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Subject[PATCH v3 1/2] iio: adc: ad7192: fix null pointer de-reference crash during probe
Date
When the 'spi_device_id' table was removed, it omitted to cleanup/fix the
assignment:
'indio_dev->name = spi_get_device_id(spi)->name;'

After that patch 'spi_get_device_id(spi)' returns NULL, so this crashes
during probe with null de-ref.

This change fixes this by introducing an ad7192_chip_info struct, and
defines all part-names [that should be assigned to indio_dev->name] in a
'ad7192_chip_info_tbl' table.

With this change, the old 'st->devid' is also moved to be a
'chip_info->chip_id'. And the old 'ID_AD719X' macros have been renamed to
'CHIPID_AD719X'. Tld identifiers have been re-purposed to be enum/index
values in the new 'ad7192_chip_info_tbl'.

This should fix the bug, and maintain the ABI for the 'indio_dev->name'
field.

Fixes: 66614ab2be38 ("staging: iio: adc: ad7192: removed spi_device_id")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
---

Changelog v2 -> v3:
* reworked patch to introduce a chip_info struct for the part-name
* added 2nd patch to move of-table closer to the end of the file; this
patch is more cosmetic; has no fixes tag, but is on top of the previous

Changelog v1 -> v2:
* fix colon for Fixes tag
* updated commit title a bit; to make it longer

drivers/iio/adc/ad7192.c | 61 ++++++++++++++++++++++++++++++----------
1 file changed, 46 insertions(+), 15 deletions(-)

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index 8ec28aa8fa8a..7e8662c5cb0e 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -125,10 +125,10 @@
#define AD7193_CH_AINCOM 0x600 /* AINCOM - AINCOM */

/* ID Register Bit Designations (AD7192_REG_ID) */
-#define ID_AD7190 0x4
-#define ID_AD7192 0x0
-#define ID_AD7193 0x2
-#define ID_AD7195 0x6
+#define CHIPID_AD7190 0x4
+#define CHIPID_AD7192 0x0
+#define CHIPID_AD7193 0x2
+#define CHIPID_AD7195 0x6
#define AD7192_ID_MASK 0x0F

/* GPOCON Register Bit Designations (AD7192_REG_GPOCON) */
@@ -161,7 +161,20 @@ enum {
AD7192_SYSCALIB_FULL_SCALE,
};

+enum {
+ ID_AD7190,
+ ID_AD7192,
+ ID_AD7193,
+ ID_AD7195,
+};
+
+struct ad7192_chip_info {
+ unsigned int chip_id;
+ const char *name;
+};
+
struct ad7192_state {
+ const struct ad7192_chip_info *chip_info;
struct regulator *avdd;
struct regulator *dvdd;
struct clk *mclk;
@@ -172,7 +185,6 @@ struct ad7192_state {
u32 conf;
u32 scale_avail[8][2];
u8 gpocon;
- u8 devid;
u8 clock_sel;
struct mutex lock; /* protect sensor state */
u8 syscalib_mode[8];
@@ -348,7 +360,7 @@ static int ad7192_setup(struct ad7192_state *st, struct device_node *np)

id &= AD7192_ID_MASK;

- if (id != st->devid)
+ if (id != st->chip_info->chip_id)
dev_warn(&st->sd.spi->dev, "device ID query failed (0x%X)\n",
id);

@@ -363,7 +375,7 @@ static int ad7192_setup(struct ad7192_state *st, struct device_node *np)
st->mode |= AD7192_MODE_REJ60;

refin2_en = of_property_read_bool(np, "adi,refin2-pins-enable");
- if (refin2_en && st->devid != ID_AD7195)
+ if (refin2_en && st->chip_info->chip_id != CHIPID_AD7195)
st->conf |= AD7192_CONF_REFSEL;

st->conf &= ~AD7192_CONF_CHOP;
@@ -859,11 +871,30 @@ static const struct iio_chan_spec ad7193_channels[] = {
IIO_CHAN_SOFT_TIMESTAMP(14),
};

+static const struct ad7192_chip_info ad7192_chip_info_tbl[] = {
+ [ID_AD7190] = {
+ .chip_id = CHIPID_AD7190,
+ .name = "ad7190",
+ },
+ [ID_AD7192] = {
+ .chip_id = CHIPID_AD7192,
+ .name = "ad7192",
+ },
+ [ID_AD7193] = {
+ .chip_id = CHIPID_AD7193,
+ .name = "ad7193",
+ },
+ [ID_AD7195] = {
+ .chip_id = CHIPID_AD7195,
+ .name = "ad7195",
+ },
+};
+
static int ad7192_channels_config(struct iio_dev *indio_dev)
{
struct ad7192_state *st = iio_priv(indio_dev);

- switch (st->devid) {
+ switch (st->chip_info->chip_id) {
case ID_AD7193:
indio_dev->channels = ad7193_channels;
indio_dev->num_channels = ARRAY_SIZE(ad7193_channels);
@@ -878,10 +909,10 @@ static int ad7192_channels_config(struct iio_dev *indio_dev)
}

static const struct of_device_id ad7192_of_match[] = {
- { .compatible = "adi,ad7190", .data = (void *)ID_AD7190 },
- { .compatible = "adi,ad7192", .data = (void *)ID_AD7192 },
- { .compatible = "adi,ad7193", .data = (void *)ID_AD7193 },
- { .compatible = "adi,ad7195", .data = (void *)ID_AD7195 },
+ { .compatible = "adi,ad7190", .data = &ad7192_chip_info_tbl[ID_AD7190] },
+ { .compatible = "adi,ad7192", .data = &ad7192_chip_info_tbl[ID_AD7192] },
+ { .compatible = "adi,ad7193", .data = &ad7192_chip_info_tbl[ID_AD7193] },
+ { .compatible = "adi,ad7195", .data = &ad7192_chip_info_tbl[ID_AD7195] },
{}
};
MODULE_DEVICE_TABLE(of, ad7192_of_match);
@@ -938,16 +969,16 @@ static int ad7192_probe(struct spi_device *spi)
}

spi_set_drvdata(spi, indio_dev);
- st->devid = (unsigned long)of_device_get_match_data(&spi->dev);
+ st->chip_info = of_device_get_match_data(&spi->dev);
indio_dev->dev.parent = &spi->dev;
- indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->name = st->chip_info->name;
indio_dev->modes = INDIO_DIRECT_MODE;

ret = ad7192_channels_config(indio_dev);
if (ret < 0)
goto error_disable_dvdd;

- if (st->devid == ID_AD7195)
+ if (st->chip_info->chip_id == CHIPID_AD7195)
indio_dev->info = &ad7195_info;
else
indio_dev->info = &ad7192_info;
--
2.17.1
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