Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

4 files changed, 1204 insertions, 0 deletions

diff --git a/drivers/misc/c2port/Kconfig b/drivers/misc/c2port/Kconfig
new file mode 100644
index 000000000..e20516ffd
--- /dev/null
+++ b/drivers/misc/c2port/Kconfig
@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# C2 port devices
+#
+
+menuconfig C2PORT
+	tristate "Silicon Labs C2 port support"
+	help
+	  This option enables support for Silicon Labs C2 port used to
+	  program Silicon micro controller chips (and other 8051 compatible).
+
+	  If your board have no such micro controllers you don't need this
+	  interface at all.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called c2port_core. Note that you also need a client module
+	  usually called c2port-*.
+
+	  If you are not sure, say N here.
+
+if C2PORT
+
+config C2PORT_DURAMAR_2150
+	tristate "C2 port support for Eurotech's Duramar 2150"
+	depends on X86
+	help
+	  This option enables C2 support for the Eurotech's Duramar 2150
+	  on board micro controller.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called c2port-duramar2150.
+
+endif # C2PORT
diff --git a/drivers/misc/c2port/Makefile b/drivers/misc/c2port/Makefile
new file mode 100644
index 000000000..1dfe6ab06
--- /dev/null
+++ b/drivers/misc/c2port/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_C2PORT)		+= core.o
+
+obj-$(CONFIG_C2PORT_DURAMAR_2150)	+= c2port-duramar2150.o
diff --git a/drivers/misc/c2port/c2port-duramar2150.c b/drivers/misc/c2port/c2port-duramar2150.c
new file mode 100644
index 000000000..7e370949e
--- /dev/null
+++ b/drivers/misc/c2port/c2port-duramar2150.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Silicon Labs C2 port Linux support for Eurotech Duramar 2150
+ *
+ *  Copyright (c) 2008 Rodolfo Giometti <giometti@linux.it>
+ *  Copyright (c) 2008 Eurotech S.p.A. <info@eurotech.it>
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/c2port.h>
+
+#define DATA_PORT	0x325
+#define DIR_PORT	0x326
+#define    C2D		   (1 << 0)
+#define    C2CK		   (1 << 1)
+
+static DEFINE_MUTEX(update_lock);
+
+/*
+ * C2 port operations
+ */
+
+static void duramar2150_c2port_access(struct c2port_device *dev, int status)
+{
+	u8 v;
+
+	mutex_lock(&update_lock);
+
+	v = inb(DIR_PORT);
+
+	/* 0 = input, 1 = output */
+	if (status)
+		outb(v | (C2D | C2CK), DIR_PORT);
+	else
+		/* When access is "off" is important that both lines are set
+		 * as inputs or hi-impedance */
+		outb(v & ~(C2D | C2CK), DIR_PORT);
+
+	mutex_unlock(&update_lock);
+}
+
+static void duramar2150_c2port_c2d_dir(struct c2port_device *dev, int dir)
+{
+	u8 v;
+
+	mutex_lock(&update_lock);
+
+	v = inb(DIR_PORT);
+
+	if (dir)
+		outb(v & ~C2D, DIR_PORT);
+	else
+		outb(v | C2D, DIR_PORT);
+
+	mutex_unlock(&update_lock);
+}
+
+static int duramar2150_c2port_c2d_get(struct c2port_device *dev)
+{
+	return inb(DATA_PORT) & C2D;
+}
+
+static void duramar2150_c2port_c2d_set(struct c2port_device *dev, int status)
+{
+	u8 v;
+
+	mutex_lock(&update_lock);
+
+	v = inb(DATA_PORT);
+
+	if (status)
+		outb(v | C2D, DATA_PORT);
+	else
+		outb(v & ~C2D, DATA_PORT);
+
