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Diffstat (limited to 'arch/mips/lantiq/xway/gpio_ebu.c')
-rw-r--r--arch/mips/lantiq/xway/gpio_ebu.c126
1 files changed, 126 insertions, 0 deletions
diff --git a/arch/mips/lantiq/xway/gpio_ebu.c b/arch/mips/lantiq/xway/gpio_ebu.c
new file mode 100644
index 0000000..a479355
--- /dev/null
+++ b/arch/mips/lantiq/xway/gpio_ebu.c
@@ -0,0 +1,126 @@
+/*
+ * 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) 2010 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/io.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 */
+
+/* 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;
+
+static void ltq_ebu_apply(void)
+{
+ 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;
+ 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)
+{
+ if (value)
+ ltq_ebu_gpio_shadow |= (1 << offset);
+ else
+ ltq_ebu_gpio_shadow &= ~(1 << offset);
+ ltq_ebu_apply();
+}
+
+static int ltq_ebu_direction_output(struct gpio_chip *chip, unsigned offset,
+ int value)
+{
+ ltq_ebu_set(chip, 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,
+};
+
+static int ltq_ebu_probe(struct platform_device *pdev)
+{
+ int ret = 0;
+ struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 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");
+ return -ENOMEM;
+ }
+
+ /* grab the default shadow value passed form the platform code */
+ ltq_ebu_gpio_shadow = (unsigned int) pdev->dev.platform_data;
+
+ /* tell the ebu controller which memory address we will be using */
+ ltq_ebu_w32(pdev->resource->start | 0x1, LTQ_EBU_ADDRSEL1);
+
+ /* 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();
+ return ret;
+}
+
+static struct platform_driver ltq_ebu_driver = {
+ .probe = ltq_ebu_probe,
+ .driver = {
+ .name = "ltq_ebu",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init ltq_ebu_init(void)
+{
+ int ret = platform_driver_register(&ltq_ebu_driver);
+
+ if (ret)
+ pr_info("ltq_ebu : Error registering platfom driver!");
+ return ret;
+}
+
+postcore_initcall(ltq_ebu_init);
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