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Date: Tue, 14 Jul 2020 08:11:11 +0300
From: Alexandru Ardelean <alexandru.ardelean@...log.com>
To: <linux-iio@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <jic23@...nel.org>,
Alexandru Ardelean <alexandru.ardelean@...log.com>
Subject: [PATCH] iio: adc: ad7124: move chip ID & name on the chip_info table
This change does the following:
* removes the SPI device table in favor of the OF device table
* adds 'name' && 'chip_id' fields to chip_info
* implements chip ID & silicon revision checking; the device ID for
AD7124-4 is 0x0, so just checking that value can be useless;
but at least the silicon revision isn't 0, so a non-zero value can be
used to check that "a" device is on the SPI bus; it's probably the best
way to narrow it down to one of the 2 AD7124 chip IDs
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
---
drivers/iio/adc/ad7124.c | 73 ++++++++++++++++++++++++++++++++--------
1 file changed, 59 insertions(+), 14 deletions(-)
diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index bb53ab265b64..8dce06e9e69c 100644
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -12,6 +12,7 @@
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/of_device.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
@@ -47,6 +48,15 @@
#define AD7124_ADC_CTRL_MODE_MSK GENMASK(5, 2)
#define AD7124_ADC_CTRL_MODE(x) FIELD_PREP(AD7124_ADC_CTRL_MODE_MSK, x)
+/* AD7124 ID */
+#define AD7124_DEVICE_ID_MSK GENMASK(7, 4)
+#define AD7124_DEVICE_ID_GET(x) FIELD_GET(AD7124_DEVICE_ID_MSK, x)
+#define AD7124_SILICON_REV_MSK GENMASK(3, 0)
+#define AD7124_SILICON_REV_GET(x) FIELD_GET(AD7124_SILICON_REV_MSK, x)
+
+#define CHIPID_AD7124_4 0x0
+#define CHIPID_AD7124_8 0x1
+
/* AD7124_CHANNEL_X */
#define AD7124_CHANNEL_EN_MSK BIT(15)
#define AD7124_CHANNEL_EN(x) FIELD_PREP(AD7124_CHANNEL_EN_MSK, x)
@@ -120,6 +130,8 @@ static const char * const ad7124_ref_names[] = {
};
struct ad7124_chip_info {
+ const char *name;
+ unsigned int chip_id;
unsigned int num_inputs;
};
@@ -165,9 +177,13 @@ static const struct iio_chan_spec ad7124_channel_template = {
static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
[ID_AD7124_4] = {
+ .name = "ad7127-4",
+ .chip_id = CHIPID_AD7124_4,
.num_inputs = 8,
},
[ID_AD7124_8] = {
+ .name = "ad7127-8",
+ .chip_id = CHIPID_AD7124_8,
.num_inputs = 16,
},
};
@@ -503,6 +519,34 @@ static int ad7124_soft_reset(struct ad7124_state *st)
return -EIO;
}
+static int ad7124_check_chip_id(struct ad7124_state *st)
+{
+ unsigned int readval, chip_id, silicon_rev;
+ int ret;
+
+ ret = ad_sd_read_reg(&st->sd, AD7124_ID, 1, &readval);
+ if (ret < 0)
+ return ret;
+
+ chip_id = AD7124_DEVICE_ID_GET(readval);
+ silicon_rev = AD7124_SILICON_REV_GET(readval);
+
+ if (chip_id != st->chip_info->chip_id) {
+ dev_err(&st->sd.spi->dev,
+ "Chip ID mismatch: expected %u, got %u\n",
+ st->chip_info->chip_id, chip_id);
+ return -ENODEV;
+ }
+
+ if (silicon_rev == 0) {
+ dev_err(&st->sd.spi->dev,
+ "Silicon revision empty. Chip may not be present\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
static int ad7124_init_channel_vref(struct ad7124_state *st,
unsigned int channel_number)
{
@@ -665,25 +709,28 @@ static int ad7124_setup(struct ad7124_state *st)
static int ad7124_probe(struct spi_device *spi)
{
- const struct spi_device_id *id;
+ const struct ad7124_chip_info *info;
struct ad7124_state *st;
struct iio_dev *indio_dev;
int i, ret;
+ info = of_device_get_match_data(&spi->dev);
+ if (!info)
+ return -ENODEV;
+
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
if (!indio_dev)
return -ENOMEM;
st = iio_priv(indio_dev);
- id = spi_get_device_id(spi);
- st->chip_info = &ad7124_chip_info_tbl[id->driver_data];
+ st->chip_info = info;
ad_sd_init(&st->sd, indio_dev, spi, &ad7124_sigma_delta_info);
spi_set_drvdata(spi, indio_dev);
- indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->name = st->chip_info->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &ad7124_info;
@@ -721,6 +768,10 @@ static int ad7124_probe(struct spi_device *spi)
if (ret < 0)
goto error_clk_disable_unprepare;
+ ret = ad7124_check_chip_id(st);
+ if (ret)
+ goto error_clk_disable_unprepare;
+
ret = ad7124_setup(st);
if (ret < 0)
goto error_clk_disable_unprepare;
@@ -768,16 +819,11 @@ static int ad7124_remove(struct spi_device *spi)
return 0;
}
-static const struct spi_device_id ad7124_id_table[] = {
- { "ad7124-4", ID_AD7124_4 },
- { "ad7124-8", ID_AD7124_8 },
- {}
-};
-MODULE_DEVICE_TABLE(spi, ad7124_id_table);
-
static const struct of_device_id ad7124_of_match[] = {
- { .compatible = "adi,ad7124-4" },
- { .compatible = "adi,ad7124-8" },
+ { .compatible = "adi,ad7124-4",
+ .data = &ad7124_chip_info_tbl[ID_AD7124_4], },
+ { .compatible = "adi,ad7124-8",
+ .data = &ad7124_chip_info_tbl[ID_AD7124_8], },
{ },
};
MODULE_DEVICE_TABLE(of, ad7124_of_match);
@@ -789,7 +835,6 @@ static struct spi_driver ad71124_driver = {
},
.probe = ad7124_probe,
.remove = ad7124_remove,
- .id_table = ad7124_id_table,
};
module_spi_driver(ad71124_driver);
--
2.17.1
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