+	mutex_unlock(&update_lock);
+}
+
+static void duramar2150_c2port_c2ck_set(struct c2port_device *dev, int status)
+{
+	u8 v;
+
+	mutex_lock(&update_lock);
+
+	v = inb(DATA_PORT);
+
+	if (status)
+		outb(v | C2CK, DATA_PORT);
+	else
+		outb(v & ~C2CK, DATA_PORT);
+
+	mutex_unlock(&update_lock);
+}
+
+static struct c2port_ops duramar2150_c2port_ops = {
+	.block_size	= 512,	/* bytes */
+	.blocks_num	= 30,	/* total flash size: 15360 bytes */
+
+	.access		= duramar2150_c2port_access,
+	.c2d_dir	= duramar2150_c2port_c2d_dir,
+	.c2d_get	= duramar2150_c2port_c2d_get,
+	.c2d_set	= duramar2150_c2port_c2d_set,
+	.c2ck_set	= duramar2150_c2port_c2ck_set,
+};
+
+static struct c2port_device *duramar2150_c2port_dev;
+
+/*
+ * Module stuff
+ */
+
+static int __init duramar2150_c2port_init(void)
+{
+	struct resource *res;
+	int ret = 0;
+
+	res = request_region(0x325, 2, "c2port");
+	if (!res)
+		return -EBUSY;
+
+	duramar2150_c2port_dev = c2port_device_register("uc",
+					&duramar2150_c2port_ops, NULL);
+	if (IS_ERR(duramar2150_c2port_dev)) {
+		ret = PTR_ERR(duramar2150_c2port_dev);
+		goto free_region;
+	}
+
+	return 0;
+
+free_region:
+	release_region(0x325, 2);
+	return ret;
+}
+
+static void __exit duramar2150_c2port_exit(void)
+{
+	/* Setup the GPIOs as input by default (access = 0) */
+	duramar2150_c2port_access(duramar2150_c2port_dev, 0);
+
+	c2port_device_unregister(duramar2150_c2port_dev);
+
+	release_region(0x325, 2);
+}
+
+module_init(duramar2150_c2port_init);
+module_exit(duramar2150_c2port_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("Silicon Labs C2 port Linux support for Duramar 2150");
+MODULE_LICENSE("GPL");
diff --git a/drivers/misc/c2port/core.c b/drivers/misc/c2port/core.c
new file mode 100644
index 000000000..54742e849
--- /dev/null
+++ b/drivers/misc/c2port/core.c
@@ -0,0 +1,1011 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Silicon Labs C2 port core Linux support
+ *
+ *  Copyright (c) 2007 Rodolfo Giometti <giometti@linux.it>
+ *  Copyright (c) 2007 Eurotech S.p.A. <info@eurotech.it>
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/idr.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <linux/c2port.h>
+
+#define DRIVER_NAME             "c2port"
+#define DRIVER_VERSION          "0.51.0"
+
+static DEFINE_SPINLOCK(c2port_idr_lock);
+static DEFINE_IDR(c2port_idr);
+
+/*
+ * Local variables
+ */
+
+static struct class *c2port_class;
+
+/*
+ * C2 registers & commands defines
+ */
+
+/* C2 registers */
+#define C2PORT_DEVICEID		0x00
+#define C2PORT_REVID		0x01
+#define C2PORT_FPCTL		0x02
+#define C2PORT_FPDAT		0xB4
+
+/* C2 interface commands */
+#define C2PORT_GET_VERSION	0x01
+#define C2PORT_DEVICE_ERASE	0x03
+#define C2PORT_BLOCK_READ	0x06
+#define C2PORT_BLOCK_WRITE	0x07
+#define C2PORT_PAGE_ERASE	0x08
+
+/* C2 status return codes */
+#define C2PORT_INVALID_COMMAND	0x00
+#define C2PORT_COMMAND_FAILED	0x02
+#define C2PORT_COMMAND_OK	0x0d
+
+/*
+ * C2 port low level signal managements
+ */
+
+static void c2port_reset(struct c2port_device *dev)
+{
+	struct c2port_ops *ops = dev->ops;
+
+	/* To reset the device we have to keep clock line low for at least
+	 * 20us.
