[PATCH] i2c: brcmstb: Add support for atomic transfers

* [PATCH] i2c: brcmstb: Add support for atomic transfers
       [not found] <CGME20231006144123eucas1p111cbbdbd70927ffbd697f7edf6b7ae1c@eucas1p1.samsung.com>
@ 2023-10-06 14:41 ` Marek Szyprowski
  2023-10-09 20:41   ` Florian Fainelli
                     ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Marek Szyprowski @ 2023-10-06 14:41 UTC (permalink / raw)
  To: linux-i2c, linux-arm-kernel, linux-kernel
  Cc: Marek Szyprowski, Kamal Dasu,
	Broadcom internal kernel review list, Andi Shyti,
	Florian Fainelli, Wolfram Sang

Add support for atomic transfers using polling mode with interrupts
intentionally disabled to get rid of the warning introduced by commit
63b96983a5dd ("i2c: core: introduce callbacks for atomic transfers")
during system reboot and power-off.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/i2c/busses/i2c-brcmstb.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-brcmstb.c b/drivers/i2c/busses/i2c-brcmstb.c
index acee76732544..38f276c99193 100644
--- a/drivers/i2c/busses/i2c-brcmstb.c
+++ b/drivers/i2c/busses/i2c-brcmstb.c
@@ -160,6 +160,7 @@ struct brcmstb_i2c_dev {
 	struct completion done;
 	u32 clk_freq_hz;
 	int data_regsz;
+	bool atomic;
 };
 
 /* register accessors for both be and le cpu arch */
@@ -240,7 +241,7 @@ static int brcmstb_i2c_wait_for_completion(struct brcmstb_i2c_dev *dev)
 	int ret = 0;
 	unsigned long timeout = msecs_to_jiffies(I2C_TIMEOUT);
 
-	if (dev->irq >= 0) {
+	if (dev->irq >= 0 && !dev->atomic) {
 		if (!wait_for_completion_timeout(&dev->done, timeout))
 			ret = -ETIMEDOUT;
 	} else {
@@ -287,7 +288,7 @@ static int brcmstb_send_i2c_cmd(struct brcmstb_i2c_dev *dev,
 		return rc;
 
 	/* only if we are in interrupt mode */
-	if (dev->irq >= 0)
+	if (dev->irq >= 0 && !dev->atomic)
 		reinit_completion(&dev->done);
 
 	/* enable BSC CTL interrupt line */
@@ -520,6 +521,23 @@ static int brcmstb_i2c_xfer(struct i2c_adapter *adapter,
 
 }
 
+static int brcmstb_i2c_xfer_atomic(struct i2c_adapter *adapter,
+				   struct i2c_msg msgs[], int num)
+{
+	struct brcmstb_i2c_dev *dev = i2c_get_adapdata(adapter);
+	int ret;
+
+	if (dev->irq >= 0)
+		disable_irq(dev->irq);
+	dev->atomic = true;
+	ret = brcmstb_i2c_xfer(adapter, msgs, num);
+	dev->atomic = false;
+	if (dev->irq >= 0)
+		enable_irq(dev->irq);
+
+	return ret;
+}
+
 static u32 brcmstb_i2c_functionality(struct i2c_adapter *adap)
 {
 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR
@@ -528,6 +546,7 @@ static u32 brcmstb_i2c_functionality(struct i2c_adapter *adap)
 
 static const struct i2c_algorithm brcmstb_i2c_algo = {
 	.master_xfer = brcmstb_i2c_xfer,
+	.master_xfer_atomic = brcmstb_i2c_xfer_atomic,
 	.functionality = brcmstb_i2c_functionality,
 };
 
-- 
2.34.1


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