[PATCH v4 00/31] Improvements for Tegra I2C driver

[PATCH v4 00/31] Improvements for Tegra I2C driver

[Dmitry Osipenko]

Hello!

This series performs refactoring of the Tegra I2C driver code and hardens
the atomic-transfer mode.

Changelog:

v4: - Reordered patches in the fixes/features/cleanups order like it was
      suggested by Andy Shevchenko.

    - Now using clk-bulk API, which was suggested by Andy Shevchenko.

    - Reworked "Make tegra_i2c_flush_fifos() usable in atomic transfer"
      patch to use iopoll API, which was suggested by Andy Shevchenko.

    - Separated "Clean up probe function" into several smaller patches.

    - Squashed "Add missing newline before returns" patch into
      "Clean up whitespaces, newlines and indentation".

    - The "Drop '_timeout' from wait/poll function names" is renamed to
      "Rename wait/poll functions".

    - The "Use reset_control_reset()" is changed to not fail tegra_i2c_init(),
      but only emit warning. This should be more friendly behaviour in oppose
      to having a non-bootable machine if reset-control fails.

    - New patches:

        i2c: tegra: Remove error message used for devm_request_irq() failure
        i2c: tegra: Use devm_platform_get_and_ioremap_resource()
        i2c: tegra: Use platform_get_irq()
        i2c: tegra: Use clk-bulk helpers
        i2c: tegra: Remove bogus barrier()
        i2c: tegra: Factor out register polling into separate function
        i2c: tegra: Consolidate error handling in tegra_i2c_xfer_msg()
        i2c: tegra: Clean up and improve comments
        i2c: tegra: Rename couple "ret" variables to "err"

v3: - Optimized "Make tegra_i2c_flush_fifos() usable in atomic transfer"
      patch by pre-checking FIFO state before starting to poll using
      ktime API, which may be expensive under some circumstances.

    - The "Clean up messages in the code" patch now makes all messages
      to use proper capitalization of abbreviations. Thanks to Andy Shevchenko
      and Michał Mirosław for the suggestion.

    - The "Remove unnecessary whitespaces and newlines" patch is transformed
      into "Clean up whitespaces and newlines", it now also adds missing
      newlines and spaces.

    - Reworked the "Clean up probe function" patch in accordance to
      suggestion from Michał Mirosław by factoring out only parts of
      the code that make error unwinding cleaner.

    - Added r-b from Michał Mirosław.

    - Added more patches:

        i2c: tegra: Reorder location of functions in the code
        i2c: tegra: Factor out packet header setup from tegra_i2c_xfer_msg()
        i2c: tegra: Remove "dma" variable
        i2c: tegra: Initialization div-clk rate unconditionally
        i2c: tegra: Remove i2c_dev.clk_divisor_non_hs_mode member

v2: - Cleaned more messages in the "Clean up messages in the code" patch.

    - The error code of reset_control_reset() is checked now.

    - Added these new patches to clean up couple more things:

        i2c: tegra: Check errors for both positive and negative values
        i2c: tegra: Improve coding style of tegra_i2c_wait_for_config_load()
        i2c: tegra: Remove unnecessary whitespaces and newlines
        i2c: tegra: Rename variable in tegra_i2c_issue_bus_clear()
        i2c: tegra: Improve driver module description

Dmitry Osipenko (31):
  i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer
  i2c: tegra: Handle potential error of tegra_i2c_flush_fifos()
  i2c: tegra: Initialization div-clk rate unconditionally
  i2c: tegra: Remove i2c_dev.clk_divisor_non_hs_mode member
  i2c: tegra: Runtime PM always available on Tegra
  i2c: tegra: Remove error message used for devm_request_irq() failure
  i2c: tegra: Use reset_control_reset()
  i2c: tegra: Use devm_platform_get_and_ioremap_resource()
  i2c: tegra: Use platform_get_irq()
  i2c: tegra: Use clk-bulk helpers
  i2c: tegra: Factor out runtime PM and hardware initialization
  i2c: tegra: Move out all device-tree parsing into tegra_i2c_parse_dt()
  i2c: tegra: Clean up probe function
  i2c: tegra: Remove likely/unlikely from the code
  i2c: tegra: Remove bogus barrier()
  i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg()
  i2c: tegra: Improve formatting of function variables
  i2c: tegra: Improve coding style of tegra_i2c_wait_for_config_load()
  i2c: tegra: Rename wait/poll functions
  i2c: tegra: Rename variable in tegra_i2c_issue_bus_clear()
  i2c: tegra: Factor out error recovery from tegra_i2c_xfer_msg()
  i2c: tegra: Factor out packet header setup from tegra_i2c_xfer_msg()
  i2c: tegra: Factor out register polling into separate function
  i2c: tegra: Reorder location of functions in the code
  i2c: tegra: Check errors for both positive and negative values
  i2c: tegra: Consolidate error handling in tegra_i2c_xfer_msg()
  i2c: tegra: Clean up printk messages
  i2c: tegra: Clean up whitespaces, newlines and indentation
  i2c: tegra: Improve driver module description
  i2c: tegra: Clean up and improve comments
  i2c: tegra: Rename couple "ret" variables to "err"

 drivers/i2c/busses/i2c-tegra.c | 1272 +++++++++++++++-----------------
 1 file changed, 612 insertions(+), 660 deletions(-)

-- 
2.27.0

[PATCH v4 01/31] i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer

[Dmitry Osipenko]

The tegra_i2c_flush_fifos() shouldn't sleep in atomic transfer and jiffies
are not updating if interrupts are disabled. Let's switch to use iopoll
API helpers for register-polling. The iopoll API provides helpers for both
atomic and non-atomic cases.

Note that this patch doesn't fix any known problem because normally FIFO
is flushed at the time of starting a new transfer.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 00d3e4d7a01e..ab88cdd70376 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -470,9 +470,9 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 
 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 {
-	unsigned long timeout = jiffies + HZ;
-	unsigned int offset;
-	u32 mask, val;
+	u32 mask, val, offset, reg_offset;
+	void __iomem *addr;
+	int err;
 
 	if (i2c_dev->hw->has_mst_fifo) {
 		mask = I2C_MST_FIFO_CONTROL_TX_FLUSH |
@@ -488,12 +488,19 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 	val |= mask;
 	i2c_writel(i2c_dev, val, offset);
 
-	while (i2c_readl(i2c_dev, offset) & mask) {
-		if (time_after(jiffies, timeout)) {
-			dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");
-			return -ETIMEDOUT;
-		}
-		usleep_range(1000, 2000);
+	reg_offset = tegra_i2c_reg_addr(i2c_dev, offset);
+	addr = i2c_dev->base + reg_offset;
+
+	if (i2c_dev->is_curr_atomic_xfer)
+		err = readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),
+							1000, 1000000);
+	else
+		err = readl_relaxed_poll_timeout(addr, val, !(val & mask),
+						 1000, 1000000);
+
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to flush FIFO\n");
+		return err;
 	}
 	return 0;
 }
-- 
2.27.0

[PATCH v4 02/31] i2c: tegra: Handle potential error of tegra_i2c_flush_fifos()

[Dmitry Osipenko]

Technically the tegra_i2c_flush_fifos() may fail and transfer should be
aborted in this case, but this shouldn't ever happen in practice unless
there is a bug somewhere in the driver. Let's add the error check just
for completeness.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index ab88cdd70376..307df6f97ed0 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1177,7 +1177,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	bool dma;
 	u16 xfer_time = 100;
 
-	tegra_i2c_flush_fifos(i2c_dev);
+	err = tegra_i2c_flush_fifos(i2c_dev);
+	if (err)
+		return err;
 
 	i2c_dev->msg_buf = msg->buf;
 	i2c_dev->msg_buf_remaining = msg->len;
-- 
2.27.0

[PATCH v4 03/31] i2c: tegra: Initialization div-clk rate unconditionally

[Dmitry Osipenko]

It doesn't make sense to conditionalize the div-clk rate changes because
rate is fixed and it won't ever change once it's set at the driver's probe
time. All further changes are NO-OPs because CCF caches rate and skips
rate-change if rate is unchanged.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 307df6f97ed0..56c5aff579b6 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -293,7 +293,7 @@ struct tegra_i2c_dev {
 	bool is_curr_atomic_xfer;
 };
 
-static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit);
+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)
@@ -691,7 +691,7 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 	 * domain ON.
 	 */
 	if (i2c_dev->is_vi) {
-		ret = tegra_i2c_init(i2c_dev, true);
+		ret = tegra_i2c_init(i2c_dev);
 		if (ret)
 			goto disable_div_clk;
 	}
@@ -778,7 +778,7 @@ static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
 	i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
 }
 
-static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit)
+static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 {
 	u32 val;
 	int err;
@@ -836,16 +836,14 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev, bool clk_reinit)
 	if (i2c_dev->hw->has_interface_timing_reg && tsu_thd)
 		i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1);
 
-	if (!clk_reinit) {
-		clk_multiplier = (tlow + thigh + 2);
-		clk_multiplier *= (i2c_dev->clk_divisor_non_hs_mode + 1);
-		err = clk_set_rate(i2c_dev->div_clk,
-				   i2c_dev->bus_clk_rate * clk_multiplier);
-		if (err) {
-			dev_err(i2c_dev->dev,
-				"failed changing clock rate: %d\n", err);
-			return err;
-		}
+	clk_multiplier  = tlow + thigh + 2;
+	clk_multiplier *= i2c_dev->clk_divisor_non_hs_mode + 1;
+
+	err = clk_set_rate(i2c_dev->div_clk,
+			   i2c_dev->bus_clk_rate * clk_multiplier);
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to set div-clk rate: %d\n", err);
+		return err;
 	}
 
 	if (!i2c_dev->is_dvc && !i2c_dev->is_vi) {
@@ -1317,7 +1315,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 		if (!time_left && !completion_done(&i2c_dev->dma_complete)) {
 			dev_err(i2c_dev->dev, "DMA transfer timeout\n");
-			tegra_i2c_init(i2c_dev, true);
+			tegra_i2c_init(i2c_dev);
 			return -ETIMEDOUT;
 		}
 
@@ -1338,7 +1336,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (time_left == 0) {
 		dev_err(i2c_dev->dev, "i2c transfer timed out\n");
-		tegra_i2c_init(i2c_dev, true);
+		tegra_i2c_init(i2c_dev);
 		return -ETIMEDOUT;
 	}
 
@@ -1350,7 +1348,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
 		return 0;
 
-	tegra_i2c_init(i2c_dev, true);
+	tegra_i2c_init(i2c_dev);
 	/* start recovery upon arbitration loss in single master mode */
 	if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) {
 		if (!i2c_dev->is_multimaster_mode)
@@ -1808,7 +1806,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	if (ret < 0)
 		goto disable_div_clk;
 
-	ret = tegra_i2c_init(i2c_dev, false);
+	ret = tegra_i2c_init(i2c_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to initialize i2c controller\n");
 		goto release_dma;
@@ -1916,7 +1914,7 @@ static int __maybe_unused tegra_i2c_resume(struct device *dev)
 	if (err)
 		return err;
 
-	err = tegra_i2c_init(i2c_dev, false);
+	err = tegra_i2c_init(i2c_dev);
 	if (err)
 		return err;
 
-- 
2.27.0

[PATCH v4 04/31] i2c: tegra: Remove i2c_dev.clk_divisor_non_hs_mode member

[Dmitry Osipenko]

The "non_hs_mode" divisor value is fixed, thus there is no need to have
the variable i2c_dev.clk_divisor_non_hs_mode struct member. Let's remove
it and move the mode selection into tegra_i2c_init() where it can be
united with the timing selection.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 45 +++++++++++++++-------------------
 1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 56c5aff579b6..f5b9cdb65182 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -250,7 +250,6 @@ struct tegra_i2c_hw_feature {
  * @msg_buf_remaining: size of unsent data in the message buffer
  * @msg_read: identifies read transfers
  * @bus_clk_rate: current I2C bus clock rate
- * @clk_divisor_non_hs_mode: clock divider for non-high-speed modes
  * @is_multimaster_mode: track if I2C controller is in multi-master mode
  * @tx_dma_chan: DMA transmit channel
  * @rx_dma_chan: DMA receive channel
@@ -281,7 +280,6 @@ struct tegra_i2c_dev {
 	size_t msg_buf_remaining;
 	int msg_read;
 	u32 bus_clk_rate;
-	u16 clk_divisor_non_hs_mode;
 	bool is_multimaster_mode;
 	struct dma_chan *tx_dma_chan;
 	struct dma_chan *rx_dma_chan;
@@ -783,6 +781,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	u32 val;
 	int err;
 	u32 clk_divisor, clk_multiplier;
+	u32 non_hs_mode;
 	u32 tsu_thd;
 	u8 tlow, thigh;
 
@@ -805,24 +804,32 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	if (i2c_dev->is_vi)
 		tegra_i2c_vi_init(i2c_dev);
 
