diff mbox series

[v6,16/35] i2c: tegra: Reorder location of functions in the code

Message ID 20200908021021.9123-17-digetx@gmail.com
State Superseded
Headers show
Series Improvements for Tegra I2C driver | expand

Commit Message

Dmitry Osipenko Sept. 8, 2020, 2:10 a.m. UTC
Reorder location of functions in the code in order to have definition
of functions closer to the place of the invocation. This change makes
easier to navigate around the code and removes the need to have a
prototype for tegra_i2c_init().

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 486 ++++++++++++++++-----------------
 1 file changed, 242 insertions(+), 244 deletions(-)

Comments

Andy Shevchenko Sept. 8, 2020, 8:43 a.m. UTC | #1
On Tue, Sep 8, 2020 at 5:11 AM Dmitry Osipenko <digetx@gmail.com> wrote:
>
> Reorder location of functions in the code in order to have definition
> of functions closer to the place of the invocation. This change makes
> easier to navigate around the code and removes the need to have a
> prototype for tegra_i2c_init().

Still seems to have ordering issues (it moves pieces you actually
change in the next patches).
Have you considered which one looks neat this variant or if you move
it closer to the end of the series?
Dmitry Osipenko Sept. 8, 2020, 12:55 p.m. UTC | #2
08.09.2020 11:43, Andy Shevchenko пишет:
> On Tue, Sep 8, 2020 at 5:11 AM Dmitry Osipenko <digetx@gmail.com> wrote:
>>
>> Reorder location of functions in the code in order to have definition
>> of functions closer to the place of the invocation. This change makes
>> easier to navigate around the code and removes the need to have a
>> prototype for tegra_i2c_init().
> 
> Still seems to have ordering issues (it moves pieces you actually
> change in the next patches).

It's unavoidable that this patch either touches previous or next
changes. You actually had an opposite complaint to v5.

This diver has a long overdue for the refactoring. I think it's a good
time to do it right now because driver works stable and it's quite
unlikely that there will ever be fixes for the older code. Hence it
should be good to have the code reordered now, so that we could have a
nicer code base for the future changes.

> Have you considered which one looks neat this variant or if you move
> it closer to the end of the series?
> 

This variant should be more logical because changes have this order:

1. fixes
2. features
3. code reorder
4. more important cleanups
5. less important cleanups

The 3 merely shuffles code around without any changes to the code, hence
it's a safe change.

The 4 has a potential danger since there are cleanups of the outdated
features and some changes may change semantic in a case of a bug. Hence,
if in the future we'll happen to find a problem in one of the 4 patches,
then there is a better chance that the problem could be fixed with a
simple revert. If 3 is placed after 4, then the chance is completely gone.
Andy Shevchenko Sept. 8, 2020, 1:03 p.m. UTC | #3
On Tue, Sep 8, 2020 at 3:55 PM Dmitry Osipenko <digetx@gmail.com> wrote:
> 08.09.2020 11:43, Andy Shevchenko пишет:
> > On Tue, Sep 8, 2020 at 5:11 AM Dmitry Osipenko <digetx@gmail.com> wrote:
> >>
> >> Reorder location of functions in the code in order to have definition
> >> of functions closer to the place of the invocation. This change makes
> >> easier to navigate around the code and removes the need to have a
> >> prototype for tegra_i2c_init().
> >
> > Still seems to have ordering issues (it moves pieces you actually
> > change in the next patches).
>
> It's unavoidable that this patch either touches previous or next
> changes. You actually had an opposite complaint to v5.

Nice :-)

> This diver has a long overdue for the refactoring. I think it's a good
> time to do it right now because driver works stable and it's quite
> unlikely that there will ever be fixes for the older code. Hence it
> should be good to have the code reordered now, so that we could have a
> nicer code base for the future changes.

I agree.

> > Have you considered which one looks neat this variant or if you move
> > it closer to the end of the series?

> This variant should be more logical because changes have this order:
>
> 1. fixes
> 2. features
> 3. code reorder
> 4. more important cleanups
> 5. less important cleanups
>
> The 3 merely shuffles code around without any changes to the code, hence
> it's a safe change.
>
> The 4 has a potential danger since there are cleanups of the outdated
> features and some changes may change semantic in a case of a bug. Hence,
> if in the future we'll happen to find a problem in one of the 4 patches,
> then there is a better chance that the problem could be fixed with a
> simple revert. If 3 is placed after 4, then the chance is completely gone.

