On 01/05/18 10:45, Lee Jones wrote:
The COMP1 and COMP2 elements are in 0 and 1 respectively so this code is
accessing the wrong elements and one space beyond the end of the array.
The "id" variable is never COMP (0) so that code can be removed.
Fixes: 6851ad3ab346 ("TPS65911: Comparator: Add comparator driver")
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
---
History:
Dan was the originator of this patch and the author of the commit log,
but produced 2 code solutions which I wasn't happy with. The first
submission [0] introduced a COMP device, which after a quick check of
the datasheet [1] appeared to be fictitious. A subsequent submission
[2] conducted arithmetic in array indexes.
It is my belief that the correct solution is to roll which the
situation the hardware engineers presented us with and define COMP1
at position 0 and COMP2 at position 1 such that we can use the
simplest code possible to select them.
Dan wasn't happy to put his name to this, which I completely
understand. Calling SOMETHING1 0 (zero) is a little unnatural.
However, since I have no shame, I offered to submit it.
As an idly-curious passer-by, this looks perfectly reasonable to me - I
don't see why a mapping between names and indices should have to be
artificially constrained just because the names happen to contain
numerals. If it's really that abhorrent, then I guess they could be
named something like COMPn_ID for even more clarity.
That said, now that I've gone and looked, the whole business seems
ridiculously over-engineered. AFAICS it would be infinitely simpler to
just pass the register address directly where id is currently passed,
statically define UV_MAX, and get rid of the otherwise-pointless struct
comparator entirely. The current abstraction doesn't look like it could
actually scale to support different chips without major surgery anyway.
Robin.
[0] https://lkml.org/lkml/2018/4/19/449
[1] http://www.ti.com/lit/ds/symlink/tps65911.pdf (page 52)
[2] https://lkml.org/lkml/2018/4/20/204
drivers/mfd/tps65911-comparator.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/drivers/mfd/tps65911-comparator.c
b/drivers/mfd/tps65911-comparator.c
index d223857fb4ad..33591767fb9b 100644
--- a/drivers/mfd/tps65911-comparator.c
+++ b/drivers/mfd/tps65911-comparator.c
@@ -22,9 +22,8 @@
#include <linux/gpio.h>
#include <linux/mfd/tps65910.h>
-#define COMP 0
-#define COMP1 1
-#define COMP2 2
+#define COMP1 0
+#define COMP2 1
/* Comparator 1 voltage selection table in millivolts */
static const u16 COMP_VSEL_TABLE[] = {
@@ -63,9 +62,6 @@ static int comp_threshold_set(struct tps65910 *tps65910, int
id, int voltage)
int ret;
u8 index = 0, val;
- if (id == COMP)
- return 0;
-
while (curr_voltage < tps_comp.uV_max) {
curr_voltage = tps_comp.vsel_table[index];
if (curr_voltage >= voltage)
@@ -89,9 +85,6 @@ static int comp_threshold_get(struct tps65910 *tps65910, int
id)
unsigned int val;
int ret;
- if (id == COMP)
- return 0;
-
ret = tps65910_reg_read(tps65910, tps_comp.reg, &val);
if (ret < 0)
return ret;