-	/* Make sure clock divisor programmed correctly */
-	clk_divisor = FIELD_PREP(I2C_CLK_DIVISOR_HSMODE,
-				 i2c_dev->hw->clk_divisor_hs_mode) |
-		      FIELD_PREP(I2C_CLK_DIVISOR_STD_FAST_MODE,
-				 i2c_dev->clk_divisor_non_hs_mode);
-	i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);
-
-	if (i2c_dev->bus_clk_rate > I2C_MAX_STANDARD_MODE_FREQ &&
-	    i2c_dev->bus_clk_rate <= I2C_MAX_FAST_MODE_PLUS_FREQ) {
+	switch (i2c_dev->bus_clk_rate) {
+	case I2C_MAX_STANDARD_MODE_FREQ + 1 ... I2C_MAX_FAST_MODE_PLUS_FREQ:
 		tlow = i2c_dev->hw->tlow_fast_fastplus_mode;
 		thigh = i2c_dev->hw->thigh_fast_fastplus_mode;
 		tsu_thd = i2c_dev->hw->setup_hold_time_fast_fast_plus_mode;
-	} else {
+
+		if (i2c_dev->bus_clk_rate > I2C_MAX_FAST_MODE_FREQ)
+			non_hs_mode = i2c_dev->hw->clk_divisor_fast_plus_mode;
+		else
+			non_hs_mode = i2c_dev->hw->clk_divisor_fast_mode;
+		break;
+
+	default:
 		tlow = i2c_dev->hw->tlow_std_mode;
 		thigh = i2c_dev->hw->thigh_std_mode;
 		tsu_thd = i2c_dev->hw->setup_hold_time_std_mode;
+		non_hs_mode = i2c_dev->hw->clk_divisor_std_mode;
+		break;
 	}
 
+	/* Make sure clock divisor programmed correctly */
+	clk_divisor = FIELD_PREP(I2C_CLK_DIVISOR_HSMODE,
+				 i2c_dev->hw->clk_divisor_hs_mode) |
+		      FIELD_PREP(I2C_CLK_DIVISOR_STD_FAST_MODE, non_hs_mode);
+	i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);
+
 	if (i2c_dev->hw->has_interface_timing_reg) {
 		val = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, thigh) |
 		      FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, tlow);
@@ -837,7 +844,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 		i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1);
 
 	clk_multiplier  = tlow + thigh + 2;
-	clk_multiplier *= i2c_dev->clk_divisor_non_hs_mode + 1;
+	clk_multiplier *= non_hs_mode + 1;
 
 	err = clk_set_rate(i2c_dev->div_clk,
 			   i2c_dev->bus_clk_rate * clk_multiplier);
@@ -1748,18 +1755,6 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 		goto unprepare_fast_clk;
 	}
 
-	if (i2c_dev->bus_clk_rate > I2C_MAX_FAST_MODE_FREQ &&
-	    i2c_dev->bus_clk_rate <= I2C_MAX_FAST_MODE_PLUS_FREQ)
-		i2c_dev->clk_divisor_non_hs_mode =
-				i2c_dev->hw->clk_divisor_fast_plus_mode;
-	else if (i2c_dev->bus_clk_rate > I2C_MAX_STANDARD_MODE_FREQ &&
-		 i2c_dev->bus_clk_rate <= I2C_MAX_FAST_MODE_FREQ)
-		i2c_dev->clk_divisor_non_hs_mode =
-				i2c_dev->hw->clk_divisor_fast_mode;
-	else
-		i2c_dev->clk_divisor_non_hs_mode =
-				i2c_dev->hw->clk_divisor_std_mode;
-
 	ret = clk_prepare(i2c_dev->div_clk);
 	if (ret < 0) {
 		dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
-- 
2.27.0

[PATCH v4 05/31] i2c: tegra: Runtime PM always available on Tegra

[Dmitry Osipenko]

The runtime PM is guaranteed to be always available on Tegra after commit
40b2bb1b132a ("ARM: tegra: enforce PM requirement"). Hence let's remove
all the RPM-availability checking and handling from the code.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 28 ++++++----------------------
 1 file changed, 6 insertions(+), 22 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index f5b9cdb65182..9f0269bffab4 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1771,18 +1771,10 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	if (!i2c_dev->is_vi)
 		pm_runtime_irq_safe(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
-	if (!pm_runtime_enabled(&pdev->dev)) {
-		ret = tegra_i2c_runtime_resume(&pdev->dev);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "runtime resume failed\n");
-			goto unprepare_div_clk;
-		}
-	} else {
-		ret = pm_runtime_get_sync(i2c_dev->dev);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "runtime resume failed\n");
-			goto disable_rpm;
-		}
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0) {
+		dev_err(dev, "runtime resume failed\n");
+		goto disable_rpm;
 	}
 
 	if (i2c_dev->is_multimaster_mode) {
@@ -1841,16 +1833,10 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 		clk_disable(i2c_dev->div_clk);
 
 put_rpm:
-	if (pm_runtime_enabled(&pdev->dev))
-		pm_runtime_put_sync(&pdev->dev);
-	else
-		tegra_i2c_runtime_suspend(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
 
 disable_rpm:
-	if (pm_runtime_enabled(&pdev->dev))
-		pm_runtime_disable(&pdev->dev);
-
-unprepare_div_clk:
+	pm_runtime_disable(&pdev->dev);
 	clk_unprepare(i2c_dev->div_clk);
 
 unprepare_slow_clk:
@@ -1872,8 +1858,6 @@ static int tegra_i2c_remove(struct platform_device *pdev)
 		clk_disable(i2c_dev->div_clk);
 
 	pm_runtime_disable(&pdev->dev);
-	if (!pm_runtime_status_suspended(&pdev->dev))
-		tegra_i2c_runtime_suspend(&pdev->dev);
 
 	clk_unprepare(i2c_dev->div_clk);
 	clk_unprepare(i2c_dev->slow_clk);
-- 
2.27.0

[PATCH v4 06/31] i2c: tegra: Remove error message used for devm_request_irq() failure

[Dmitry Osipenko]

The error message prints number of vIRQ, which isn't a useful information.
In practice devm_request_irq() never fails, hence let's remove the bogus
message in order to make code cleaner.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 9f0269bffab4..2f74bdd75e1c 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1803,10 +1803,8 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 
 	ret = devm_request_irq(&pdev->dev, i2c_dev->irq, tegra_i2c_isr,
 			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c_dev);
-	if (ret) {
-		dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
+	if (ret)
 		goto release_dma;
-	}
 
 	i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
 	i2c_dev->adapter.owner = THIS_MODULE;
-- 
2.27.0

[PATCH v4 07/31] i2c: tegra: Use reset_control_reset()

[Dmitry Osipenko]

Use a single reset_control_reset() instead of assert/deasset couple in
order to make code cleaner a tad. Note that the reset_control_reset()
uses 1 microsecond delay instead of 2 that was used previously, but this
shouldn't matter. In addition don't ignore potential error of the reset
control by emitting a noisy warning if it fails, which shouldn't ever
happen in practice.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 2f74bdd75e1c..940b5f15ef11 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -785,9 +785,8 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	u32 tsu_thd;
 	u8 tlow, thigh;
 
-	reset_control_assert(i2c_dev->rst);
-	udelay(2);
-	reset_control_deassert(i2c_dev->rst);
+	err = reset_control_reset(i2c_dev->rst);
+	WARN_ON_ONCE(err);
 
 	if (i2c_dev->is_dvc)
 		tegra_dvc_init(i2c_dev);
-- 
2.27.0

[PATCH v4 08/31] i2c: tegra: Use devm_platform_get_and_ioremap_resource()

[Dmitry Osipenko]

Driver now uses devm_platform_get_and_ioremap_resource() which replaces
the typical boilerplate code and makes code cleaner.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 940b5f15ef11..abcfb53d649c 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1666,12 +1666,12 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	int irq;
 	int ret;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base_phys = res->start;
-	base = devm_ioremap_resource(&pdev->dev, res);
+	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 	if (IS_ERR(base))
 		return PTR_ERR(base);
 
+	base_phys = res->start;
+
 	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 	if (!res) {
 		dev_err(&pdev->dev, "no irq resource\n");
-- 
2.27.0

[PATCH v4 09/31] i2c: tegra: Use platform_get_irq()

[Dmitry Osipenko]

Use common helper for retrieval of the interrupt number in order to make
code cleaner. Note that platform_get_irq() prints error message by itself.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index abcfb53d649c..f1c4334faed3 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1672,12 +1672,9 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 
 	base_phys = res->start;
 
-	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
-	if (!res) {
-		dev_err(&pdev->dev, "no irq resource\n");
-		return -EINVAL;
-	}
-	irq = res->start;
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
 
 	div_clk = devm_clk_get(&pdev->dev, "div-clk");
 	if (IS_ERR(div_clk)) {
-- 
2.27.0

[PATCH v4 10/31] i2c: tegra: Use clk-bulk helpers

[Dmitry Osipenko]

Use clk-bulk helpers and factor out clocks initialization into separate
function in order to make code cleaner.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 184 ++++++++++++---------------------
 1 file changed, 65 insertions(+), 119 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index f1c4334faed3..8e4e72dec6ea 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -165,9 +165,6 @@ enum msg_end_type {
  * @has_continue_xfer_support: Continue transfer supports.
  * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer
  *		complete interrupt per packet basis.
- * @has_single_clk_source: The I2C controller has single clock source. Tegra30
- *		and earlier SoCs have two clock sources i.e. div-clk and
- *		fast-clk.
  * @has_config_load_reg: Has the config load register to load the new
  *		configuration.
  * @clk_divisor_hs_mode: Clock divisor in HS mode.
@@ -208,7 +205,6 @@ enum msg_end_type {
 struct tegra_i2c_hw_feature {
 	bool has_continue_xfer_support;
 	bool has_per_pkt_xfer_complete_irq;
-	bool has_single_clk_source;
 	bool has_config_load_reg;
 	int clk_divisor_hs_mode;
 	int clk_divisor_std_mode;
@@ -236,7 +232,8 @@ struct tegra_i2c_hw_feature {
  * @hw: Tegra I2C HW feature
  * @adapter: core I2C layer adapter information
  * @div_clk: clock reference for div clock of I2C controller
- * @fast_clk: clock reference for fast clock of I2C controller
+ * @clocks: array of I2C controller clocks
+ * @nclocks: number of clocks in the array
  * @rst: reset control for the I2C controller
  * @base: ioremapped registers cookie
  * @base_phys: physical base address of the I2C controller
@@ -265,8 +262,8 @@ struct tegra_i2c_dev {
 	const struct tegra_i2c_hw_feature *hw;
 	struct i2c_adapter adapter;
 	struct clk *div_clk;
-	struct clk *fast_clk;
-	struct clk *slow_clk;
+	struct clk_bulk_data *clocks;
+	unsigned int nclocks;
 	struct reset_control *rst;
 	void __iomem *base;
 	phys_addr_t base_phys;
@@ -662,25 +659,9 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 	if (ret)
 		return ret;
 
-	ret = clk_enable(i2c_dev->fast_clk);
-	if (ret < 0) {
-		dev_err(i2c_dev->dev,
-			"Enabling fast clk failed, err %d\n", ret);
+	ret = clk_bulk_enable(i2c_dev->nclocks, i2c_dev->clocks);
+	if (ret)
 		return ret;
-	}
-
-	ret = clk_enable(i2c_dev->slow_clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to enable slow clock: %d\n", ret);
-		goto disable_fast_clk;
-	}
-
-	ret = clk_enable(i2c_dev->div_clk);
-	if (ret < 0) {
-		dev_err(i2c_dev->dev,
-			"Enabling div clk failed, err %d\n", ret);
-		goto disable_slow_clk;
-	}
 
 	/*
 	 * VI I2C device is attached to VE power domain which goes through
@@ -691,17 +672,14 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 	if (i2c_dev->is_vi) {
 		ret = tegra_i2c_init(i2c_dev);
 		if (ret)
-			goto disable_div_clk;
+			goto disable_clocks;
 	}
 
 	return 0;
 
-disable_div_clk:
-	clk_disable(i2c_dev->div_clk);
-disable_slow_clk:
-	clk_disable(i2c_dev->slow_clk);
-disable_fast_clk:
-	clk_disable(i2c_dev->fast_clk);
+disable_clocks:
+	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
+
 	return ret;
 }
 
@@ -709,9 +687,7 @@ static int __maybe_unused tegra_i2c_runtime_suspend(struct device *dev)
 {
 	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
 