+	 */
+	local_irq_disable();
+	ops->c2ck_set(dev, 0);
+	udelay(25);
+	ops->c2ck_set(dev, 1);
+	local_irq_enable();
+
+	udelay(1);
+}
+
+static void c2port_strobe_ck(struct c2port_device *dev)
+{
+	struct c2port_ops *ops = dev->ops;
+
+	/* During hi-low-hi transition we disable local IRQs to avoid
+	 * interructions since C2 port specification says that it must be
+	 * shorter than 5us, otherwise the microcontroller may consider
+	 * it as a reset signal!
+	 */
+	local_irq_disable();
+	ops->c2ck_set(dev, 0);
+	udelay(1);
+	ops->c2ck_set(dev, 1);
+	local_irq_enable();
+
+	udelay(1);
+}
+
+/*
+ * C2 port basic functions
+ */
+
+static void c2port_write_ar(struct c2port_device *dev, u8 addr)
+{
+	struct c2port_ops *ops = dev->ops;
+	int i;
+
+	/* START field */
+	c2port_strobe_ck(dev);
+
+	/* INS field (11b, LSB first) */
+	ops->c2d_dir(dev, 0);
+	ops->c2d_set(dev, 1);
+	c2port_strobe_ck(dev);
+	ops->c2d_set(dev, 1);
+	c2port_strobe_ck(dev);
+
+	/* ADDRESS field */
+	for (i = 0; i < 8; i++) {
+		ops->c2d_set(dev, addr & 0x01);
+		c2port_strobe_ck(dev);
+
+		addr >>= 1;
+	}
+
+	/* STOP field */
+	ops->c2d_dir(dev, 1);
+	c2port_strobe_ck(dev);
+}
+
+static int c2port_read_ar(struct c2port_device *dev, u8 *addr)
+{
+	struct c2port_ops *ops = dev->ops;
+	int i;
+
+	/* START field */
+	c2port_strobe_ck(dev);
+
+	/* INS field (10b, LSB first) */
+	ops->c2d_dir(dev, 0);
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+	ops->c2d_set(dev, 1);
+	c2port_strobe_ck(dev);
+
+	/* ADDRESS field */
+	ops->c2d_dir(dev, 1);
+	*addr = 0;
+	for (i = 0; i < 8; i++) {
+		*addr >>= 1;	/* shift in 8-bit ADDRESS field LSB first */
+
+		c2port_strobe_ck(dev);
+		if (ops->c2d_get(dev))
+			*addr |= 0x80;
+	}
+
+	/* STOP field */
+	c2port_strobe_ck(dev);
+
+	return 0;
+}
+
+static int c2port_write_dr(struct c2port_device *dev, u8 data)
+{
+	struct c2port_ops *ops = dev->ops;
+	int timeout, i;
+
+	/* START field */
+	c2port_strobe_ck(dev);
+
+	/* INS field (01b, LSB first) */
+	ops->c2d_dir(dev, 0);
+	ops->c2d_set(dev, 1);
+	c2port_strobe_ck(dev);
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+
+	/* LENGTH field (00b, LSB first -> 1 byte) */
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+
+	/* DATA field */
+	for (i = 0; i < 8; i++) {
+		ops->c2d_set(dev, data & 0x01);
+		c2port_strobe_ck(dev);
+
+		data >>= 1;
+	}
+
+	/* WAIT field */
+	ops->c2d_dir(dev, 1);
+	timeout = 20;
+	do {
+		c2port_strobe_ck(dev);
+		if (ops->c2d_get(dev))
+			break;
+
+		udelay(1);
+	} while (--timeout > 0);
+	if (timeout == 0)
+		return -EIO;
+
+	/* STOP field */
+	c2port_strobe_ck(dev);
+
+	return 0;
+}
+
+static int c2port_read_dr(struct c2port_device *dev, u8 *data)
+{
+	struct c2port_ops *ops = dev->ops;
+	int timeout, i;
+
+	/* START field */
+	c2port_strobe_ck(dev);
+
+	/* INS field (00b, LSB first) */
+	ops->c2d_dir(dev, 0);
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+
+	/* LENGTH field (00b, LSB first -> 1 byte) */
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+	ops->c2d_set(dev, 0);
+	c2port_strobe_ck(dev);
+
+	/* WAIT field */
+	ops->c2d_dir(dev, 1);
+	timeout = 20;
+	do {
+		c2port_strobe_ck(dev);
+		if (ops->c2d_get(dev))
+			break;
+
+		udelay(1);
