SYSCON driver was designed for using memory areas (registers)
that are used in several subsystems. There are systems (CPUs)
which use bits in one register for various purposes and thus
should be handled by various kernel subsystems. This driver
allows you to use the individual SYSCON bits as GPIOs.
Signed-off-by: Alexander Shiyan <shc_work@xxxxxxx>
---
.../devicetree/bindings/gpio/gpio-syscon.txt | 22 +++
drivers/gpio/Kconfig | 6 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-syscon.c | 159 +++++++++++++++++++++
4 files changed, 188 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-syscon.txt
create mode 100644 drivers/gpio/gpio-syscon.c
diff --git a/Documentation/devicetree/bindings/gpio/gpio-syscon.txt b/Documentation/devicetree/bindings/gpio/gpio-syscon.txt
new file mode 100644
index 0000000..d8ecfe2
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-syscon.txt
@@ -0,0 +1,22 @@
+* SYSCON-based GPIO driver
+
+Required properties:
+- compatible: Should be "gpio-syscon".
+- syscon: Phandle to syscon device node.
+- gpio-controller: Marks the device node as a gpio controller.
+- #gpio-cells: Should be two. The first cell is the pin number and
+ the second cell is used to specify the gpio polarity:
+ 0 = Active high,
+ 1 = Active low.
+- bit-offset: Offset to the first bit used by driver.
+- bit-count: Number of bits used.
+
+Example:
+ sysgpio: sysgpio {
+ compatible = "gpio-syscon";
+ syscon = <&syscon>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ bit-offset = <4>;
+ bit-count = <1>;
+ };
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 365ea61..5eee6e7 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -259,6 +259,12 @@ config GPIO_STA2X11
Say yes here to support the STA2x11/ConneXt GPIO device.
The GPIO module has 128 GPIO pins with alternate functions.
+config GPIO_SYSCON
+ tristate "GPIO based on SYSCON"
+ depends on MFD_SYSCON && OF
+ help
+ Say yes here to support GPIO functionality though SYSCON driver.
+
config GPIO_TS5500
tristate "TS-5500 DIO blocks and compatibles"
help
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 95d7359..130bc76 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_GPIO_STA2X11) += gpio-sta2x11.o
obj-$(CONFIG_GPIO_STMPE) += gpio-stmpe.o
obj-$(CONFIG_GPIO_STP_XWAY) += gpio-stp-xway.o
obj-$(CONFIG_GPIO_SX150X) += gpio-sx150x.o
+obj-$(CONFIG_GPIO_SYSCON) += gpio-syscon.o
obj-$(CONFIG_GPIO_TB10X) += gpio-tb10x.o
obj-$(CONFIG_GPIO_TC3589X) += gpio-tc3589x.o
obj-$(CONFIG_ARCH_TEGRA) += gpio-tegra.o
diff --git a/drivers/gpio/gpio-syscon.c b/drivers/gpio/gpio-syscon.c
new file mode 100644
index 0000000..2d02cc1
--- /dev/null
+++ b/drivers/gpio/gpio-syscon.c
@@ -0,0 +1,159 @@
+/*
+ * SYSCON GPIO driver
+ *
+ * Copyright (C) 2013 Alexander Shiyan <shc_work@xxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#define GPIO_SYSCON_INPUT (1 << 0)
+#define GPIO_SYSCON_OUTPUT (1 << 1)
+
+/* SYSCON driver is designed to use 32-bit wide registers */
+#define SYSCON_REG_SIZE (4)
+#define SYSCON_REG_BITS (SYSCON_REG_SIZE * 8)
+
+struct syscon_gpio_priv {
+ struct gpio_chip chip;
+ struct regmap *syscon;
+ unsigned int bit_offset;