Thanks for elaboration. If you think so (and I guess you are), go ahead!
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 8ab31f8100a8..542436cb7823 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -288,8 +288,6 @@  struct tegra_i2c_dev {
 	bool is_curr_atomic_xfer;
 };
 
-static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev);
-
 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
 		       unsigned long reg)
 {
@@ -466,6 +464,56 @@  static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 	return err;
 }
 
+/*
+ * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
+ * block.  This block is identical to the rest of the I2C blocks, except that
+ * it only supports master mode, it has registers moved around, and it needs
+ * some extra init to get it into I2C mode.  The register moves are handled
+ * by i2c_readl and i2c_writel
+ */
+static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
+{
+	u32 val;
+
+	val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
+	val |= DVC_CTRL_REG3_SW_PROG;
+	val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
+	dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
+
+	val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
+	val |= DVC_CTRL_REG1_INTR_EN;
+	dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
+}
+
+static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
+{
+	u32 value;
+
+	value = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, 2) |
+		FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, 4);
+	i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_0);
+
+	value = FIELD_PREP(I2C_INTERFACE_TIMING_TBUF, 4) |
+		FIELD_PREP(I2C_INTERFACE_TIMING_TSU_STO, 7) |
+		FIELD_PREP(I2C_INTERFACE_TIMING_THD_STA, 4) |
+		FIELD_PREP(I2C_INTERFACE_TIMING_TSU_STA, 4);
+	i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_1);
+
+	value = FIELD_PREP(I2C_HS_INTERFACE_TIMING_THIGH, 3) |
+		FIELD_PREP(I2C_HS_INTERFACE_TIMING_TLOW, 8);
+	i2c_writel(i2c_dev, value, I2C_HS_INTERFACE_TIMING_0);
+
+	value = FIELD_PREP(I2C_HS_INTERFACE_TIMING_TSU_STO, 11) |
+		FIELD_PREP(I2C_HS_INTERFACE_TIMING_THD_STA, 11) |
+		FIELD_PREP(I2C_HS_INTERFACE_TIMING_TSU_STA, 11);
+	i2c_writel(i2c_dev, value, I2C_HS_INTERFACE_TIMING_1);
+
+	value = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND;
+	i2c_writel(i2c_dev, value, I2C_BUS_CLEAR_CNFG);
+
+	i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
+}
+
 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 {
 	u32 mask, val, offset, reg_offset;
@@ -503,198 +551,6 @@  static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 	return 0;
 }
 
