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

Pull i2c fixes from Wolfram Sang:
 "Two driver bugfixes, a documentation fix, and a removal of a spec
  violation for the bus recovery algorithm in the core"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: fix bus recovery stop mode timing
  i2c: bcm2835: Store pointer to bus clock
  dt-bindings: i2c: at91: fix i2c-sda-hold-time-ns documentation for sam9x60
  i2c: at91: fix clk_offset for sam9x60

3 files changed, 19 insertions, 13 deletions

diff --git a/drivers/i2c/busses/i2c-at91-core.c b/drivers/i2c/busses/i2c-at91-core.c
index e13af4874976..5137e6297022 100644
--- a/drivers/i2c/busses/i2c-at91-core.c
+++ b/drivers/i2c/busses/i2c-at91-core.c
@@ -174,7 +174,7 @@ static struct at91_twi_pdata sama5d2_config = {
 
 static struct at91_twi_pdata sam9x60_config = {
 	.clk_max_div = 7,
-	.clk_offset = 4,
+	.clk_offset = 3,
 	.has_unre_flag = true,
 	.has_alt_cmd = true,
 	.has_hold_field = true,
diff --git a/drivers/i2c/busses/i2c-bcm2835.c b/drivers/i2c/busses/i2c-bcm2835.c
index e01b2b57e724..5ab901ad615d 100644
--- a/drivers/i2c/busses/i2c-bcm2835.c
+++ b/drivers/i2c/busses/i2c-bcm2835.c
@@ -58,6 +58,7 @@ struct bcm2835_i2c_dev {
 	struct i2c_adapter adapter;
 	struct completion completion;
 	struct i2c_msg *curr_msg;
+	struct clk *bus_clk;
 	int num_msgs;
 	u32 msg_err;
 	u8 *msg_buf;
@@ -404,7 +405,6 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 	struct resource *mem, *irq;
 	int ret;
 	struct i2c_adapter *adap;
-	struct clk *bus_clk;
 	struct clk *mclk;
 	u32 bus_clk_rate;
 
@@ -427,11 +427,11 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 		return PTR_ERR(mclk);
 	}
 
-	bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev);
+	i2c_dev->bus_clk = bcm2835_i2c_register_div(&pdev->dev, mclk, i2c_dev);
 
-	if (IS_ERR(bus_clk)) {
+	if (IS_ERR(i2c_dev->bus_clk)) {
 		dev_err(&pdev->dev, "Could not register clock\n");
-		return PTR_ERR(bus_clk);
+		return PTR_ERR(i2c_dev->bus_clk);
 	}
 
 	ret = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
@@ -442,13 +442,13 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 		bus_clk_rate = 100000;
 	}
 
-	ret = clk_set_rate_exclusive(bus_clk, bus_clk_rate);
+	ret = clk_set_rate_exclusive(i2c_dev->bus_clk, bus_clk_rate);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Could not set clock frequency\n");
 		return ret;
 	}
 
-	ret = clk_prepare_enable(bus_clk);
+	ret = clk_prepare_enable(i2c_dev->bus_clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Couldn't prepare clock");
 		return ret;
@@ -491,10 +491,9 @@ static int bcm2835_i2c_probe(struct platform_device *pdev)
 static int bcm2835_i2c_remove(struct platform_device *pdev)
 {
 	struct bcm2835_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
-	struct clk *bus_clk = devm_clk_get(i2c_dev->dev, "div");
 
-	clk_rate_exclusive_put(bus_clk);
-	clk_disable_unprepare(bus_clk);
+	clk_rate_exclusive_put(i2c_dev->bus_clk);
+	clk_disable_unprepare(i2c_dev->bus_clk);
 
 	free_irq(i2c_dev->irq, i2c_dev);
 	i2c_del_adapter(&i2c_dev->adapter);
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 9f8dcd3f8385..35b209797d7b 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -186,10 +186,11 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 	 * If we can set SDA, we will always create a STOP to ensure additional
 	 * pulses will do no harm. This is achieved by letting SDA follow SCL
 	 * half a cycle later. Check the 'incomplete_write_byte' fault injector
-	 * for details.
+	 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
+	 * here for simplicity.
 	 */
 	bri->set_scl(adap, scl);
-	ndelay(RECOVERY_NDELAY / 2);
+	ndelay(RECOVERY_NDELAY);
 	if (bri->set_sda)
 		bri->set_sda(adap, scl);
 	ndelay(RECOVERY_NDELAY / 2);
@@ -211,7 +212,13 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 		scl = !scl;
 		bri->set_scl(adap, scl);
 		/* Creating STOP again, see above */
-		ndelay(RECOVERY_NDELAY / 2);
+		if (scl)  {
+			/* Honour minimum tsu:sto */
+			ndelay(RECOVERY_NDELAY);
+		} else {
+			/* Honour minimum tf and thd:dat */
+			ndelay(RECOVERY_NDELAY / 2);
+		}
 		if (bri->set_sda)
 			bri->set_sda(adap, scl);
 		ndelay(RECOVERY_NDELAY / 2);