Merge branch 'next-i2c' of git://aeryn.fluff.org.uk/bjdooks/linux

* 'next-i2c' of git://aeryn.fluff.org.uk/bjdooks/linux:
  i2c-stu300: Make driver depend on MACH_U300
  i2c-s3c2410: use resource_size()
  i2c: Use resource_size macro
  i2c: ST DDC I2C U300 bus driver v3
  i2c-bfin-twi: pull in io.h for ioremap()

15 files changed, 1074 insertions, 33 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 0d04d3ebfc2..3c259ee7ddd 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -513,6 +513,19 @@ config I2C_SIMTEC
 	  This driver can also be built as a module. If so, the module
 	  will be called i2c-simtec.
 
+config I2C_STU300
+	tristate "ST Microelectronics DDC I2C interface"
+	depends on MACH_U300
+	default y if MACH_U300
+	help
+	  If you say yes to this option, support will be included for the
+	  I2C interface from ST Microelectronics simply called "DDC I2C"
+	  supporting both I2C and DDC, used in e.g. the U300 series
+	  mobile platforms.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called i2c-stu300.
+
 config I2C_VERSATILE
 	tristate "ARM Versatile/Realview I2C bus support"
 	depends on ARCH_VERSATILE || ARCH_REALVIEW
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 776acb6403a..edeabf00310 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
 obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
+obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 
 # External I2C/SMBus adapter drivers
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index 67d9dc5b351..06e1ecb4919 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -200,10 +200,10 @@ static int __devinit at91_i2c_probe(struct platform_device *pdev)
 	if (!res)
 		return -ENXIO;
 
-	if (!request_mem_region(res->start, res->end - res->start + 1, "at91_i2c"))
+	if (!request_mem_region(res->start, resource_size(res), "at91_i2c"))
 		return -EBUSY;
 
-	twi_base = ioremap(res->start, res->end - res->start + 1);
+	twi_base = ioremap(res->start, resource_size(res));
 	if (!twi_base) {
 		rc = -ENOMEM;
 		goto fail0;
@@ -252,7 +252,7 @@ fail2:
 fail1:
 	iounmap(twi_base);
 fail0:
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 
 	return rc;
 }
@@ -268,7 +268,7 @@ static int __devexit at91_i2c_remove(struct platform_device *pdev)
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	iounmap(twi_base);
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 
 	clk_disable(twi_clk);		/* disable peripheral clock */
 	clk_put(twi_clk);
diff --git a/drivers/i2c/busses/i2c-au1550.c b/drivers/i2c/busses/i2c-au1550.c
index f78ce523e3d..532828bc50e 100644
--- a/drivers/i2c/busses/i2c-au1550.c
+++ b/drivers/i2c/busses/i2c-au1550.c
@@ -389,7 +389,7 @@ i2c_au1550_probe(struct platform_device *pdev)
 		goto out;
 	}
 
-	priv->ioarea = request_mem_region(r->start, r->end - r->start + 1,
+	priv->ioarea = request_mem_region(r->start, resource_size(r),
 					  pdev->name);
 	if (!priv->ioarea) {
 		ret = -EBUSY;
diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c
index 26d8987e69b..b309ac2c3d5 100644
--- a/drivers/i2c/busses/i2c-bfin-twi.c
+++ b/drivers/i2c/busses/i2c-bfin-twi.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/i2c.h>
+#include <linux/io.h>
 #include <linux/mm.h>
 #include <linux/timer.h>
 #include <linux/spinlock.h>
@@ -651,7 +652,7 @@ static int i2c_bfin_twi_probe(struct platform_device *pdev)
 		goto out_error_get_res;
 	}
 
-	iface->regs_base = ioremap(res->start, res->end - res->start + 1);
+	iface->regs_base = ioremap(res->start, resource_size(res));
 	if (iface->regs_base == NULL) {
 		dev_err(&pdev->dev, "Cannot map IO\n");
 		rc = -ENXIO;
diff --git a/drivers/i2c/busses/i2c-highlander.c b/drivers/i2c/busses/i2c-highlander.c
index e5a8dae4a28..87ecace415d 100644
--- a/drivers/i2c/busses/i2c-highlander.c
+++ b/drivers/i2c/busses/i2c-highlander.c
@@ -373,7 +373,7 @@ static int __devinit highlander_i2c_probe(struct platform_device *pdev)
 	if (unlikely(!dev))
 		return -ENOMEM;
 