-static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
-{
-	u32 val;
-	unsigned int rx_fifo_avail;
-	u8 *buf = i2c_dev->msg_buf;
-	size_t buf_remaining = i2c_dev->msg_buf_remaining;
-	unsigned int words_to_transfer;
-
-	/*
-	 * Catch overflow due to message fully sent
-	 * before the check for RX FIFO availability.
-	 */
-	if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining)))
-		return -EINVAL;
-
-	if (i2c_dev->hw->has_mst_fifo) {
-		val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
-		rx_fifo_avail = FIELD_GET(I2C_MST_FIFO_STATUS_RX, val);
-	} else {
-		val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
-		rx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_RX, val);
-	}
-
-	/* Rounds down to not include partial word at the end of buf */
-	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
-	if (words_to_transfer > rx_fifo_avail)
-		words_to_transfer = rx_fifo_avail;
-
-	i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
-
-	buf += words_to_transfer * BYTES_PER_FIFO_WORD;
-	buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
-	rx_fifo_avail -= words_to_transfer;
-
-	/*
-	 * If there is a partial word at the end of buf, handle it manually to
-	 * prevent overwriting past the end of buf
-	 */
-	if (rx_fifo_avail > 0 && buf_remaining > 0) {
-		/*
-		 * buf_remaining > 3 check not needed as rx_fifo_avail == 0
-		 * when (words_to_transfer was > rx_fifo_avail) earlier
-		 * in this function.
-		 */
-		val = i2c_readl(i2c_dev, I2C_RX_FIFO);
-		val = cpu_to_le32(val);
-		memcpy(buf, &val, buf_remaining);
-		buf_remaining = 0;
-		rx_fifo_avail--;
-	}
-
-	/* RX FIFO must be drained, otherwise it's an Overflow case. */
-	if (WARN_ON_ONCE(rx_fifo_avail))
-		return -EINVAL;
-
-	i2c_dev->msg_buf_remaining = buf_remaining;
-	i2c_dev->msg_buf = buf;
-
-	return 0;
-}
-
-static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
-{
-	u32 val;
-	unsigned int tx_fifo_avail;
-	u8 *buf = i2c_dev->msg_buf;
-	size_t buf_remaining = i2c_dev->msg_buf_remaining;
-	unsigned int words_to_transfer;
-
-	if (i2c_dev->hw->has_mst_fifo) {
-		val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
-		tx_fifo_avail = FIELD_GET(I2C_MST_FIFO_STATUS_TX, val);
-	} else {
-		val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
-		tx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_TX, val);
-	}
-
-	/* Rounds down to not include partial word at the end of buf */
-	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
-
-	/* It's very common to have < 4 bytes, so optimize that case. */
-	if (words_to_transfer) {
-		if (words_to_transfer > tx_fifo_avail)
-			words_to_transfer = tx_fifo_avail;
-
-		/*
-		 * Update state before writing to FIFO.  If this casues us
-		 * to finish writing all bytes (AKA buf_remaining goes to 0) we
-		 * have a potential for an interrupt (PACKET_XFER_COMPLETE is
-		 * not maskable).  We need to make sure that the isr sees
-		 * buf_remaining as 0 and doesn't call us back re-entrantly.
-		 */
-		buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
-		tx_fifo_avail -= words_to_transfer;
-		i2c_dev->msg_buf_remaining = buf_remaining;
-		i2c_dev->msg_buf = buf +
-			words_to_transfer * BYTES_PER_FIFO_WORD;
-		barrier();
-
-		i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
-
-		buf += words_to_transfer * BYTES_PER_FIFO_WORD;
-	}
-
-	/*
-	 * If there is a partial word at the end of buf, handle it manually to
-	 * prevent reading past the end of buf, which could cross a page
-	 * boundary and fault.
-	 */
-	if (tx_fifo_avail > 0 && buf_remaining > 0) {
-		/*
-		 * buf_remaining > 3 check not needed as tx_fifo_avail == 0
-		 * when (words_to_transfer was > tx_fifo_avail) earlier
-		 * in this function for non-zero words_to_transfer.
-		 */
-		memcpy(&val, buf, buf_remaining);
-		val = le32_to_cpu(val);
-
-		/* Again update before writing to FIFO to make sure isr sees. */
-		i2c_dev->msg_buf_remaining = 0;
-		i2c_dev->msg_buf = NULL;
-		barrier();
-
-		i2c_writel(i2c_dev, val, I2C_TX_FIFO);
-	}
-
-	return 0;
-}
-
-/*
- * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
- * block.  This block is identical to the rest of the I2C blocks, except that
- * it only supports master mode, it has registers moved around, and it needs
- * some extra init to get it into I2C mode.  The register moves are handled
- * by i2c_readl and i2c_writel
- */
-static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
-{
-	u32 val;
-
-	val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
-	val |= DVC_CTRL_REG3_SW_PROG;
-	val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
-	dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
-
-	val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
-	val |= DVC_CTRL_REG1_INTR_EN;
-	dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
-}
-
-static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
-{
-	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
-	int ret;
-
-	ret = pinctrl_pm_select_default_state(i2c_dev->dev);
-	if (ret)
-		return ret;
-
-	ret = clk_bulk_enable(i2c_dev->nclocks, i2c_dev->clocks);
-	if (ret)
-		return ret;
-
-	/*
-	 * VI I2C device is attached to VE power domain which goes through
-	 * power ON/OFF during PM runtime resume/suspend. So, controller
-	 * should go through reset and need to re-initialize after power
-	 * domain ON.
-	 */
-	if (i2c_dev->is_vi) {
-		ret = tegra_i2c_init(i2c_dev);
-		if (ret)
-			goto disable_clocks;
-	}
-
-	return 0;
-
-disable_clocks:
-	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
-
-	return ret;
-}
-
-static int __maybe_unused tegra_i2c_runtime_suspend(struct device *dev)
-{
-	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
-
-	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
-
-	return pinctrl_pm_select_idle_state(i2c_dev->dev);
-}
-
 static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 {
 	unsigned long reg_offset;
@@ -726,35 +582,6 @@  static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 	return 0;
 }
 