+	} while (--timeout > 0);
+	if (timeout == 0)
+		return -EIO;
+
+	/* DATA field */
+	*data = 0;
+	for (i = 0; i < 8; i++) {
+		*data >>= 1;	/* shift in 8-bit DATA field LSB first */
+
+		c2port_strobe_ck(dev);
+		if (ops->c2d_get(dev))
+			*data |= 0x80;
+	}
+
+	/* STOP field */
+	c2port_strobe_ck(dev);
+
+	return 0;
+}
+
+static int c2port_poll_in_busy(struct c2port_device *dev)
+{
+	u8 addr;
+	int ret, timeout = 20;
+
+	do {
+		ret = (c2port_read_ar(dev, &addr));
+		if (ret < 0)
+			return -EIO;
+
+		if (!(addr & 0x02))
+			break;
+
+		udelay(1);
+	} while (--timeout > 0);
+	if (timeout == 0)
+		return -EIO;
+
+	return 0;
+}
+
+static int c2port_poll_out_ready(struct c2port_device *dev)
+{
+	u8 addr;
+	int ret, timeout = 10000; /* erase flash needs long time... */
+
+	do {
+		ret = (c2port_read_ar(dev, &addr));
+		if (ret < 0)
+			return -EIO;
+
+		if (addr & 0x01)
+			break;
+
+		udelay(1);
+	} while (--timeout > 0);
+	if (timeout == 0)
+		return -EIO;
+
+	return 0;
+}
+
+/*
+ * sysfs methods
+ */
+
+static ssize_t c2port_show_name(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", c2dev->name);
+}
+static DEVICE_ATTR(name, 0444, c2port_show_name, NULL);
+
+static ssize_t c2port_show_flash_blocks_num(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	struct c2port_ops *ops = c2dev->ops;
+
+	return sprintf(buf, "%d\n", ops->blocks_num);
+}
+static DEVICE_ATTR(flash_blocks_num, 0444, c2port_show_flash_blocks_num, NULL);
+
+static ssize_t c2port_show_flash_block_size(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	struct c2port_ops *ops = c2dev->ops;
+
+	return sprintf(buf, "%d\n", ops->block_size);
+}
+static DEVICE_ATTR(flash_block_size, 0444, c2port_show_flash_block_size, NULL);
+
+static ssize_t c2port_show_flash_size(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	struct c2port_ops *ops = c2dev->ops;
+
+	return sprintf(buf, "%d\n", ops->blocks_num * ops->block_size);
+}
+static DEVICE_ATTR(flash_size, 0444, c2port_show_flash_size, NULL);
+
+static ssize_t access_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", c2dev->access);
+}
+
+static ssize_t access_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	struct c2port_ops *ops = c2dev->ops;
+	int status, ret;
+
+	ret = sscanf(buf, "%d", &status);
+	if (ret != 1)
+		return -EINVAL;
+
+	mutex_lock(&c2dev->mutex);
+
+	c2dev->access = !!status;
+
+	/* If access is "on" clock should be HIGH _before_ setting the line
+	 * as output and data line should be set as INPUT anyway */
+	if (c2dev->access)
+		ops->c2ck_set(c2dev, 1);
+	ops->access(c2dev, c2dev->access);
+	if (c2dev->access)
+		ops->c2d_dir(c2dev, 1);
+
+	mutex_unlock(&c2dev->mutex);
+
+	return count;
+}
+static DEVICE_ATTR_RW(access);
+
+static ssize_t c2port_store_reset(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+
+	/* Check the device access status */
+	if (!c2dev->access)
+		return -EBUSY;
+
+	mutex_lock(&c2dev->mutex);
+
+	c2port_reset(c2dev);
+	c2dev->flash_access = 0;
+
+	mutex_unlock(&c2dev->mutex);
+
+	return count;
+}
+static DEVICE_ATTR(reset, 0200, NULL, c2port_store_reset);
+
+static ssize_t __c2port_show_dev_id(struct c2port_device *dev, char *buf)
+{
+	u8 data;
+	int ret;
+
