x86: Add an ICH6 pin configuration driver

Add a driver which sets up the pin configuration on x86 devices with an ICH6
(or later) Platform Controller Hub.

The driver is not in the pinctrl uclass due to some oddities of the way x86
devices work:

- The GPIO controller is not present in I/O space until it is set up
- This is done by writing a register in the PCH
- The PCH has a driver which itself uses PCI, another driver
- The pinctrl uclass requires that a pinctrl device be available before any
other device can be probed

It would be possible to work around the limitations by:
- Hard-coding the GPIO address rather than reading it from the PCH
- Using special x86 PCI access to set the GPIO address in the PCH

However it is not clear that this is better, since the pin configuration
driver does not actually provide normal pin configuration services - it
simply sets up all the pins statically when probed. While this remains the
case, it seems better to use a syscon uclass instead. This can be probed
whenever it is needed, without any limitations.

Also add an 'invert' property to support inverting the input.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/include/asm/cpu.h

@@ -54,6 +54,7 @@ enum {
 	X86_NONE,
 	X86_SYSCON_ME,		/* Intel Management Engine */
 	X86_SYSCON_GMA,		/* Intel Graphics Media Accelerator */
+	X86_SYSCON_PINCONF,	/* Intel x86 pin configuration */
 };
 
 struct cpuid_result {

arch/x86/lib/Makefile

@@ -23,6 +23,7 @@ obj-y += cmd_mtrr.o
 obj-y	+= northbridge-uclass.o
 obj-$(CONFIG_I8259_PIC) += i8259.o
 obj-$(CONFIG_I8254_TIMER) += i8254.o
+obj-y	+= pinctrl_ich6.o
 obj-y	+= pirq_routing.o
 obj-y	+= relocate.o
 obj-y += physmem.o

