Add single register pin controller driver

This patch adds a pin controller driver supporting devices
using a single configuration register per pin.
Signed-off-by: Felix Brack <fb@ltec.ch>

drivers/pinctrl/Kconfig

@@ -212,6 +212,16 @@ config PINCTRL_STM32
 	  definitions and pin control functions for each available multiplex
 	  function.
 
+config PINCTRL_SINGLE
+	bool "Single register pin-control and pin-multiplex driver"
+	depends on DM
+	help
+	  This enables pinctrl driver for systems using a single register for
+	  pin configuration and multiplexing. TI's AM335X SoCs are examples of
+	  such systems.
+	  Depending on the platform make sure to also enable OF_TRANSLATE and
+	  eventually SPL_OF_TRANSLATE to get correct address translations.
+
 endif
 
 source "drivers/pinctrl/meson/Kconfig"

drivers/pinctrl/Makefile

@@ -16,5 +16,6 @@ obj-$(CONFIG_PIC32_PINCTRL)	+= pinctrl_pic32.o
 obj-$(CONFIG_PINCTRL_EXYNOS)	+= exynos/
 obj-$(CONFIG_PINCTRL_MESON)	+= meson/
 obj-$(CONFIG_PINCTRL_MVEBU)	+= mvebu/
+obj-$(CONFIG_PINCTRL_SINGLE)	+= pinctrl-single.o
 obj-$(CONFIG_PINCTRL_STI)	+= pinctrl-sti.o
 obj-$(CONFIG_PINCTRL_STM32)	+= pinctrl_stm32.o

drivers/pinctrl/pinctrl-single.c

@@ -0,0 +1,142 @@
+/*
+ * Copyright (C) EETS GmbH, 2017, Felix Brack <f.brack@eets.ch>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm/device.h>
+#include <dm/pinctrl.h>
+#include <libfdt.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct single_pdata {
+	fdt_addr_t base;	/* first configuration register */
+	int offset;		/* index of last configuration register */
+	u32 mask;		/* configuration-value mask bits */
+	int width;		/* configuration register bit width */
+};
+
+struct single_fdt_pin_cfg {
+	fdt32_t reg;		/* configuration register offset */
+	fdt32_t val;		/* configuration register value */
+};
+
+/**
+ * single_configure_pins() - Configure pins based on FDT data
+ *
+ * @dev: Pointer to single pin configuration device which is the parent of
+ *       the pins node holding the pin configuration data.
+ * @pins: Pointer to the first element of an array of register/value pairs
+ *        of type 'struct single_fdt_pin_cfg'. Each such pair describes the
+ *        the pin to be configured and the value to be used for configuration.
+ *        This pointer points to a 'pinctrl-single,pins' property in the
+ *        device-tree.
+ * @size: Size of the 'pins' array in bytes.
+ *        The number of register/value pairs in the 'pins' array therefore
+ *        equals to 'size / sizeof(struct single_fdt_pin_cfg)'.
+ */
+static int single_configure_pins(struct udevice *dev,
+				 const struct single_fdt_pin_cfg *pins,
+				 int size)
+{
+	struct single_pdata *pdata = dev->platdata;
+	int count = size / sizeof(struct single_fdt_pin_cfg);
+	int n, reg;
+	u32 val;
+
+	for (n = 0; n < count; n++) {
+		reg = fdt32_to_cpu(pins->reg);
+		if ((reg < 0) || (reg > pdata->offset)) {
+			dev_dbg(dev, "  invalid register offset 0x%08x\n", reg);
+			pins++;
+			continue;
+		}
+		reg += pdata->base;
+		switch (pdata->width) {
+		case 32:
+			val = readl(reg) & ~pdata->mask;
+			val |= fdt32_to_cpu(pins->val) & pdata->mask;
+			writel(val, reg);
+			dev_dbg(dev, "  reg/val 0x%08x/0x%08x\n",
+				reg, val);
+			break;
+		default:
+			dev_warn(dev, "unsupported register width %i\n",
+				 pdata->width);
+		}
+		pins++;
+	}
+	return 0;
+}
+
+static int single_set_state(struct udevice *dev,
+			    struct udevice *config)
+{
+	const void *fdt = gd->fdt_blob;
+	const struct single_fdt_pin_cfg *prop;
+	int len;
+
+	prop = fdt_getprop(fdt, config->of_offset, "pinctrl-single,pins", &len);
+	if (prop) {
+		dev_dbg(dev, "configuring pins for %s\n", config->name);
+		if (len % sizeof(struct single_fdt_pin_cfg)) {
+			dev_dbg(dev, "  invalid pin configuration in fdt\n");
+			return -FDT_ERR_BADSTRUCTURE;
+		}
+		single_configure_pins(dev, prop, len);
+		len = 0;
+	}
+
+	return len;
+}
+
+static int single_ofdata_to_platdata(struct udevice *dev)
+{
+	fdt_addr_t addr;
+	u32 of_reg[2];
+	int res;
+	struct single_pdata *pdata = dev->platdata;
+
+	pdata->width = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+				      "pinctrl-single,register-width", 0);
+
+	res = fdtdec_get_int_array(gd->fdt_blob, dev->of_offset,
+				   "reg", of_reg, 2);
+	if (res)
+		return res;
+	pdata->offset = of_reg[1] - pdata->width / 8;
+
+	addr = dev_get_addr(dev);
+	if (addr == FDT_ADDR_T_NONE) {
+		dev_dbg(dev, "no valid base register address\n");
+		return -EINVAL;
+	}
+	pdata->base = addr;
+
+	pdata->mask = fdtdec_get_int(gd->fdt_blob, dev->of_offset,
+				     "pinctrl-single,function-mask",
+				     0xffffffff);
+	return 0;
+}
+
+const struct pinctrl_ops single_pinctrl_ops = {
+	.set_state = single_set_state,
+};
+
+static const struct udevice_id single_pinctrl_match[] = {
+	{ .compatible = "pinctrl-single" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(single_pinctrl) = {
+	.name = "single-pinctrl",
+	.id = UCLASS_PINCTRL,
+	.of_match = single_pinctrl_match,
+	.ops = &single_pinctrl_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+	.platdata_auto_alloc_size = sizeof(struct single_pdata),
+	.ofdata_to_platdata = single_ofdata_to_platdata,
+};