Merge branch 'i2c/for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
 "i2c core:

   - huge improvements and refactorizations of the Linux I2C
     documentation (lots of thanks to Luca for doing it and Jean for the
     careful review)

   - subsystem wide API conversion to i2c_new_client_device()

   - remove obsolete parport-light driver

   - smaller core updates (removal of 'extern', enabling more compile
     testing, use more helper macros)

   - and quite a bunch of driver updates (new IDs, simplifications,
     better PM, support of atomic transfers and other improvements)

  i2c-mux:

   - The main feature is the idle-state rework of the pca954x driver
     from Biwen Li

  at24 driver:

   - minor maintenance: update the license tag, sort headers

   - move support for the write-protect pin into nvmem core

   - add a reference to the new wp-gpios property in nvmem to at25
     bindings

   - add support for regulator and pm_runtime control"

* 'i2c/for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (91 commits)
  i2c: cros-ec-tunnel: Fix ACPI identifier
  i2c: cros-ec-tunnel: Fix slave device enumeration
  i2c: stm32f7: add PM_SLEEP suspend/resume support
  i2c: cadence: Fix wording in i2c-cadence driver
  i2c: cadence: Fix power management order of operations
  i2c: cadence: Fix error printing in case of defer
  i2c: cadence: Handle transfer_size rollover
  i2c: i801: Add support for Intel Comet Lake PCH-V
  docs: i2c: writing-clients: properly name the stop condition
  docs: i2c: i2c-protocol: use same wording as smbus-protocol
  docs: i2c: rename sections so the overall picture is clearer
  docs: i2c: old-module-parameters: use monospace instead of ""
  docs: i2c: old-module-parameters: clarify this is for obsolete kernels
  docs: i2c: old-module-parameters: fix internal hyperlink
  docs: i2c: instantiating-devices: use monospace for sysfs attributes
  docs: i2c: instantiating-devices: rearrange static instatiation
  docs: i2c: instantiating-devices: fix internal hyperlink
  docs: i2c: smbus-protocol: improve I2C Block transactions description
  docs: i2c: smbus-protocol: fix punctuation
  docs: i2c: smbus-protocol: fix typo
  ...

1 files changed, 65 insertions, 32 deletions

diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
index 1e2647f9a2a7..06b3bed78421 100644
--- a/drivers/i2c/busses/i2c-meson.c
+++ b/drivers/i2c/busses/i2c-meson.c
@@ -10,6 +10,7 @@
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -213,6 +214,30 @@ static void meson_i2c_prepare_xfer(struct meson_i2c *i2c)
 	writel(i2c->tokens[1], i2c->regs + REG_TOK_LIST1);
 }
 
+static void meson_i2c_transfer_complete(struct meson_i2c *i2c, u32 ctrl)
+{
+	if (ctrl & REG_CTRL_ERROR) {
+		/*
+		 * The bit is set when the IGNORE_NAK bit is cleared
+		 * and the device didn't respond. In this case, the
+		 * I2C controller automatically generates a STOP
+		 * condition.
+		 */
+		dev_dbg(i2c->dev, "error bit set\n");
+		i2c->error = -ENXIO;
+		i2c->state = STATE_IDLE;
+	} else {
+		if (i2c->state == STATE_READ && i2c->count)
+			meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos,
+					   i2c->count);
+
+		i2c->pos += i2c->count;
+
+		if (i2c->pos >= i2c->msg->len)
+			i2c->state = STATE_IDLE;
+	}
+}
+
 static irqreturn_t meson_i2c_irq(int irqno, void *dev_id)
 {
 	struct meson_i2c *i2c = dev_id;
@@ -232,27 +257,9 @@ static irqreturn_t meson_i2c_irq(int irqno, void *dev_id)
 		return IRQ_NONE;
 	}
 