-	clk_disable(i2c_dev->div_clk);
-	clk_disable(i2c_dev->slow_clk);
-	clk_disable(i2c_dev->fast_clk);
+	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
 
 	return pinctrl_pm_select_idle_state(i2c_dev->dev);
 }
@@ -1467,7 +1443,6 @@ static struct i2c_bus_recovery_info tegra_i2c_recovery_info = {
 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
 	.has_continue_xfer_support = false,
 	.has_per_pkt_xfer_complete_irq = false,
-	.has_single_clk_source = false,
 	.clk_divisor_hs_mode = 3,
 	.clk_divisor_std_mode = 0,
 	.clk_divisor_fast_mode = 0,
@@ -1492,7 +1467,6 @@ static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
 static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
 	.has_continue_xfer_support = true,
 	.has_per_pkt_xfer_complete_irq = false,
-	.has_single_clk_source = false,
 	.clk_divisor_hs_mode = 3,
 	.clk_divisor_std_mode = 0,
 	.clk_divisor_fast_mode = 0,
@@ -1517,7 +1491,6 @@ static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
 static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
 	.has_continue_xfer_support = true,
 	.has_per_pkt_xfer_complete_irq = true,
-	.has_single_clk_source = true,
 	.clk_divisor_hs_mode = 1,
 	.clk_divisor_std_mode = 0x19,
 	.clk_divisor_fast_mode = 0x19,
@@ -1542,7 +1515,6 @@ static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
 static const struct tegra_i2c_hw_feature tegra124_i2c_hw = {
 	.has_continue_xfer_support = true,
 	.has_per_pkt_xfer_complete_irq = true,
-	.has_single_clk_source = true,
 	.clk_divisor_hs_mode = 1,
 	.clk_divisor_std_mode = 0x19,
 	.clk_divisor_fast_mode = 0x19,
@@ -1567,7 +1539,6 @@ static const struct tegra_i2c_hw_feature tegra124_i2c_hw = {
 static const struct tegra_i2c_hw_feature tegra210_i2c_hw = {
 	.has_continue_xfer_support = true,
 	.has_per_pkt_xfer_complete_irq = true,
-	.has_single_clk_source = true,
 	.clk_divisor_hs_mode = 1,
 	.clk_divisor_std_mode = 0x19,
 	.clk_divisor_fast_mode = 0x19,
@@ -1592,7 +1563,6 @@ static const struct tegra_i2c_hw_feature tegra210_i2c_hw = {
 static const struct tegra_i2c_hw_feature tegra186_i2c_hw = {
 	.has_continue_xfer_support = true,
 	.has_per_pkt_xfer_complete_irq = true,
-	.has_single_clk_source = true,
 	.clk_divisor_hs_mode = 1,
 	.clk_divisor_std_mode = 0x16,
 	.clk_divisor_fast_mode = 0x19,
@@ -1617,7 +1587,6 @@ static const struct tegra_i2c_hw_feature tegra186_i2c_hw = {
 static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
 	.has_continue_xfer_support = true,
 	.has_per_pkt_xfer_complete_irq = true,
-	.has_single_clk_source = true,
 	.clk_divisor_hs_mode = 1,
 	.clk_divisor_std_mode = 0x4f,
 	.clk_divisor_fast_mode = 0x3c,
@@ -1654,13 +1623,58 @@ static const struct of_device_id tegra_i2c_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
 
+static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev)
+{
+	unsigned int i;
+	int err;
+
+	err = devm_clk_bulk_get_all(i2c_dev->dev, &i2c_dev->clocks);
+	if (err < 0)
+		return err;
+
+	i2c_dev->nclocks = err;
+
+	err = clk_bulk_prepare(i2c_dev->nclocks, i2c_dev->clocks);
+	if (err)
+		return err;
+
+	for (i = 0; i < i2c_dev->nclocks; i++) {
+		if (!strcmp(i2c_dev->clocks[i].id, "div-clk")) {
+			i2c_dev->div_clk = i2c_dev->clocks[i].clk;
+			break;
+		}
+	}
+
+	if (!i2c_dev->is_multimaster_mode)
+		return 0;
+
+	err = clk_enable(i2c_dev->div_clk);
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to enable div-clk: %d\n", err);
+		goto unprepare_clocks;
+	}
+
+	return 0;
+
+unprepare_clocks:
+	clk_bulk_unprepare(i2c_dev->nclocks, i2c_dev->clocks);
+
+	return err;
+}
+
+static void tegra_i2c_release_clocks(struct tegra_i2c_dev *i2c_dev)
+{
+	if (i2c_dev->is_multimaster_mode)
+		clk_disable(i2c_dev->div_clk);
+
+	clk_bulk_unprepare(i2c_dev->nclocks, i2c_dev->clocks);
+}
+
 static int tegra_i2c_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct tegra_i2c_dev *i2c_dev;
 	struct resource *res;
-	struct clk *div_clk;
-	struct clk *fast_clk;
 	void __iomem *base;
 	phys_addr_t base_phys;
 	int irq;
@@ -1676,21 +1690,12 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	if (irq < 0)
 		return irq;
 
-	div_clk = devm_clk_get(&pdev->dev, "div-clk");
-	if (IS_ERR(div_clk)) {
-		if (PTR_ERR(div_clk) != -EPROBE_DEFER)
-			dev_err(&pdev->dev, "missing controller clock\n");
-
-		return PTR_ERR(div_clk);
-	}
-
 	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
 	if (!i2c_dev)
 		return -ENOMEM;
 
 	i2c_dev->base = base;
 	i2c_dev->base_phys = base_phys;
-	i2c_dev->div_clk = div_clk;
 	i2c_dev->adapter.algo = &tegra_i2c_algo;
 	i2c_dev->adapter.retries = 1;
 	i2c_dev->adapter.timeout = 6 * HZ;
@@ -1706,6 +1711,10 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 
 	tegra_i2c_parse_dt(i2c_dev);
 
+	ret = tegra_i2c_init_clocks(i2c_dev);
+	if (ret)
+		return ret;
+
 	i2c_dev->hw = of_device_get_match_data(&pdev->dev);
 	i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
 						  "nvidia,tegra20-i2c-dvc");
@@ -1717,46 +1726,8 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	init_completion(&i2c_dev->msg_complete);
 	init_completion(&i2c_dev->dma_complete);
 
-	if (!i2c_dev->hw->has_single_clk_source) {
-		fast_clk = devm_clk_get(&pdev->dev, "fast-clk");
-		if (IS_ERR(fast_clk)) {
-			dev_err(&pdev->dev, "missing fast clock\n");
-			return PTR_ERR(fast_clk);
-		}
-		i2c_dev->fast_clk = fast_clk;
-	}
-
-	if (i2c_dev->is_vi) {
-		i2c_dev->slow_clk = devm_clk_get(dev, "slow");
-		if (IS_ERR(i2c_dev->slow_clk)) {
-			if (PTR_ERR(i2c_dev->slow_clk) != -EPROBE_DEFER)
-				dev_err(dev, "failed to get slow clock: %ld\n",
-					PTR_ERR(i2c_dev->slow_clk));
-
-			return PTR_ERR(i2c_dev->slow_clk);
-		}
-	}
-
 	platform_set_drvdata(pdev, i2c_dev);
 
-	ret = clk_prepare(i2c_dev->fast_clk);
-	if (ret < 0) {
-		dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
-		return ret;
-	}
-
-	ret = clk_prepare(i2c_dev->slow_clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to prepare slow clock: %d\n", ret);
-		goto unprepare_fast_clk;
-	}
-
-	ret = clk_prepare(i2c_dev->div_clk);
-	if (ret < 0) {
-		dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
-		goto unprepare_slow_clk;
-	}
-
 	/*
 	 * VI I2C is in VE power domain which is not always on and not
 	 * an IRQ safe. So, IRQ safe device can't be attached to a non-IRQ
@@ -1773,21 +1744,12 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 		goto disable_rpm;
 	}
 
-	if (i2c_dev->is_multimaster_mode) {
-		ret = clk_enable(i2c_dev->div_clk);
-		if (ret < 0) {
-			dev_err(i2c_dev->dev, "div_clk enable failed %d\n",
-				ret);
-			goto put_rpm;
-		}
-	}
-
 	if (i2c_dev->hw->supports_bus_clear)
 		i2c_dev->adapter.bus_recovery_info = &tegra_i2c_recovery_info;
 
 	ret = tegra_i2c_init_dma(i2c_dev);
 	if (ret < 0)
-		goto disable_div_clk;
+		goto put_rpm;
 
 	ret = tegra_i2c_init(i2c_dev);
 	if (ret) {
@@ -1822,22 +1784,12 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 release_dma:
 	tegra_i2c_release_dma(i2c_dev);
 
-disable_div_clk:
-	if (i2c_dev->is_multimaster_mode)
-		clk_disable(i2c_dev->div_clk);
-
 put_rpm:
 	pm_runtime_put_sync(&pdev->dev);
 
 disable_rpm:
 	pm_runtime_disable(&pdev->dev);
-	clk_unprepare(i2c_dev->div_clk);
-
-unprepare_slow_clk:
-	clk_unprepare(i2c_dev->slow_clk);
-
-unprepare_fast_clk:
-	clk_unprepare(i2c_dev->fast_clk);
+	tegra_i2c_release_clocks(i2c_dev);
 
 	return ret;
 }
@@ -1848,16 +1800,10 @@ static int tegra_i2c_remove(struct platform_device *pdev)
 
 	i2c_del_adapter(&i2c_dev->adapter);
 
-	if (i2c_dev->is_multimaster_mode)
-		clk_disable(i2c_dev->div_clk);
-
 	pm_runtime_disable(&pdev->dev);
 
-	clk_unprepare(i2c_dev->div_clk);
-	clk_unprepare(i2c_dev->slow_clk);
-	clk_unprepare(i2c_dev->fast_clk);
-
 	tegra_i2c_release_dma(i2c_dev);
+	tegra_i2c_release_clocks(i2c_dev);
 	return 0;
 }
 
-- 
2.27.0

Re: [PATCH v4 10/31] i2c: tegra: Use clk-bulk helpers

[Michał Mirosław]

On Sat, Sep 05, 2020 at 11:41:30PM +0300, Dmitry Osipenko wrote:
> Use clk-bulk helpers and factor out clocks initialization into separate
> function in order to make code cleaner.
[...]
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
[...]
>  static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
>  	.has_continue_xfer_support = true,
>  	.has_per_pkt_xfer_complete_irq = true,
> -	.has_single_clk_source = true,
>  	.clk_divisor_hs_mode = 1,
>  	.clk_divisor_std_mode = 0x4f,
>  	.clk_divisor_fast_mode = 0x3c,
[...]
> +static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev)
> +{
> +	unsigned int i;
> +	int err;
> +
> +	err = devm_clk_bulk_get_all(i2c_dev->dev, &i2c_dev->clocks);
> +	if (err < 0)
> +		return err;
> +
> +	i2c_dev->nclocks = err
[...]

You loose checking whether number of clocks matches the device version.
Is this intended?

Best Regards,
Michał Mirosław

Re: [PATCH v4 10/31] i2c: tegra: Use clk-bulk helpers

[Dmitry Osipenko]

06.09.2020 00:56, Michał Mirosław пишет:
> On Sat, Sep 05, 2020 at 11:41:30PM +0300, Dmitry Osipenko wrote:
>> Use clk-bulk helpers and factor out clocks initialization into separate
>> function in order to make code cleaner.
> [...]
>> --- a/drivers/i2c/busses/i2c-tegra.c
>> +++ b/drivers/i2c/busses/i2c-tegra.c
> [...]
>>  static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
>>  	.has_continue_xfer_support = true,
>>  	.has_per_pkt_xfer_complete_irq = true,
>> -	.has_single_clk_source = true,
>>  	.clk_divisor_hs_mode = 1,
>>  	.clk_divisor_std_mode = 0x4f,
>>  	.clk_divisor_fast_mode = 0x3c,
> [...]
>> +static int tegra_i2c_init_clocks(struct tegra_i2c_dev *i2c_dev)
>> +{
>> +	unsigned int i;
>> +	int err;
>> +
>> +	err = devm_clk_bulk_get_all(i2c_dev->dev, &i2c_dev->clocks);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	i2c_dev->nclocks = err
> [...]
> 
> You loose checking whether number of clocks matches the device version.
> Is this intended?

Yes, it's not needed. The check wasn't really needed in the first place.

[PATCH v4 11/31] i2c: tegra: Factor out runtime PM and hardware initialization

[Dmitry Osipenko]

Factor out runtime PM and hardware initialization into separate function
in order have a cleaner error unwinding in the probe function.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 68 +++++++++++++++++++---------------
 1 file changed, 38 insertions(+), 30 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 8e4e72dec6ea..6e5af03d0b1d 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1670,6 +1670,37 @@ static void tegra_i2c_release_clocks(struct tegra_i2c_dev *i2c_dev)
 	clk_bulk_unprepare(i2c_dev->nclocks, i2c_dev->clocks);
 }
 
+static int tegra_i2c_init_runtime_pm_and_hardware(struct tegra_i2c_dev *i2c_dev)
+{
+	int ret;
+
+	/*
+	 * VI I2C is in VE power domain which is not always on and not
+	 * an IRQ safe. So, IRQ safe device can't be attached to a non-IRQ
+	 * safe domain as it prevents powering off the PM domain.
+	 * Also, VI I2C device don't need to use runtime IRQ safe as it will
+	 * not be used for atomic transfers.
+	 */
+	if (!i2c_dev->is_vi)
+		pm_runtime_irq_safe(i2c_dev->dev);
+
+	pm_runtime_enable(i2c_dev->dev);
+
+	ret = pm_runtime_get_sync(i2c_dev->dev);
+	if (ret < 0) {
+		dev_err(i2c_dev->dev, "runtime resume failed: %d\n", ret);
+		pm_runtime_disable(i2c_dev->dev);
+		return ret;
+	}
+
+	/* initialize hardware state */
+	ret = tegra_i2c_init(i2c_dev);
+
+	pm_runtime_put(i2c_dev->dev);
+
+	return ret;
+}
+
 static int tegra_i2c_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -1728,41 +1759,23 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, i2c_dev);
 
-	/*
-	 * VI I2C is in VE power domain which is not always on and not
-	 * an IRQ safe. So, IRQ safe device can't be attached to a non-IRQ
-	 * safe domain as it prevents powering off the PM domain.
-	 * Also, VI I2C device don't need to use runtime IRQ safe as it will
-	 * not be used for atomic transfers.
-	 */
-	if (!i2c_dev->is_vi)
-		pm_runtime_irq_safe(&pdev->dev);
-	pm_runtime_enable(&pdev->dev);
-	ret = pm_runtime_get_sync(i2c_dev->dev);
-	if (ret < 0) {
-		dev_err(dev, "runtime resume failed\n");
-		goto disable_rpm;
-	}
-
 	if (i2c_dev->hw->supports_bus_clear)
 		i2c_dev->adapter.bus_recovery_info = &tegra_i2c_recovery_info;
 
 	ret = tegra_i2c_init_dma(i2c_dev);
 	if (ret < 0)
-		goto put_rpm;
+		goto release_clocks;
 
-	ret = tegra_i2c_init(i2c_dev);
-	if (ret) {
-		dev_err(&pdev->dev, "Failed to initialize i2c controller\n");
+	ret = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
+	if (ret)
 		goto release_dma;
-	}
 
 	irq_set_status_flags(i2c_dev->irq, IRQ_NOAUTOEN);
 
 	ret = devm_request_irq(&pdev->dev, i2c_dev->irq, tegra_i2c_isr,
 			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c_dev);
 	if (ret)
-		goto release_dma;
+		goto release_rpm;
 
 	i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
 	i2c_dev->adapter.owner = THIS_MODULE;
@@ -1777,18 +1790,13 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 	if (ret)
 		goto release_dma;
 
-	pm_runtime_put(&pdev->dev);
-
 	return 0;
 
+release_rpm:
+	pm_runtime_disable(i2c_dev->dev);
 release_dma:
 	tegra_i2c_release_dma(i2c_dev);
-
-put_rpm:
-	pm_runtime_put_sync(&pdev->dev);
-
-disable_rpm:
-	pm_runtime_disable(&pdev->dev);
+release_clocks:
 	tegra_i2c_release_clocks(i2c_dev);
 
 	return ret;
-- 
2.27.0

Re: [PATCH v4 11/31] i2c: tegra: Factor out runtime PM and hardware initialization

[Michał Mirosław]

On Sat, Sep 05, 2020 at 11:41:31PM +0300, Dmitry Osipenko wrote:
> Factor out runtime PM and hardware initialization into separate function
> in order have a cleaner error unwinding in the probe function.
[...]
> +	ret = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
[...]

