openwrt/target/linux/starfive/patches-6.1/1009-pinctrl-starfive-Reset-pinmux-settings.patch

From 89c86fda8cee5b93ce213dcc46b2cf27e5ee3312 Mon Sep 17 00:00:00 2001
From: Emil Renner Berthing <kernel@esmil.dk>
Date: Sat, 17 Jul 2021 21:50:38 +0200
Subject: [PATCH 1009/1024] pinctrl: starfive: Reset pinmux settings

Current u-boot doesn't seem to take into account that some GPIOs are
configured as inputs/outputs of certain peripherals on power-up. This
means it ends up configuring some GPIOs as inputs to more than one
peripheral which the documentation explicitly says is illegal. Similarly
it also ends up configuring more than one GPIO as output of the same
peripheral. While not explicitly mentioned by the documentation this
also seems like a bad idea.

The easiest way to remedy this mess is to just disconnect all GPIOs from
peripherals and have our pinmux configuration set everything up
properly. This, however, means that we'd disconnect the serial console
from its pins for a while, so add a device tree property to keep
certain GPIOs from being reset.

Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
---
 .../pinctrl/starfive,jh7100-pinctrl.yaml      |  4 ++
 .../starfive/pinctrl-starfive-jh7100.c        | 66 +++++++++++++++++++
 2 files changed, 70 insertions(+)

--- a/Documentation/devicetree/bindings/pinctrl/starfive,jh7100-pinctrl.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/starfive,jh7100-pinctrl.yaml
@@ -88,6 +88,10 @@ properties:
     $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 1, 2, 3, 4, 5, 6]
 
+  starfive,keep-gpiomux:
+    description: Keep pinmux for these GPIOs from being reset at boot.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
 required:
   - compatible
   - reg
--- a/drivers/pinctrl/starfive/pinctrl-starfive-jh7100.c
+++ b/drivers/pinctrl/starfive/pinctrl-starfive-jh7100.c
@@ -200,6 +200,10 @@ static u16 starfive_drive_strength_from_
 	return (clamp(i, 14U, 63U) - 14) / 7;
 }
 
+static bool keepmux;
+module_param(keepmux, bool, 0644);
+MODULE_PARM_DESC(keepmux, "Keep pinmux settings from previous boot stage");
+
 struct starfive_pinctrl {
 	struct gpio_chip gc;
 	struct pinctrl_gpio_range gpios;
@@ -1222,6 +1226,65 @@ static void starfive_disable_clock(void
 	clk_disable_unprepare(data);
 }
 
+#define GPI_END (GPI_USB_OVER_CURRENT + 1)
+static void starfive_pinmux_reset(struct starfive_pinctrl *sfp)
+{
+	static const DECLARE_BITMAP(defaults, GPI_END) = {
+		BIT_MASK(GPI_I2C0_PAD_SCK_IN) |
+		BIT_MASK(GPI_I2C0_PAD_SDA_IN) |
+		BIT_MASK(GPI_I2C1_PAD_SCK_IN) |
+		BIT_MASK(GPI_I2C1_PAD_SDA_IN) |
+		BIT_MASK(GPI_I2C2_PAD_SCK_IN) |
+		BIT_MASK(GPI_I2C2_PAD_SDA_IN) |
+		BIT_MASK(GPI_I2C3_PAD_SCK_IN) |
+		BIT_MASK(GPI_I2C3_PAD_SDA_IN) |
+		BIT_MASK(GPI_SDIO0_PAD_CARD_DETECT_N) |
+
+		BIT_MASK(GPI_SDIO1_PAD_CARD_DETECT_N) |
+		BIT_MASK(GPI_SPI0_PAD_SS_IN_N) |
+		BIT_MASK(GPI_SPI1_PAD_SS_IN_N) |
+		BIT_MASK(GPI_SPI2_PAD_SS_IN_N) |
+		BIT_MASK(GPI_SPI2AHB_PAD_SS_N) |
+		BIT_MASK(GPI_SPI3_PAD_SS_IN_N),
+
+		BIT_MASK(GPI_UART0_PAD_SIN) |
+		BIT_MASK(GPI_UART1_PAD_SIN) |
+		BIT_MASK(GPI_UART2_PAD_SIN) |
+		BIT_MASK(GPI_UART3_PAD_SIN) |
+		BIT_MASK(GPI_USB_OVER_CURRENT)
+	};
+	DECLARE_BITMAP(keep, NR_GPIOS) = {};
+	struct device_node *np = sfp->gc.parent->of_node;
+	int len = of_property_count_u32_elems(np, "starfive,keep-gpiomux");
+	int i;
+
+	for (i = 0; i < len; i++) {
+		u32 gpio;
+
+		of_property_read_u32_index(np, "starfive,keep-gpiomux", i, &gpio);
+		if (gpio < NR_GPIOS)
+			set_bit(gpio, keep);
+	}
+
+	for (i = 0; i < NR_GPIOS; i++) {
+		if (test_bit(i, keep))
+			continue;
+
+		writel_relaxed(GPO_DISABLE, sfp->base + GPON_DOEN_CFG + 8 * i);
+		writel_relaxed(GPO_LOW,     sfp->base + GPON_DOUT_CFG + 8 * i);
+	}
+
+	for (i = 0; i < GPI_END; i++) {
+		void __iomem *reg = sfp->base + GPI_CFG_OFFSET + 4 * i;
+		u32 din = readl_relaxed(reg);
+
+		if (din >= 2 && din < (NR_GPIOS + 2) && test_bit(din - 2, keep))
+			continue;
+
+		writel_relaxed(test_bit(i, defaults), reg);
+	}
+}
+
 static int starfive_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1283,6 +1346,9 @@ static int starfive_probe(struct platfor
 		writel(value, sfp->padctl + IO_PADSHARE_SEL);
 	}
 
+	if (!keepmux)
+		starfive_pinmux_reset(sfp);
+
 	value = readl(sfp->padctl + IO_PADSHARE_SEL);
 	switch (value) {
 	case 0: