[PATCH v2 1/3] iio: ad_sigma_delta: Allow to provide custom data register address

From: Stefan Popa
Date: Fri Oct 19 2018 - 03:48:23 EST


From: Lars-Peter Clausen <lars@xxxxxxxxxx>

Some newer devices from the Sigma-Delta ADC family do have their data
register at a different address than the current default address. Add a
parameter to the ad_sigma_delta_info struct which allows to override the
default address.

Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Signed-off-by: Stefan Popa <stefan.popa@xxxxxxxxxx>
---
Changes in v2:
- Added this commit.

drivers/iio/adc/ad_sigma_delta.c | 22 +++++++++++++++++-----
include/linux/iio/adc/ad_sigma_delta.h | 3 +++
2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index fc95107..ff5f2da 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -278,6 +278,7 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
{
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
unsigned int sample, raw_sample;
+ unsigned int data_reg;
int ret = 0;

if (iio_buffer_enabled(indio_dev))
@@ -305,7 +306,12 @@ int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
if (ret < 0)
goto out;

- ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
+ if (sigma_delta->info->data_reg != 0)
+ data_reg = sigma_delta->info->data_reg;
+ else
+ data_reg = AD_SD_REG_DATA;
+
+ ret = ad_sd_read_reg(sigma_delta, data_reg,
DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
&raw_sample);

@@ -392,6 +398,7 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
struct iio_dev *indio_dev = pf->indio_dev;
struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
unsigned int reg_size;
+ unsigned int data_reg;
uint8_t data[16];
int ret;

@@ -401,18 +408,23 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
indio_dev->channels[0].scan_type.shift;
reg_size = DIV_ROUND_UP(reg_size, 8);

+ if (sigma_delta->info->data_reg != 0)
+ data_reg = sigma_delta->info->data_reg;
+ else
+ data_reg = AD_SD_REG_DATA;
+
switch (reg_size) {
case 4:
case 2:
case 1:
- ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
- reg_size, &data[0]);
+ ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
+ &data[0]);
break;
case 3:
/* We store 24 bit samples in a 32 bit word. Keep the upper
* byte set to zero. */
- ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
- reg_size, &data[1]);
+ ret = ad_sd_read_reg_raw(sigma_delta, data_reg, reg_size,
+ &data[1]);
break;
}

diff --git a/include/linux/iio/adc/ad_sigma_delta.h b/include/linux/iio/adc/ad_sigma_delta.h
index 730ead1..7e84351 100644
--- a/include/linux/iio/adc/ad_sigma_delta.h
+++ b/include/linux/iio/adc/ad_sigma_delta.h
@@ -39,6 +39,8 @@ struct iio_dev;
* if there is just one read-only sample data shift register.
* @addr_shift: Shift of the register address in the communications register.
* @read_mask: Mask for the communications register having the read bit set.
+ * @data_reg: Address of the data register, if 0 the default address of 0x3 will
+ * be used.
*/
struct ad_sigma_delta_info {
int (*set_channel)(struct ad_sigma_delta *, unsigned int channel);
@@ -47,6 +49,7 @@ struct ad_sigma_delta_info {
bool has_registers;
unsigned int addr_shift;
unsigned int read_mask;
+ unsigned int data_reg;
};

/**
--
2.7.4