mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
synced 2024-10-30 09:06:16 +02:00
115a129a30
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@11933 3c298f89-4303-0410-b956-a3cf2f4a3e73
377 lines
9.9 KiB
Diff
377 lines
9.9 KiB
Diff
--- /dev/null
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+++ b/include/linux/spi/spi_gpio.h
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@@ -0,0 +1,73 @@
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+/*
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+ * spi_gpio interface to platform code
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+ *
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+ * Copyright (c) 2008 Piotr Skamruk
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+ * Copyright (c) 2008 Michael Buesch
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+#ifndef _LINUX_SPI_SPI_GPIO
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+#define _LINUX_SPI_SPI_GPIO
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+
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+#include <linux/types.h>
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+#include <linux/spi/spi.h>
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+
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+
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+/**
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+ * struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
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+ *
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+ * This structure holds information about a GPIO-based SPI device.
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+ *
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+ * @pin_clk: The GPIO pin number of the CLOCK pin.
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+ *
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+ * @pin_miso: The GPIO pin number of the MISO pin.
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+ *
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+ * @pin_mosi: The GPIO pin number of the MOSI pin.
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+ *
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+ * @pin_cs: The GPIO pin number of the CHIPSELECT pin.
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+ *
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+ * @cs_activelow: If true, the chip is selected when the CS line is low.
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+ *
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+ * @no_spi_delay: If true, no delay is done in the lowlevel bitbanging.
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+ * Note that doing no delay is not standards compliant,
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+ * but it might be needed to speed up transfers on some
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+ * slow embedded machines.
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+ *
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+ * @boardinfo_setup: This callback is called after the
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+ * SPI master device was registered, but before the
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+ * device is registered.
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+ * @boardinfo_setup_data: Data argument passed to boardinfo_setup().
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+ */
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+struct spi_gpio_platform_data {
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+ unsigned int pin_clk;
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+ unsigned int pin_miso;
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+ unsigned int pin_mosi;
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+ unsigned int pin_cs;
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+ bool cs_activelow;
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+ bool no_spi_delay;
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+ int (*boardinfo_setup)(struct spi_board_info *bi,
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+ struct spi_master *master,
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+ void *data);
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+ void *boardinfo_setup_data;
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+};
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+
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+/**
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+ * SPI_GPIO_PLATDEV_NAME - The platform device name string.
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+ *
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+ * The name string that has to be used for platform_device_alloc
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+ * when allocating a spi-gpio device.
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+ */
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+#define SPI_GPIO_PLATDEV_NAME "spi-gpio"
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+
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+/**
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+ * spi_gpio_next_id - Get another platform device ID number.
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+ *
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+ * This returns the next platform device ID number that has to be used
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+ * for platform_device_alloc. The ID is opaque and should not be used for
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+ * anything else.
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+ */
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+int spi_gpio_next_id(void);
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+
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+#endif /* _LINUX_SPI_SPI_GPIO */
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--- /dev/null
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+++ b/drivers/spi/spi_gpio.c
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@@ -0,0 +1,251 @@
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+/*
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+ * Bitbanging SPI bus driver using GPIO API
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+ *
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+ * Copyright (c) 2008 Piotr Skamruk
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+ * Copyright (c) 2008 Michael Buesch
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+ *
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+ * based on spi_s3c2410_gpio.c
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+ * Copyright (c) 2006 Ben Dooks
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+ * Copyright (c) 2006 Simtec Electronics
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+ * and on i2c-gpio.c
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+ * Copyright (C) 2007 Atmel Corporation
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+
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+#include <linux/kernel.h>
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+#include <linux/init.h>
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+#include <linux/delay.h>
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+#include <linux/spinlock.h>
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+#include <linux/workqueue.h>
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+#include <linux/module.h>
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+#include <linux/platform_device.h>
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+#include <linux/spi/spi.h>
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+#include <linux/spi/spi_bitbang.h>
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+#include <linux/spi/spi_gpio.h>
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+#include <linux/gpio.h>
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+#include <asm/atomic.h>
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+
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+
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+struct spi_gpio {
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+ struct spi_bitbang bitbang;
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+ struct spi_gpio_platform_data *info;
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+ struct platform_device *pdev;
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+ struct spi_board_info bi;
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+};
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+
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+
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+static inline struct spi_gpio *spidev_to_sg(struct spi_device *dev)
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+{
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+ return dev->controller_data;
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+}
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+
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+static inline void setsck(struct spi_device *dev, int val)
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+{
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+ struct spi_gpio *sp = spidev_to_sg(dev);
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+ gpio_set_value(sp->info->pin_clk, val ? 1 : 0);
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+}
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+
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+static inline void setmosi(struct spi_device *dev, int val)
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+{
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+ struct spi_gpio *sp = spidev_to_sg(dev);
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+ gpio_set_value(sp->info->pin_mosi, val ? 1 : 0);
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+}
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+
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+static inline u32 getmiso(struct spi_device *dev)
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+{
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+ struct spi_gpio *sp = spidev_to_sg(dev);
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+ return gpio_get_value(sp->info->pin_miso) ? 1 : 0;
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+}
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+
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+static inline void do_spidelay(struct spi_device *dev, unsigned nsecs)
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+{
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+ struct spi_gpio *sp = spidev_to_sg(dev);
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+
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+ if (!sp->info->no_spi_delay)
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+ ndelay(nsecs);
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+}
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+
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+#define spidelay(nsecs) do { \
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+ /* Steal the spi_device pointer from our caller. \
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+ * The bitbang-API should probably get fixed here... */ \
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+ do_spidelay(spi, nsecs); \
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+ } while (0)
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+
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+#define EXPAND_BITBANG_TXRX
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+#include <linux/spi/spi_bitbang.h>
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+
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+static u32 spi_gpio_txrx_mode0(struct spi_device *spi,
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+ unsigned nsecs, u32 word, u8 bits)
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+{
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+ return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
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+}
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+
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+static u32 spi_gpio_txrx_mode1(struct spi_device *spi,
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+ unsigned nsecs, u32 word, u8 bits)
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+{
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+ return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
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+}
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+
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+static u32 spi_gpio_txrx_mode2(struct spi_device *spi,
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+ unsigned nsecs, u32 word, u8 bits)
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+{
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+ return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
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+}
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+
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+static u32 spi_gpio_txrx_mode3(struct spi_device *spi,
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+ unsigned nsecs, u32 word, u8 bits)
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+{
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+ return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
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+}
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+
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+static void spi_gpio_chipselect(struct spi_device *dev, int on)
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+{
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+ struct spi_gpio *sp = spidev_to_sg(dev);
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+
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+ if (sp->info->cs_activelow)
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+ on = !on;
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+ gpio_set_value(sp->info->pin_cs, on ? 1 : 0);
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+}
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+
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+static int spi_gpio_probe(struct platform_device *pdev)
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+{
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+ struct spi_master *master;
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+ struct spi_gpio_platform_data *pdata;
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+ struct spi_gpio *sp;
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+ struct spi_device *spidev;
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+ int err;
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+
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+ pdata = pdev->dev.platform_data;
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+ if (!pdata)
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+ return -ENXIO;
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+
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+ err = -ENOMEM;
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+ master = spi_alloc_master(&pdev->dev, sizeof(struct spi_gpio));
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+ if (!master)
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+ goto err_alloc_master;
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+
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+ sp = spi_master_get_devdata(master);
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+ platform_set_drvdata(pdev, sp);
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+ sp->info = pdata;
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+
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+ err = gpio_request(pdata->pin_clk, "spi_clock");
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+ if (err)
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+ goto err_request_clk;
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+ err = gpio_request(pdata->pin_mosi, "spi_mosi");
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+ if (err)
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+ goto err_request_mosi;
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+ err = gpio_request(pdata->pin_miso, "spi_miso");
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+ if (err)
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+ goto err_request_miso;
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+ err = gpio_request(pdata->pin_cs, "spi_cs");
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+ if (err)
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+ goto err_request_cs;
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+
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+ sp->bitbang.master = spi_master_get(master);
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+ sp->bitbang.master->bus_num = -1;
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+ sp->bitbang.master->num_chipselect = 1;
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+ sp->bitbang.chipselect = spi_gpio_chipselect;
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+ sp->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_mode0;
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+ sp->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_mode1;
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+ sp->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_mode2;
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+ sp->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_mode3;
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+
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+ gpio_direction_output(pdata->pin_clk, 0);
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+ gpio_direction_output(pdata->pin_mosi, 0);
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+ gpio_direction_output(pdata->pin_cs,
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+ pdata->cs_activelow ? 1 : 0);
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+ gpio_direction_input(pdata->pin_miso);
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+
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+ err = spi_bitbang_start(&sp->bitbang);
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+ if (err)
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+ goto err_no_bitbang;
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+ err = pdata->boardinfo_setup(&sp->bi, master,
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+ pdata->boardinfo_setup_data);
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+ if (err)
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+ goto err_bi_setup;
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+ sp->bi.controller_data = sp;
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+ spidev = spi_new_device(master, &sp->bi);
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+ if (!spidev)
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+ goto err_new_dev;
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+
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+ return 0;
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+
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+err_new_dev:
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+err_bi_setup:
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+ spi_bitbang_stop(&sp->bitbang);
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+err_no_bitbang:
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+ spi_master_put(sp->bitbang.master);
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+ gpio_free(pdata->pin_cs);
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+err_request_cs:
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+ gpio_free(pdata->pin_miso);
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+err_request_miso:
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+ gpio_free(pdata->pin_mosi);
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+err_request_mosi:
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+ gpio_free(pdata->pin_clk);
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+err_request_clk:
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+ kfree(master);
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+
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+err_alloc_master:
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+ return err;
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+}
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+
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+static int __devexit spi_gpio_remove(struct platform_device *pdev)
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+{
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+ struct spi_gpio *sp;
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+ struct spi_gpio_platform_data *pdata;
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+
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+ pdata = pdev->dev.platform_data;
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+ sp = platform_get_drvdata(pdev);
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+
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+ gpio_free(pdata->pin_clk);
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+ gpio_free(pdata->pin_mosi);
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+ gpio_free(pdata->pin_miso);
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+ gpio_free(pdata->pin_cs);
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+ spi_bitbang_stop(&sp->bitbang);
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+ spi_master_put(sp->bitbang.master);
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+
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+ return 0;
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+}
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+
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+static struct platform_driver spi_gpio_driver = {
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+ .driver = {
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+ .name = SPI_GPIO_PLATDEV_NAME,
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+ .owner = THIS_MODULE,
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+ },
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+ .probe = spi_gpio_probe,
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+ .remove = __devexit_p(spi_gpio_remove),
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+};
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+
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+int spi_gpio_next_id(void)
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+{
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+ static atomic_t counter = ATOMIC_INIT(-1);
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+
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+ return atomic_inc_return(&counter);
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+}
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+EXPORT_SYMBOL(spi_gpio_next_id);
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+
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+static int __init spi_gpio_init(void)
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+{
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+ int err;
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+
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+ err = platform_driver_register(&spi_gpio_driver);
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+ if (err)
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+ printk(KERN_ERR "spi-gpio: register failed: %d\n", err);
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+
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+ return err;
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+}
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+module_init(spi_gpio_init);
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+
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+static void __exit spi_gpio_exit(void)
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+{
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+ platform_driver_unregister(&spi_gpio_driver);
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+}
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+module_exit(spi_gpio_exit);
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+
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+MODULE_AUTHOR("Piot Skamruk <piotr.skamruk at gmail.com>");
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+MODULE_AUTHOR("Michael Buesch");
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+MODULE_DESCRIPTION("Platform independent GPIO bitbanging SPI driver");
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+MODULE_LICENSE("GPL v2");
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--- a/drivers/spi/Kconfig
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+++ b/drivers/spi/Kconfig
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@@ -100,6 +100,19 @@
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inexpensive battery powered microcontroller evaluation board.
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This same cable can be used to flash new firmware.
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+config SPI_GPIO
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+ tristate "GPIO API based bitbanging SPI controller"
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+ depends on SPI_MASTER && GENERIC_GPIO
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+ select SPI_BITBANG
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+ help
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+ This is a platform driver that can be used for bitbanging
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+ an SPI bus over GPIO pins.
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+ Select this if you have any SPI device that is connected via
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+ GPIO pins.
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+ The module will be called spi_gpio.
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+
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+ If unsure, say N.
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+
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config SPI_IMX
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tristate "Freescale iMX SPI controller"
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depends on SPI_MASTER && ARCH_IMX && EXPERIMENTAL
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--- a/drivers/spi/Makefile
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+++ b/drivers/spi/Makefile
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@@ -16,6 +16,7 @@
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obj-$(CONFIG_SPI_BITBANG) += spi_bitbang.o
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obj-$(CONFIG_SPI_AU1550) += au1550_spi.o
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obj-$(CONFIG_SPI_BUTTERFLY) += spi_butterfly.o
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+obj-$(CONFIG_SPI_GPIO) += spi_gpio.o
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obj-$(CONFIG_SPI_IMX) += spi_imx.o
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obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o
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obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o
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--- a/MAINTAINERS
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+++ b/MAINTAINERS
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@@ -3685,6 +3685,11 @@
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L: spi-devel-general@lists.sourceforge.net
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S: Maintained
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+SPI GPIO MASTER DRIVER
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+P: Michael Buesch
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+M: mb@bu3sch.de
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+S: Maintained
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+
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STABLE BRANCH:
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P: Greg Kroah-Hartman
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M: greg@kroah.com
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