pinctrl: renesas: Add support for R-Car SoCs with pull-down only pins

Currently, the common R-Car bias handling supports pin controllers with
either:
  1. Separate pin Pull-Enable (PUEN) and pin Pull-Up/Down control (PUD)
     registers, for controlling both pin pull-up and pin pull-down,
  2. A single pin Pull-Up control register (PUPR), for controlling pin
     pull-up.

Add support for a variant of #2, where some bits in the single pin
Pull-Up control register (PUPR) control pin pull-down instead of pin
pull-up.  This is the case for the "ASEBRK#/ACK" pin on R-Car M2-W,
M2-N, and E2, and the "ACK" pin on RZ/G1M, RZ/G1N, RZ/G1E, and RZ/G1C.
To describe such a register, SoC-specific drivers need to provide two
instances of pinmux_bias_reg: 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.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20210303132619.3938128-6-geert+renesas@glider.be

diff --git a/drivers/pinctrl/renesas/pinctrl.c b/drivers/pinctrl/renesas/pinctrl.c
index b7ebbc8..bb488af 100644 (file)
--- a/drivers/pinctrl/renesas/pinctrl.c
+++ b/drivers/pinctrl/renesas/pinctrl.c
@@ -847,7 +847,7 @@ rcar_pin_to_bias_reg(const struct sh_pfc *pfc, unsigned int pin,
 {
        unsigned int i, j;
 
-       for (i = 0; pfc->info->bias_regs[i].puen; i++) {
+       for (i = 0; pfc->info->bias_regs[i].puen || pfc->info->bias_regs[i].pud; i++) {
                for (j = 0; j < ARRAY_SIZE(pfc->info->bias_regs[i].pins); j++) {
                        if (pfc->info->bias_regs[i].pins[j] == pin) {
                                *bit = j;
@@ -870,12 +870,19 @@ unsigned int rcar_pinmux_get_bias(struct sh_pfc *pfc, unsigned int pin)
        if (!reg)
                return PIN_CONFIG_BIAS_DISABLE;
 
-       if (!(sh_pfc_read(pfc, reg->puen) & BIT(bit)))
-               return PIN_CONFIG_BIAS_DISABLE;
-       else if (!reg->pud || (sh_pfc_read(pfc, reg->pud) & BIT(bit)))
-               return PIN_CONFIG_BIAS_PULL_UP;
-       else
-               return PIN_CONFIG_BIAS_PULL_DOWN;
+       if (reg->puen) {
+               if (!(sh_pfc_read(pfc, reg->puen) & BIT(bit)))
+                       return PIN_CONFIG_BIAS_DISABLE;
+               else if (!reg->pud || (sh_pfc_read(pfc, reg->pud) & BIT(bit)))
+                       return PIN_CONFIG_BIAS_PULL_UP;
+               else
+                       return PIN_CONFIG_BIAS_PULL_DOWN;
+       } else {
+               if (sh_pfc_read(pfc, reg->pud) & BIT(bit))
+                       return PIN_CONFIG_BIAS_PULL_DOWN;
+               else
+                       return PIN_CONFIG_BIAS_DISABLE;
+       }
 }
 
 void rcar_pinmux_set_bias(struct sh_pfc *pfc, unsigned int pin,
@@ -889,19 +896,27 @@ void rcar_pinmux_set_bias(struct sh_pfc *pfc, unsigned int pin,
        if (!reg)
                return;
 
-       enable = sh_pfc_read(pfc, reg->puen) & ~BIT(bit);
-       if (bias != PIN_CONFIG_BIAS_DISABLE)
-               enable |= BIT(bit);
+       if (reg->puen) {
+               enable = sh_pfc_read(pfc, reg->puen) & ~BIT(bit);
+               if (bias != PIN_CONFIG_BIAS_DISABLE)
+                       enable |= BIT(bit);
 
-       if (reg->pud) {
-               updown = sh_pfc_read(pfc, reg->pud) & ~BIT(bit);
-               if (bias == PIN_CONFIG_BIAS_PULL_UP)
-                       updown |= BIT(bit);
+               if (reg->pud) {
+                       updown = sh_pfc_read(pfc, reg->pud) & ~BIT(bit);
+                       if (bias == PIN_CONFIG_BIAS_PULL_UP)
+                               updown |= BIT(bit);
 
-               sh_pfc_write(pfc, reg->pud, updown);
-       }
+                       sh_pfc_write(pfc, reg->pud, updown);
+               }
 
-       sh_pfc_write(pfc, reg->puen, enable);
+               sh_pfc_write(pfc, reg->puen, enable);
+       } else {
+               enable = sh_pfc_read(pfc, reg->pud) & ~BIT(bit);
+               if (bias == PIN_CONFIG_BIAS_PULL_DOWN)
+                       enable |= BIT(bit);
+
+               sh_pfc_write(pfc, reg->pud, enable);
+       }
 }
 
 #define PORTnCR_PULMD_OFF      (0 << 6)

diff --git a/drivers/pinctrl/renesas/sh_pfc.h b/drivers/pinctrl/renesas/sh_pfc.h
index fc83917..3208988 100644 (file)
--- a/drivers/pinctrl/renesas/sh_pfc.h
+++ b/drivers/pinctrl/renesas/sh_pfc.h
@@ -188,9 +188,9 @@ struct pinmux_drive_reg {
        .reg = r, \
        .fields =
 
-struct pinmux_bias_reg {
+struct pinmux_bias_reg {       /* At least one of puen/pud must exist */
        u32 puen;               /* Pull-enable or pull-up control register */
-       u32 pud;                /* Pull-up/down control register (optional) */
+       u32 pud;                /* Pull-up/down or pull-down control register */
        const u16 pins[32];
 };