arch/x86/lib/pinctrl_ich6.c

@@ -0,0 +1,216 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <pch.h>
+#include <pci.h>
+#include <asm/cpu.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+#include <asm/pci.h>
+#include <dm/pinctrl.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define GPIO_USESEL_OFFSET(x)	(x)
+#define GPIO_IOSEL_OFFSET(x)	(x + 4)
+#define GPIO_LVL_OFFSET(x)	((x) ? (x) + 8 : 0xc)
+#define GPI_INV			0x2c
+
+#define IOPAD_MODE_MASK			0x7
+#define IOPAD_PULL_ASSIGN_SHIFT		7
+#define IOPAD_PULL_ASSIGN_MASK		(0x3 << IOPAD_PULL_ASSIGN_SHIFT)
+#define IOPAD_PULL_STRENGTH_SHIFT	9
+#define IOPAD_PULL_STRENGTH_MASK	(0x3 << IOPAD_PULL_STRENGTH_SHIFT)
+
+static int ich6_pinctrl_set_value(uint16_t base, unsigned offset, int value)
+{
+	if (value)
+		setio_32(base, 1UL << offset);
+	else
+		clrio_32(base, 1UL << offset);
+
+	return 0;
+}
+
+static int ich6_pinctrl_set_function(uint16_t base, unsigned offset, int func)
+{
+	if (func)
+		setio_32(base, 1UL << offset);
+	else
+		clrio_32(base, 1UL << offset);
+
+	return 0;
+}
+
+static int ich6_pinctrl_set_direction(uint16_t base, unsigned offset, int dir)
+{
+	if (!dir)
+		setio_32(base, 1UL << offset);
+	else
+		clrio_32(base, 1UL << offset);
+
+	return 0;
+}
+
+static int ich6_pinctrl_cfg_pin(s32 gpiobase, s32 iobase, int pin_node)
+{
+	bool is_gpio, invert;
+	u32 gpio_offset[2];
+	int pad_offset;
+	int dir, val;
+	int ret;
+
+	/*
+	 * GPIO node is not mandatory, so we only do the pinmuxing if the
+	 * node exists.
+	 */
+	ret = fdtdec_get_int_array(gd->fdt_blob, pin_node, "gpio-offset",
+				   gpio_offset, 2);
+	if (!ret) {
+		/* Do we want to force the GPIO mode? */
+		is_gpio = fdtdec_get_bool(gd->fdt_blob, pin_node, "mode-gpio");
+		if (is_gpio)
+			ich6_pinctrl_set_function(GPIO_USESEL_OFFSET(gpiobase) +
+						gpio_offset[0], gpio_offset[1],
+						1);
+
+		dir = fdtdec_get_int(gd->fdt_blob, pin_node, "direction", -1);
+		if (dir != -1)
+			ich6_pinctrl_set_direction(GPIO_IOSEL_OFFSET(gpiobase) +
+						 gpio_offset[0], gpio_offset[1],
+						 dir);
+
+		val = fdtdec_get_int(gd->fdt_blob, pin_node, "output-value",
+				     -1);
+		if (val != -1)
+			ich6_pinctrl_set_value(GPIO_LVL_OFFSET(gpiobase) +
+					     gpio_offset[0], gpio_offset[1],
+					     val);
+
+		invert = fdtdec_get_bool(gd->fdt_blob, pin_node, "invert");
+		if (invert)
+			setio_32(gpiobase + GPI_INV, 1 << gpio_offset[1]);
+		debug("gpio %#x bit %d, is_gpio %d, dir %d, val %d, invert %d\n",
+		      gpio_offset[0], gpio_offset[1], is_gpio, dir, val,
+		      invert);
+	}
+
+	/* if iobase is present, let's configure the pad */
+	if (iobase != -1) {
+		int iobase_addr;
+
+		/*
+		 * The offset for the same pin for the IOBASE and GPIOBASE are
+		 * different, so instead of maintaining a lookup table,
+		 * the device tree should provide directly the correct
+		 * value for both mapping.
+		 */
+		pad_offset = fdtdec_get_int(gd->fdt_blob, pin_node,
+					    "pad-offset", -1);
+		if (pad_offset == -1)
+			return 0;
+
+		/* compute the absolute pad address */
+		iobase_addr = iobase + pad_offset;
+
+		/*
+		 * Do we need to set a specific function mode?
+		 * If someone put also 'mode-gpio', this option will
+		 * be just ignored by the controller
+		 */
+		val = fdtdec_get_int(gd->fdt_blob, pin_node, "mode-func", -1);
+		if (val != -1)
+			clrsetbits_le32(iobase_addr, IOPAD_MODE_MASK, val);
+
+		/* Configure the pull-up/down if needed */
+		val = fdtdec_get_int(gd->fdt_blob, pin_node, "pull-assign", -1);
+		if (val != -1)
+			clrsetbits_le32(iobase_addr,
+					IOPAD_PULL_ASSIGN_MASK,
+					val << IOPAD_PULL_ASSIGN_SHIFT);
+
+		val = fdtdec_get_int(gd->fdt_blob, pin_node, "pull-strength",
+				     -1);
+		if (val != -1)
+			clrsetbits_le32(iobase_addr,
+					IOPAD_PULL_STRENGTH_MASK,
+					val << IOPAD_PULL_STRENGTH_SHIFT);
+
+		debug("%s: pad cfg [0x%x]: %08x\n", __func__, pad_offset,
+		      readl(iobase_addr));
+	}
+
+	return 0;
+}
+
+static int ich6_pinctrl_probe(struct udevice *dev)
+{
+	struct udevice *pch;
+	int pin_node;
+	int ret;
+	u32 gpiobase;
+	u32 iobase = -1;
+
+	debug("%s: start\n", __func__);
+	ret = uclass_first_device(UCLASS_PCH, &pch);
+	if (ret)
+		return ret;
+	if (!pch)
+		return -ENODEV;
+
+	/*
+	 * Get the memory/io base address to configure every pins.
+	 * IOBASE is used to configure the mode/pads
+	 * GPIOBASE is used to configure the direction and default value
+	 */
+	ret = pch_get_gpio_base(pch, &gpiobase);
+	if (ret) {
+		debug("%s: invalid GPIOBASE address (%08x)\n", __func__,
+		      gpiobase);
+		return -EINVAL;
+	}
+
+	/*
+	 * Get the IOBASE, this is not mandatory as this is not
+	 * supported by all the CPU
+	 */
+	ret = pch_get_io_base(pch, &iobase);
+	if (ret && ret != -ENOSYS) {
+		debug("%s: invalid IOBASE address (%08x)\n", __func__, iobase);
+		return -EINVAL;
+	}
+
+	for (pin_node = fdt_first_subnode(gd->fdt_blob, dev->of_offset);
+	     pin_node > 0;
+	     pin_node = fdt_next_subnode(gd->fdt_blob, pin_node)) {
+		/* Configure the pin */
+		ret = ich6_pinctrl_cfg_pin(gpiobase, iobase, pin_node);
+		if (ret != 0) {
+			debug("%s: invalid configuration for the pin %d\n",
+			      __func__, pin_node);
+			return ret;
+		}
+	}
+	debug("%s: done\n", __func__);
+
+	return 0;
+}
+
+static const struct udevice_id ich6_pinctrl_match[] = {
+	{ .compatible = "intel,x86-pinctrl", .data = X86_SYSCON_PINCONF },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(ich6_pinctrl) = {
+	.name = "ich6_pinctrl",
+	.id = UCLASS_SYSCON,
+	.of_match = ich6_pinctrl_match,
+	.probe = ich6_pinctrl_probe,
+};

doc/device-tree-bindings/gpio/intel,x86-pinctrl.txt

@@ -19,6 +19,7 @@ in case of 'mode-gpio' property set:
 - direction         - (optional) this set the direction of the gpio.
 - pull-str          - (optional) this set the pull strength of the pin.
 - pull-assign       - (optional) this set the pull assignement (up/down) of the pin.
+- invert            - (optional) this input pin is inverted
 
 Example: