[PATCH 3.16 031/328] pinctrl: msm: Fix msm_config_group_get() to be compliant

[Ben Hutchings]

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Douglas Anderson <dianders@xxxxxxxxxxxx>

commit 05e0c828955c1cab58dd71a04539442e5375d917 upstream.

If you do this on an sdm845 board:
  cat /sys/kernel/debug/pinctrl/3400000.pinctrl/pinconf-groups

...it looks like nonsense.  For every pin you see listed:
  input bias bus hold, input bias disabled, input bias pull down, input bias pull up

That's because msm_config_group_get() isn't complying with the rules
that pinconf_generic_dump_one() expects.  Specifically for boolean
parameters (anything with a "struct pin_config_item" where has_arg is
false) the function expects that the function should return its value
not through the "config" parameter but should return "0" if the value
is set and "-EINVAL" if the value isn't set.

Let's fix this.

=46roma quick sample of other pinctrl drivers, it appears to be
tradition to also return 1 through the config parameter for these
boolean parameters when they exist.  I'm not one to knock tradition,
so I'll follow tradition and return 1 in these cases.  While I'm at
it, I'll also continue searching for four leaf clovers, kocking on
wood three times, and trying not to break mirrors.

Fixes: f365be092572 ("pinctrl: Add Qualcomm TLMM driver")
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
[bwh: Backported to 3.16:
 - Drop change to case PIN_CONFIG_BIAS_BUS_HOLD
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/pinctrl/pinctrl-msm.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/drivers/pinctrl/pinctrl-msm.c
+++ b/drivers/pinctrl/pinctrl-msm.c
@@ -275,13 +275,19 @@ static int msm_config_group_get(struct p
 	/* Convert register value to pinconf value */
 	switch (param) {
 	case PIN_CONFIG_BIAS_DISABLE:
-		arg = arg == MSM_NO_PULL;
+		if (arg != MSM_NO_PULL)
+			return -EINVAL;
+		arg = 1;
 		break;
 	case PIN_CONFIG_BIAS_PULL_DOWN:
-		arg = arg == MSM_PULL_DOWN;
+		if (arg != MSM_PULL_DOWN)
+			return -EINVAL;
+		arg = 1;
 		break;
 	case PIN_CONFIG_BIAS_PULL_UP:
 		arg = arg == MSM_PULL_UP;
+		if (!arg)
+			return -EINVAL;
 		break;
 	case PIN_CONFIG_DRIVE_STRENGTH:
 		arg = msm_regval_to_drive(arg);