pinctrl: renesas: checker: Fix bias checks on SoCs with pull-down only pins

If some bits in a pin Pull-Up control register (PUPR) control pin
pull-down instead of pin pull-up, there are two pinmux_bias_reg entries:
a first one with the puen field filled in, listing pins with pull-up
functionality, and a second one with the pud field filled in, listing
pins with pull-down functionality.  On encountering the second entry,
where puen is NULL, the for-loop terminates early, causing the remaining
bias registers not to be checked.  In addition, sh_pfc_check_bias_reg()
does not handle such entries.

Fix this by treating pinmux_bias_reg.puen and pinmux_bias_reg.pud the
same.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/29526d06fa223cffd785cdb264b756a202b11cea.1633615652.git.geert+renesas@glider.be

drivers/pinctrl/renesas/core.c

@@ -919,7 +919,8 @@ static void __init sh_pfc_check_bias_reg(const struct sh_pfc_soc_info *info,
 		if (bias->pins[i] != SH_PFC_PIN_NONE)
 			bits |= BIT(i);
 
-	sh_pfc_check_reg(info->name, bias->puen, bits);
+	if (bias->puen)
+		sh_pfc_check_reg(info->name, bias->puen, bits);
 	if (bias->pud)
 		sh_pfc_check_reg(info->name, bias->pud, bits);
 	for (i = 0; i < ARRAY_SIZE(bias->pins); i++)
@@ -928,6 +929,7 @@ static void __init sh_pfc_check_bias_reg(const struct sh_pfc_soc_info *info,
 
 static void __init sh_pfc_check_info(const struct sh_pfc_soc_info *info)
 {
+	const struct pinmux_bias_reg *bias_regs = info->bias_regs;
 	const char *drvname = info->name;
 	unsigned int *refcnts;
 	unsigned int i, j, k;
@@ -1024,8 +1026,8 @@ static void __init sh_pfc_check_info(const struct sh_pfc_soc_info *info)
 		sh_pfc_check_drive_reg(info, &info->drive_regs[i]);
 
 	/* Check bias registers */
-	for (i = 0; info->bias_regs && info->bias_regs[i].puen; i++)
-		sh_pfc_check_bias_reg(info, &info->bias_regs[i]);
+	for (i = 0; bias_regs && (bias_regs[i].puen || bias_regs[i].pud); i++)
+		sh_pfc_check_bias_reg(info, &bias_regs[i]);
 
 	/* Check ioctrl registers */
 	for (i = 0; info->ioctrl_regs && info->ioctrl_regs[i].reg; i++)