -	iowrite16(val, priv->base + chan_addr_offset);
> +	iowrite16(val, priv->reg->da + chan->channel);
>  
>  	return 0;
>  }
> @@ -106,8 +114,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
>  	}
>  
>  	priv = iio_priv(indio_dev);
> -	priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
> -	if (!priv->base)
> +	priv->reg = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
> +	if (!priv->reg)
>  		return -ENOMEM;
>  
>  	indio_dev->info = &cio_dac_info;
> @@ -117,8 +125,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
>  	indio_dev->name = dev_name(dev);
>  
>  	/* initialize DAC outputs to 0V */
> -	for (i = 0; i < 32; i += 2)
> -		iowrite16(0, priv->base + i);
> +	for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
> +		iowrite16(0, priv->reg->da + i);
>  
>  	return devm_iio_device_register(dev, indio_dev);
>  }

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 7484 bytes --]

On Tue, Jun 14, 2022 at 12:22:48PM +0100, Jonathan Cameron wrote:
> On Mon,  6 Jun 2022 10:15:17 -0400
> William Breathitt Gray <william.gray@linaro.org> wrote:
> 
> > Reduce magic numbers and improve code readability by implementing and
> > utilizing named register data structures.
> > 
> > Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
> 
> A few comments inline, but looks fine to me otherwise.
> 
> Jonathan
> 
> > ---
> >  drivers/iio/adc/stx104.c | 70 +++++++++++++++++++++++++++-------------
> >  1 file changed, 47 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c
> > index 7552351bfed9..7656b363e281 100644
> > --- a/drivers/iio/adc/stx104.c
> > +++ b/drivers/iio/adc/stx104.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/module.h>
> >  #include <linux/moduleparam.h>
> >  #include <linux/spinlock.h>
> > +#include <linux/types.h>
> >  
> >  #define STX104_OUT_CHAN(chan) {				\
> >  	.type = IIO_VOLTAGE,				\
> > @@ -44,14 +45,36 @@ static unsigned int num_stx104;
> >  module_param_hw_array(base, uint, ioport, &num_stx104, 0);
> >  MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
> >  
> > +/**
> > + * struct stx104_reg - device register structure
> > + * @ad:		ADC Data
> > + * @achan:	ADC Channel
> > + * @dio:	Digital I/O
> > + * @dac:	DAC Channels
> > + * @cir_asr:	Clear Interrupts and ADC Status
> > + * @acr:	ADC Control
> > + * @pccr_fsh:	Pacer Clock Control and FIFO Status MSB
> > + * @acfg:	ADC Configuration
> > + */
> > +struct stx104_reg {
> > +	u16 ad;
> > +	u8 achan;
> > +	u8 dio;
> > +	u16 dac[2];
> > +	u8 cir_asr;
> > +	u8 acr;
> > +	u8 pccr_fsh;
> > +	u8 acfg;
> > +};
> > +
> >  /**
> >   * struct stx104_iio - IIO device private data structure
> >   * @chan_out_states:	channels' output states
> > - * @base:		base port address of the IIO device
> > + * @reg:		I/O address offset for the device registers
> >   */
> >  struct stx104_iio {
> >  	unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
> > -	void __iomem *base;
> > +	struct stx104_reg __iomem *reg;
> >  };
> >  
> >  /**
> > @@ -64,7 +87,7 @@ struct stx104_iio {
> >  struct stx104_gpio {
> >  	struct gpio_chip chip;
> >  	spinlock_t lock;
> > -	void __iomem *base;
> > +	u8 __iomem *base;
> >  	unsigned int out_state;
> >  };
> >  
> > @@ -72,6 +95,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
> >  	struct iio_chan_spec const *chan, int *val, int *val2, long mask)
> >  {
> >  	struct stx104_iio *const priv = iio_priv(indio_dev);
> > +	struct stx104_reg __iomem *const reg = priv->reg;
> >  	unsigned int adc_config;
> >  	int adbu;
> >  	int gain;
> > @@ -79,7 +103,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
> >  	switch (mask) {
> >  	case IIO_CHAN_INFO_HARDWAREGAIN:
> >  		/* get gain configuration */
> > -		adc_config = ioread8(priv->base + 11);
> > +		adc_config = ioread8(&reg->acfg);
> >  		gain = adc_config & 0x3;
> >  
> >  		*val = 1 << gain;
> > @@ -91,24 +115,24 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
> >  		}
> >  
> >  		/* select ADC channel */
> > -		iowrite8(chan->channel | (chan->channel << 4), priv->base + 2);
> > +		iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
> >  
> >  		/* trigger ADC sample capture and wait for completion */
> > -		iowrite8(0, priv->base);
> > -		while (ioread8(priv->base + 8) & BIT(7));
> > +		iowrite8(0, &reg->ad);
> 
> Curious - 8 bit write to a 16 bit address?  Maybe worth a comment
> on why.