-	dev->base = ioremap_nocache(res->start, res->end - res->start + 1);
+	dev->base = ioremap_nocache(res->start, resource_size(res));
 	if (unlikely(!dev->base)) {
 		ret = -ENXIO;
 		goto err;
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 5a4945d1dba..c3869d94ad4 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -469,7 +469,7 @@ mv64xxx_i2c_map_regs(struct platform_device *pd,
 	if (!r)
 		return -ENODEV;
 
-	size = r->end - r->start + 1;
+	size = resource_size(r);
 
 	if (!request_mem_region(r->start, size, drv_data->adapter.name))
 		return -EBUSY;
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index 3542c6ba98f..0dabe643ec5 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -234,14 +234,14 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
 	if (!i2c)
 		return -ENOMEM;
 
-	if (!request_mem_region(res->start, res->end - res->start + 1,
+	if (!request_mem_region(res->start, resource_size(res),
 				pdev->name)) {
 		dev_err(&pdev->dev, "Memory region busy\n");
 		ret = -EBUSY;
 		goto request_mem_failed;
 	}
 
-	i2c->base = ioremap(res->start, res->end - res->start + 1);
+	i2c->base = ioremap(res->start, resource_size(res));
 	if (!i2c->base) {
 		dev_err(&pdev->dev, "Unable to map registers\n");
 		ret = -EIO;
@@ -283,7 +283,7 @@ add_adapter_failed:
 request_irq_failed:
 	iounmap(i2c->base);
 map_failed:
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 request_mem_failed:
 	kfree(i2c);
 
@@ -311,7 +311,7 @@ static int __devexit ocores_i2c_remove(struct platform_device* pdev)
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (res)
-		release_mem_region(res->start, res->end - res->start + 1);
+		release_mem_region(res->start, resource_size(res));
 
 	kfree(i2c);
 
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index c73475dd0fb..b606db85525 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -828,7 +828,7 @@ omap_i2c_probe(struct platform_device *pdev)
 	dev->idle = 1;
 	dev->dev = &pdev->dev;
 	dev->irq = irq->start;
-	dev->base = ioremap(mem->start, mem->end - mem->start + 1);
+	dev->base = ioremap(mem->start, resource_size(mem));
 	if (!dev->base) {
 		r = -ENOMEM;
 		goto err_free_mem;
diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
index 7b23891b7d5..c4df9d411cd 100644
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -27,8 +27,6 @@
 #include <asm/irq.h>
 #include <asm/io.h>
 
-#define res_len(r)		((r)->end - (r)->start + 1)
-
 struct i2c_pca_pf_data {
 	void __iomem			*reg_base;
 	int				irq;	/* if 0, use polling */
@@ -148,7 +146,7 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 		goto e_print;
 	}
 
-	if (!request_mem_region(res->start, res_len(res), res->name)) {
+	if (!request_mem_region(res->start, resource_size(res), res->name)) {
 		ret = -ENOMEM;
 		goto e_print;
 	}
@@ -161,13 +159,13 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 
 	init_waitqueue_head(&i2c->wait);
 
-	i2c->reg_base = ioremap(res->start, res_len(res));
+	i2c->reg_base = ioremap(res->start, resource_size(res));
 	if (!i2c->reg_base) {
 		ret = -ENOMEM;
 		goto e_remap;
 	}
 	i2c->io_base = res->start;
-	i2c->io_size = res_len(res);
+	i2c->io_size = resource_size(res);
 	i2c->irq = irq;
 
 	i2c->adap.nr = pdev->id >= 0 ? pdev->id : 0;
@@ -250,7 +248,7 @@ e_reqirq:
 e_remap:
 	kfree(i2c);
 e_alloc:
-	release_mem_region(res->start, res_len(res));
+	release_mem_region(res->start, resource_size(res));
 e_print:
 	printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)\n", ret);
 	return ret;
diff --git a/drivers/i2c/busses/i2c-pmcmsp.c b/drivers/i2c/busses/i2c-pmcmsp.c
index 0bdb2d7f057..7b57d5f267e 100644
--- a/drivers/i2c/busses/i2c-pmcmsp.c
+++ b/drivers/i2c/busses/i2c-pmcmsp.c
@@ -283,7 +283,7 @@ static int __devinit pmcmsptwi_probe(struct platform_device *pldev)
 	}
 