+	/* Select DEVICEID register for C2 data register accesses */
+	c2port_write_ar(dev, C2PORT_DEVICEID);
+
+	/* Read and return the device ID register */
+	ret = c2port_read_dr(dev, &data);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", data);
+}
+
+static ssize_t c2port_show_dev_id(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	ssize_t ret;
+
+	/* Check the device access status */
+	if (!c2dev->access)
+		return -EBUSY;
+
+	mutex_lock(&c2dev->mutex);
+	ret = __c2port_show_dev_id(c2dev, buf);
+	mutex_unlock(&c2dev->mutex);
+
+	if (ret < 0)
+		dev_err(dev, "cannot read from %s\n", c2dev->name);
+
+	return ret;
+}
+static DEVICE_ATTR(dev_id, 0444, c2port_show_dev_id, NULL);
+
+static ssize_t __c2port_show_rev_id(struct c2port_device *dev, char *buf)
+{
+	u8 data;
+	int ret;
+
+	/* Select REVID register for C2 data register accesses */
+	c2port_write_ar(dev, C2PORT_REVID);
+
+	/* Read and return the revision ID register */
+	ret = c2port_read_dr(dev, &data);
+	if (ret < 0)
+		return ret;
+
+	return sprintf(buf, "%d\n", data);
+}
+
+static ssize_t c2port_show_rev_id(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	ssize_t ret;
+
+	/* Check the device access status */
+	if (!c2dev->access)
+		return -EBUSY;
+
+	mutex_lock(&c2dev->mutex);
+	ret = __c2port_show_rev_id(c2dev, buf);
+	mutex_unlock(&c2dev->mutex);
+
+	if (ret < 0)
+		dev_err(c2dev->dev, "cannot read from %s\n", c2dev->name);
+
+	return ret;
+}
+static DEVICE_ATTR(rev_id, 0444, c2port_show_rev_id, NULL);
+
+static ssize_t c2port_show_flash_access(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", c2dev->flash_access);
+}
+
+static ssize_t __c2port_store_flash_access(struct c2port_device *dev,
+						int status)
+{
+	int ret;
+
+	/* Check the device access status */
+	if (!dev->access)
+		return -EBUSY;
+
+	dev->flash_access = !!status;
+
+	/* If flash_access is off we have nothing to do... */
+	if (dev->flash_access == 0)
+		return 0;
+
+	/* Target the C2 flash programming control register for C2 data
+	 * register access */
+	c2port_write_ar(dev, C2PORT_FPCTL);
+
+	/* Write the first keycode to enable C2 Flash programming */
+	ret = c2port_write_dr(dev, 0x02);
+	if (ret < 0)
+		return ret;
+
+	/* Write the second keycode to enable C2 Flash programming */
+	ret = c2port_write_dr(dev, 0x01);
+	if (ret < 0)
+		return ret;
+
+	/* Delay for at least 20ms to ensure the target is ready for
+	 * C2 flash programming */
+	mdelay(25);
+
+	return 0;
+}
+
+static ssize_t c2port_store_flash_access(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	int status;
+	ssize_t ret;
+
+	ret = sscanf(buf, "%d", &status);
+	if (ret != 1)
+		return -EINVAL;
+
+	mutex_lock(&c2dev->mutex);
+	ret = __c2port_store_flash_access(c2dev, status);
+	mutex_unlock(&c2dev->mutex);
+
+	if (ret < 0) {
+		dev_err(c2dev->dev, "cannot enable %s flash programming\n",
+			c2dev->name);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR(flash_access, 0644, c2port_show_flash_access,
+		   c2port_store_flash_access);
+
+static ssize_t __c2port_write_flash_erase(struct c2port_device *dev)
+{
+	u8 status;
+	int ret;
+
+	/* Target the C2 flash programming data register for C2 data register
+	 * access.