This one doesn't improve the code for me. The problems are: 1) putting two
unrelated parts in one function, 2) silently reordered initialization.

Best Regards,
Michał Mirosław

Re: [PATCH v4 11/31] i2c: tegra: Factor out runtime PM and hardware initialization

[Dmitry Osipenko]

06.09.2020 01:10, Michał Mirosław пишет:
> On Sat, Sep 05, 2020 at 11:41:31PM +0300, Dmitry Osipenko wrote:
>> Factor out runtime PM and hardware initialization into separate function
>> in order have a cleaner error unwinding in the probe function.
> [...]
>> +	ret = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
> [...]
> 
> This one doesn't improve the code for me. The problems are: 1) putting two
> unrelated parts in one function, 2) silently reordered initialization.

The hardware initialization depends on the resumed RPM and the rest of
the probe function doesn't care about the RPM. I don't quite understand
why you're saying that they are unrelated, could you please explain?

The DMA/RPM initialization is intentionally reordered in order to clean
up the error handling, like the commit message says. To me it's a clear
improvement :)

Re: [PATCH v4 11/31] i2c: tegra: Factor out runtime PM and hardware initialization

[Michał Mirosław]

On Sun, Sep 06, 2020 at 01:24:14AM +0300, Dmitry Osipenko wrote:
> 06.09.2020 01:10, Michał Mirosław пишет:
> > On Sat, Sep 05, 2020 at 11:41:31PM +0300, Dmitry Osipenko wrote:
> >> Factor out runtime PM and hardware initialization into separate function
> >> in order have a cleaner error unwinding in the probe function.
> > [...]
> >> +	ret = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
> > [...]
> > 
> > This one doesn't improve the code for me. The problems are: 1) putting two
> > unrelated parts in one function, 2) silently reordered initialization.
> 
> The hardware initialization depends on the resumed RPM and the rest of
> the probe function doesn't care about the RPM. I don't quite understand
> why you're saying that they are unrelated, could you please explain?
> 
> The DMA/RPM initialization is intentionally reordered in order to clean
> up the error handling, like the commit message says. To me it's a clear
> improvement :)

Ok, then wouldn't it be enough to just move this part in the probe()?
A sign of a problem for me is how much information you had to put in
the name of the new function.

Best Regards,
Michał Mirosław

Re: [PATCH v4 11/31] i2c: tegra: Factor out runtime PM and hardware initialization

[Dmitry Osipenko]

06.09.2020 01:51, Michał Mirosław пишет:
> On Sun, Sep 06, 2020 at 01:24:14AM +0300, Dmitry Osipenko wrote:
>> 06.09.2020 01:10, Michał Mirosław пишет:
>>> On Sat, Sep 05, 2020 at 11:41:31PM +0300, Dmitry Osipenko wrote:
>>>> Factor out runtime PM and hardware initialization into separate function
>>>> in order have a cleaner error unwinding in the probe function.
>>> [...]
>>>> +	ret = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
>>> [...]
>>>
>>> This one doesn't improve the code for me. The problems are: 1) putting two
>>> unrelated parts in one function, 2) silently reordered initialization.
>>
>> The hardware initialization depends on the resumed RPM and the rest of
>> the probe function doesn't care about the RPM. I don't quite understand
>> why you're saying that they are unrelated, could you please explain?
>>
>> The DMA/RPM initialization is intentionally reordered in order to clean
>> up the error handling, like the commit message says. To me it's a clear
>> improvement :)
> 
> Ok, then wouldn't it be enough to just move this part in the probe()?
> A sign of a problem for me is how much information you had to put in
> the name of the new function.

Looking at it again now, I think you're right. I also now noticed that
the RPM isn't disabled now if tegra_i2c_init() fails.

I'll try to take another look, but probably will lean to yours variant
in the v5. Thanks!

[PATCH v4 12/31] i2c: tegra: Move out all device-tree parsing into tegra_i2c_parse_dt()

[Dmitry Osipenko]

Move out code related to device-tree parsing from the probe function into
tegra_i2c_parse_dt() in order to make code more consistent.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6e5af03d0b1d..d6bc23bf765e 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1416,6 +1416,12 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
 
 	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 = {
@@ -1703,7 +1709,6 @@ static int tegra_i2c_init_runtime_pm_and_hardware(struct tegra_i2c_dev *i2c_dev)
 
 static int tegra_i2c_probe(struct platform_device *pdev)
 {
-	struct device *dev = &pdev->dev;
 	struct tegra_i2c_dev *i2c_dev;
 	struct resource *res;
 	void __iomem *base;
@@ -1747,10 +1752,6 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 		return ret;
 
 	i2c_dev->hw = of_device_get_match_data(&pdev->dev);
-	i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
-						  "nvidia,tegra20-i2c-dvc");
-	i2c_dev->is_vi = of_device_is_compatible(dev->of_node,
-						 "nvidia,tegra210-i2c-vi");
 	i2c_dev->adapter.quirks = i2c_dev->hw->quirks;
 	i2c_dev->dma_buf_size = i2c_dev->adapter.quirks->max_write_len +
 				I2C_PACKET_HEADER_SIZE;
-- 
2.27.0

[PATCH v4 13/31] i2c: tegra: Clean up probe function

[Dmitry Osipenko]

The driver's probe function code is a bit difficult to read. This patch
reorders code of the probe function, forming groups of code that are easy
to work with. The reset_control_get() now may return -EPROBE_DEFER on
newer Tegra SoCs because they use BPMP driver that provides reset controls
and BPMP doesn't come up early during boot, previously rst was protected
by other checks error checks in the code, hence dev_err_probe() is used
now for the rst.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 120 +++++++++++++++++----------------
 1 file changed, 63 insertions(+), 57 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index d6bc23bf765e..d8b7373673ea 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -440,6 +440,9 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 
 	i2c_dev->tx_dma_chan = chan;
 
+	i2c_dev->dma_buf_size = i2c_dev->hw->quirks->max_write_len +
+				I2C_PACKET_HEADER_SIZE;
+
 	dma_buf = dma_alloc_coherent(i2c_dev->dev, i2c_dev->dma_buf_size,
 				     &dma_phys, GFP_KERNEL | __GFP_NOWARN);
 	if (!dma_buf) {
@@ -1711,85 +1714,88 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 {
 	struct tegra_i2c_dev *i2c_dev;
 	struct resource *res;
-	void __iomem *base;
-	phys_addr_t base_phys;
-	int irq;
-	int ret;
-
-	base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
-
-	base_phys = res->start;
-
-	irq = platform_get_irq(pdev, 0);
-	if (irq < 0)
-		return irq;
+	int err;
 
 	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
 	if (!i2c_dev)
 		return -ENOMEM;
 
-	i2c_dev->base = base;
-	i2c_dev->base_phys = base_phys;
-	i2c_dev->adapter.algo = &tegra_i2c_algo;
-	i2c_dev->adapter.retries = 1;
-	i2c_dev->adapter.timeout = 6 * HZ;
-	i2c_dev->irq = irq;
+	platform_set_drvdata(pdev, i2c_dev);
+
+	init_completion(&i2c_dev->msg_complete);
+	init_completion(&i2c_dev->dma_complete);
+
+	i2c_dev->hw = of_device_get_match_data(&pdev->dev);
 	i2c_dev->cont_id = pdev->id;
 	i2c_dev->dev = &pdev->dev;
 
-	i2c_dev->rst = devm_reset_control_get_exclusive(&pdev->dev, "i2c");
+	/* initialize virt base of hardware registers */
+	i2c_dev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(i2c_dev->base))
+		return PTR_ERR(i2c_dev->base);
+
+	/* initialize phys base of hardware registers */
+	i2c_dev->base_phys = res->start;
+
+	/* initialize controller's interrupt */
+	err = platform_get_irq(pdev, 0);
+	if (err < 0)
+		return err;
+
+	i2c_dev->irq = err;
+
+	/* interrupt will be enabled during of transfer time */
+	irq_set_status_flags(i2c_dev->irq, IRQ_NOAUTOEN);
+
+	err = devm_request_irq(i2c_dev->dev, i2c_dev->irq, tegra_i2c_isr,
+			       IRQF_NO_SUSPEND, dev_name(i2c_dev->dev),
+			       i2c_dev);
+	if (err)
+		return err;
+
+	/* initialize hardware reset control */
+	i2c_dev->rst = devm_reset_control_get_exclusive(i2c_dev->dev, "i2c");
 	if (IS_ERR(i2c_dev->rst)) {
-		dev_err(&pdev->dev, "missing controller reset\n");
+		dev_err_probe(i2c_dev->dev, PTR_ERR(i2c_dev->rst),
+			      "failed to get reset control\n");
 		return PTR_ERR(i2c_dev->rst);
 	}
 
 	tegra_i2c_parse_dt(i2c_dev);
 
-	ret = tegra_i2c_init_clocks(i2c_dev);
-	if (ret)
-		return ret;
-
-	i2c_dev->hw = of_device_get_match_data(&pdev->dev);
-	i2c_dev->adapter.quirks = i2c_dev->hw->quirks;
-	i2c_dev->dma_buf_size = i2c_dev->adapter.quirks->max_write_len +
-				I2C_PACKET_HEADER_SIZE;
-	init_completion(&i2c_dev->msg_complete);
-	init_completion(&i2c_dev->dma_complete);
-
-	platform_set_drvdata(pdev, i2c_dev);
-
-	if (i2c_dev->hw->supports_bus_clear)
-		i2c_dev->adapter.bus_recovery_info = &tegra_i2c_recovery_info;
+	err = tegra_i2c_init_clocks(i2c_dev);
+	if (err)
+		return err;
 
-	ret = tegra_i2c_init_dma(i2c_dev);
-	if (ret < 0)
+	err = tegra_i2c_init_dma(i2c_dev);
+	if (err)
 		goto release_clocks;
 
-	ret = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
-	if (ret)
+	err = tegra_i2c_init_runtime_pm_and_hardware(i2c_dev);
+	if (err)
 		goto release_dma;
 
-	irq_set_status_flags(i2c_dev->irq, IRQ_NOAUTOEN);
-
-	ret = devm_request_irq(&pdev->dev, i2c_dev->irq, tegra_i2c_isr,
-			       IRQF_NO_SUSPEND, dev_name(&pdev->dev), i2c_dev);
-	if (ret)
-		goto release_rpm;
-
-	i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
+	i2c_dev->adapter.dev.of_node = i2c_dev->dev->of_node;
+	i2c_dev->adapter.dev.parent = i2c_dev->dev;
+	i2c_dev->adapter.retries = 1;
+	i2c_dev->adapter.timeout = 6 * HZ;
+	i2c_dev->adapter.quirks = i2c_dev->hw->quirks;
 	i2c_dev->adapter.owner = THIS_MODULE;
 	i2c_dev->adapter.class = I2C_CLASS_DEPRECATED;
-	strlcpy(i2c_dev->adapter.name, dev_name(&pdev->dev),
+	i2c_dev->adapter.algo = &tegra_i2c_algo;
+	i2c_dev->adapter.nr = i2c_dev->cont_id;
+
+	if (i2c_dev->hw->supports_bus_clear)
+		i2c_dev->adapter.bus_recovery_info = &tegra_i2c_recovery_info;
+
+	strlcpy(i2c_dev->adapter.name, dev_name(i2c_dev->dev),
 		sizeof(i2c_dev->adapter.name));
-	i2c_dev->adapter.dev.parent = &pdev->dev;
-	i2c_dev->adapter.nr = pdev->id;
-	i2c_dev->adapter.dev.of_node = pdev->dev.of_node;
 
-	ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
-	if (ret)
-		goto release_dma;
+	i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
+
+	err = i2c_add_numbered_adapter(&i2c_dev->adapter);
+	if (err)
+		goto release_rpm;
 
 	return 0;
 