 	/* reserve the memory region */
-	if (!request_mem_region(res->start, res->end - res->start + 1,
+	if (!request_mem_region(res->start, resource_size(res),
 				pldev->name)) {
 		dev_err(&pldev->dev,
 			"Unable to get memory/io address region 0x%08x\n",
@@ -294,7 +294,7 @@ static int __devinit pmcmsptwi_probe(struct platform_device *pldev)
 
 	/* remap the memory */
 	pmcmsptwi_data.iobase = ioremap_nocache(res->start,
-						res->end - res->start + 1);
+						resource_size(res));
 	if (!pmcmsptwi_data.iobase) {
 		dev_err(&pldev->dev,
 			"Unable to ioremap address 0x%08x\n", res->start);
@@ -360,7 +360,7 @@ ret_unmap:
 	iounmap(pmcmsptwi_data.iobase);
 
 ret_unreserve:
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 
 ret_err:
 	return rc;
@@ -385,7 +385,7 @@ static int __devexit pmcmsptwi_remove(struct platform_device *pldev)
 	iounmap(pmcmsptwi_data.iobase);
 
 	res = platform_get_resource(pldev, IORESOURCE_MEM, 0);
-	release_mem_region(res->start, res->end - res->start + 1);
+	release_mem_region(res->start, resource_size(res));
 
 	return 0;
 }
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 035a6c7e59d..762e1e53088 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -993,7 +993,6 @@ static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
 	.functionality	= i2c_pxa_functionality,
 };
 
-#define res_len(r)		((r)->end - (r)->start + 1)
 static int i2c_pxa_probe(struct platform_device *dev)
 {
 	struct pxa_i2c *i2c;
@@ -1008,7 +1007,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
 	if (res == NULL || irq < 0)
 		return -ENODEV;
 
-	if (!request_mem_region(res->start, res_len(res), res->name))
+	if (!request_mem_region(res->start, resource_size(res), res->name))
 		return -ENOMEM;
 
 	i2c = kzalloc(sizeof(struct pxa_i2c), GFP_KERNEL);
@@ -1038,7 +1037,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
 		goto eclk;
 	}
 
-	i2c->reg_base = ioremap(res->start, res_len(res));
+	i2c->reg_base = ioremap(res->start, resource_size(res));
 	if (!i2c->reg_base) {
 		ret = -EIO;
 		goto eremap;
@@ -1046,7 +1045,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
 	i2c->reg_shift = REG_SHIFT(id->driver_data);
 
 	i2c->iobase = res->start;
-	i2c->iosize = res_len(res);
+	i2c->iosize = resource_size(res);
 
 	i2c->irq = irq;
 
@@ -1110,7 +1109,7 @@ eremap:
 eclk:
 	kfree(i2c);
 emalloc:
-	release_mem_region(res->start, res_len(res));
+	release_mem_region(res->start, resource_size(res));
 	return ret;
 }
 
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 079a312d36f..8f42a4536cd 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -828,7 +828,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 		goto err_clk;
 	}
 
-	i2c->ioarea = request_mem_region(res->start, (res->end-res->start)+1,
+	i2c->ioarea = request_mem_region(res->start, resource_size(res),
 					 pdev->name);
 
 	if (i2c->ioarea == NULL) {
@@ -837,7 +837,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 		goto err_clk;
 	}
 
-	i2c->regs = ioremap(res->start, (res->end-res->start)+1);
+	i2c->regs = ioremap(res->start, resource_size(res));
 