+	 */
+	c2port_write_ar(dev, C2PORT_FPDAT);
+
+	/* Send device erase command */
+	c2port_write_dr(dev, C2PORT_DEVICE_ERASE);
+
+	/* Wait for input acknowledge */
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Should check status before starting FLASH access sequence */
+
+	/* Wait for status information */
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Read flash programming interface status */
+	ret = c2port_read_dr(dev, &status);
+	if (ret < 0)
+		return ret;
+	if (status != C2PORT_COMMAND_OK)
+		return -EBUSY;
+
+	/* Send a three-byte arming sequence to enable the device erase.
+	 * If the sequence is not received correctly, the command will be
+	 * ignored.
+	 * Sequence is: 0xde, 0xad, 0xa5.
+	 */
+	c2port_write_dr(dev, 0xde);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+	c2port_write_dr(dev, 0xad);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+	c2port_write_dr(dev, 0xa5);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static ssize_t c2port_store_flash_erase(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(dev);
+	int ret;
+
+	/* Check the device and flash access status */
+	if (!c2dev->access || !c2dev->flash_access)
+		return -EBUSY;
+
+	mutex_lock(&c2dev->mutex);
+	ret = __c2port_write_flash_erase(c2dev);
+	mutex_unlock(&c2dev->mutex);
+
+	if (ret < 0) {
+		dev_err(c2dev->dev, "cannot erase %s flash\n", c2dev->name);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR(flash_erase, 0200, NULL, c2port_store_flash_erase);
+
+static ssize_t __c2port_read_flash_data(struct c2port_device *dev,
+				char *buffer, loff_t offset, size_t count)
+{
+	struct c2port_ops *ops = dev->ops;
+	u8 status, nread = 128;
+	int i, ret;
+
+	/* Check for flash end */
+	if (offset >= ops->block_size * ops->blocks_num)
+		return 0;
+
+	if (ops->block_size * ops->blocks_num - offset < nread)
+		nread = ops->block_size * ops->blocks_num - offset;
+	if (count < nread)
+		nread = count;
+	if (nread == 0)
+		return nread;
+
+	/* Target the C2 flash programming data register for C2 data register
+	 * access */
+	c2port_write_ar(dev, C2PORT_FPDAT);
+
+	/* Send flash block read command */
+	c2port_write_dr(dev, C2PORT_BLOCK_READ);
+
+	/* Wait for input acknowledge */
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Should check status before starting FLASH access sequence */
+
+	/* Wait for status information */
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Read flash programming interface status */
+	ret = c2port_read_dr(dev, &status);
+	if (ret < 0)
+		return ret;
+	if (status != C2PORT_COMMAND_OK)
+		return -EBUSY;
+
+	/* Send address high byte */
+	c2port_write_dr(dev, offset >> 8);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Send address low byte */
+	c2port_write_dr(dev, offset & 0x00ff);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Send address block size */
+	c2port_write_dr(dev, nread);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Should check status before reading FLASH block */
+
+	/* Wait for status information */
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Read flash programming interface status */
+	ret = c2port_read_dr(dev, &status);
+	if (ret < 0)
+		return ret;
+	if (status != C2PORT_COMMAND_OK)
+		return -EBUSY;
+
+	/* Read flash block */
+	for (i = 0; i < nread; i++) {
+		ret = c2port_poll_out_ready(dev);
+		if (ret < 0)
+			return ret;
+
+		ret = c2port_read_dr(dev, buffer+i);
+		if (ret < 0)
+			return ret;
+	}
+
+	return nread;
+}
+
+static ssize_t c2port_read_flash_data(struct file *filp, struct kobject *kobj,