This address doubles as the 8-bit Software Strobe Register; writing an
8-bit value to this address will initiate an ADC sample capture. I'll
rename this member to ssr_ad and add some comments to make this more
explicit.

> 
> > +		while (ioread8(&reg->cir_asr) & BIT(7));
> >  
> > -		*val = ioread16(priv->base);
> > +		*val = ioread16(&reg->ad);
> >  		return IIO_VAL_INT;
> >  	case IIO_CHAN_INFO_OFFSET:
> >  		/* get ADC bipolar/unipolar configuration */
> > -		adc_config = ioread8(priv->base + 11);
> > +		adc_config = ioread8(&reg->acfg);
> >  		adbu = !(adc_config & BIT(2));
> >  
> >  		*val = -32768 * adbu;
> >  		return IIO_VAL_INT;
> >  	case IIO_CHAN_INFO_SCALE:
> >  		/* get ADC bipolar/unipolar and gain configuration */
> > -		adc_config = ioread8(priv->base + 11);
> > +		adc_config = ioread8(&reg->acfg);
> >  		adbu = !(adc_config & BIT(2));
> >  		gain = adc_config & 0x3;
> >  
> > @@ -130,16 +154,16 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
> >  		/* Only four gain states (x1, x2, x4, x8) */
> >  		switch (val) {
> >  		case 1:
> > -			iowrite8(0, priv->base + 11);
> > +			iowrite8(0, &priv->reg->acfg);
> >  			break;
> >  		case 2:
> > -			iowrite8(1, priv->base + 11);
> > +			iowrite8(1, &priv->reg->acfg);
> >  			break;
> >  		case 4:
> > -			iowrite8(2, priv->base + 11);
> > +			iowrite8(2, &priv->reg->acfg);
> >  			break;
> >  		case 8:
> > -			iowrite8(3, priv->base + 11);
> > +			iowrite8(3, &priv->reg->acfg);
> >  			break;
> >  		default:
> >  			return -EINVAL;
> > @@ -153,7 +177,7 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
> >  				return -EINVAL;
> >  
> >  			priv->chan_out_states[chan->channel] = val;
> > -			iowrite16(val, priv->base + 4 + 2 * chan->channel);
> > +			iowrite16(val, priv->reg->dac + chan->channel);
> Perhaps for consistency with below go with
> &priv->reg->dac[chan->channels];

Ack.