 	if (i2c->regs == NULL) {
 		dev_err(&pdev->dev, "cannot map IO\n");
diff --git a/drivers/i2c/busses/i2c-stu300.c b/drivers/i2c/busses/i2c-stu300.c
new file mode 100644
index 00000000000..182e711318b
--- /dev/null
+++ b/drivers/i2c/busses/i2c-stu300.c
@@ -0,0 +1,1029 @@
+/*
+ * Copyright (C) 2007-2009 ST-Ericsson AB
+ * License terms: GNU General Public License (GPL) version 2
+ * ST DDC I2C master mode driver, used in e.g. U300 series platforms.
+ * Author: Linus Walleij <linus.walleij@stericsson.com>
+ * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+/* the name of this kernel module */
+#define NAME "stu300"
+
+/* CR (Control Register) 8bit (R/W) */
+#define I2C_CR					(0x00000000)
+#define I2C_CR_RESET_VALUE			(0x00)
+#define I2C_CR_RESET_UMASK			(0x00)
+#define I2C_CR_DDC1_ENABLE			(0x80)
+#define I2C_CR_TRANS_ENABLE			(0x40)
+#define I2C_CR_PERIPHERAL_ENABLE		(0x20)
+#define I2C_CR_DDC2B_ENABLE			(0x10)
+#define I2C_CR_START_ENABLE			(0x08)
+#define I2C_CR_ACK_ENABLE			(0x04)
+#define I2C_CR_STOP_ENABLE			(0x02)
+#define I2C_CR_INTERRUPT_ENABLE			(0x01)
+/* SR1 (Status Register 1) 8bit (R/-) */
+#define I2C_SR1					(0x00000004)
+#define I2C_SR1_RESET_VALUE			(0x00)
+#define I2C_SR1_RESET_UMASK			(0x00)
+#define I2C_SR1_EVF_IND				(0x80)
+#define I2C_SR1_ADD10_IND			(0x40)
+#define I2C_SR1_TRA_IND				(0x20)
+#define I2C_SR1_BUSY_IND			(0x10)
+#define I2C_SR1_BTF_IND				(0x08)
+#define I2C_SR1_ADSL_IND			(0x04)
+#define I2C_SR1_MSL_IND				(0x02)
+#define I2C_SR1_SB_IND				(0x01)
+/* SR2 (Status Register 2) 8bit (R/-) */
+#define I2C_SR2					(0x00000008)
+#define I2C_SR2_RESET_VALUE			(0x00)
+#define I2C_SR2_RESET_UMASK			(0x40)
+#define I2C_SR2_MASK				(0xBF)
+#define I2C_SR2_SCLFAL_IND			(0x80)
+#define I2C_SR2_ENDAD_IND			(0x20)
+#define I2C_SR2_AF_IND				(0x10)
+#define I2C_SR2_STOPF_IND			(0x08)
+#define I2C_SR2_ARLO_IND			(0x04)
+#define I2C_SR2_BERR_IND			(0x02)
+#define I2C_SR2_DDC2BF_IND			(0x01)
+/* CCR (Clock Control Register) 8bit (R/W) */
+#define I2C_CCR					(0x0000000C)
+#define I2C_CCR_RESET_VALUE			(0x00)
+#define I2C_CCR_RESET_UMASK			(0x00)
+#define I2C_CCR_MASK				(0xFF)
+#define I2C_CCR_FMSM				(0x80)
+#define I2C_CCR_CC_MASK				(0x7F)
+/* OAR1 (Own Address Register 1) 8bit (R/W) */
+#define I2C_OAR1				(0x00000010)
+#define I2C_OAR1_RESET_VALUE			(0x00)
+#define I2C_OAR1_RESET_UMASK			(0x00)
+#define I2C_OAR1_ADD_MASK			(0xFF)
+/* OAR2 (Own Address Register 2) 8bit (R/W) */
+#define I2C_OAR2				(0x00000014)
+#define I2C_OAR2_RESET_VALUE			(0x40)
+#define I2C_OAR2_RESET_UMASK			(0x19)
+#define I2C_OAR2_MASK				(0xE6)
+#define I2C_OAR2_FR_25_10MHZ			(0x00)
+#define I2C_OAR2_FR_10_1667MHZ			(0x20)
+#define I2C_OAR2_FR_1667_2667MHZ		(0x40)
+#define I2C_OAR2_FR_2667_40MHZ			(0x60)
+#define I2C_OAR2_FR_40_5333MHZ			(0x80)
+#define I2C_OAR2_FR_5333_66MHZ			(0xA0)
+#define I2C_OAR2_FR_66_80MHZ			(0xC0)
+#define I2C_OAR2_FR_80_100MHZ			(0xE0)
+#define I2C_OAR2_FR_MASK			(0xE0)
+#define I2C_OAR2_ADD_MASK			(0x06)
+/* DR (Data Register) 8bit (R/W) */
+#define I2C_DR					(0x00000018)
+#define I2C_DR_RESET_VALUE			(0x00)
+#define I2C_DR_RESET_UMASK			(0xFF)
+#define I2C_DR_D_MASK				(0xFF)
+/* ECCR (Extended Clock Control Register) 8bit (R/W) */
+#define I2C_ECCR				(0x0000001C)
+#define I2C_ECCR_RESET_VALUE			(0x00)
+#define I2C_ECCR_RESET_UMASK			(0xE0)
