Implements OF support and convert to of_mm_gpio.
By attaching hardware latches to the External Bus Unit (EBU) on Lantiq SoC, it
is possible to create output only gpios. This driver configures a special
memory address, which when written to, outputs 16 bit to the latches.
Signed-off-by: John Crispin <blogic@xxxxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
This patch is part of a series moving the mips/lantiq target to OF and clkdev
support. The patch, once Acked, should go upstream via Ralf's MIPS tree.
drivers/gpio/gpio-mm-lantiq.c | 147 +++++++++++++++++++++++++----------------
1 files changed, 89 insertions(+), 58 deletions(-)
diff --git a/drivers/gpio/gpio-mm-lantiq.c b/drivers/gpio/gpio-mm-lantiq.c
index b91c7f1..9296801 100644
--- a/drivers/gpio/gpio-mm-lantiq.c
+++ b/drivers/gpio/gpio-mm-lantiq.c
@@ -3,16 +3,18 @@
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
- * Copyright (C) 2010 John Crispin <blogic@xxxxxxxxxxx>
+ * Copyright (C) 2012 John Crispin <blogic@xxxxxxxxxxx>
*/
#include <linux/init.h>
-#include <linux/export.h>
+#include <linux/module.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
-#include <linux/gpio.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
#include <linux/io.h>
+#include <linux/slab.h>
#include <lantiq_soc.h>
@@ -25,102 +27,131 @@
#define LTQ_EBU_BUSCON 0x1e7ff /* 16 bit access, slowest timing */
#define LTQ_EBU_WP 0x80000000 /* write protect bit */
-/* we keep a shadow value of the last value written to the ebu */
-static int ltq_ebu_gpio_shadow = 0x0;
-static void __iomem *ltq_ebu_gpio_membase;
+struct ltq_mm {
+ struct of_mm_gpio_chip mmchip;
+ u16 shadow; /* shadow the latches state */
+};
-static void ltq_ebu_apply(void)
+/*
+ * ltq_mm_apply - write the shadow value to the ebu address.
+ * @chip: Pointer to our private data structure.
+ *
+ * Write the shadow value to the EBU to set the gpios. We need to set the
+ * global EBU lock to make sure that PCI/MTD dont break.
+ */
+static void ltq_mm_apply(struct ltq_mm *chip)
{
unsigned long flags;
spin_lock_irqsave(&ebu_lock, flags);
ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1);
- *((__u16 *)ltq_ebu_gpio_membase) = ltq_ebu_gpio_shadow;
+ *((__u16 *)chip->mmchip.regs) = chip->shadow;
ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);
spin_unlock_irqrestore(&ebu_lock, flags);
}
-static void ltq_ebu_set(struct gpio_chip *chip, unsigned offset, int value)
+/*
+ * ltq_mm_set - gpio_chip->set - set gpios.
+ * @gc: Pointer to gpio_chip device structure.
+ * @gpio: GPIO signal number.
+ * @val: Value to be written to specified signal.
+ *
+ * Set the shadow value and call ltq_mm_apply.
+ */
+static void ltq_mm_set(struct gpio_chip *gc, unsigned offset, int value)
{
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+ struct ltq_mm *chip =
+ container_of(mm_gc, struct ltq_mm, mmchip);
+
if (value)
- ltq_ebu_gpio_shadow |= (1 << offset);
+ chip->shadow |= (1 << offset);
else
- ltq_ebu_gpio_shadow &= ~(1 << offset);
- ltq_ebu_apply();
+ chip->shadow &= ~(1 << offset);
+ ltq_mm_apply(chip);
}
-static int ltq_ebu_direction_output(struct gpio_chip *chip, unsigned offset,
- int value)
+/*
+ * ltq_mm_dir_out - gpio_chip->dir_out - set gpio direction.
+ * @gc: Pointer to gpio_chip device structure.
+ * @gpio: GPIO signal number.
+ * @val: Value to be written to specified signal.
+ *
+ * Same as ltq_mm_set, always returns 0.