-static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
-{
-	u32 value;
-
-	value = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, 2) |
-		FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, 4);
-	i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_0);
-
-	value = FIELD_PREP(I2C_INTERFACE_TIMING_TBUF, 4) |
-		FIELD_PREP(I2C_INTERFACE_TIMING_TSU_STO, 7) |
-		FIELD_PREP(I2C_INTERFACE_TIMING_THD_STA, 4) |
-		FIELD_PREP(I2C_INTERFACE_TIMING_TSU_STA, 4);
-	i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_1);
-
-	value = FIELD_PREP(I2C_HS_INTERFACE_TIMING_THIGH, 3) |
-		FIELD_PREP(I2C_HS_INTERFACE_TIMING_TLOW, 8);
-	i2c_writel(i2c_dev, value, I2C_HS_INTERFACE_TIMING_0);
-
-	value = FIELD_PREP(I2C_HS_INTERFACE_TIMING_TSU_STO, 11) |
-		FIELD_PREP(I2C_HS_INTERFACE_TIMING_THD_STA, 11) |
-		FIELD_PREP(I2C_HS_INTERFACE_TIMING_TSU_STA, 11);
-	i2c_writel(i2c_dev, value, I2C_HS_INTERFACE_TIMING_1);
-
-	value = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND;
-	i2c_writel(i2c_dev, value, I2C_BUS_CLEAR_CNFG);
-
-	i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
-}
-
 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 {
 	u32 val;
@@ -882,6 +709,135 @@  static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
 	return tegra_i2c_wait_for_config_load(i2c_dev);
 }
 
+static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
+{
+	u32 val;
+	unsigned int rx_fifo_avail;
+	u8 *buf = i2c_dev->msg_buf;
+	size_t buf_remaining = i2c_dev->msg_buf_remaining;
+	unsigned int words_to_transfer;
+
+	/*
+	 * Catch overflow due to message fully sent
+	 * before the check for RX FIFO availability.
+	 */
+	if (WARN_ON_ONCE(!(i2c_dev->msg_buf_remaining)))
+		return -EINVAL;
+
+	if (i2c_dev->hw->has_mst_fifo) {
+		val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
+		rx_fifo_avail = FIELD_GET(I2C_MST_FIFO_STATUS_RX, val);
+	} else {
+		val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
+		rx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_RX, val);
+	}
+
+	/* Rounds down to not include partial word at the end of buf */
+	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
+	if (words_to_transfer > rx_fifo_avail)
+		words_to_transfer = rx_fifo_avail;
+
+	i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
+
+	buf += words_to_transfer * BYTES_PER_FIFO_WORD;
+	buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
+	rx_fifo_avail -= words_to_transfer;
+
+	/*
+	 * If there is a partial word at the end of buf, handle it manually to
+	 * prevent overwriting past the end of buf
+	 */
+	if (rx_fifo_avail > 0 && buf_remaining > 0) {
+		/*
+		 * buf_remaining > 3 check not needed as rx_fifo_avail == 0
+		 * when (words_to_transfer was > rx_fifo_avail) earlier
+		 * in this function.
+		 */
+		val = i2c_readl(i2c_dev, I2C_RX_FIFO);
+		val = cpu_to_le32(val);
+		memcpy(buf, &val, buf_remaining);
+		buf_remaining = 0;
+		rx_fifo_avail--;
+	}
+
+	/* RX FIFO must be drained, otherwise it's an Overflow case. */
+	if (WARN_ON_ONCE(rx_fifo_avail))
+		return -EINVAL;
+
+	i2c_dev->msg_buf_remaining = buf_remaining;
+	i2c_dev->msg_buf = buf;
+
+	return 0;
+}
+
+static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
+{
+	u32 val;
+	unsigned int tx_fifo_avail;
+	u8 *buf = i2c_dev->msg_buf;
+	size_t buf_remaining = i2c_dev->msg_buf_remaining;
+	unsigned int words_to_transfer;
+
+	if (i2c_dev->hw->has_mst_fifo) {
+		val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
+		tx_fifo_avail = FIELD_GET(I2C_MST_FIFO_STATUS_TX, val);
+	} else {
+		val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
+		tx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_TX, val);
+	}
+
+	/* Rounds down to not include partial word at the end of buf */
+	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
+
+	/* It's very common to have < 4 bytes, so optimize that case. */
+	if (words_to_transfer) {
+		if (words_to_transfer > tx_fifo_avail)
+			words_to_transfer = tx_fifo_avail;
+
+		/*
+		 * Update state before writing to FIFO.  If this casues us
+		 * to finish writing all bytes (AKA buf_remaining goes to 0) we
+		 * have a potential for an interrupt (PACKET_XFER_COMPLETE is
+		 * not maskable).  We need to make sure that the isr sees
+		 * buf_remaining as 0 and doesn't call us back re-entrantly.
+		 */
+		buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
+		tx_fifo_avail -= words_to_transfer;
+		i2c_dev->msg_buf_remaining = buf_remaining;
+		i2c_dev->msg_buf = buf +
+			words_to_transfer * BYTES_PER_FIFO_WORD;
+		barrier();
+
+		i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
+
+		buf += words_to_transfer * BYTES_PER_FIFO_WORD;
+	}
+
+	/*
+	 * If there is a partial word at the end of buf, handle it manually to
+	 * prevent reading past the end of buf, which could cross a page
+	 * boundary and fault.
+	 */
+	if (tx_fifo_avail > 0 && buf_remaining > 0) {
+		/*
+		 * buf_remaining > 3 check not needed as tx_fifo_avail == 0
+		 * when (words_to_transfer was > tx_fifo_avail) earlier
+		 * in this function for non-zero words_to_transfer.
+		 */
+		memcpy(&val, buf, buf_remaining);
+		val = le32_to_cpu(val);
+
+		/* Again update before writing to FIFO to make sure isr sees. */
+		i2c_dev->msg_buf_remaining = 0;
+		i2c_dev->msg_buf = NULL;
+		barrier();
+
+		i2c_writel(i2c_dev, val, I2C_TX_FIFO);
+	}
+
+	return 0;
+}
+
 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 {
 	u32 status;
@@ -1418,27 +1374,6 @@  static u32 tegra_i2c_func(struct i2c_adapter *adap)
 	return ret;
 }
 