+#define I2C_ECCR_MASK				(0x1F)
+#define I2C_ECCR_CC_MASK			(0x1F)
+
+/*
+ * These events are more or less responses to commands
+ * sent into the hardware, presumably reflecting the state
+ * of an internal state machine.
+ */
+enum stu300_event {
+	STU300_EVENT_NONE = 0,
+	STU300_EVENT_1,
+	STU300_EVENT_2,
+	STU300_EVENT_3,
+	STU300_EVENT_4,
+	STU300_EVENT_5,
+	STU300_EVENT_6,
+	STU300_EVENT_7,
+	STU300_EVENT_8,
+	STU300_EVENT_9
+};
+
+enum stu300_error {
+	STU300_ERROR_NONE = 0,
+	STU300_ERROR_ACKNOWLEDGE_FAILURE,
+	STU300_ERROR_BUS_ERROR,
+	STU300_ERROR_ARBITRATION_LOST
+};
+
+/* timeout waiting for the controller to respond */
+#define STU300_TIMEOUT (msecs_to_jiffies(1000))
+
+/*
+ * The number of address send athemps tried before giving up.
+ * If the first one failes it seems like 5 to 8 attempts are required.
+ */
+#define NUM_ADDR_RESEND_ATTEMPTS 10
+
+/* I2C clock speed, in Hz 0-400kHz*/
+static unsigned int scl_frequency = 100000;
+module_param(scl_frequency, uint,  0644);
+
+/**
+ * struct stu300_dev - the stu300 driver state holder
+ * @pdev: parent platform device
+ * @adapter: corresponding I2C adapter
+ * @phybase: location of I/O area in memory
+ * @physize: size of I/O area in memory
+ * @clk: hardware block clock
+ * @irq: assigned interrupt line
+ * @cmd_issue_lock: this locks the following cmd_ variables
+ * @cmd_complete: acknowledge completion for an I2C command
+ * @cmd_event: expected event coming in as a response to a command
+ * @cmd_err: error code as response to a command
+ * @speed: current bus speed in Hz
+ * @msg_index: index of current message
+ * @msg_len: length of current message
+ */
+struct stu300_dev {
+	struct platform_device	*pdev;
+	struct i2c_adapter	adapter;
+	resource_size_t		phybase;
+	resource_size_t		physize;
+	void __iomem		*virtbase;
+	struct clk		*clk;
+	int			irq;
+	spinlock_t		cmd_issue_lock;
+	struct completion	cmd_complete;
+	enum stu300_event	cmd_event;
+	enum stu300_error	cmd_err;
+	unsigned int		speed;
+	int			msg_index;
+	int			msg_len;
+};
+
+/* Local forward function declarations */
+static int stu300_init_hw(struct stu300_dev *dev);
+
+/*
+ * The block needs writes in both MSW and LSW in order
+ * for all data lines to reach their destination.
+ */
+static inline void stu300_wr8(u32 value, void __iomem *address)
+{
+	writel((value << 16) | value, address);
+}
+
+/*
+ * This merely masks off the duplicates which appear
+ * in bytes 1-3. You _MUST_ use 32-bit bus access on this
+ * device, else it will not work.
+ */
+static inline u32 stu300_r8(void __iomem *address)
+{
+	return readl(address) & 0x000000FFU;
+}
+
+/*
+ * Tells whether a certain event or events occurred in
+ * response to a command. The events represent states in
+ * the internal state machine of the hardware. The events
+ * are not very well described in the hardware
+ * documentation and can only be treated as abstract state
+ * machine states.
+ *
+ * @ret 0 = event has not occurred, any other value means
+ * the event occurred.
+ */
+static int stu300_event_occurred(struct stu300_dev *dev,
+				   enum stu300_event mr_event) {
+	u32 status1;
+	u32 status2;
+
+	/* What event happened? */
+	status1 = stu300_r8(dev->virtbase + I2C_SR1);
+	if (!(status1 & I2C_SR1_EVF_IND))
+		/* No event at all */
+		return 0;
+	status2 = stu300_r8(dev->virtbase + I2C_SR2);
+