+ */
+static int ltq_mm_dir_out(struct gpio_chip *gc, unsigned offset, int value)
{
- ltq_ebu_set(chip, offset, value);
+ ltq_mm_set(gc, offset, value);
return 0;
}
-static struct gpio_chip ltq_ebu_chip = {
- .label = "ltq_ebu",
- .direction_output = ltq_ebu_direction_output,
- .set = ltq_ebu_set,
- .base = 72,
- .ngpio = 16,
- .can_sleep = 1,
- .owner = THIS_MODULE,
-};
+/*
+ * ltq_mm_save_regs - Set initial values of GPIO pins
+ * @mm_gc: pointer to memory mapped GPIO chip structure
+ */
+static void ltq_mm_save_regs(struct of_mm_gpio_chip *mm_gc)
+{
+ struct ltq_mm *chip =
+ container_of(mm_gc, struct ltq_mm, mmchip);
+
+ /* tell the ebu controller which memory address we will be using */
+ ltq_ebu_w32(CPHYSADDR(chip->mmchip.regs) | 0x1, LTQ_EBU_ADDRSEL1);
-static int ltq_ebu_probe(struct platform_device *pdev)
+ ltq_mm_apply(chip);
+}
+
+static int ltq_mm_probe(struct platform_device *pdev)
{
- int ret = 0;
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ struct ltq_mm *chip;
+ const __be32 *shadow;
+ int ret = 0;
if (!res) {
dev_err(&pdev->dev, "failed to get memory resource\n");
return -ENOENT;
}
- res = devm_request_mem_region(&pdev->dev, res->start,
- resource_size(res), dev_name(&pdev->dev));
- if (!res) {
- dev_err(&pdev->dev, "failed to request memory resource\n");
- return -EBUSY;
- }
-
- ltq_ebu_gpio_membase = devm_ioremap_nocache(&pdev->dev, res->start,
- resource_size(res));
- if (!ltq_ebu_gpio_membase) {
- dev_err(&pdev->dev, "Failed to ioremap mem region\n");
+ chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+ if (!chip)
return -ENOMEM;
- }
- /* grab the default shadow value passed form the platform code */
- ltq_ebu_gpio_shadow = (unsigned int) pdev->dev.platform_data;
+ chip->mmchip.gc.ngpio = 16;
+ chip->mmchip.gc.label = "gpio-mm-ltq";
+ chip->mmchip.gc.direction_output = ltq_mm_dir_out;
+ chip->mmchip.gc.set = ltq_mm_set;
+ chip->mmchip.save_regs = ltq_mm_save_regs;
- /* tell the ebu controller which memory address we will be using */
- ltq_ebu_w32(pdev->resource->start | 0x1, LTQ_EBU_ADDRSEL1);
+ /* store the shadow value if one was passed by the devicetree */
+ shadow = of_get_property(pdev->dev.of_node, "lantiq,shadow", NULL);
+ if (shadow)
+ chip->shadow = *shadow;
- /* write protect the region */
- ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);
-
- ret = gpiochip_add(<q_ebu_chip);
- if (!ret)
- ltq_ebu_apply();
+ ret = of_mm_gpiochip_add(pdev->dev.of_node, &chip->mmchip);
+ if (ret)
+ kfree(chip);
return ret;
}
-static struct platform_driver ltq_ebu_driver = {
- .probe = ltq_ebu_probe,
+static const struct of_device_id ltq_mm_match[] = {
+ { .compatible = "lantiq,gpio-mm" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ltq_mm_match);
+
+static struct platform_driver ltq_mm_driver = {
+ .probe = ltq_mm_probe,
.driver = {
- .name = "ltq_ebu",
+ .name = "gpio-mm-ltq",
.owner = THIS_MODULE,
+ .of_match_table = ltq_mm_match,
},
};
-static int __init ltq_ebu_init(void)
+static int __init ltq_mm_init(void)
{
- int ret = platform_driver_register(<q_ebu_driver);
-
- if (ret)
- pr_info("ltq_ebu : Error registering platfom driver!");
- return ret;
+ return platform_driver_register(<q_mm_driver);
}
-postcore_initcall(ltq_ebu_init);
+subsys_initcall(ltq_mm_init);
--
1.7.9.1