-static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
-{
-	struct device_node *np = i2c_dev->dev->of_node;
-	int ret;
-	bool multi_mode;
-
-	ret = of_property_read_u32(np, "clock-frequency",
-				   &i2c_dev->bus_clk_rate);
-	if (ret)
-		i2c_dev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ; /* default clock rate */
-
-	multi_mode = of_property_read_bool(np, "multi-master");
-	i2c_dev->is_multimaster_mode = multi_mode;
-
-	if (of_device_is_compatible(np, "nvidia,tegra20-i2c-dvc"))
-		i2c_dev->is_dvc = true;
-
-	if (of_device_is_compatible(np, "nvidia,tegra210-i2c-vi"))
-		i2c_dev->is_vi = true;
-}
-
 static const struct i2c_algorithm tegra_i2c_algo = {
 	.master_xfer		= tegra_i2c_xfer,
 	.master_xfer_atomic	= tegra_i2c_xfer_atomic,
@@ -1644,6 +1579,27 @@  static const struct of_device_id tegra_i2c_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
 
+static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
+{
+	struct device_node *np = i2c_dev->dev->of_node;
+	int ret;
+	bool multi_mode;
+
+	ret = of_property_read_u32(np, "clock-frequency",
+				   &i2c_dev->bus_clk_rate);
+	if (ret)
+		i2c_dev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ; /* default clock rate */
+
+	multi_mode = of_property_read_bool(np, "multi-master");
+	i2c_dev->is_multimaster_mode = multi_mode;
+
+	if (of_device_is_compatible(np, "nvidia,tegra20-i2c-dvc"))
+		i2c_dev->is_dvc = true;
+
+	if (of_device_is_compatible(np, "nvidia,tegra210-i2c-vi"))
+		i2c_dev->is_vi = true;
+}
+
 static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev)
 {
 	unsigned int i;
@@ -1821,6 +1777,48 @@  static int tegra_i2c_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
+{
+	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pinctrl_pm_select_default_state(i2c_dev->dev);
+	if (ret)
+		return ret;
+
+	ret = clk_bulk_enable(i2c_dev->nclocks, i2c_dev->clocks);
+	if (ret)
+		return ret;
+
+	/*
+	 * VI I2C device is attached to VE power domain which goes through
+	 * power ON/OFF during PM runtime resume/suspend. So, controller
+	 * should go through reset and need to re-initialize after power
+	 * domain ON.
+	 */
+	if (i2c_dev->is_vi) {
+		ret = tegra_i2c_init(i2c_dev);
+		if (ret)
+			goto disable_clocks;
+	}
+
+	return 0;
+
+disable_clocks:
+	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
+
+	return ret;
+}
+
+static int __maybe_unused tegra_i2c_runtime_suspend(struct device *dev)
+{
+	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+
+	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
+
+	return pinctrl_pm_select_idle_state(i2c_dev->dev);
+}
+
 static int __maybe_unused tegra_i2c_suspend(struct device *dev)
 {
 	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);