+	switch (mr_event) {
+	case STU300_EVENT_1:
+		if (status1 & I2C_SR1_ADSL_IND)
+			return 1;
+		break;
+	case STU300_EVENT_2:
+	case STU300_EVENT_3:
+	case STU300_EVENT_7:
+	case STU300_EVENT_8:
+		if (status1 & I2C_SR1_BTF_IND) {
+			if (status2 & I2C_SR2_AF_IND)
+				dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE;
+			else if (status2 & I2C_SR2_BERR_IND)
+				dev->cmd_err = STU300_ERROR_BUS_ERROR;
+			return 1;
+		}
+		break;
+	case STU300_EVENT_4:
+		if (status2 & I2C_SR2_STOPF_IND)
+			return 1;
+		break;
+	case STU300_EVENT_5:
+		if (status1 & I2C_SR1_SB_IND)
+			/* Clear start bit */
+			return 1;
+		break;
+	case STU300_EVENT_6:
+		if (status2 & I2C_SR2_ENDAD_IND) {
+			/* First check for any errors */
+			if (status2 & I2C_SR2_AF_IND)
+				dev->cmd_err = STU300_ERROR_ACKNOWLEDGE_FAILURE;
+			return 1;
+		}
+		break;
+	case STU300_EVENT_9:
+		if (status1 & I2C_SR1_ADD10_IND)
+			return 1;
+		break;
+	default:
+		break;
+	}
+	if (status2 & I2C_SR2_ARLO_IND)
+		dev->cmd_err = STU300_ERROR_ARBITRATION_LOST;
+	return 0;
+}
+
+static irqreturn_t stu300_irh(int irq, void *data)
+{
+	struct stu300_dev *dev = data;
+	int res;
+
+	/* See if this was what we were waiting for */
+	spin_lock(&dev->cmd_issue_lock);
+	if (dev->cmd_event != STU300_EVENT_NONE) {
+		res = stu300_event_occurred(dev, dev->cmd_event);
+		if (res || dev->cmd_err != STU300_ERROR_NONE) {
+			u32 val;
+
+			complete(&dev->cmd_complete);
+			/* Block any multiple interrupts */
+			val = stu300_r8(dev->virtbase + I2C_CR);
+			val &= ~I2C_CR_INTERRUPT_ENABLE;
+			stu300_wr8(val, dev->virtbase + I2C_CR);
+		}
+	}
+	spin_unlock(&dev->cmd_issue_lock);
+	return IRQ_HANDLED;
+}
+
+/*
+ * Sends a command and then waits for the bits masked by *flagmask*
+ * to go high or low by IRQ awaiting.
+ */
+static int stu300_start_and_await_event(struct stu300_dev *dev,
+					  u8 cr_value,
+					  enum stu300_event mr_event)
+{
+	int ret;
+
+	if (unlikely(irqs_disabled())) {
+		/* TODO: implement polling for this case if need be. */
+		WARN(1, "irqs are disabled, cannot poll for event\n");
+		return -EIO;
+	}
+
+	/* Lock command issue, fill in an event we wait for */
+	spin_lock_irq(&dev->cmd_issue_lock);
+	init_completion(&dev->cmd_complete);
+	dev->cmd_err = STU300_ERROR_NONE;
+	dev->cmd_event = mr_event;
+	spin_unlock_irq(&dev->cmd_issue_lock);
+
+	/* Turn on interrupt, send command and wait. */
+	cr_value |= I2C_CR_INTERRUPT_ENABLE;
+	stu300_wr8(cr_value, dev->virtbase + I2C_CR);
+	ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+							STU300_TIMEOUT);
+
+	if (ret < 0) {
+		dev_err(&dev->pdev->dev,
+		       "wait_for_completion_interruptible_timeout() "
+		       "returned %d waiting for event %04x\n", ret, mr_event);
+		return ret;
+	}
+
+	if (ret == 0) {
+		dev_err(&dev->pdev->dev, "controller timed out "
+		       "waiting for event %d, reinit hardware\n", mr_event);
+		(void) stu300_init_hw(dev);
+		return -ETIMEDOUT;
+	}
+
+	if (dev->cmd_err != STU300_ERROR_NONE) {
+		dev_err(&dev->pdev->dev, "controller (start) "
+		       "error %d waiting for event %d, reinit hardware\n",
+		       dev->cmd_err, mr_event);
+		(void) stu300_init_hw(dev);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * This waits for a flag to be set, if it is not set on entry, an interrupt is
+ * configured to wait for the flag using a completion.
