1 files changed, 158 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-mm-lantiq.c b/drivers/gpio/gpio-mm-lantiq.c
new file mode 100644
index 000000000000..2983dfbd0668
--- /dev/null
+++ b/drivers/gpio/gpio-mm-lantiq.c
@@ -0,0 +1,158 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2012 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/init.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>
+
+/*
+ * 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.
+ */
+
+#define LTQ_EBU_BUSCON  0x1e7ff         /* 16 bit access, slowest timing */
+#define LTQ_EBU_WP      0x80000000      /* write protect bit */
+
+struct ltq_mm {
+        struct of_mm_gpio_chip mmchip;
+        u16 shadow;     /* shadow the latches state */
+};
+
+/**
+ * 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);
+        __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);
+}
+
+/**
+ * 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)
+                chip->shadow |= (1 << offset);
+        else
+                chip->shadow &= ~(1 << offset);
+        ltq_mm_apply(chip);
+}
+
+/**
+ * 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_mm_set(gc, offset, value);
+
+        return 0;
+}
+
+/**
+ * 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_mm_probe(struct platform_device *pdev)
+{
+        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;
+        }
+
+        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+        if (!chip)
+                return -ENOMEM;
+
+        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;
+
+        /* 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);
+
+        ret = of_mm_gpiochip_add(pdev->dev.of_node, &chip->mmchip);
+        if (ret)
+                kfree(chip);
+        return ret;
+}
+
+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 = "gpio-mm-ltq",
+                .owner = THIS_MODULE,
+                .of_match_table = ltq_mm_match,
+        },
+};
+
+static int __init ltq_mm_init(void)
+{
+        return platform_driver_register(&ltq_mm_driver);
+}
+
+subsys_initcall(ltq_mm_init);