Merge branch 'i2c/for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
 "Highlights:

   - new drivers for Mediatek I2C, APM X-Gene, Broadcom Settop
   - major updates to at91, davinci
   - bugfixes to the mux infrastructure when dealing with the new quirk
     mechanism
   - more users for the bus recovery feature
   - further improvements to the slave framework

  Plus the usual bunch of smaller driver and core improvements and
  fixes.

  There is one patch removing old code from an ARM platform.  This has
  been acked by the sh_mobile maintainer Simon Horman"

* 'i2c/for-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (48 commits)
  i2c: busses: i2c-bcm2835: limits cdiv to allowed values
  i2c: sh_mobile: use proper type for timeout
  i2c: sh_mobile: use adapter default for timeout
  i2c: rcar: use proper type for timeout
  i2c: rcar: use adapter default for timeout
  i2c: designware: Make sure the device is suspended before disabling runtime PM
  i2c: tegra: apply size limit quirk
  i2c: tegra: don't advertise SMBUS_QUICK
  i2c: octeon: remove unused signal handling
  i2c: davinci: Optimize SCL generation
  i2c: mux: pca954x: Use __i2c_transfer because of quirks
  i2c: mux: Use __i2c_transfer() instead of calling parent's master_xfer()
  i2c: use parent adapter quirks in mux
  i2c: bcm2835: clear reserved bits in S-Register
  ARM: shmobile: r8a7740: remove I2C errata handling
  i2c: sh_mobile: add errata workaround
  i2c: at91: fix code checker warnings
  i2c: busses: xgene-slimpro: fix incorrect __init declation for probe
  i2c: davinci: Avoid sending to own address
  i2c: davinci: Refactor i2c_davinci_wait_bus_not_busy()
  ...

1 files changed, 51 insertions, 29 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 4788a32afb86..3fbb9a035532 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -41,8 +41,8 @@
 
 #define DAVINCI_I2C_TIMEOUT	(1*HZ)
 #define DAVINCI_I2C_MAX_TRIES	2
-#define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
-				 DAVINCI_I2C_IMR_SCD | \
+#define DAVINCI_I2C_OWN_ADDRESS	0x08
+#define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_SCD | \
 				 DAVINCI_I2C_IMR_ARDY | \
 				 DAVINCI_I2C_IMR_NACK | \
 				 DAVINCI_I2C_IMR_AL)
@@ -204,9 +204,30 @@ static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 		psc++;	/* better to run under spec than over */
 	d = (psc >= 2) ? 5 : 7 - psc;
 
-	clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
-	clkh = clk >> 1;
-	clkl = clk - clkh;
+	clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000));
+	/* Avoid driving the bus too fast because of rounding errors above */
+	if (input_clock / (psc + 1) / clk > pdata->bus_freq * 1000)
+		clk++;
+	/*
+	 * According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at
+	 * least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH
+	 * to LOW ratio as 1 to 2 is more safe.
+	 */
+	if (pdata->bus_freq > 100)
+		clkl = (clk << 1) / 3;
+	else
+		clkl = (clk >> 1);
+	/*
+	 * It's not always possible to have 1 to 2 ratio when d=7, so fall back
+	 * to minimal possible clkh in this case.
+	 */
+	if (clk >= clkl + d) {
+		clkh = clk - clkl - d;
+		clkl -= d;
+	} else {
+		clkh = 0;
+		clkl = clk - (d << 1);
+	}
 
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
@@ -233,7 +254,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 	/* Respond at reserved "SMBus Host" slave address" (and zero);
 	 * we seem to have no option to not respond...
 	 */
-	davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
+	davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS);
 
 	dev_dbg(dev->dev, "PSC  = %d\n",
 		davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
@@ -350,29 +371,25 @@ static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
 /*
  * Waiting for bus not busy
  */
-static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
-					 char allow_sleep)
+static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev)
 {
-	unsigned long timeout;
-	static u16 to_cnt;
-
-	timeout = jiffies + dev->adapter.timeout;
-	while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
-	       & DAVINCI_I2C_STR_BB) {
-		if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
-			if (time_after(jiffies, timeout)) {
-				dev_warn(dev->dev,
-				"timeout waiting for bus ready\n");
-				to_cnt++;
-				return -ETIMEDOUT;
-			} else {
-				to_cnt = 0;
-				i2c_recover_bus(&dev->adapter);
-			}
-		}
-		if (allow_sleep)
-			schedule_timeout(1);
-	}
+	unsigned long timeout = jiffies + dev->adapter.timeout;
+
+	do {
+		if (!(davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB))
+			return 0;
+		schedule_timeout_uninterruptible(1);
+	} while (time_before_eq(jiffies, timeout));
+
+	dev_warn(dev->dev, "timeout waiting for bus ready\n");
+	i2c_recover_bus(&dev->adapter);
+
+	/*
+	 * if bus is still "busy" here, it's most probably a HW problem like
+	 * short-circuit
+	 */
+	if (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB)
+		return -EIO;
 
 	return 0;
 }
@@ -390,6 +407,11 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 	u16 w;
 	unsigned long time_left;
 
+	if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) {
+		dev_warn(dev->dev, "transfer to own address aborted\n");
+		return -EADDRNOTAVAIL;
+	}
+
 	/* Introduce a delay, required for some boards (e.g Davinci EVM) */
 	if (pdata->bus_delay)
 		udelay(pdata->bus_delay);
@@ -505,7 +527,7 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
 	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 
-	ret = i2c_davinci_wait_bus_not_busy(dev, 1);
+	ret = i2c_davinci_wait_bus_not_busy(dev);
 	if (ret < 0) {
 		dev_warn(dev->dev, "timeout waiting for bus ready\n");
 		return ret;