William Breathitt Gray

> >  
> >  			return 0;
> >  		}
> > @@ -307,15 +331,15 @@ static int stx104_probe(struct device *dev, unsigned int id)
> >  	}
> >  
> >  	priv = iio_priv(indio_dev);
> > -	priv->base = devm_ioport_map(dev, base[id], STX104_EXTENT);
> > -	if (!priv->base)
> > +	priv->reg = devm_ioport_map(dev, base[id], STX104_EXTENT);
> > +	if (!priv->reg)
> >  		return -ENOMEM;
> >  
> >  	indio_dev->info = &stx104_info;
> >  	indio_dev->modes = INDIO_DIRECT_MODE;
> >  
> >  	/* determine if differential inputs */
> > -	if (ioread8(priv->base + 8) & BIT(5)) {
> > +	if (ioread8(&priv->reg->cir_asr) & BIT(5)) {
> >  		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
> >  		indio_dev->channels = stx104_channels_diff;
> >  	} else {
> > @@ -326,14 +350,14 @@ static int stx104_probe(struct device *dev, unsigned int id)
> >  	indio_dev->name = dev_name(dev);
> >  
> >  	/* configure device for software trigger operation */
> > -	iowrite8(0, priv->base + 9);
> > +	iowrite8(0, &priv->reg->acr);
> >  
> >  	/* initialize gain setting to x1 */
> > -	iowrite8(0, priv->base + 11);
> > +	iowrite8(0, &priv->reg->acfg);
> >  
> >  	/* initialize DAC output to 0V */
> > -	iowrite16(0, priv->base + 4);
> > -	iowrite16(0, priv->base + 6);
> > +	iowrite16(0, &priv->reg->dac[0]);
> > +	iowrite16(0, &priv->reg->dac[1]);
> >  
> >  	stx104gpio->chip.label = dev_name(dev);
> >  	stx104gpio->chip.parent = dev;
> > @@ -348,7 +372,7 @@ static int stx104_probe(struct device *dev, unsigned int id)
> >  	stx104gpio->chip.get_multiple = stx104_gpio_get_multiple;
> >  	stx104gpio->chip.set = stx104_gpio_set;
> >  	stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
> > -	stx104gpio->base = priv->base + 3;
> > +	stx104gpio->base = &priv->reg->dio;
> >  	stx104gpio->out_state = 0x0;
> >  
> >  	spin_lock_init(&stx104gpio->lock);
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH 2/2] iio: dac: cio-dac: Implement and utilize register structures

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 3628 bytes --]

On Tue, Jun 14, 2022 at 12:26:18PM +0100, Jonathan Cameron wrote:
> On Mon,  6 Jun 2022 10:15:18 -0400
> William Breathitt Gray <william.gray@linaro.org> wrote:
> 
> > Reduce magic numbers and improve code readability by implementing and
> > utilizing named register data structures.
> > 
> > Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
> 
> I'm unconvinced this one really helps readability seeing
> as you are only indexing a straight forward array.
> 
> Simply using u16 __iomem *
> would provide the main cleanup which is avoiding the indexing
> via * 2.
> 
> Thanks,
> 
> Jonathan

I agree, that is a much simpler approach and reduces the changes we need
to make to this file. I'll adjust this to u16 __iomem * in v2.

