Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c changes from Wolfram Sang:

 - an arbitration driver.  While the driver is quite simple, it caused
   discussion if we need additional arbitration on top of the one
   specified in the I2C standard.  Conclusion is that I accept a few
   generic mechanisms, but not very specific ones.

 - the core lost the detach_adapter() call.  It has no users anymore and
   was in the way for other cleanups.  attach_adapter() is sadly still
   there since there are users waiting to be converted.

 - the core gained a bus recovery infrastructure.  I2C defines a way to
   recover if the data line is stalled.  This mechanism is now in the
   core and drivers can now pass some data to make use of it.

 - bigger driver cleanups for designware, s3c2410

 - removing superfluous refcounting from drivers

 - removing Ben Dooks as second maintainer due to inactivity.  Thanks
   for all your work so far, Ben!

 - bugfixes, feature additions, devicetree fixups, simplifications...

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (38 commits)
  i2c: xiic: must always write 16-bit words to TX_FIFO
  i2c: octeon: use HZ in timeout value
  i2c: octeon: Fix i2c fail problem when a process is terminated by a signal
  i2c: designware-pci: drop superfluous {get|put}_device
  i2c: designware-plat: drop superfluous {get|put}_device
  i2c: davinci: drop superfluous {get|put}_device
  MAINTAINERS: Ben Dooks is inactive regarding I2C
  i2c: mux: Add i2c-arb-gpio-challenge 'mux' driver
  i2c: at91: convert to dma_request_slave_channel_compat()
  i2c: mxs: do error checking and handling in PIO mode
  i2c: mxs: remove races in PIO code
  i2c-designware: switch to use runtime PM autosuspend
  i2c-designware: use usleep_range() in the busy-loop
  i2c-designware: enable/disable the controller properly
  i2c-designware: use dynamic adapter numbering on Lynxpoint
  i2c-designware-pci: use managed functions pcim_* and devm_*
  i2c-designware-pci: use dev_err() instead of printk()
  i2c-designware: move to managed functions (devm_*)
  i2c: remove CONFIG_HOTPLUG ifdefs
  i2c: s3c2410: Add SMBus emulation for block read
  ...

1 files changed, 31 insertions, 8 deletions

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 94fd81875409..21fbb340ad66 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -68,6 +68,7 @@
 #define DW_IC_TXFLR		0x74
 #define DW_IC_RXFLR		0x78
 #define DW_IC_TX_ABRT_SOURCE	0x80
+#define DW_IC_ENABLE_STATUS	0x9c
 #define DW_IC_COMP_PARAM_1	0xf4
 #define DW_IC_COMP_TYPE		0xfc
 #define DW_IC_COMP_TYPE_VALUE	0x44570140
@@ -248,6 +249,27 @@ static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
 	return ((ic_clk * (tLOW + tf) + 5000) / 10000) - 1 + offset;
 }
 
+static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
+{
+	int timeout = 100;
+
+	do {
+		dw_writel(dev, enable, DW_IC_ENABLE);
+		if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable)
+			return;
+
+		/*
+		 * Wait 10 times the signaling period of the highest I2C
+		 * transfer supported by the driver (for 400KHz this is
+		 * 25us) as described in the DesignWare I2C databook.
+		 */
+		usleep_range(25, 250);
+	} while (timeout--);
+
+	dev_warn(dev->dev, "timeout in %sabling adapter\n",
+		 enable ? "en" : "dis");
+}
+
 /**
  * i2c_dw_init() - initialize the designware i2c master hardware
  * @dev: device private data
@@ -278,7 +300,7 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
 	}
 
 	/* Disable the adapter */
-	dw_writel(dev, 0, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, false);
 
 	/* set standard and fast speed deviders for high/low periods */
 
@@ -333,7 +355,7 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
 			return -ETIMEDOUT;
 		}
 		timeout--;
-		mdelay(1);
+		usleep_range(1000, 1100);
 	}
 
 	return 0;
@@ -345,7 +367,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	u32 ic_con;
 
 	/* Disable the adapter */
-	dw_writel(dev, 0, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, false);
 
 	/* set the slave (target) address */
 	dw_writel(dev, msgs[dev->msg_write_idx].addr, DW_IC_TAR);
@@ -359,7 +381,7 @@ static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
 	dw_writel(dev, ic_con, DW_IC_CON);
 
 	/* Enable the adapter */
-	dw_writel(dev, 1, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, true);
 
 	/* Enable interrupts */
 	dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
@@ -565,7 +587,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	/* no error */
 	if (likely(!dev->cmd_err)) {
 		/* Disable the adapter */
-		dw_writel(dev, 0, DW_IC_ENABLE);
+		__i2c_dw_enable(dev, false);
 		ret = num;
 		goto done;
 	}
@@ -578,7 +600,8 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	ret = -EIO;
 
 done:
-	pm_runtime_put(dev->dev);
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
 	mutex_unlock(&dev->lock);
 
 	return ret;
@@ -700,7 +723,7 @@ EXPORT_SYMBOL_GPL(i2c_dw_isr);
 void i2c_dw_enable(struct dw_i2c_dev *dev)
 {
        /* Enable the adapter */
-	dw_writel(dev, 1, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, true);
 }
 EXPORT_SYMBOL_GPL(i2c_dw_enable);
 
@@ -713,7 +736,7 @@ EXPORT_SYMBOL_GPL(i2c_dw_is_enabled);
 void i2c_dw_disable(struct dw_i2c_dev *dev)
 {
 	/* Disable controller */
-	dw_writel(dev, 0, DW_IC_ENABLE);
+	__i2c_dw_enable(dev, false);
 
 	/* Disable all interupts */
 	dw_writel(dev, 0, DW_IC_INTR_MASK);