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Message-Id: <1337355777-1680-2-git-send-email-blogic@openwrt.org>
Date: Fri, 18 May 2012 17:42:56 +0200
From: John Crispin <blogic@...nwrt.org>
To: Ralf Baechle <ralf@...ux-mips.org>
Cc: linux-mips@...ux-mips.org, John Crispin <blogic@...nwrt.org>,
Grant Likely <grant.likely@...retlab.ca>,
linux-kernel@...r.kernel.org
Subject: [PATCH V4 2/3] GPIO: MIPS: lantiq: convert gpio-mm-lantiq to OF and of_mm_gpio
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@...nwrt.org>
Cc: Grant Likely <grant.likely@...retlab.ca>
Cc: linux-kernel@...r.kernel.org
---
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.
Changes in V4
* add #include "linux/gpio.h"
* fix casting
* fix doc style
* make use of be32_to_cpu()
.../devicetree/bindings/gpio/gpio-mm-lantiq.txt | 38 +++++
drivers/gpio/gpio-mm-lantiq.c | 146 ++++++++++++--------
2 files changed, 127 insertions(+), 57 deletions(-)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt
diff --git a/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt b/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt
new file mode 100644
index 0000000..f93d514
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-mm-lantiq.txt
@@ -0,0 +1,38 @@
+Lantiq SoC External Bus memory mapped GPIO controller
+
+By attaching hardware latches to the EBU 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.
+
+The node describing the memory mapped GPIOs needs to be a child of the node
+describing the "lantiq,localbus".
+
+Required properties:
+- compatible : Should be "lantiq,gpio-mm-lantiq"
+- reg : Address and length of the register set for the device
+- #gpio-cells : Should be two. The first cell is the pin number and
+ the second cell is used to specify optional parameters (currently
+ unused).
+- gpio-controller : Marks the device node as a gpio controller.
+
+Optional properties:
+- lantiq,shadow : The default value that we shall assume as already set on the
+ shift register cascade.
+
+Example:
+
+localbus@0 {
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges = <0 0 0x0 0x3ffffff /* addrsel0 */
+ 1 0 0x4000000 0x4000010>; /* addsel1 */
+ compatible = "lantiq,localbus", "simple-bus";
+
+ gpio_mm0: gpio@...0000 {
+ compatible = "lantiq,gpio-mm";
+ reg = <1 0x0 0x10>;
+ gpio-controller;
+ #gpio-cells = <2>;
+ lantiq,shadow = <0x77f>
+ };
+}
diff --git a/drivers/gpio/gpio-mm-lantiq.c b/drivers/gpio/gpio-mm-lantiq.c
index b91c7f1..2983dfb 100644
--- a/drivers/gpio/gpio-mm-lantiq.c
+++ b/drivers/gpio/gpio-mm-lantiq.c
@@ -3,16 +3,19 @@
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
- * Copyright (C) 2010 John Crispin <blogic@...nwrt.org>
+ * Copyright (C) 2012 John Crispin <blogic@...nwrt.org>
*/
#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 +28,131 @@
#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;
+ __raw_writew(chip->shadow, chip->mmchip.regs);
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);
+
+ ltq_mm_apply(chip);
+}
-static int ltq_ebu_probe(struct platform_device *pdev)
+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 = be32_to_cpu(*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
--
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