William Breathitt Gray

> 
> 
> > ---
> >  drivers/iio/dac/cio-dac.c | 24 ++++++++++++++++--------
> >  1 file changed, 16 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
> > index 8080984dcb03..7860450ceaf3 100644
> > --- a/drivers/iio/dac/cio-dac.c
> > +++ b/drivers/iio/dac/cio-dac.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/isa.h>
> >  #include <linux/module.h>
> >  #include <linux/moduleparam.h>
> > +#include <linux/types.h>
> >  
> >  #define CIO_DAC_NUM_CHAN 16
> >  
> > @@ -34,14 +35,22 @@ static unsigned int num_cio_dac;
> >  module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
> >  MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
> >  
> > +/**
> > + * struct cio_dac_reg - device register structure
> > + * @da:	D/A data
> > + */
> > +struct cio_dac_reg {
> > +	u16 da[CIO_DAC_NUM_CHAN];
> > +};
> > +
> >  /**
> >   * struct cio_dac_iio - IIO device private data structure
> >   * @chan_out_states:	channels' output states
> > - * @base:		base port address of the IIO device
> > + * @reg:		I/O address offset for the device registers
> >   */
> >  struct cio_dac_iio {
> >  	int chan_out_states[CIO_DAC_NUM_CHAN];
> > -	void __iomem *base;
> > +	struct cio_dac_reg __iomem *reg;
> >  };
> >  
> >  static int cio_dac_read_raw(struct iio_dev *indio_dev,
> > @@ -61,7 +70,6 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
> >  	struct iio_chan_spec const *chan, int val, int val2, long mask)
> >  {
> >  	struct cio_dac_iio *const priv = iio_priv(indio_dev);
> > -	const unsigned int chan_addr_offset = 2 * chan->channel;
> >  
> >  	if (mask != IIO_CHAN_INFO_RAW)
> >  		return -EINVAL;
> > @@ -71,7 +79,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
> >  		return -EINVAL;
> >  
> >  	priv->chan_out_states[chan->channel] = val;
> > -	iowrite16(val, priv->base + chan_addr_offset);
> > +	iowrite16(val, priv->reg->da + chan->channel);
> >  
> >  	return 0;
> >  }
> > @@ -106,8 +114,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
> >  	}
> >  
> >  	priv = iio_priv(indio_dev);
> > -	priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
> > -	if (!priv->base)
> > +	priv->reg = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
> > +	if (!priv->reg)
> >  		return -ENOMEM;
> >  
> >  	indio_dev->info = &cio_dac_info;
> > @@ -117,8 +125,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
> >  	indio_dev->name = dev_name(dev);
> >  
> >  	/* initialize DAC outputs to 0V */
> > -	for (i = 0; i < 32; i += 2)
> > -		iowrite16(0, priv->base + i);
> > +	for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
> > +		iowrite16(0, priv->reg->da + i);
> >  
> >  	return devm_iio_device_register(dev, indio_dev);
> >  }
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[Andy Shevchenko]

On Mon, Jun 6, 2022 at 4:27 PM William Breathitt Gray
<william.gray@linaro.org> wrote:
>
> Reduce magic numbers and improve code readability by implementing and
> utilizing named register data structures.

Can we consider using regmap APIs instead?


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 526 bytes --]

On Wed, Jun 15, 2022 at 11:44:54AM +0200, Andy Shevchenko wrote:
> On Mon, Jun 6, 2022 at 4:27 PM William Breathitt Gray
> <william.gray@linaro.org> wrote:
> >
> > Reduce magic numbers and improve code readability by implementing and
> > utilizing named register data structures.
> 
> Can we consider using regmap APIs instead?
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko

The regmap API may be more appropriate here. I'll investigate and see if
I can convert this over to it.

William Breathitt Gray

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[Andy Shevchenko]

On Wed, Jun 15, 2022 at 1:55 PM William Breathitt Gray
<william.gray@linaro.org> wrote:
> On Wed, Jun 15, 2022 at 11:44:54AM +0200, Andy Shevchenko wrote:
> > On Mon, Jun 6, 2022 at 4:27 PM William Breathitt Gray
> > <william.gray@linaro.org> wrote:
> > >
> > > Reduce magic numbers and improve code readability by implementing and
> > > utilizing named register data structures.
> >
> > Can we consider using regmap APIs instead?

> The regmap API may be more appropriate here. I'll investigate and see if
> I can convert this over to it.

I just realized that this driver is for the old PC104 (like?) hardware
that most likely uses IO ports, I don't remember if we have support
for IO ports in regmap (MMIO -- yes for sure).

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 1250 bytes --]

On Wed, Jun 15, 2022 at 02:00:26PM +0200, Andy Shevchenko wrote:
> On Wed, Jun 15, 2022 at 1:55 PM William Breathitt Gray
> <william.gray@linaro.org> wrote:
> > On Wed, Jun 15, 2022 at 11:44:54AM +0200, Andy Shevchenko wrote:
> > > On Mon, Jun 6, 2022 at 4:27 PM William Breathitt Gray
> > > <william.gray@linaro.org> wrote:
> > > >
> > > > Reduce magic numbers and improve code readability by implementing and
> > > > utilizing named register data structures.
> > >
> > > Can we consider using regmap APIs instead?
> 
> > The regmap API may be more appropriate here. I'll investigate and see if
> > I can convert this over to it.
> 
> I just realized that this driver is for the old PC104 (like?) hardware
> that most likely uses IO ports, I don't remember if we have support
> for IO ports in regmap (MMIO -- yes for sure).
> 
> -- 
> With Best Regards,
> Andy Shevchenko