@@ -1800,7 +1806,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
 release_clocks:
 	tegra_i2c_release_clocks(i2c_dev);
 
-	return ret;
+	return err;
 }
 
 static int tegra_i2c_remove(struct platform_device *pdev)
-- 
2.27.0

[PATCH v4 14/31] i2c: tegra: Remove likely/unlikely from the code

[Dmitry Osipenko]

The likely/unlikely annotations should be used only in a hot paths of
performance-critical code. The I2C driver doesn't have such paths, and
thus, there is no justification for usage of likely/unlikely annotations
in the code. Hence remove them.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index d8b7373673ea..33d37a40fa83 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -890,7 +890,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 		goto err;
 	}
 
-	if (unlikely(status & status_err)) {
+	if (status & status_err) {
 		tegra_i2c_disable_packet_mode(i2c_dev);
 		if (status & I2C_INT_NO_ACK)
 			i2c_dev->msg_err |= I2C_ERR_NO_ACK;
@@ -1330,7 +1330,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		i2c_dev->msg_err);
 
 	i2c_dev->is_curr_dma_xfer = false;
-	if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
+	if (i2c_dev->msg_err == I2C_ERR_NONE)
 		return 0;
 
 	tegra_i2c_init(i2c_dev);
-- 
2.27.0

[PATCH v4 15/31] i2c: tegra: Remove bogus barrier()

[Dmitry Osipenko]

Apparently barrier() was intended to reduce possibility of racing
with the interrupt handler, but driver's code evolved significantly
and today's driver enables interrupt only when it waits for completion
notification. Hence barrier() has no good use anymore, let's remove it.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 33d37a40fa83..f69587ca163b 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -600,7 +600,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		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);
 
@@ -624,7 +623,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		/* 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);
 	}
-- 
2.27.0

Re: [PATCH v4 15/31] i2c: tegra: Remove bogus barrier()

[Dmitry Osipenko]

05.09.2020 23:41, Dmitry Osipenko пишет:
> Apparently barrier() was intended to reduce possibility of racing
> with the interrupt handler, but driver's code evolved significantly
> and today's driver enables interrupt only when it waits for completion
> notification. Hence barrier() has no good use anymore, let's remove it.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 33d37a40fa83..f69587ca163b 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -600,7 +600,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
>  		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);
>  
> @@ -624,7 +623,6 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
>  		/* 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);
>  	}
> 

It just caught my eye that there is actually a comment there saying that
barrier() was intended to mitigate the racing with the ISR. Hence that
comment is outdated now and needs to be removed. I'll correct it in v5.

[PATCH v4 16/31] i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg()

[Dmitry Osipenko]

The "dma" variable of tegra_i2c_xfer_msg() function doesn't bring much in
regards to readability and generation of the code, hence let's remove it
to clean up code a tad.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index f69587ca163b..f52046593b8b 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1155,7 +1155,6 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	size_t xfer_size;
 	u32 *buffer = NULL;
 	int err = 0;
-	bool dma;
 	u16 xfer_time = 100;
 
 	err = tegra_i2c_flush_fifos(i2c_dev);
@@ -1178,7 +1177,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 				    i2c_dev->dma_buf &&
 				    !i2c_dev->is_curr_atomic_xfer;
 	tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
-	dma = i2c_dev->is_curr_dma_xfer;
+
 	/*
 	 * Transfer time in mSec = Total bits / transfer rate
 	 * Total bits = 9 bits per byte (including ACK bit) + Start & stop bits
@@ -1188,7 +1187,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 	tegra_i2c_unmask_irq(i2c_dev, int_mask);
-	if (dma) {
+	if (i2c_dev->is_curr_dma_xfer) {
 		if (i2c_dev->msg_read) {
 			dma_sync_single_for_device(i2c_dev->dev,
 						   i2c_dev->dma_phys,
@@ -1216,13 +1215,13 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 				   PACKET_HEADER0_PROTOCOL_I2C) |
 			FIELD_PREP(PACKET_HEADER0_CONT_ID, i2c_dev->cont_id) |
 			FIELD_PREP(PACKET_HEADER0_PACKET_ID, 1);
-	if (dma && !i2c_dev->msg_read)
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
 		*buffer++ = packet_header;
 	else
 		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 
 	packet_header = msg->len - 1;
-	if (dma && !i2c_dev->msg_read)
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
 		*buffer++ = packet_header;
 	else
 		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
@@ -1242,13 +1241,13 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		packet_header |= I2C_HEADER_CONT_ON_NAK;
 	if (msg->flags & I2C_M_RD)
 		packet_header |= I2C_HEADER_READ;
-	if (dma && !i2c_dev->msg_read)
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
 		*buffer++ = packet_header;
 	else
 		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 
 	if (!i2c_dev->msg_read) {
-		if (dma) {
+		if (i2c_dev->is_curr_dma_xfer) {
 			memcpy(buffer, msg->buf, msg->len);
 			dma_sync_single_for_device(i2c_dev->dev,
 						   i2c_dev->dma_phys,
@@ -1268,7 +1267,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
 		int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
-	if (!dma) {
+	if (!i2c_dev->is_curr_dma_xfer) {
 		if (msg->flags & I2C_M_RD)
 			int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
 		else if (i2c_dev->msg_buf_remaining)
@@ -1279,7 +1278,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
 		i2c_readl(i2c_dev, I2C_INT_MASK));
 
-	if (dma) {
+	if (i2c_dev->is_curr_dma_xfer) {
 		time_left = tegra_i2c_wait_completion_timeout(
 				i2c_dev, &i2c_dev->dma_complete, xfer_time);
 
-- 
2.27.0

Re: [PATCH v4 16/31] i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg()

[Michał Mirosław]

On Sat, Sep 05, 2020 at 11:41:36PM +0300, Dmitry Osipenko wrote:
> The "dma" variable of tegra_i2c_xfer_msg() function doesn't bring much in
> regards to readability and generation of the code, hence let's remove it
> to clean up code a tad.
[...]
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
[...]
> +	if (i2c_dev->is_curr_dma_xfer) {
[...]

In this case I like the previous code better: just because there are
less letters to read. :-)

Best Regards,
Michał Mirosław

Re: [PATCH v4 16/31] i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg()

[Dmitry Osipenko]

06.09.2020 01:23, Michał Mirosław пишет:
> On Sat, Sep 05, 2020 at 11:41:36PM +0300, Dmitry Osipenko wrote:
>> The "dma" variable of tegra_i2c_xfer_msg() function doesn't bring much in
>> regards to readability and generation of the code, hence let's remove it
>> to clean up code a tad.
> [...]
>> --- a/drivers/i2c/busses/i2c-tegra.c
>> +++ b/drivers/i2c/busses/i2c-tegra.c
> [...]
>> +	if (i2c_dev->is_curr_dma_xfer) {
> [...]
> 
> In this case I like the previous code better: just because there are
> less letters to read. :-)

Besides readability, I also don't like much that the is_curr_dma_xfer is
initialized in tegra_i2c_xfer_msg() and then could be overridden by
tegra_i2c_config_fifo_trig(). In a result the "dma" variable confuses me
since it's not instantly obvious why it's set after
tegra_i2c_config_fifo_trig().

Looking at the final result, I think it's better to have the variable
removed. It makes code more consistent, IMO.

Re: [PATCH v4 16/31] i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg()

[Michał Mirosław]

On Sun, Sep 06, 2020 at 01:36:20AM +0300, Dmitry Osipenko wrote:
> 06.09.2020 01:23, Michał Mirosław пишет:
> > On Sat, Sep 05, 2020 at 11:41:36PM +0300, Dmitry Osipenko wrote:
> >> The "dma" variable of tegra_i2c_xfer_msg() function doesn't bring much in
> >> regards to readability and generation of the code, hence let's remove it
> >> to clean up code a tad.
> > [...]
> >> --- a/drivers/i2c/busses/i2c-tegra.c
> >> +++ b/drivers/i2c/busses/i2c-tegra.c
> > [...]
> >> +	if (i2c_dev->is_curr_dma_xfer) {
> > [...]
> > 
> > In this case I like the previous code better: just because there are
> > less letters to read. :-)
> 
> Besides readability, I also don't like much that the is_curr_dma_xfer is
> initialized in tegra_i2c_xfer_msg() and then could be overridden by
> tegra_i2c_config_fifo_trig(). In a result the "dma" variable confuses me
> since it's not instantly obvious why it's set after
> tegra_i2c_config_fifo_trig().
> 
> Looking at the final result, I think it's better to have the variable
> removed. It makes code more consistent, IMO.

If it could be changed in some callee, then indeed it is better. In this
case I would include this information in the commit msg.

Best Regards,
Michał Mirosław

Re: [PATCH v4 16/31] i2c: tegra: Remove "dma" variable from tegra_i2c_xfer_msg()

[Dmitry Osipenko]

06.09.2020 01:49, Michał Mirosław пишет:
> On Sun, Sep 06, 2020 at 01:36:20AM +0300, Dmitry Osipenko wrote:
>> 06.09.2020 01:23, Michał Mirosław пишет:
>>> On Sat, Sep 05, 2020 at 11:41:36PM +0300, Dmitry Osipenko wrote:
>>>> The "dma" variable of tegra_i2c_xfer_msg() function doesn't bring much in
>>>> regards to readability and generation of the code, hence let's remove it
>>>> to clean up code a tad.
>>> [...]
>>>> --- a/drivers/i2c/busses/i2c-tegra.c
>>>> +++ b/drivers/i2c/busses/i2c-tegra.c
>>> [...]
>>>> +	if (i2c_dev->is_curr_dma_xfer) {
>>> [...]
>>>
>>> In this case I like the previous code better: just because there are
>>> less letters to read. :-)
>>
>> Besides readability, I also don't like much that the is_curr_dma_xfer is
>> initialized in tegra_i2c_xfer_msg() and then could be overridden by
>> tegra_i2c_config_fifo_trig(). In a result the "dma" variable confuses me
>> since it's not instantly obvious why it's set after
>> tegra_i2c_config_fifo_trig().
>>
>> Looking at the final result, I think it's better to have the variable
>> removed. It makes code more consistent, IMO.
> 
> If it could be changed in some callee, then indeed it is better. In this
> case I would include this information in the commit msg.

That's a good suggestion, thanks.

[PATCH v4 17/31] i2c: tegra: Improve formatting of function variables

[Dmitry Osipenko]

Reorder the definition of variables in the code in order to make code
easier to read.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 44 ++++++++++++++--------------------
 1 file changed, 18 insertions(+), 26 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index f52046593b8b..a2ae4dab8001 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -412,8 +412,8 @@ static void tegra_i2c_release_dma(struct tegra_i2c_dev *i2c_dev)
 static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 {
 	struct dma_chan *chan;
-	u32 *dma_buf;
 	dma_addr_t dma_phys;
+	u32 *dma_buf;
 	int err;
 
 	if (!i2c_dev->hw->has_apb_dma || i2c_dev->is_vi)
@@ -505,11 +505,11 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 
 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 {
-	u32 val;
-	int rx_fifo_avail;
-	u8 *buf = i2c_dev->msg_buf;
 	size_t buf_remaining = i2c_dev->msg_buf_remaining;
+	u8 *buf = i2c_dev->msg_buf;
 	int words_to_transfer;
+	int rx_fifo_avail;
+	u32 val;
 
 	/*
 	 * Catch overflow due to message fully sent
@@ -566,11 +566,11 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 
 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 {
-	u32 val;
-	int tx_fifo_avail;
-	u8 *buf = i2c_dev->msg_buf;
 	size_t buf_remaining = i2c_dev->msg_buf_remaining;
+	u8 *buf = i2c_dev->msg_buf;
 	int words_to_transfer;
+	int tx_fifo_avail;
+	u32 val;
 
 	if (i2c_dev->hw->has_mst_fifo) {
 		val = i2c_readl(i2c_dev, I2C_MST_FIFO_STATUS);
@@ -755,12 +755,8 @@ static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
 
 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 {
-	u32 val;
+	u32 val, clk_divisor, clk_multiplier, tsu_thd, tlow, thigh, non_hs_mode;
 	int err;
-	u32 clk_divisor, clk_multiplier;
-	u32 non_hs_mode;
-	u32 tsu_thd;
-	u8 tlow, thigh;
 
 	err = reset_control_reset(i2c_dev->rst);
 	WARN_ON_ONCE(err);
@@ -873,9 +869,9 @@ static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
 
 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 {
-	u32 status;
 	const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 	struct tegra_i2c_dev *i2c_dev = dev_id;
+	u32 status;
 
 	status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 
@@ -979,12 +975,11 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 				       size_t len)
 {
-	u32 val, reg;
-	u8 dma_burst;
 	struct dma_slave_config slv_config = {0};
+	unsigned long reg_offset;
+	u32 val, reg, dma_burst;
 	struct dma_chan *chan;
 	int ret;
-	unsigned long reg_offset;
 
 	if (i2c_dev->hw->has_mst_fifo)
 		reg = I2C_MST_FIFO_CONTROL;
@@ -1110,9 +1105,9 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev,
 static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 {
 	struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
-	int err;
 	unsigned long time_left;
 	u32 reg;
+	int err;
 
 	reinit_completion(&i2c_dev->msg_complete);
 	reg = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND |
@@ -1149,13 +1144,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 			      struct i2c_msg *msg,
 			      enum msg_end_type end_state)
 {
-	u32 packet_header;
-	u32 int_mask;
-	unsigned long time_left;
-	size_t xfer_size;
+	unsigned long time_left, xfer_time = 100;
+	u32 packet_header, int_mask;
 	u32 *buffer = NULL;
-	int err = 0;
-	u16 xfer_time = 100;
+	size_t xfer_size;
+	int err;
 
 	err = tegra_i2c_flush_fifos(i2c_dev);
 	if (err)
@@ -1351,8 +1344,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 			  int num)
 {
 	struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
-	int i;
-	int ret;
+	int i, ret;
 
 	ret = pm_runtime_get_sync(i2c_dev->dev);
 	if (ret < 0) {
@@ -1406,8 +1398,8 @@ static u32 tegra_i2c_func(struct i2c_adapter *adap)
 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;
+	int ret;
 
 	ret = of_property_read_u32(np, "clock-frequency",
 				   &i2c_dev->bus_clk_rate);
-- 
2.27.0

