Merge tag 'i2c-fixes-7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux

Pull i2c fixes from Andi Shyti:
 "A handful of small fixes for host controller drivers.

  One patch also adds Wolfram Sang to CREDITS after more than a decade
  of work on I2C"

* tag 'i2c-fixes-7.2-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/andi.shyti/linux:
  i2c: mediatek: fix WRRD for SoCs without auto_restart option
  i2c: mlxbf: Fix use-after-free in mlxbf_i2c_init_resource()
  i2c: spacemit: fix spurious IRQ handling returning IRQ_HANDLED
  i2c: imx: fix locked bus on SMBus block-read of 0 (IRQ)
  i2c: imx: fix locked bus on SMBus block-read of 0 (atomic)
  CREDITS: Add Wolfram Sang

5 files changed, 45 insertions, 6 deletions

diff --git a/CREDITS b/CREDITS
index 84793a967a0b..91c51c14e993 100644
--- a/CREDITS
+++ b/CREDITS
@@ -3626,6 +3626,13 @@ S: 69 rue Dunois
 S: 75013 Paris
 S: France
 
+N: Wolfram Sang
+E: wsa@kernel.org
+W: sang-engineering.com
+P: rsa4096/140DE4CC14A029B6 3991 B1EA B9E2 6751 A4F7 645D 140D E4CC 14A0 29B6
+D: I2C Maintainer 2012 - 2026
+S: Berlin, Germany
+
 N: Aleksa Sarai
 E: cyphar@cyphar.com
 W: https://www.cyphar.com/
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 28313d0fad37..d5e6e2eca3b3 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1061,11 +1061,28 @@ static inline enum imx_i2c_state i2c_imx_isr_read_continue(struct imx_i2c_struct
 static inline void i2c_imx_isr_read_block_data_len(struct imx_i2c_struct *i2c_imx)
 {
 	u8 len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
+	unsigned int temp;
 
 	if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) {
+		/*
+		 * SMBus 3.1 6.5.7: support count byte of 0.
+		 * I2C_SMBUS_BLOCK_MAX case should not hold the SDA either.
+		 * So NACK it (TXAK) to not hold the bus.
+		 */
+		temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+		temp |= I2CR_TXAK;
+		imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
+
+		if (len == 0) {
+			i2c_imx->msg->buf[i2c_imx->msg_buf_idx++] = 0;
+			i2c_imx->msg->len = 2;
+			return;
+		}
+
 		i2c_imx->isr_result = -EPROTO;
 		i2c_imx->state = IMX_I2C_STATE_FAILED;
 		wake_up(&i2c_imx->queue);
+		return;
 	}
 	i2c_imx->msg->len += len;
 	i2c_imx->msg->buf[i2c_imx->msg_buf_idx++] = len;
@@ -1415,6 +1432,7 @@ static int i2c_imx_atomic_read(struct imx_i2c_struct *i2c_imx,
 	int i, result;
 	unsigned int temp;
 	int block_data = msgs->flags & I2C_M_RECV_LEN;
+	int block_err = 0;
 
 	result = i2c_imx_prepare_read(i2c_imx, msgs, false);
 	if (result)
@@ -1436,8 +1454,20 @@ static int i2c_imx_atomic_read(struct imx_i2c_struct *i2c_imx,
 		 */
 		if ((!i) && block_data) {
 			len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
-			if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX))
-				return -EPROTO;
+			if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX)) {
+				/*
+				 * SMBus 3.1 6.5.7: support count byte of 0.
+				 * I2C_SMBUS_BLOCK_MAX case should not hold the SDA either.
+				 */
+				if (len > I2C_SMBUS_BLOCK_MAX)
+					block_err = -EPROTO;
+				temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+				temp |= I2CR_TXAK;
+				imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
+				msgs->buf[0] = 0;
+				msgs->len = 2;
+				continue;
+			}
 			dev_dbg(&i2c_imx->adapter.dev,
 				"<%s> read length: 0x%X\n",
 				__func__, len);
@@ -1485,7 +1515,7 @@ static int i2c_imx_atomic_read(struct imx_i2c_struct *i2c_imx,
 			"<%s> read byte: B%d=0x%X\n",
 			__func__, i, msgs->buf[i]);
 	}
-	return 0;
+	return block_err;
 }
 
 static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs,
diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
index 9152cf436bea..51a0c3d80fc9 100644
--- a/drivers/i2c/busses/i2c-k1.c
+++ b/drivers/i2c/busses/i2c-k1.c
@@ -596,7 +596,7 @@ static irqreturn_t spacemit_i2c_irq_handler(int irq, void *devid)
 
 	status = readl(i2c->base + SPACEMIT_ISR);
 	if (!status)
-		return IRQ_HANDLED;
+		return IRQ_NONE;
 
 	i2c->status = status;
 
diff --git a/drivers/i2c/busses/i2c-mlxbf.c b/drivers/i2c/busses/i2c-mlxbf.c
index 6c1cfe9ec8ac..e33512b25353 100644
--- a/drivers/i2c/busses/i2c-mlxbf.c
+++ b/drivers/i2c/busses/i2c-mlxbf.c
@@ -1051,8 +1051,10 @@ static int mlxbf_i2c_init_resource(struct platform_device *pdev,
 
 	tmp_res->io = devm_platform_get_and_ioremap_resource(pdev, type, &tmp_res->params);
 	if (IS_ERR(tmp_res->io)) {
+		int ret = PTR_ERR(tmp_res->io);
+
 		devm_kfree(dev, tmp_res);
-		return PTR_ERR(tmp_res->io);
+		return ret;
 	}
 
 	tmp_res->type = type;
diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
index 126040ca05f1..307925fb78e3 100644
--- a/drivers/i2c/busses/i2c-mt65xx.c
+++ b/drivers/i2c/busses/i2c-mt65xx.c
@@ -1258,7 +1258,7 @@ static int mtk_i2c_transfer(struct i2c_adapter *adap,
 	i2c->auto_restart = i2c->dev_comp->auto_restart;
 
 	/* checking if we can skip restart and optimize using WRRD mode */
-	if (i2c->auto_restart && num == 2) {
+	if (num == 2) {
 		if (!(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD) &&
 		    msgs[0].addr == msgs[1].addr) {
 			i2c->auto_restart = 0;