+ */
+static int stu300_await_event(struct stu300_dev *dev,
+				enum stu300_event mr_event)
+{
+	int ret;
+	u32 val;
+
+	if (unlikely(irqs_disabled())) {
+		/* TODO: implement polling for this case if need be. */
+		dev_err(&dev->pdev->dev, "irqs are disabled on this "
+			"system!\n");
+		return -EIO;
+	}
+
+	/* Is it already here? */
+	spin_lock_irq(&dev->cmd_issue_lock);
+	dev->cmd_err = STU300_ERROR_NONE;
+	if (stu300_event_occurred(dev, mr_event)) {
+		spin_unlock_irq(&dev->cmd_issue_lock);
+		goto exit_await_check_err;
+	}
+	init_completion(&dev->cmd_complete);
+	dev->cmd_err = STU300_ERROR_NONE;
+	dev->cmd_event = mr_event;
+
+	/* Turn on the I2C interrupt for current operation */
+	val = stu300_r8(dev->virtbase + I2C_CR);
+	val |= I2C_CR_INTERRUPT_ENABLE;
+	stu300_wr8(val, dev->virtbase + I2C_CR);
+
+	/* Twice paranoia (possible HW glitch) */
+	stu300_wr8(val, dev->virtbase + I2C_CR);
+
+	/* Check again: is it already here? */
+	if (unlikely(stu300_event_occurred(dev, mr_event))) {
+		/* Disable IRQ again. */
+		val &= ~I2C_CR_INTERRUPT_ENABLE;
+		stu300_wr8(val, dev->virtbase + I2C_CR);
+		spin_unlock_irq(&dev->cmd_issue_lock);
+		goto exit_await_check_err;
+	}
+
+	/* Unlock the command block and wait for the event to occur */
+	spin_unlock_irq(&dev->cmd_issue_lock);
+	ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
+							STU300_TIMEOUT);
+
+	if (ret < 0) {
+		dev_err(&dev->pdev->dev,
+		       "wait_for_completion_interruptible_timeout()"
+		       "returned %d waiting for event %04x\n", ret, mr_event);
+		return ret;
+	}
+
+	if (ret == 0) {
+		if (mr_event != STU300_EVENT_6) {
+			dev_err(&dev->pdev->dev, "controller "
+				"timed out waiting for event %d, reinit "
+				"hardware\n", mr_event);
+			(void) stu300_init_hw(dev);
+		}
+		return -ETIMEDOUT;
+	}
+
+ exit_await_check_err:
+	if (dev->cmd_err != STU300_ERROR_NONE) {
+		if (mr_event != STU300_EVENT_6) {
+			dev_err(&dev->pdev->dev, "controller "
+				"error (await_event) %d waiting for event %d, "
+			       "reinit hardware\n", dev->cmd_err, mr_event);
+			(void) stu300_init_hw(dev);
+		}
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * Waits for the busy bit to go low by repeated polling.
+ */
+#define BUSY_RELEASE_ATTEMPTS 10
+static int stu300_wait_while_busy(struct stu300_dev *dev)
+{
+	unsigned long timeout;
+	int i;
+
+	for (i = 0; i < BUSY_RELEASE_ATTEMPTS; i++) {
+		timeout = jiffies + STU300_TIMEOUT;
+
+		while (!time_after(jiffies, timeout)) {
+			/* Is not busy? */
+			if ((stu300_r8(dev->virtbase + I2C_SR1) &
+			     I2C_SR1_BUSY_IND) == 0)
+				return 0;
+			msleep(1);
+		}
+
+		dev_err(&dev->pdev->dev, "transaction timed out "
+			"waiting for device to be free (not busy). "
+		       "Attempt: %d\n", i+1);
+
+		dev_err(&dev->pdev->dev, "base address = "
+			"0x%08x, reinit hardware\n", (u32) dev->virtbase);
+
+		(void) stu300_init_hw(dev);
+	}
+
+	dev_err(&dev->pdev->dev, "giving up after %d attempts "
+		"to reset the bus.\n",  BUSY_RELEASE_ATTEMPTS);
+
+	return -ETIMEDOUT;
+}
+
+struct stu300_clkset {
+	unsigned long rate;
+	u32 setting;
+};
+
+static const struct stu300_clkset stu300_clktable[] = {
+	{ 0, 0xFFU },
+	{ 2500000, I2C_OAR2_FR_25_10MHZ },
+	{ 10000000, I2C_OAR2_FR_10_1667MHZ },
+	{ 16670000, I2C_OAR2_FR_1667_2667MHZ },
+	{ 26670000, I2C_OAR2_FR_2667_40MHZ },