[PATCH v4 18/31] i2c: tegra: Improve coding style of tegra_i2c_wait_for_config_load()

[Dmitry Osipenko]

Improve coding style of the tegra_i2c_wait_for_config_load() function by
removing need to wrap code in order make it more readable and to adhere to
the common kernel coding style.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 34 ++++++++++++++++------------------
 1 file changed, 16 insertions(+), 18 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index a2ae4dab8001..dc9948d816ac 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -700,25 +700,23 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 	u32 val;
 	int err;
 
-	if (i2c_dev->hw->has_config_load_reg) {
-		reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_CONFIG_LOAD);
-		addr = i2c_dev->base + reg_offset;
-		i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
-
-		if (i2c_dev->is_curr_atomic_xfer)
-			err = readl_relaxed_poll_timeout_atomic(
-						addr, val, val == 0, 1000,
-						I2C_CONFIG_LOAD_TIMEOUT);
-		else
-			err = readl_relaxed_poll_timeout(
-						addr, val, val == 0, 1000,
-						I2C_CONFIG_LOAD_TIMEOUT);
+	if (!i2c_dev->hw->has_config_load_reg)
+		return 0;
 
-		if (err) {
-			dev_warn(i2c_dev->dev,
-				 "timeout waiting for config load\n");
-			return err;
-		}
+	reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_CONFIG_LOAD);
+	addr = i2c_dev->base + reg_offset;
+	i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
+
+	if (i2c_dev->is_curr_atomic_xfer)
+		err = readl_relaxed_poll_timeout_atomic(addr, val, val == 0, 1000,
+							I2C_CONFIG_LOAD_TIMEOUT);
+	else
+		err = readl_relaxed_poll_timeout(addr, val, val == 0, 1000,
+						 I2C_CONFIG_LOAD_TIMEOUT);
+
+	if (err) {
+		dev_warn(i2c_dev->dev, "timeout waiting for config load\n");
+		return err;
 	}
 
 	return 0;
-- 
2.27.0

[PATCH v4 19/31] i2c: tegra: Rename wait/poll functions

[Dmitry Osipenko]

Drop '_timeout' postfix from the wait/poll completion function names in
order to make the names shorter, making code cleaner a tad.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 33 +++++++++++++++------------------
 1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index dc9948d816ac..c2ff55e8db54 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1039,10 +1039,9 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 	i2c_writel(i2c_dev, val, reg);
 }
 
-static unsigned long
-tegra_i2c_poll_completion_timeout(struct tegra_i2c_dev *i2c_dev,
-				  struct completion *complete,
-				  unsigned int timeout_ms)
+static unsigned long tegra_i2c_poll_completion(struct tegra_i2c_dev *i2c_dev,
+					       struct completion *complete,
+					       unsigned int timeout_ms)
 {
 	ktime_t ktime = ktime_get();
 	ktime_t ktimeout = ktime_add_ms(ktime, timeout_ms);
@@ -1066,16 +1065,14 @@ tegra_i2c_poll_completion_timeout(struct tegra_i2c_dev *i2c_dev,
 	return 0;
 }
 
-static unsigned long
-tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev,
-				  struct completion *complete,
-				  unsigned int timeout_ms)
+static unsigned long tegra_i2c_wait_completion(struct tegra_i2c_dev *i2c_dev,
+					       struct completion *complete,
+					       unsigned int timeout_ms)
 {
 	unsigned long ret;
 
 	if (i2c_dev->is_curr_atomic_xfer) {
-		ret = tegra_i2c_poll_completion_timeout(i2c_dev, complete,
-							timeout_ms);
+		ret = tegra_i2c_poll_completion(i2c_dev, complete, timeout_ms);
 	} else {
 		enable_irq(i2c_dev->irq);
 		ret = wait_for_completion_timeout(complete,
@@ -1093,8 +1090,7 @@ tegra_i2c_wait_completion_timeout(struct tegra_i2c_dev *i2c_dev,
 		 * needs to be checked after timeout.
 		 */
 		if (ret == 0)
-			ret = tegra_i2c_poll_completion_timeout(i2c_dev,
-								complete, 0);
+			ret = tegra_i2c_poll_completion(i2c_dev, complete, 0);
 	}
 
 	return ret;
@@ -1121,8 +1117,8 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 	i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG);
 	tegra_i2c_unmask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE);
 
-	time_left = tegra_i2c_wait_completion_timeout(
-			i2c_dev, &i2c_dev->msg_complete, 50);
+	time_left = tegra_i2c_wait_completion(i2c_dev, &i2c_dev->msg_complete,
+					      50);
 	if (time_left == 0) {
 		dev_err(i2c_dev->dev, "timed out for bus clear\n");
 		return -ETIMEDOUT;
@@ -1270,8 +1266,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		i2c_readl(i2c_dev, I2C_INT_MASK));
 
 	if (i2c_dev->is_curr_dma_xfer) {
-		time_left = tegra_i2c_wait_completion_timeout(
-				i2c_dev, &i2c_dev->dma_complete, xfer_time);
+		time_left = tegra_i2c_wait_completion(i2c_dev,
+						      &i2c_dev->dma_complete,
+						      xfer_time);
 
 		/*
 		 * Synchronize DMA first, since dmaengine_terminate_sync()
@@ -1302,8 +1299,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		}
 	}
 
-	time_left = tegra_i2c_wait_completion_timeout(
-			i2c_dev, &i2c_dev->msg_complete, xfer_time);
+	time_left = tegra_i2c_wait_completion(i2c_dev, &i2c_dev->msg_complete,
+					      xfer_time);
 
 	tegra_i2c_mask_irq(i2c_dev, int_mask);
 
-- 
2.27.0

[PATCH v4 20/31] i2c: tegra: Rename variable in tegra_i2c_issue_bus_clear()

[Dmitry Osipenko]

Rename variable "reg" to "val" in order to better reflect the actual usage
of the variable in the code and to make naming consistent with the rest of
the code.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index c2ff55e8db54..6ec6161a1895 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1100,21 +1100,21 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 {
 	struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 	unsigned long time_left;
-	u32 reg;
+	u32 val;
 	int err;
 
 	reinit_completion(&i2c_dev->msg_complete);
-	reg = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND |
+	val = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND |
 	      I2C_BC_TERMINATE;
-	i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG);
+	i2c_writel(i2c_dev, val, I2C_BUS_CLEAR_CNFG);
 	if (i2c_dev->hw->has_config_load_reg) {
 		err = tegra_i2c_wait_for_config_load(i2c_dev);
 		if (err)
 			return err;
 	}
 
-	reg |= I2C_BC_ENABLE;
-	i2c_writel(i2c_dev, reg, I2C_BUS_CLEAR_CNFG);
+	val |= I2C_BC_ENABLE;
+	i2c_writel(i2c_dev, val, I2C_BUS_CLEAR_CNFG);
 	tegra_i2c_unmask_irq(i2c_dev, I2C_INT_BUS_CLR_DONE);
 
 	time_left = tegra_i2c_wait_completion(i2c_dev, &i2c_dev->msg_complete,
@@ -1124,8 +1124,8 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 		return -ETIMEDOUT;
 	}
 
-	reg = i2c_readl(i2c_dev, I2C_BUS_CLEAR_STATUS);
-	if (!(reg & I2C_BC_STATUS)) {
+	val = i2c_readl(i2c_dev, I2C_BUS_CLEAR_STATUS);
+	if (!(val & I2C_BC_STATUS)) {
 		dev_err(i2c_dev->dev,
 			"un-recovered arbitration lost\n");
 		return -EIO;
-- 
2.27.0

[PATCH v4 21/31] i2c: tegra: Factor out error recovery from tegra_i2c_xfer_msg()

[Dmitry Osipenko]

Factor out error recovery code from tegra_i2c_xfer_msg() in order to
make this function easier to read and follow.

Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 46 ++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 16 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 6ec6161a1895..aa7adf8df668 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1134,6 +1134,32 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 	return -EAGAIN;
 }
 
+static int tegra_i2c_error_recover(struct tegra_i2c_dev *i2c_dev,
+				   struct i2c_msg *msg)
+{
+	if (i2c_dev->msg_err == I2C_ERR_NONE)
+		return 0;
+
+	tegra_i2c_init(i2c_dev);
+
+	/* start recovery upon arbitration loss in single master mode */
+	if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) {
+		if (!i2c_dev->is_multimaster_mode)
+			return i2c_recover_bus(&i2c_dev->adapter);
+
+		return -EAGAIN;
+	}
+
+	if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
+		if (msg->flags & I2C_M_IGNORE_NAK)
+			return 0;
+
+		return -EREMOTEIO;
+	}
+
+	return -EIO;
+}
+
 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 			      struct i2c_msg *msg,
 			      enum msg_end_type end_state)
@@ -1315,24 +1341,12 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		i2c_dev->msg_err);
 
 	i2c_dev->is_curr_dma_xfer = false;
-	if (i2c_dev->msg_err == I2C_ERR_NONE)
-		return 0;
 
-	tegra_i2c_init(i2c_dev);
-	/* start recovery upon arbitration loss in single master mode */
-	if (i2c_dev->msg_err == I2C_ERR_ARBITRATION_LOST) {
-		if (!i2c_dev->is_multimaster_mode)
-			return i2c_recover_bus(&i2c_dev->adapter);
-		return -EAGAIN;
-	}
-
-	if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
-		if (msg->flags & I2C_M_IGNORE_NAK)
-			return 0;
-		return -EREMOTEIO;
-	}
+	err = tegra_i2c_error_recover(i2c_dev, msg);
+	if (err)
+		return err;
 
-	return -EIO;
+	return 0;
 }
 
 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
-- 
2.27.0

[PATCH v4 22/31] i2c: tegra: Factor out packet header setup from tegra_i2c_xfer_msg()

[Dmitry Osipenko]

The code related to packet header setting up is a bit messy and makes
tegra_i2c_xfer_msg() more difficult to read than it could be. Let's
factor the packet header setup from tegra_i2c_xfer_msg() into separate
function in order to make code easier to read and follow.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 93 ++++++++++++++++++++--------------
 1 file changed, 54 insertions(+), 39 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index aa7adf8df668..129ca5a6cb85 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1134,6 +1134,57 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 	return -EAGAIN;
 }
 
+static void tegra_i2c_push_packet_header(struct tegra_i2c_dev *i2c_dev,
+					 struct i2c_msg *msg,
+					 enum msg_end_type end_state)
+{
+	u32 *dma_buf = i2c_dev->dma_buf;
+	u32 packet_header;
+
+	packet_header = FIELD_PREP(PACKET_HEADER0_HEADER_SIZE, 0) |
+			FIELD_PREP(PACKET_HEADER0_PROTOCOL,
+				   PACKET_HEADER0_PROTOCOL_I2C) |
+			FIELD_PREP(PACKET_HEADER0_CONT_ID, i2c_dev->cont_id) |
+			FIELD_PREP(PACKET_HEADER0_PACKET_ID, 1);
+
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
+		*dma_buf++ = packet_header;
+	else
+		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+
+	packet_header = msg->len - 1;
+
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
+		*dma_buf++ = packet_header;
+	else
+		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+
+	packet_header = I2C_HEADER_IE_ENABLE;
+
+	if (end_state == MSG_END_CONTINUE)
+		packet_header |= I2C_HEADER_CONTINUE_XFER;
+	else if (end_state == MSG_END_REPEAT_START)
+		packet_header |= I2C_HEADER_REPEAT_START;
+
+	if (msg->flags & I2C_M_TEN) {
+		packet_header |= msg->addr;
+		packet_header |= I2C_HEADER_10BIT_ADDR;
+	} else {
+		packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
+	}
+
+	if (msg->flags & I2C_M_IGNORE_NAK)
+		packet_header |= I2C_HEADER_CONT_ON_NAK;
+
+	if (msg->flags & I2C_M_RD)
+		packet_header |= I2C_HEADER_READ;
+
+	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
+		*dma_buf++ = packet_header;
+	else
+		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+}
+
 static int tegra_i2c_error_recover(struct tegra_i2c_dev *i2c_dev,
 				   struct i2c_msg *msg)
 {
@@ -1165,9 +1216,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 			      enum msg_end_type end_state)
 {
 	unsigned long time_left, xfer_time = 100;
-	u32 packet_header, int_mask;
-	u32 *buffer = NULL;
 	size_t xfer_size;
+	u32 int_mask;
 	int err;
 
 	err = tegra_i2c_flush_fifos(i2c_dev);
@@ -1219,49 +1269,14 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 						i2c_dev->dma_phys,
 						xfer_size,
 						DMA_TO_DEVICE);
-			buffer = i2c_dev->dma_buf;
 		}
 	}
 
