pinctrl: meson: add pinctrl driver support for Meson-A1 SoC

Meson A1 SoC share the same register layout of pinmux with previous
Meson-G12A, however there is difference for gpio and pin config register
in A1. The main difference is that registers before A1 are grouped by
function while those of A1 are by bank. The new register layout is as
below:

/* first bank */              /* addr */
- P_PADCTRL_GPIOP_I         base + 0x00 << 2
- P_PADCTRL_GPIOP_O         base + 0x01 << 2
- P_PADCTRL_GPIOP_OEN       base + 0x02 << 2
- P_PADCTRL_GPIOP_PULL_EN   base + 0x03 << 2
- P_PADCTRL_GPIOP_PULL_UP   base + 0x04 << 2
- P_PADCTRL_GPIOP_DS        base + 0x05 << 2

/* second bank */
- P_PADCTRL_GPIOB_I         base + 0x10 << 2
- P_PADCTRL_GPIOB_O         base + 0x11 << 2
- P_PADCTRL_GPIOB_OEN       base + 0x12 << 2
- P_PADCTRL_GPIOB_PULL_EN   base + 0x13 << 2
- P_PADCTRL_GPIOB_PULL_UP   base + 0x14 << 2
- P_PADCTRL_GPIOB_DS        base + 0x15 << 2

Each bank contains at least 6 registers to be configured, if one bank
has more than 16 gpios, an extra P_PADCTRL_GPIO[X]_DS_EXT is included.
Between two adjacent P_PADCTRL_GPIO[X]_I, there is an offset 0x10, that
is to say, for third bank, the offsets will be 0x20,0x21,0x22,0x23,0x24
,0x25 according to above register layout. For previous chips, registers
are grouped according to their functions while registers of A1 are
according to bank.Also note that there is no AO bank any more in A1.

Current Meson pinctrl driver can cover such change by using base address
of GPIO as that of drive-strength. While simply giving reg_ds = reg_pullen
make wrong value to reg_ds for Socs that do not support drive-strength
like AXG.To make things simple, add an extra dt parser function for
a1 and remain the old dt parser function for only reg parsing.
Signed-off-by: Qianggui Song <qianggui.song@amlogic.com>
Link: https://lore.kernel.org/r/1573819429-6937-3-git-send-email-qianggui.song@amlogic.comReviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/meson/Kconfig

@@ -54,4 +54,10 @@ config PINCTRL_MESON_G12A
 	select PINCTRL_MESON_AXG_PMX
 	default y
 
+config PINCTRL_MESON_A1
+	bool "Meson a1 Soc pinctrl driver"
+	depends on ARM64
+	select PINCTRL_MESON_AXG_PMX
+	default y
+
 endif

drivers/pinctrl/meson/Makefile

@@ -8,3 +8,4 @@ obj-$(CONFIG_PINCTRL_MESON_GXL) += pinctrl-meson-gxl.o
 obj-$(CONFIG_PINCTRL_MESON_AXG_PMX) += pinctrl-meson-axg-pmx.o
 obj-$(CONFIG_PINCTRL_MESON_AXG) += pinctrl-meson-axg.o
 obj-$(CONFIG_PINCTRL_MESON_G12A) += pinctrl-meson-g12a.o
+obj-$(CONFIG_PINCTRL_MESON_A1) += pinctrl-meson-a1.o

drivers/pinctrl/meson/pinctrl-meson.c

@@ -706,6 +706,15 @@ int meson8_aobus_parse_dt_extra(struct meson_pinctrl *pc)
 	return 0;
 }
 
+int meson_a1_parse_dt_extra(struct meson_pinctrl *pc)
+{
+	pc->reg_pull = pc->reg_gpio;
+	pc->reg_pullen = pc->reg_gpio;
+	pc->reg_ds = pc->reg_gpio;
+
+	return 0;
+}
+
 int meson_pinctrl_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;

drivers/pinctrl/meson/pinctrl-meson.h

@@ -176,3 +176,5 @@ int meson_pmx_get_groups(struct pinctrl_dev *pcdev,
 int meson_pinctrl_probe(struct platform_device *pdev);
 /* Common ao groups extra dt parse function for SoCs before g12a  */
 int meson8_aobus_parse_dt_extra(struct meson_pinctrl *pc);
+/* Common extra dt parse function for SoCs like A1  */
+int meson_a1_parse_dt_extra(struct meson_pinctrl *pc);