[RFC v4 3/8] gpio: generic: add DT support for generic memory-mapped GPIOs

Christian Lamparter
2016-04-28T09:07:22Z

From: Álvaro Fernández Rojas <noltari@gmail.com>

This patch adds support for defining memory-mapped GPIOs
which provide a compatible interface for the existing
generic-gpio driver.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
---
drivers/gpio/Kconfig | 3 ++
drivers/gpio/gpio-mmio-compat.h | 17 ++++++++
drivers/gpio/gpio-mmio.c | 95 ++++++++++++++++++++++++++++++++++++++++-
3 files changed, 113 insertions(+), 2 deletions(-)
create mode 100644 drivers/gpio/gpio-mmio-compat.h

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index f73f26b..d1f124e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -212,6 +212,9 @@ config GPIO_GENERIC_PLATFORM
help
Say yes here to support basic platform_device memory-mapped GPIO controllers.

+if GPIO_GENERIC_PLATFORM
+endif
+
config GPIO_GRGPIO
tristate "Aeroflex Gaisler GRGPIO support"
depends on OF
diff --git a/drivers/gpio/gpio-mmio-compat.h b/drivers/gpio/gpio-mmio-compat.h
new file mode 100644
index 0000000..73c48bc
--- /dev/null
+++ b/drivers/gpio/gpio-mmio-compat.h
@@ -0,0 +1,17 @@
+#ifndef GPIO_MMIO_COMPAT_H
+#define GPIO_MMIO_COMPAT_H
+
+#include <linux/ioport.h>
+
+#define ADD(_name, _func) { .compatible = _name, .data = _func }
+
+#undef ADD
+
+static inline void set_resource_address(struct resource *res,
+ resource_size_t start,
+ resource_size_t len)
+{
+ res->start = start;
+ res->end = start + len - 1;
+}
+#endif /* GPIO_MMIO_COMPAT_H */
diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index 6c1cb3b..4de9846 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -61,6 +61,9 @@ o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
#include <linux/bitops.h>
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include "gpio-mmio-compat.h"

static void bgpio_write8(void __iomem *reg, unsigned long data)
{
@@ -569,6 +572,83 @@ static void __iomem *bgpio_map(struct platform_device *pdev,
return devm_ioremap_resource(&pdev->dev, r);
}

+#ifdef CONFIG_OF
+static int bgpio_basic_mmio_parse_dt(struct platform_device *pdev,
+ struct bgpio_pdata *pdata,
+ unsigned long *flags)
+{
+ struct device *dev = &pdev->dev;
+ int err;
+
+ err = of_property_read_u32(dev->of_node, "ngpio", &pdata->ngpio);
+ if (err && err != -EINVAL)
+ return err;
+
+ if (of_device_is_big_endian(dev->of_node))
+ *flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
+
+ if (of_property_read_bool(dev->of_node, "unreadable-reg-set"))
+ *flags |= BGPIOF_UNREADABLE_REG_SET;
+
+ if (of_property_read_bool(dev->of_node, "unreadable-reg-dir"))
+ *flags |= BGPIOF_UNREADABLE_REG_DIR;
+
+ if (of_property_read_bool(dev->of_node, "big-endian-byte-order"))
+ *flags |= BGPIOF_BIG_ENDIAN;
+
+ if (of_property_read_bool(dev->of_node, "read-output-reg-set"))
+ *flags |= BGPIOF_READ_OUTPUT_REG_SET;
+
+ if (of_property_read_bool(dev->of_node, "no-output"))
+ *flags |= BGPIOF_NO_OUTPUT;
+ return 0;
+}
+
+#define ADD(_name, _func) { .compatible = _name, .data = _func }
+
+static const struct of_device_id bgpio_of_match[] = {
+ ADD("linux,gpio-mmio", bgpio_basic_mmio_parse_dt),
+
+ { }
+};
+#undef ADD
+MODULE_DEVICE_TABLE(of, bgpio_of_match);
+
+static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
+ unsigned long *flags)
+{
+ int (*parse_dt)(struct platform_device *,
+ struct bgpio_pdata *, unsigned long *);
+ const struct device_node *node = pdev->dev.of_node;
+ const struct of_device_id *of_id;
+ struct bgpio_pdata *pdata;
+ int err = -ENODEV;
+
+ of_id = of_match_node(bgpio_of_match, node);
+ if (!of_id)
+ return NULL;
+
+ pdata = devm_kzalloc(&pdev->dev, sizeof(struct bgpio_pdata),
+ GFP_KERNEL);
+ if (!pdata)
+ return ERR_PTR(-ENOMEM);
+
+ parse_dt = of_id->data;
+ if (parse_dt)
+ err = parse_dt(pdev, pdata, flags);
+ if (err)
+ return ERR_PTR(err);
+
+ return pdata;
+}
+#else
+static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
+ unsigned long *flags)
+{
+ return NULL;
+}
+#endif /* CONFIG_OF */
+
static int bgpio_pdev_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -579,10 +659,18 @@ static int bgpio_pdev_probe(struct platform_device *pdev)
void __iomem *dirout;
void __iomem *dirin;
unsigned long sz;
- unsigned long flags = pdev->id_entry->driver_data;
+ unsigned long flags = 0;
int err;
struct gpio_chip *gc;
- struct bgpio_pdata *pdata = dev_get_platdata(dev);
+ struct bgpio_pdata *pdata;
+
+ pdata = bgpio_parse_dt(pdev, &flags);
+ if (IS_ERR(pdata)) {
+ return PTR_ERR(pdata);
+ } else if (!pdata) {
+ pdata = dev_get_platdata(dev);
+ flags = pdev->id_entry->driver_data;
+ }

r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
if (!r)
@@ -646,6 +734,9 @@ MODULE_DEVICE_TABLE(platform, bgpio_id_table);
static struct platform_driver bgpio_driver = {
.driver = {
.name = "basic-mmio-gpio",
+#ifdef CONFIG_OF
+ .of_match_table = of_match_ptr(bgpio_of_match),
+#endif
},
.id_table = bgpio_id_table,
.probe = bgpio_pdev_probe,
--
2.8.1