+				const struct bin_attribute *attr,
+				char *buffer, loff_t offset, size_t count)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
+	ssize_t ret;
+
+	/* Check the device and flash access status */
+	if (!c2dev->access || !c2dev->flash_access)
+		return -EBUSY;
+
+	mutex_lock(&c2dev->mutex);
+	ret = __c2port_read_flash_data(c2dev, buffer, offset, count);
+	mutex_unlock(&c2dev->mutex);
+
+	if (ret < 0)
+		dev_err(c2dev->dev, "cannot read %s flash\n", c2dev->name);
+
+	return ret;
+}
+
+static ssize_t __c2port_write_flash_data(struct c2port_device *dev,
+				char *buffer, loff_t offset, size_t count)
+{
+	struct c2port_ops *ops = dev->ops;
+	u8 status, nwrite = 128;
+	int i, ret;
+
+	if (nwrite > count)
+		nwrite = count;
+	if (ops->block_size * ops->blocks_num - offset < nwrite)
+		nwrite = ops->block_size * ops->blocks_num - offset;
+
+	/* Check for flash end */
+	if (offset >= ops->block_size * ops->blocks_num)
+		return -EINVAL;
+
+	/* Target the C2 flash programming data register for C2 data register
+	 * access */
+	c2port_write_ar(dev, C2PORT_FPDAT);
+
+	/* Send flash block write command */
+	c2port_write_dr(dev, C2PORT_BLOCK_WRITE);
+
+	/* Wait for input acknowledge */
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Should check status before starting FLASH access sequence */
+
+	/* Wait for status information */
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Read flash programming interface status */
+	ret = c2port_read_dr(dev, &status);
+	if (ret < 0)
+		return ret;
+	if (status != C2PORT_COMMAND_OK)
+		return -EBUSY;
+
+	/* Send address high byte */
+	c2port_write_dr(dev, offset >> 8);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Send address low byte */
+	c2port_write_dr(dev, offset & 0x00ff);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Send address block size */
+	c2port_write_dr(dev, nwrite);
+	ret = c2port_poll_in_busy(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Should check status before writing FLASH block */
+
+	/* Wait for status information */
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	/* Read flash programming interface status */
+	ret = c2port_read_dr(dev, &status);
+	if (ret < 0)
+		return ret;
+	if (status != C2PORT_COMMAND_OK)
+		return -EBUSY;
+
+	/* Write flash block */
+	for (i = 0; i < nwrite; i++) {
+		ret = c2port_write_dr(dev, *(buffer+i));
+		if (ret < 0)
+			return ret;
+
+		ret = c2port_poll_in_busy(dev);
+		if (ret < 0)
+			return ret;
+
+	}
+
+	/* Wait for last flash write to complete */
+	ret = c2port_poll_out_ready(dev);
+	if (ret < 0)
+		return ret;
+
+	return nwrite;
+}
+
+static ssize_t c2port_write_flash_data(struct file *filp, struct kobject *kobj,
+				const struct bin_attribute *attr,
+				char *buffer, loff_t offset, size_t count)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
+	int ret;
+
+	/* Check the device access status */
+	if (!c2dev->access || !c2dev->flash_access)
+		return -EBUSY;
+
+	mutex_lock(&c2dev->mutex);
+	ret = __c2port_write_flash_data(c2dev, buffer, offset, count);
+	mutex_unlock(&c2dev->mutex);
+
+	if (ret < 0)
+		dev_err(c2dev->dev, "cannot write %s flash\n", c2dev->name);
+
+	return ret;
+}
+/* size is computed at run-time */
+static const BIN_ATTR(flash_data, 0644, c2port_read_flash_data,
+		      c2port_write_flash_data, 0);
+
+/*
+ * Class attributes
+ */
+static struct attribute *c2port_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_flash_blocks_num.attr,
+	&dev_attr_flash_block_size.attr,
+	&dev_attr_flash_size.attr,
