pinctrl: renesas: Fix save/restore 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 saved/restored during PSCI system suspend.
Fortunately this does not trigger on any supported system yet, as PSCI
is only used on R-Car Gen3 and RZ/G2 systems, which all have separate
pin Pull-Enable (PUEN) and pin Pull-Up/Down control (PUD) registers.

Avoid this ever becoming a problem by treating pinmux_bias_reg.puen and
pinmux_bias_reg.pud the same.  Note that a register controlling both
pull-up and pull-down pins would be saved and restored twice, which is
harmless.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/59d2fbddff685b6a7a82ff17d2b37633e30e8860.1633615652.git.geert+renesas@glider.be

diff --git a/drivers/pinctrl/renesas/core.c b/drivers/pinctrl/renesas/core.c
index ef8ef05ba93030b91a03b2619c1d1aecafece9da..b0d6103d012e78214911bee653efc0b00e32ae57 100644 (file)
--- a/drivers/pinctrl/renesas/core.c
+++ b/drivers/pinctrl/renesas/core.c
@@ -675,8 +675,10 @@ static unsigned int sh_pfc_walk_regs(struct sh_pfc *pfc,
                        do_reg(pfc, pfc->info->drive_regs[i].reg, n++);
 
        if (pfc->info->bias_regs)
-               for (i = 0; pfc->info->bias_regs[i].puen; i++) {
-                       do_reg(pfc, pfc->info->bias_regs[i].puen, n++);
+               for (i = 0; pfc->info->bias_regs[i].puen ||
+                           pfc->info->bias_regs[i].pud; i++) {
+                       if (pfc->info->bias_regs[i].puen)
+                               do_reg(pfc, pfc->info->bias_regs[i].puen, n++);
                        if (pfc->info->bias_regs[i].pud)
                                do_reg(pfc, pfc->info->bias_regs[i].pud, n++);
                }