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[PATCH V3 2/3] GPIO: MIPS: lantiq: convert gpio-mm-lantiq to OF and of_m

To: Grant Likely <grant.likely@secretlab.ca>
Subject: [PATCH V3 2/3] GPIO: MIPS: lantiq: convert gpio-mm-lantiq to OF and of_mm_gpio
From: John Crispin <blogic@openwrt.org>
Date: Wed, 16 May 2012 22:49:53 +0200
Cc: linux-mips@linux-mips.org, John Crispin <blogic@openwrt.org>, linux-kernel@vger.kernel.org
In-reply-to: <1337201394-11431-1-git-send-email-blogic@openwrt.org>
References: <1337201394-11431-1-git-send-email-blogic@openwrt.org>
Sender: linux-mips-bounce@linux-mips.org
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@openwrt.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-kernel@vger.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.

 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@openwrt.org>
+ *  Copyright (C) 2012 John Crispin <blogic@openwrt.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 +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(&ltq_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(&ltq_ebu_driver);
-
-       if (ret)
-               pr_info("ltq_ebu : Error registering platfom driver!");
-       return ret;
+       return platform_driver_register(&ltq_mm_driver);
 }
 
-postcore_initcall(ltq_ebu_init);
+subsys_initcall(ltq_mm_init);
-- 
1.7.9.1


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