+	{ 40000000, I2C_OAR2_FR_40_5333MHZ },
+	{ 53330000, I2C_OAR2_FR_5333_66MHZ },
+	{ 66000000, I2C_OAR2_FR_66_80MHZ },
+	{ 80000000, I2C_OAR2_FR_80_100MHZ },
+	{ 100000000, 0xFFU },
+};
+
+static int stu300_set_clk(struct stu300_dev *dev, unsigned long clkrate)
+{
+
+	u32 val;
+	int i = 0;
+
+	/* Locate the apropriate clock setting */
+	while (i < ARRAY_SIZE(stu300_clktable) &&
+	       stu300_clktable[i].rate < clkrate)
+		i++;
+
+	if (stu300_clktable[i].setting == 0xFFU) {
+		dev_err(&dev->pdev->dev, "too %s clock rate requested "
+			"(%lu Hz).\n", i ? "high" : "low", clkrate);
+		return -EINVAL;
+	}
+
+	stu300_wr8(stu300_clktable[i].setting,
+		   dev->virtbase + I2C_OAR2);
+
+	dev_dbg(&dev->pdev->dev, "Clock rate %lu Hz, I2C bus speed %d Hz "
+		"virtbase %p\n", clkrate, dev->speed, dev->virtbase);
+
+	if (dev->speed > 100000)
+		/* Fast Mode I2C */
+		val = ((clkrate/dev->speed)-9)/3;
+	else
+		/* Standard Mode I2C */
+		val = ((clkrate/dev->speed)-7)/2;
+
+	/* According to spec the divider must be > 2 */
+	if (val < 0x002) {
+		dev_err(&dev->pdev->dev, "too low clock rate (%lu Hz).\n",
+			clkrate);
+		return -EINVAL;
+	}
+
+	/* We have 12 bits clock divider only! */
+	if (val & 0xFFFFF000U) {
+		dev_err(&dev->pdev->dev, "too high clock rate (%lu Hz).\n",
+			clkrate);
+		return -EINVAL;
+	}
+
+	if (dev->speed > 100000) {
+		/* CC6..CC0 */
+		stu300_wr8((val & I2C_CCR_CC_MASK) | I2C_CCR_FMSM,
+			   dev->virtbase + I2C_CCR);
+		dev_dbg(&dev->pdev->dev, "set clock divider to 0x%08x, "
+			"Fast Mode I2C\n", val);
+	} else {
+		/* CC6..CC0 */
+		stu300_wr8((val & I2C_CCR_CC_MASK),
+			   dev->virtbase + I2C_CCR);
+		dev_dbg(&dev->pdev->dev, "set clock divider to "
+			"0x%08x, Standard Mode I2C\n", val);
+	}
+
+	/* CC11..CC7 */
+	stu300_wr8(((val >> 7) & 0x1F),
+		   dev->virtbase + I2C_ECCR);
+
+	return 0;
+}
+
+
+static int stu300_init_hw(struct stu300_dev *dev)
+{
+	u32 dummy;
+	unsigned long clkrate;
+	int ret;
+
+	/* Disable controller */
+	stu300_wr8(0x00, dev->virtbase + I2C_CR);
+	/*
+	 * Set own address to some default value (0x00).
+	 * We do not support slave mode anyway.
+	 */
+	stu300_wr8(0x00, dev->virtbase + I2C_OAR1);
+	/*
+	 * The I2C controller only operates properly in 26 MHz but we
+	 * program this driver as if we didn't know. This will also set the two
+	 * high bits of the own address to zero as well.
+	 * There is no known hardware issue with running in 13 MHz
+	 * However, speeds over 200 kHz are not used.
+	 */
+	clkrate = clk_get_rate(dev->clk);
+	ret = stu300_set_clk(dev, clkrate);
+	if (ret)
+		return ret;
+	/*
+	 * Enable block, do it TWICE (hardware glitch)
+	 * Setting bit 7 can enable DDC mode. (Not used currently.)
+	 */
+	stu300_wr8(I2C_CR_PERIPHERAL_ENABLE,
+				  dev->virtbase + I2C_CR);
+	stu300_wr8(I2C_CR_PERIPHERAL_ENABLE,
+				  dev->virtbase + I2C_CR);
+	/* Make a dummy read of the status register SR1 & SR2 */
+	dummy = stu300_r8(dev->virtbase + I2C_SR2);
+	dummy = stu300_r8(dev->virtbase + I2C_SR1);
+
+	return 0;
+}
+
+
+
+/* Send slave address. */
+static int stu300_send_address(struct stu300_dev *dev,
+				 struct i2c_msg *msg, int resend)
+{
+	u32 val;
+	int ret;
+
+	if (msg->flags & I2C_M_TEN)
+		/* This is probably how 10 bit addresses look */
+		val = (0xf0 | (((u32) msg->addr & 0x300) >> 7)) &
+			I2C_DR_D_MASK;
+	else
+		val