[PATCH v2] leds: is31fl32xx: Fix NULL pointer dereference when binding via I2C ID table

[Rosen Penev <rosenp@gmail.com>]

If the device binds via the I2C ID table (e.g. sysfs new_device, a
software node, or a firmware node without a matching compatible),
device_get_match_data() in is31fl32xx_probe() returns NULL, since only
the OF match table carries the chip definition. is31fl32xx_parse_dt()
then dereferences cdef->output_frequency_setting_reg and
is31fl32xx_parse_child_dt() dereferences cdef->channels, causing a
kernel oops.

Populate .driver_data in is31fl32xx_id with the same chip definitions
as the OF table and use i2c_get_match_data(), which falls back to the
I2C ID table when no firmware match data is available. Every entry
now carries match data, so cdef can no longer be NULL.

Drop the comment above the ID table, as the table is now used for
matching data as well.

Fixes: 2779f4724b2f ("leds: various: use device_get_match_data")
Cc: stable@vger.kernel.org
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 v2: use i2c_get_match_data()
 drivers/leds/leds-is31fl32xx.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/leds/leds-is31fl32xx.c b/drivers/leds/leds-is31fl32xx.c
index 285085d27453..5ef4fd649d60 100644
--- a/drivers/leds/leds-is31fl32xx.c
+++ b/drivers/leds/leds-is31fl32xx.c
@@ -574,7 +574,7 @@ static int is31fl32xx_probe(struct i2c_client *client)
 	int count;
 	int ret = 0;
 
-	cdef = device_get_match_data(dev);
+	cdef = i2c_get_match_data(client);
 
 	count = device_get_child_node_count(dev);
 	if (!count)
@@ -611,19 +611,15 @@ static void is31fl32xx_remove(struct i2c_client *client)
 			ERR_PTR(ret));
 }
 
-/*
- * i2c-core (and modalias) requires that id_table be properly filled,
- * even though it is not used for DeviceTree based instantiation.
- */
 static const struct i2c_device_id is31fl32xx_id[] = {
-	{ .name = "is31fl3293" },
-	{ .name = "is31fl3236" },
-	{ .name = "is31fl3236a" },
-	{ .name = "is31fl3235" },
-	{ .name = "is31fl3218" },
-	{ .name = "sn3218" },
-	{ .name = "is31fl3216" },
-	{ .name = "sn3216" },
+	{ "is31fl3293",  (kernel_ulong_t)&is31fl3293_cdef },
+	{ "is31fl3236",  (kernel_ulong_t)&is31fl3236_cdef },
+	{ "is31fl3236a", (kernel_ulong_t)&is31fl3236a_cdef },
+	{ "is31fl3235",  (kernel_ulong_t)&is31fl3235_cdef },
+	{ "is31fl3218",  (kernel_ulong_t)&is31fl3218_cdef },
+	{ "sn3218",      (kernel_ulong_t)&is31fl3218_cdef },
+	{ "is31fl3216",  (kernel_ulong_t)&is31fl3216_cdef },
+	{ "sn3216",      (kernel_ulong_t)&is31fl3216_cdef },
 	{ }
 };
 
-- 
2.56.0