-	packet_header = FIELD_PREP(PACKET_HEADER0_HEADER_SIZE, 0) |
-			FIELD_PREP(PACKET_HEADER0_PROTOCOL,
-				   PACKET_HEADER0_PROTOCOL_I2C) |
-			FIELD_PREP(PACKET_HEADER0_CONT_ID, i2c_dev->cont_id) |
-			FIELD_PREP(PACKET_HEADER0_PACKET_ID, 1);
-	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
-		*buffer++ = packet_header;
-	else
-		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
-
-	packet_header = msg->len - 1;
-	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
-		*buffer++ = packet_header;
-	else
-		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
-
-	packet_header = I2C_HEADER_IE_ENABLE;
-	if (end_state == MSG_END_CONTINUE)
-		packet_header |= I2C_HEADER_CONTINUE_XFER;
-	else if (end_state == MSG_END_REPEAT_START)
-		packet_header |= I2C_HEADER_REPEAT_START;
-	if (msg->flags & I2C_M_TEN) {
-		packet_header |= msg->addr;
-		packet_header |= I2C_HEADER_10BIT_ADDR;
-	} else {
-		packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
-	}
-	if (msg->flags & I2C_M_IGNORE_NAK)
-		packet_header |= I2C_HEADER_CONT_ON_NAK;
-	if (msg->flags & I2C_M_RD)
-		packet_header |= I2C_HEADER_READ;
-	if (i2c_dev->is_curr_dma_xfer && !i2c_dev->msg_read)
-		*buffer++ = packet_header;
-	else
-		i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
+	tegra_i2c_push_packet_header(i2c_dev, msg, end_state);
 
 	if (!i2c_dev->msg_read) {
 		if (i2c_dev->is_curr_dma_xfer) {
-			memcpy(buffer, msg->buf, msg->len);
+			memcpy(i2c_dev->dma_buf, msg->buf, msg->len);
 			dma_sync_single_for_device(i2c_dev->dev,
 						   i2c_dev->dma_phys,
 						   xfer_size,
-- 
2.27.0

[PATCH v4 23/31] i2c: tegra: Factor out register polling into separate function

[Dmitry Osipenko]

Factor out register polling into a separate function in order to remove
boilerplate code and make code cleaner.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 43 +++++++++++++++-------------------
 1 file changed, 19 insertions(+), 24 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 129ca5a6cb85..68b2be321f9a 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -466,10 +466,24 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 	return err;
 }
 
+static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
+				   u32 reg, u32 mask, u32 delay_us,
+				   u32 timeout_us)
+{
+	void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
+	u32 val;
+
+	if (!i2c_dev->is_curr_atomic_xfer)
+		return readl_relaxed_poll_timeout(addr, val, !(val & mask),
+						  delay_us, timeout_us);
+
+	return readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),
+						 delay_us, timeout_us);
+}
+
 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 {
-	u32 mask, val, offset, reg_offset;
-	void __iomem *addr;
+	u32 mask, val, offset;
 	int err;
 
 	if (i2c_dev->hw->has_mst_fifo) {
@@ -486,16 +500,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 	val |= mask;
 	i2c_writel(i2c_dev, val, offset);
 
-	reg_offset = tegra_i2c_reg_addr(i2c_dev, offset);
-	addr = i2c_dev->base + reg_offset;
-
-	if (i2c_dev->is_curr_atomic_xfer)
-		err = readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),
-							1000, 1000000);
-	else
-		err = readl_relaxed_poll_timeout(addr, val, !(val & mask),
-						 1000, 1000000);
-
+	err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
 	if (err) {
 		dev_err(i2c_dev->dev, "failed to flush FIFO\n");
 		return err;
@@ -695,25 +700,15 @@ static int __maybe_unused tegra_i2c_runtime_suspend(struct device *dev)
 
 static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 {
-	unsigned long reg_offset;
-	void __iomem *addr;
-	u32 val;
 	int err;
 
 	if (!i2c_dev->hw->has_config_load_reg)
 		return 0;
 
-	reg_offset = tegra_i2c_reg_addr(i2c_dev, I2C_CONFIG_LOAD);
-	addr = i2c_dev->base + reg_offset;
 	i2c_writel(i2c_dev, I2C_MSTR_CONFIG_LOAD, I2C_CONFIG_LOAD);
 
-	if (i2c_dev->is_curr_atomic_xfer)
-		err = readl_relaxed_poll_timeout_atomic(addr, val, val == 0, 1000,
-							I2C_CONFIG_LOAD_TIMEOUT);
-	else
-		err = readl_relaxed_poll_timeout(addr, val, val == 0, 1000,
-						 I2C_CONFIG_LOAD_TIMEOUT);
-
+	err = tegra_i2c_poll_register(i2c_dev, I2C_CONFIG_LOAD, 0xffffffff,
+				      1000, I2C_CONFIG_LOAD_TIMEOUT);
 	if (err) {
 		dev_warn(i2c_dev->dev, "timeout waiting for config load\n");
 		return err;
-- 
2.27.0

[PATCH v4 24/31] i2c: tegra: Reorder location of functions in the code

[Dmitry Osipenko]

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().

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 484 ++++++++++++++++-----------------
 1 file changed, 241 insertions(+), 243 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 68b2be321f9a..9b4107b07135 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)
 {
@@ -466,175 +464,6 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 	return err;
 }
 
-static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
-				   u32 reg, u32 mask, u32 delay_us,
-				   u32 timeout_us)
-{
-	void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
-	u32 val;
-
-	if (!i2c_dev->is_curr_atomic_xfer)
-		return readl_relaxed_poll_timeout(addr, val, !(val & mask),
-						  delay_us, timeout_us);
-
-	return readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),
-						 delay_us, timeout_us);
-}
-
-static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
-{
-	u32 mask, val, offset;
-	int err;
-
-	if (i2c_dev->hw->has_mst_fifo) {
-		mask = I2C_MST_FIFO_CONTROL_TX_FLUSH |
-		       I2C_MST_FIFO_CONTROL_RX_FLUSH;
-		offset = I2C_MST_FIFO_CONTROL;
-	} else {
-		mask = I2C_FIFO_CONTROL_TX_FLUSH |
-		       I2C_FIFO_CONTROL_RX_FLUSH;
-		offset = I2C_FIFO_CONTROL;
-	}
-
-	val = i2c_readl(i2c_dev, offset);
-	val |= mask;
-	i2c_writel(i2c_dev, val, offset);
-
-	err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
-	if (err) {
-		dev_err(i2c_dev->dev, "failed to flush FIFO\n");
-		return err;
-	}
-	return 0;
-}
-
-static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
-{
-	size_t buf_remaining = i2c_dev->msg_buf_remaining;
-	u8 *buf = i2c_dev->msg_buf;
-	int words_to_transfer;
-	int rx_fifo_avail;
-	u32 val;
-
-	/*
-	 * 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)
-{
-	size_t buf_remaining = i2c_dev->msg_buf_remaining;
-	u8 *buf = i2c_dev->msg_buf;
-	int words_to_transfer;
-	int tx_fifo_avail;
-	u32 val;
-
-	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;
-
-		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;
-
-		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
@@ -656,46 +485,48 @@ static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
 	dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
 }
 
-static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
+static void tegra_i2c_vi_init(struct tegra_i2c_dev *i2c_dev)
 {
-	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
-	int ret;
+	u32 value;
 
-	ret = pinctrl_pm_select_default_state(i2c_dev->dev);
-	if (ret)
-		return ret;
+	value = FIELD_PREP(I2C_INTERFACE_TIMING_THIGH, 2) |
+		FIELD_PREP(I2C_INTERFACE_TIMING_TLOW, 4);
+	i2c_writel(i2c_dev, value, I2C_INTERFACE_TIMING_0);
 
-	ret = clk_bulk_enable(i2c_dev->nclocks, i2c_dev->clocks);
-	if (ret)
-		return ret;
+	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);
 
-	/*
-	 * 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;
-	}
+	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);
 
-	return 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);
 
-disable_clocks:
-	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
+	value = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND;
+	i2c_writel(i2c_dev, value, I2C_BUS_CLEAR_CNFG);
 
-	return ret;
+	i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
 }
 
-static int __maybe_unused tegra_i2c_runtime_suspend(struct device *dev)
+static int tegra_i2c_poll_register(struct tegra_i2c_dev *i2c_dev,
+				   u32 reg, u32 mask, u32 delay_us,
+				   u32 timeout_us)
 {
-	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
+	void __iomem *addr = i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg);
+	u32 val;
 
-	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
+	if (!i2c_dev->is_curr_atomic_xfer)
+		return readl_relaxed_poll_timeout(addr, val, !(val & mask),
+						  delay_us, timeout_us);
 
-	return pinctrl_pm_select_idle_state(i2c_dev->dev);
+	return readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask),
+						 delay_us, timeout_us);
 }
 
 static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
@@ -717,33 +548,31 @@ 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)
+static int tegra_i2c_flush_fifos(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);
+	u32 mask, val, offset;
+	int err;
 
-	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);
+	if (i2c_dev->hw->has_mst_fifo) {
+		mask = I2C_MST_FIFO_CONTROL_TX_FLUSH |
+		       I2C_MST_FIFO_CONTROL_RX_FLUSH;
+		offset = I2C_MST_FIFO_CONTROL;
+	} else {
+		mask = I2C_FIFO_CONTROL_TX_FLUSH |
+		       I2C_FIFO_CONTROL_RX_FLUSH;
+		offset = I2C_FIFO_CONTROL;
+	}
 
-	value = FIELD_PREP(I2C_BC_SCLK_THRESHOLD, 9) | I2C_BC_STOP_COND;
-	i2c_writel(i2c_dev, value, I2C_BUS_CLEAR_CNFG);
+	val = i2c_readl(i2c_dev, offset);
+	val |= mask;
+	i2c_writel(i2c_dev, val, offset);
 
-	i2c_writel(i2c_dev, 0x0, I2C_TLOW_SEXT);
+	err = tegra_i2c_poll_register(i2c_dev, offset, mask, 1000, 1000000);
+	if (err) {
+		dev_err(i2c_dev->dev, "failed to flush FIFO\n");
+		return err;
+	}
+	return 0;
 }
 
 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
@@ -860,6 +689,133 @@ 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)
+{
+	size_t buf_remaining = i2c_dev->msg_buf_remaining;
+	u8 *buf = i2c_dev->msg_buf;
+	int words_to_transfer;
+	int rx_fifo_avail;
+	u32 val;
+
+	/*
+	 * 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)
+{
+	size_t buf_remaining = i2c_dev->msg_buf_remaining;
+	u8 *buf = i2c_dev->msg_buf;
+	int words_to_transfer;
+	int tx_fifo_avail;
+	u32 val;
+
+	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;
+
+		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;
+
+		i2c_writel(i2c_dev, val, I2C_TX_FIFO);
+	}
+
+	return 0;
+}
+
 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 {
 	const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
@@ -1414,27 +1370,6 @@ 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;
-	bool multi_mode;
-	int ret;
-
-	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,
@@ -1640,6 +1575,27 @@ 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;
+	bool multi_mode;
+	int ret;
+
+	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;
@@ -1830,6 +1786,48 @@ 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);
-- 
2.27.0

[PATCH v4 25/31] i2c: tegra: Check errors for both positive and negative values

[Dmitry Osipenko]

The driver's code is inconsistent in regards to the error values checking.
The correct way should be to check both positive and negative values.
This patch cleans up the error-checks in the code. Note that the
pm_runtime_get_sync() could return positive value on success, hence only
relevant parts of the code are changed by this patch.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 9b4107b07135..64776cd8e0ff 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -969,7 +969,7 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 
 		slv_config.device_fc = true;
 		ret = dmaengine_slave_config(chan, &slv_config);
-		if (ret < 0) {
+		if (ret) {
 			dev_err(i2c_dev->dev, "DMA slave config failed: %d\n",
 				ret);
 			dev_err(i2c_dev->dev, "falling back to PIO\n");
@@ -1208,7 +1208,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 						   xfer_size,
 						   DMA_FROM_DEVICE);
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
-			if (err < 0) {
+			if (err) {
 				dev_err(i2c_dev->dev,
 					"starting RX DMA failed, err %d\n",
 					err);
@@ -1233,7 +1233,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 						   xfer_size,
 						   DMA_TO_DEVICE);
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
-			if (err < 0) {
+			if (err) {
 				dev_err(i2c_dev->dev,
 					"starting TX DMA failed, err %d\n",
 					err);
-- 
2.27.0

[PATCH v4 26/31] i2c: tegra: Consolidate error handling in tegra_i2c_xfer_msg()

[Dmitry Osipenko]

Consolidate error handling in tegra_i2c_xfer_msg() into a common code
path in order to make code cleaner.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 64776cd8e0ff..3dd688e9462a 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1277,8 +1277,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 		if (!time_left && !completion_done(&i2c_dev->dma_complete)) {
 			dev_err(i2c_dev->dev, "DMA transfer timeout\n");
-			tegra_i2c_init(i2c_dev);
-			return -ETIMEDOUT;
+			err = -ETIMEDOUT;
+			goto reset_hardware;
 		}
 
 		if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE) {
@@ -1298,8 +1298,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (time_left == 0) {
 		dev_err(i2c_dev->dev, "i2c transfer timed out\n");
-		tegra_i2c_init(i2c_dev);
-		return -ETIMEDOUT;
+		err = -ETIMEDOUT;
+		goto reset_hardware;
 	}
 
 	dev_dbg(i2c_dev->dev, "transfer complete: %lu %d %d\n",
@@ -1313,6 +1313,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		return err;
 
 	return 0;
+
+reset_hardware:
+	tegra_i2c_init(i2c_dev);
+
+	return err;
 }
 
 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
-- 
2.27.0

[PATCH v4 27/31] i2c: tegra: Clean up printk messages

[Dmitry Osipenko]

