[PATCH] pinctrl: sh-pfc: fix a null pointer dereference of drive strength information

[Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>]

Not all SoCs describes the drive strength registers. When reading the
sysfs pinconf-pins file on such a SoC this results in a null pointer
dereference. Protect against this dereference and allow reading of the
pinconf-pins by adding a check if the drive strength registers are
described or not.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
 drivers/pinctrl/sh-pfc/pinctrl.c | 3 +++
 1 file changed, 3 insertions(+)

---

Hi Geert,

This was found on the Eagle board and is based on the latest 
renesas/devel branch.

Regards,
Niklas

diff --git a/drivers/pinctrl/sh-pfc/pinctrl.c b/drivers/pinctrl/sh-pfc/pinctrl.c
index 654dc20e171b9363..ef837676d0312e8d 100644
--- a/drivers/pinctrl/sh-pfc/pinctrl.c
+++ b/drivers/pinctrl/sh-pfc/pinctrl.c
@@ -483,6 +483,9 @@ static u32 sh_pfc_pinconf_find_drive_strength_reg(struct sh_pfc *pfc,
 	const struct pinmux_drive_reg *reg;
 	unsigned int i;
 
+	if (!pfc->info->drive_regs)
+		return 0;
+
 	for (reg = pfc->info->drive_regs; reg->reg; ++reg) {
 		for (i = 0; i < ARRAY_SIZE(reg->fields); ++i) {
 			field = &reg->fields[i];
-- 
2.17.0