+	&dev_attr_access.attr,
+	&dev_attr_reset.attr,
+	&dev_attr_dev_id.attr,
+	&dev_attr_rev_id.attr,
+	&dev_attr_flash_access.attr,
+	&dev_attr_flash_erase.attr,
+	NULL,
+};
+
+static const struct bin_attribute *const c2port_bin_attrs[] = {
+	&bin_attr_flash_data,
+	NULL,
+};
+
+static size_t c2port_bin_attr_size(struct kobject *kobj,
+				   const struct bin_attribute *attr,
+				   int i)
+{
+	struct c2port_device *c2dev = dev_get_drvdata(kobj_to_dev(kobj));
+
+	if (attr == &bin_attr_flash_data)
+		return c2dev->ops->blocks_num * c2dev->ops->block_size;
+
+	return attr->size;
+}
+
+static const struct attribute_group c2port_group = {
+	.attrs = c2port_attrs,
+	.bin_attrs = c2port_bin_attrs,
+	.bin_size = c2port_bin_attr_size,
+};
+
+static const struct attribute_group *c2port_groups[] = {
+	&c2port_group,
+	NULL,
+};
+
+/*
+ * Exported functions
+ */
+
+struct c2port_device *c2port_device_register(char *name,
+					struct c2port_ops *ops, void *devdata)
+{
+	struct c2port_device *c2dev;
+	int ret;
+
+	if (unlikely(!ops) || unlikely(!ops->access) || \
+		unlikely(!ops->c2d_dir) || unlikely(!ops->c2ck_set) || \
+		unlikely(!ops->c2d_get) || unlikely(!ops->c2d_set))
+		return ERR_PTR(-EINVAL);
+
+	c2dev = kzalloc_obj(struct c2port_device);
+	if (unlikely(!c2dev))
+		return ERR_PTR(-ENOMEM);
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_irq(&c2port_idr_lock);
+	ret = idr_alloc(&c2port_idr, c2dev, 0, 0, GFP_NOWAIT);
+	spin_unlock_irq(&c2port_idr_lock);
+	idr_preload_end();
+
+	if (ret < 0)
+		goto error_idr_alloc;
+	c2dev->id = ret;
+	c2dev->ops = ops;
+
+	c2dev->dev = device_create(c2port_class, NULL, 0, c2dev,
+				   "c2port%d", c2dev->id);
+	if (IS_ERR(c2dev->dev)) {
+		ret = PTR_ERR(c2dev->dev);
+		goto error_device_create;
+	}
+	dev_set_drvdata(c2dev->dev, c2dev);
+
+	strscpy(c2dev->name, name, sizeof(c2dev->name));
+	mutex_init(&c2dev->mutex);
+
+	/* By default C2 port access is off */
+	c2dev->access = c2dev->flash_access = 0;
+	ops->access(c2dev, 0);
+
+	dev_info(c2dev->dev, "C2 port %s added\n", name);
+	dev_info(c2dev->dev, "%s flash has %d blocks x %d bytes "
+				"(%d bytes total)\n",
+				name, ops->blocks_num, ops->block_size,
+				ops->blocks_num * ops->block_size);
+
+	return c2dev;
+
+error_device_create:
+	spin_lock_irq(&c2port_idr_lock);
+	idr_remove(&c2port_idr, c2dev->id);
+	spin_unlock_irq(&c2port_idr_lock);
+
+error_idr_alloc:
+	kfree(c2dev);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(c2port_device_register);
+
+void c2port_device_unregister(struct c2port_device *c2dev)
+{
+	if (!c2dev)
+		return;
+
+	dev_info(c2dev->dev, "C2 port %s removed\n", c2dev->name);
+
+	spin_lock_irq(&c2port_idr_lock);
+	idr_remove(&c2port_idr, c2dev->id);
+	spin_unlock_irq(&c2port_idr_lock);
+
+	device_destroy(c2port_class, c2dev->id);
+
+	kfree(c2dev);
+}
+EXPORT_SYMBOL(c2port_device_unregister);
+
+/*
+ * Module stuff
+ */
+
+static int __init c2port_init(void)
+{
+	printk(KERN_INFO "Silicon Labs C2 port support v. " DRIVER_VERSION
+		" - (C) 2007 Rodolfo Giometti\n");
+
+	c2port_class = class_create("c2port");
+	if (IS_ERR(c2port_class)) {
+		printk(KERN_ERR "c2port: failed to allocate class\n");
+		return PTR_ERR(c2port_class);
+	}
+	c2port_class->dev_groups = c2port_groups;
+
+	return 0;
+}
+
+static void __exit c2port_exit(void)
+{
+	class_destroy(c2port_class);
+}
+
+module_init(c2port_init);
+module_exit(c2port_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("Silicon Labs C2 port support v. " DRIVER_VERSION);
+MODULE_LICENSE("GPL");