[PATCH 1/2] staging: iio: adc: ad7192: Add clock for external clock reference

Mircea Caprioru
2018-12-06T09:11:16Z

This patch adds a clock to the state structure of ad7192 for getting the
external clock frequency. This modifications is in accordance with clock
framework dt bindings documentation.

Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
---
drivers/staging/iio/adc/ad7192.c | 74 +++++++++++++++++++++-----------
drivers/staging/iio/adc/ad7192.h | 2 -
2 files changed, 50 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
index acdbc07fd259..8a4e6ede42b3 100644
--- a/drivers/staging/iio/adc/ad7192.c
+++ b/drivers/staging/iio/adc/ad7192.c
@@ -6,6 +6,7 @@
* Licensed under the GPL-2.
*/

+#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
@@ -156,8 +157,9 @@
struct ad7192_state {
struct regulator *avdd;
struct regulator *dvdd;
+ struct clk *mclk;
u16 int_vref_mv;
- u32 mclk;
+ u32 fclk;
u32 f_order;
u32 mode;
u32 conf;
@@ -165,6 +167,7 @@ struct ad7192_state {
u8 gpocon;
u8 devid;
struct mutex lock; /* protect sensor state */
+ u8 clock_sel;

struct ad_sigma_delta sd;
};
@@ -250,28 +253,8 @@ static int ad7192_setup(struct ad7192_state *st,
dev_warn(&st->sd.spi->dev, "device ID query failed (0x%X)\n",
id);

- switch (pdata->clock_source_sel) {
- case AD7192_CLK_INT:
- case AD7192_CLK_INT_CO:
- st->mclk = AD7192_INT_FREQ_MHZ;
- break;
- case AD7192_CLK_EXT_MCLK1_2:
- case AD7192_CLK_EXT_MCLK2:
- if (ad7192_valid_external_frequency(pdata->ext_clk_hz)) {
- st->mclk = pdata->ext_clk_hz;
- break;
- }
- dev_err(&st->sd.spi->dev, "Invalid frequency setting %u\n",
- pdata->ext_clk_hz);
- ret = -EINVAL;
- goto out;
- default:
- ret = -EINVAL;
- goto out;
- }
-
st->mode = AD7192_MODE_SEL(AD7192_MODE_IDLE) |
- AD7192_MODE_CLKSRC(pdata->clock_source_sel) |
+ AD7192_MODE_CLKSRC(st->clock_sel) |
AD7192_MODE_RATE(480);

st->conf = AD7192_CONF_GAIN(0);
@@ -499,7 +482,7 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
*val -= 273 * ad7192_get_temp_scale(unipolar);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SAMP_FREQ:
- *val = st->mclk /
+ *val = st->fclk /
(st->f_order * 1024 * AD7192_MODE_RATE(st->mode));
return IIO_VAL_INT;
}
@@ -546,7 +529,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
break;
}

- div = st->mclk / (val * st->f_order * 1024);
+ div = st->fclk / (val * st->f_order * 1024);
if (div < 1 || div > 1023) {
ret = -EINVAL;
break;
@@ -625,6 +608,42 @@ static const struct iio_chan_spec ad7193_channels[] = {
IIO_CHAN_SOFT_TIMESTAMP(14),
};

+static int ad7192_clock_select(struct spi_device *spi, struct ad7192_state *st)
+{
+ int ret;
+
+ st->clock_sel = AD7192_CLK_EXT_MCLK2;
+ st->mclk = devm_clk_get(&spi->dev, "clk");
+ if (IS_ERR(st->mclk)) {
+ if (PTR_ERR(st->mclk) != -ENOENT)
+ return PTR_ERR(st->mclk);
+
+ /* try xtal option */
+ st->mclk = devm_clk_get(&spi->dev, "xtal");
+ st->clock_sel = AD7192_CLK_EXT_MCLK1_2;
+ if (IS_ERR(st->mclk)) {
+ if (PTR_ERR(st->mclk) != -ENOENT)
+ return PTR_ERR(st->mclk);
+
+ /* use internal clock */
+ st->clock_sel = AD7192_CLK_INT;
+ st->fclk = AD7192_INT_FREQ_MHZ;
+ }
+ }
+ if (st->clock_sel == AD7192_CLK_EXT_MCLK2 ||
+ st->clock_sel == AD7192_CLK_EXT_MCLK1_2) {
+ ret = clk_prepare_enable(st->mclk);
+ if (ret < 0)
+ return ret;
+
+ st->fclk = clk_get_rate(st->mclk);
+ if (!ad7192_valid_external_frequency(st->fclk))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int ad7192_probe(struct spi_device *spi)
{
const struct ad7192_platform_data *pdata = dev_get_platdata(&spi->dev);
@@ -672,6 +691,10 @@ static int ad7192_probe(struct spi_device *spi)
goto error_disable_avdd;
}

+ ret = ad7192_clock_select(spi, st);
+ if (ret < 0)
+ goto error_clk_disable_unprepare;
+
voltage_uv = regulator_get_voltage(st->avdd);

if (pdata->vref_mv)
@@ -720,6 +743,8 @@ static int ad7192_probe(struct spi_device *spi)

error_remove_trigger:
ad_sd_cleanup_buffer_and_trigger(indio_dev);
+error_clk_disable_unprepare:
+ clk_disable_unprepare(st->mclk);
error_disable_dvdd:
regulator_disable(st->dvdd);
error_disable_avdd:
@@ -735,6 +760,7 @@ static int ad7192_remove(struct spi_device *spi)

iio_device_unregister(indio_dev);
ad_sd_cleanup_buffer_and_trigger(indio_dev);
+ clk_disable_unprepare(st->mclk);

regulator_disable(st->dvdd);
regulator_disable(st->avdd);
diff --git a/drivers/staging/iio/adc/ad7192.h b/drivers/staging/iio/adc/ad7192.h
index 7433a43c2611..3be3ee269ed5 100644
--- a/drivers/staging/iio/adc/ad7192.h
+++ b/drivers/staging/iio/adc/ad7192.h
@@ -33,8 +33,6 @@

struct ad7192_platform_data {
u16 vref_mv;
- u8 clock_source_sel;
- u32 ext_clk_hz;
bool refin2_en;
bool rej60_en;
bool sinc3_en;
--
2.17.1