Hmm, I don't see IO ports mentioned in include/linux/regmap.h, so I
don't think the regmap API directly supports it (maybe someone familiar
with regmap knows). Although we do get a virtual mapping cookie via
ioport_map() in this driver, I don't know if we can pass that to the
regmap functions and have it actually work.

William Breathitt Gray

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[Andy Shevchenko]

On Wed, Jun 15, 2022 at 2:19 PM William Breathitt Gray
<william.gray@linaro.org> wrote:
> On Wed, Jun 15, 2022 at 02:00:26PM +0200, Andy Shevchenko wrote:
> > On Wed, Jun 15, 2022 at 1:55 PM William Breathitt Gray
> > <william.gray@linaro.org> wrote:
> > > On Wed, Jun 15, 2022 at 11:44:54AM +0200, Andy Shevchenko wrote:
> > > > On Mon, Jun 6, 2022 at 4:27 PM William Breathitt Gray
> > > > <william.gray@linaro.org> wrote:
> > > > >
> > > > > Reduce magic numbers and improve code readability by implementing and
> > > > > utilizing named register data structures.
> > > >
> > > > Can we consider using regmap APIs instead?
> >
> > > The regmap API may be more appropriate here. I'll investigate and see if
> > > I can convert this over to it.
> >
> > I just realized that this driver is for the old PC104 (like?) hardware
> > that most likely uses IO ports, I don't remember if we have support
> > for IO ports in regmap (MMIO -- yes for sure).

> Hmm, I don't see IO ports mentioned in include/linux/regmap.h, so I
> don't think the regmap API directly supports it (maybe someone familiar
> with regmap knows). Although we do get a virtual mapping cookie via
> ioport_map() in this driver, I don't know if we can pass that to the
> regmap functions and have it actually work.

The problem is with accessors which are inconsistent in regmap MMIO
implementation. I think it should be converted to use
ioreadXX()/iowriteXX() in all cases (currently only BE cases use
them). Another variant is to provide read*_be() / write*_be() for all
architectures, replace corresponding ops in regmap MMIO and introduce
regmap IO with inX()/outX. The former seems to me the best option,
while the latter is cleaner.

+Cc: Mark if he knows more about this.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/2] iio: adc: stx104: Implement and utilize register structures

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 1285 bytes --]

On Wed, Jun 15, 2022 at 02:43:27PM +0200, Andy Shevchenko wrote:
> On Wed, Jun 15, 2022 at 2:19 PM William Breathitt Gray
> > On Wed, Jun 15, 2022 at 02:00:26PM +0200, Andy Shevchenko wrote:

> > > I just realized that this driver is for the old PC104 (like?) hardware
> > > that most likely uses IO ports, I don't remember if we have support
> > > for IO ports in regmap (MMIO -- yes for sure).

> > Hmm, I don't see IO ports mentioned in include/linux/regmap.h, so I
> > don't think the regmap API directly supports it (maybe someone familiar
> > with regmap knows). Although we do get a virtual mapping cookie via
> > ioport_map() in this driver, I don't know if we can pass that to the
> > regmap functions and have it actually work.

> The problem is with accessors which are inconsistent in regmap MMIO
> implementation. I think it should be converted to use
> ioreadXX()/iowriteXX() in all cases (currently only BE cases use
> them). Another variant is to provide read*_be() / write*_be() for all
> architectures, replace corresponding ops in regmap MMIO and introduce
> regmap IO with inX()/outX. The former seems to me the best option,
> while the latter is cleaner.

I don't know what driver this is, but yes someone would have to add
ioport support to use them with regmap.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]