+};
+
+static inline struct syscon_gpio_priv *to_syscon_gpio(struct gpio_chip *chip)
+{
+ return container_of(chip, struct syscon_gpio_priv, chip);
+}
+
+static int syscon_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
+ unsigned int val, offs = priv->bit_offset + offset;
+ int ret;
+
+ ret = regmap_read(priv->syscon,
+ (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE, &val);
+ if (ret < 0)
+ return ret;
+
+ return !!(val & (offs % SYSCON_REG_BITS));
+}
+
+static void syscon_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
+{
+ struct syscon_gpio_priv *priv = to_syscon_gpio(chip);
+ unsigned int offs = priv->bit_offset + offset;
+
+ regmap_update_bits(priv->syscon,
+ (offs / SYSCON_REG_BITS) * SYSCON_REG_SIZE,
+ offs % SYSCON_REG_BITS,
+ val ? (offs % SYSCON_REG_BITS) : 0);
+}
+
+static int syscon_gpio_dir_in(struct gpio_chip *chip, unsigned offset)
+{
+ return 0;
+}
+
+static int syscon_gpio_dir_out(struct gpio_chip *chip, unsigned offset, int val)
+{
+ syscon_gpio_set(chip, offset, val);
+
+ return 0;
+}
+
+static const struct of_device_id syscon_gpio_ids[] = {
+ {
+ .compatible = "gpio-syscon-input",
+ .data = (void *)GPIO_SYSCON_INPUT,
+ },
+ {
+ .compatible = "gpio-syscon-output",
+ .data = (void *)GPIO_SYSCON_OUTPUT,
+ },
+ { }
+};
+MODULE_DEVICE_TABLE(of, syscon_gpio_ids);
+
+static int syscon_gpio_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *of_id =
+ of_match_device(syscon_gpio_ids, &pdev->dev);
+ struct device_node *np = pdev->dev.of_node;
+ struct syscon_gpio_priv *priv;
+ unsigned int flags;
+ u32 ngpio;
+ int ret;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->syscon = syscon_regmap_lookup_by_phandle(np, "syscon");
+ if (IS_ERR(priv->syscon))
+ return PTR_ERR(priv->syscon);
+
+ ret = of_property_read_u32(np, "bit-offset", &priv->bit_offset);
+ if (ret)
+ return ret;
+
+ ret = of_property_read_u32(np, "bit-count", &ngpio);
+ if (ret)
+ return ret;
+
+ /* Sanity check */
+ if (ngpio < 1 || ngpio > (u16)-1)
+ return -EINVAL;
+
+ flags = (unsigned int)of_id->data;
+
+ priv->chip.owner = THIS_MODULE;
+ priv->chip.label = dev_name(&pdev->dev);
+ priv->chip.base = -1;
+ priv->chip.ngpio = ngpio;
+ if (flags & GPIO_SYSCON_INPUT) {
+ priv->chip.get = syscon_gpio_get;
+ priv->chip.direction_input = syscon_gpio_dir_in;
+ }
+ if (flags & GPIO_SYSCON_OUTPUT) {
+ priv->chip.set = syscon_gpio_set;
+ priv->chip.direction_output = syscon_gpio_dir_out;
+ }
+
+ platform_set_drvdata(pdev, priv);
+
+ return gpiochip_add(&priv->chip);
+}
+
+static int syscon_gpio_remove(struct platform_device *pdev)
+{
+ struct syscon_gpio_priv *priv = platform_get_drvdata(pdev);
+
+ return gpiochip_remove(&priv->chip);
+}
+
+static struct platform_driver syscon_gpio_driver = {
+ .driver = {
+ .name = "gpio-syscon",
+ .owner = THIS_MODULE,
+ .of_match_table = syscon_gpio_ids,
+ },
+ .probe = syscon_gpio_probe,
+ .remove = syscon_gpio_remove,
+};
+module_platform_driver(syscon_gpio_driver);
+
+MODULE_AUTHOR("Alexander Shiyan <shc_work@xxxxxxx>");
+MODULE_DESCRIPTION("SYSCON GPIO driver");
+MODULE_LICENSE("GPL");
--
1.8.3.2
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