-	if (ctrl & REG_CTRL_ERROR) {
-		/*
-		 * The bit is set when the IGNORE_NAK bit is cleared
-		 * and the device didn't respond. In this case, the
-		 * I2C controller automatically generates a STOP
-		 * condition.
-		 */
-		dev_dbg(i2c->dev, "error bit set\n");
-		i2c->error = -ENXIO;
-		i2c->state = STATE_IDLE;
-		complete(&i2c->done);
-		goto out;
-	}
-
-	if (i2c->state == STATE_READ && i2c->count)
-		meson_i2c_get_data(i2c, i2c->msg->buf + i2c->pos, i2c->count);
+	meson_i2c_transfer_complete(i2c, ctrl);
 
-	i2c->pos += i2c->count;
-
-	if (i2c->pos >= i2c->msg->len) {
-		i2c->state = STATE_IDLE;
+	if (i2c->state == STATE_IDLE) {
 		complete(&i2c->done);
 		goto out;
 	}
@@ -279,10 +286,11 @@ static void meson_i2c_do_start(struct meson_i2c *i2c, struct i2c_msg *msg)
 }
 
 static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
-			      int last)
+			      int last, bool atomic)
 {
 	unsigned long time_left, flags;
 	int ret = 0;
+	u32 ctrl;
 
 	i2c->msg = msg;
 	i2c->last = last;
@@ -300,13 +308,24 @@ static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
 
 	i2c->state = (msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
 	meson_i2c_prepare_xfer(i2c);
-	reinit_completion(&i2c->done);
+
+	if (!atomic)
+		reinit_completion(&i2c->done);
 
 	/* Start the transfer */
 	meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, REG_CTRL_START);
 
-	time_left = msecs_to_jiffies(I2C_TIMEOUT_MS);
-	time_left = wait_for_completion_timeout(&i2c->done, time_left);
+	if (atomic) {
+		ret = readl_poll_timeout_atomic(i2c->regs + REG_CTRL, ctrl,
+						!(ctrl & REG_CTRL_STATUS),
+						10, I2C_TIMEOUT_MS * 1000);
+	} else {
+		time_left = msecs_to_jiffies(I2C_TIMEOUT_MS);
+		time_left = wait_for_completion_timeout(&i2c->done, time_left);
+
+		if (!time_left)
+			ret = -ETIMEDOUT;
+	}
 
 	/*
 	 * Protect access to i2c struct and registers from interrupt
@@ -315,13 +334,14 @@ static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
 	 */
 	spin_lock_irqsave(&i2c->lock, flags);
 
+	if (atomic && !ret)
+		meson_i2c_transfer_complete(i2c, ctrl);
+
 	/* Abort any active operation */
 	meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_START, 0);
 
-	if (!time_left) {
+	if (ret)
 		i2c->state = STATE_IDLE;
-		ret = -ETIMEDOUT;
-	}
 
 	if (i2c->error)
 		ret = i2c->error;
@@ -331,8 +351,8 @@ static int meson_i2c_xfer_msg(struct meson_i2c *i2c, struct i2c_msg *msg,
 	return ret;
 }
 
-static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
-			  int num)
+static int meson_i2c_xfer_messages(struct i2c_adapter *adap,
+				   struct i2c_msg *msgs, int num, bool atomic)
 {
 	struct meson_i2c *i2c = adap->algo_data;
 	int i, ret = 0;
@@ -340,7 +360,7 @@ static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	clk_enable(i2c->clk);
 
 	for (i = 0; i < num; i++) {
-		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1);
+		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1, atomic);
 		if (ret)
 			break;
 	}
@@ -350,14 +370,27 @@ static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	return ret ?: i;
 }
 
+static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+			  int num)
+{
+	return meson_i2c_xfer_messages(adap, msgs, num, false);
+}
+
+static int meson_i2c_xfer_atomic(struct i2c_adapter *adap,
+				 struct i2c_msg *msgs, int num)
+{
+	return meson_i2c_xfer_messages(adap, msgs, num, true);
+}
+
 static u32 meson_i2c_func(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 }
 
 static const struct i2c_algorithm meson_i2c_algorithm = {
-	.master_xfer	= meson_i2c_xfer,
-	.functionality	= meson_i2c_func,
+	.master_xfer = meson_i2c_xfer,
+	.master_xfer_atomic = meson_i2c_xfer_atomic,
+	.functionality = meson_i2c_func,
 };
 
 static int meson_i2c_probe(struct platform_device *pdev)