This patch unifies style of all messages in the driver by starting them
with a lowercase letter and using consistent capitalization and wording
for all messages.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 3dd688e9462a..2dd97540f14f 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -377,7 +377,8 @@ static int tegra_i2c_dma_submit(struct tegra_i2c_dev *i2c_dev, size_t len)
 					       len, dir, DMA_PREP_INTERRUPT |
 					       DMA_CTRL_ACK);
 	if (!dma_desc) {
-		dev_err(i2c_dev->dev, "failed to get DMA descriptor\n");
+		dev_err(i2c_dev->dev, "failed to get %s DMA descriptor\n",
+			i2c_dev->msg_read ? "RX" : "TX");
 		return -EINVAL;
 	}
 
@@ -418,7 +419,7 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 		return 0;
 
 	if (!IS_ENABLED(CONFIG_TEGRA20_APB_DMA)) {
-		dev_dbg(i2c_dev->dev, "Support for APB DMA not enabled!\n");
+		dev_dbg(i2c_dev->dev, "DMA support not enabled\n");
 		return 0;
 	}
 
@@ -444,7 +445,7 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
 	dma_buf = dma_alloc_coherent(i2c_dev->dev, i2c_dev->dma_buf_size,
 				     &dma_phys, GFP_KERNEL | __GFP_NOWARN);
 	if (!dma_buf) {
-		dev_err(i2c_dev->dev, "failed to allocate the DMA buffer\n");
+		dev_err(i2c_dev->dev, "failed to allocate DMA buffer\n");
 		err = -ENOMEM;
 		goto err_out;
 	}
@@ -541,7 +542,7 @@ static int tegra_i2c_wait_for_config_load(struct tegra_i2c_dev *i2c_dev)
 	err = tegra_i2c_poll_register(i2c_dev, I2C_CONFIG_LOAD, 0xffffffff,
 				      1000, I2C_CONFIG_LOAD_TIMEOUT);
 	if (err) {
-		dev_warn(i2c_dev->dev, "timeout waiting for config load\n");
+		dev_err(i2c_dev->dev, "failed to load config\n");
 		return err;
 	}
 
@@ -825,7 +826,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 
 	if (status == 0) {
-		dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n",
+		dev_warn(i2c_dev->dev, "IRQ status 0 %08x %08x %08x\n",
 			 i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
 			 i2c_readl(i2c_dev, I2C_STATUS),
 			 i2c_readl(i2c_dev, I2C_CNFG));
@@ -970,8 +971,7 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 		slv_config.device_fc = true;
 		ret = dmaengine_slave_config(chan, &slv_config);
 		if (ret) {
-			dev_err(i2c_dev->dev, "DMA slave config failed: %d\n",
-				ret);
+			dev_err(i2c_dev->dev, "DMA config failed: %d\n", ret);
 			dev_err(i2c_dev->dev, "falling back to PIO\n");
 			tegra_i2c_release_dma(i2c_dev);
 			i2c_dev->is_curr_dma_xfer = false;
@@ -1077,8 +1077,7 @@ static int tegra_i2c_issue_bus_clear(struct i2c_adapter *adap)
 
 	val = i2c_readl(i2c_dev, I2C_BUS_CLEAR_STATUS);
 	if (!(val & I2C_BC_STATUS)) {
-		dev_err(i2c_dev->dev,
-			"un-recovered arbitration lost\n");
+		dev_err(i2c_dev->dev, "un-recovered arbitration lost\n");
 		return -EIO;
 	}
 
@@ -1208,12 +1207,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 						   xfer_size,
 						   DMA_FROM_DEVICE);
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
-			if (err) {
-				dev_err(i2c_dev->dev,
-					"starting RX DMA failed, err %d\n",
-					err);
+			if (err)
 				return err;
-			}
 
 		} else {
 			dma_sync_single_for_cpu(i2c_dev->dev,
@@ -1233,12 +1228,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 						   xfer_size,
 						   DMA_TO_DEVICE);
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
-			if (err) {
-				dev_err(i2c_dev->dev,
-					"starting TX DMA failed, err %d\n",
-					err);
+			if (err)
 				return err;
-			}
 		} else {
 			tegra_i2c_fill_tx_fifo(i2c_dev);
 		}
@@ -1254,7 +1245,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	}
 
 	tegra_i2c_unmask_irq(i2c_dev, int_mask);
-	dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
+	dev_dbg(i2c_dev->dev, "unmasked IRQ: %02x\n",
 		i2c_readl(i2c_dev, I2C_INT_MASK));
 
 	if (i2c_dev->is_curr_dma_xfer) {
@@ -1297,7 +1288,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	tegra_i2c_mask_irq(i2c_dev, int_mask);
 
 	if (time_left == 0) {
-		dev_err(i2c_dev->dev, "i2c transfer timed out\n");
+		dev_err(i2c_dev->dev, "I2C transfer timed out\n");
 		err = -ETIMEDOUT;
 		goto reset_hardware;
 	}
-- 
2.27.0

[PATCH v4 28/31] i2c: tegra: Clean up whitespaces, newlines and indentation

[Dmitry Osipenko]

Some places in the code are missing newlines or have unnecessary
whitespaces and newlines. This creates inconsistency of the code and
hurts readability. This patch removes the unnecessary and adds necessary
whitespaces / newlines, clears indentation of the code.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 52 ++++++++++++++++++++--------------
 1 file changed, 30 insertions(+), 22 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 2dd97540f14f..c36f2bed0240 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -310,6 +310,7 @@ static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
 		reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
 	else if (i2c_dev->is_vi)
 		reg = 0xc00 + (reg << 2);
+
 	return reg;
 }
 
@@ -370,9 +371,12 @@ static int tegra_i2c_dma_submit(struct tegra_i2c_dev *i2c_dev, size_t len)
 	struct dma_chan *chan;
 
 	dev_dbg(i2c_dev->dev, "starting DMA for length: %zu\n", len);
+
 	reinit_completion(&i2c_dev->dma_complete);
+
 	dir = i2c_dev->msg_read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
 	chan = i2c_dev->msg_read ? i2c_dev->rx_dma_chan : i2c_dev->tx_dma_chan;
+
 	dma_desc = dmaengine_prep_slave_single(chan, i2c_dev->dma_phys,
 					       len, dir, DMA_PREP_INTERRUPT |
 					       DMA_CTRL_ACK);
@@ -386,6 +390,7 @@ static int tegra_i2c_dma_submit(struct tegra_i2c_dev *i2c_dev, size_t len)
 	dma_desc->callback_param = i2c_dev;
 	dmaengine_submit(dma_desc);
 	dma_async_issue_pending(chan);
+
 	return 0;
 }
 
@@ -573,6 +578,7 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 		dev_err(i2c_dev->dev, "failed to flush FIFO\n");
 		return err;
 	}
+
 	return 0;
 }
 
@@ -784,9 +790,9 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		 */
 		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;
+		i2c_dev->msg_buf = buf + words_to_transfer * BYTES_PER_FIFO_WORD;
 
 		i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
 
@@ -1186,9 +1192,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		xfer_size = msg->len + I2C_PACKET_HEADER_SIZE;
 
 	xfer_size = ALIGN(xfer_size, BYTES_PER_FIFO_WORD);
+
 	i2c_dev->is_curr_dma_xfer = (xfer_size > I2C_PIO_MODE_PREFERRED_LEN) &&
 				    i2c_dev->dma_buf &&
 				    !i2c_dev->is_curr_atomic_xfer;
+
 	tegra_i2c_config_fifo_trig(i2c_dev, xfer_size);
 
 	/*
@@ -1196,25 +1204,24 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	 * Total bits = 9 bits per byte (including ACK bit) + Start & stop bits
 	 */
 	xfer_time += DIV_ROUND_CLOSEST(((xfer_size * 9) + 2) * MSEC_PER_SEC,
-					i2c_dev->bus_clk_rate);
+				       i2c_dev->bus_clk_rate);
 
 	int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 	tegra_i2c_unmask_irq(i2c_dev, int_mask);
+
 	if (i2c_dev->is_curr_dma_xfer) {
 		if (i2c_dev->msg_read) {
 			dma_sync_single_for_device(i2c_dev->dev,
 						   i2c_dev->dma_phys,
-						   xfer_size,
-						   DMA_FROM_DEVICE);
+						   xfer_size, DMA_FROM_DEVICE);
+
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
 			if (err)
 				return err;
-
 		} else {
 			dma_sync_single_for_cpu(i2c_dev->dev,
 						i2c_dev->dma_phys,
-						xfer_size,
-						DMA_TO_DEVICE);
+						xfer_size, DMA_TO_DEVICE);
 		}
 	}
 
@@ -1223,10 +1230,11 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 	if (!i2c_dev->msg_read) {
 		if (i2c_dev->is_curr_dma_xfer) {
 			memcpy(i2c_dev->dma_buf, msg->buf, msg->len);
+
 			dma_sync_single_for_device(i2c_dev->dev,
 						   i2c_dev->dma_phys,
-						   xfer_size,
-						   DMA_TO_DEVICE);
+						   xfer_size, DMA_TO_DEVICE);
+
 			err = tegra_i2c_dma_submit(i2c_dev, xfer_size);
 			if (err)
 				return err;
@@ -1237,6 +1245,7 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 
 	if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
 		int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
+
 	if (!i2c_dev->is_curr_dma_xfer) {
 		if (msg->flags & I2C_M_RD)
 			int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
@@ -1275,10 +1284,9 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 		if (i2c_dev->msg_read && i2c_dev->msg_err == I2C_ERR_NONE) {
 			dma_sync_single_for_cpu(i2c_dev->dev,
 						i2c_dev->dma_phys,
-						xfer_size,
-						DMA_FROM_DEVICE);
-			memcpy(i2c_dev->msg_buf, i2c_dev->dma_buf,
-			       msg->len);
+						xfer_size, DMA_FROM_DEVICE);
+
+			memcpy(i2c_dev->msg_buf, i2c_dev->dma_buf, msg->len);
 		}
 	}
 
@@ -1363,6 +1371,7 @@ static u32 tegra_i2c_func(struct i2c_adapter *adap)
 
 	if (i2c_dev->hw->has_continue_xfer_support)
 		ret |= I2C_FUNC_NOSTART;
+
 	return ret;
 }
 
@@ -1774,11 +1783,11 @@ static int tegra_i2c_remove(struct platform_device *pdev)
 	struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 
 	i2c_del_adapter(&i2c_dev->adapter);
-
-	pm_runtime_disable(&pdev->dev);
+	pm_runtime_disable(i2c_dev->dev);
 
 	tegra_i2c_release_dma(i2c_dev);
 	tegra_i2c_release_clocks(i2c_dev);
+
 	return 0;
 }
 
@@ -1877,15 +1886,14 @@ static const struct dev_pm_ops tegra_i2c_pm = {
 };
 
 static struct platform_driver tegra_i2c_driver = {
-	.probe   = tegra_i2c_probe,
-	.remove  = tegra_i2c_remove,
-	.driver  = {
-		.name  = "tegra-i2c",
+	.probe = tegra_i2c_probe,
+	.remove = tegra_i2c_remove,
+	.driver = {
+		.name = "tegra-i2c",
 		.of_match_table = tegra_i2c_of_match,
-		.pm    = &tegra_i2c_pm,
+		.pm = &tegra_i2c_pm,
 	},
 };
-
 module_platform_driver(tegra_i2c_driver);
 
 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver");
-- 
2.27.0

[PATCH v4 29/31] i2c: tegra: Improve driver module description

[Dmitry Osipenko]

Use proper spelling of "NVIDIA" and don't designate driver as Tegra2-only
since newer SoC generations are supported as well.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index c36f2bed0240..dccad2429117 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -1896,6 +1896,6 @@ static struct platform_driver tegra_i2c_driver = {
 };
 module_platform_driver(tegra_i2c_driver);
 
-MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver");
+MODULE_DESCRIPTION("NVIDIA Tegra I2C Bus Controller driver");
 MODULE_AUTHOR("Colin Cross");
 MODULE_LICENSE("GPL v2");
-- 
2.27.0

[PATCH v4 30/31] i2c: tegra: Clean up and improve comments

[Dmitry Osipenko]

Make all comments to be consistent in regards to capitalization and
punctuation, correct spelling and grammar errors.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 85 +++++++++++++++++-----------------
 1 file changed, 43 insertions(+), 42 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index dccad2429117..d389ea5813c3 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -148,11 +148,10 @@
 #define I2C_PIO_MODE_PREFERRED_LEN		32
 
 /*
- * msg_end_type: The bus control which need to be send at end of transfer.
- * @MSG_END_STOP: Send stop pulse at end of transfer.
- * @MSG_END_REPEAT_START: Send repeat start at end of transfer.
- * @MSG_END_CONTINUE: The following on message is coming and so do not send
- *		stop or repeat start.
+ * msg_end_type: The bus control which needs to be sent at end of transfer.
+ * @MSG_END_STOP: Send stop pulse.
+ * @MSG_END_REPEAT_START: Send repeat-start.
+ * @MSG_END_CONTINUE: Don't send stop or repeat-start.
  */
 enum msg_end_type {
 	MSG_END_STOP,
@@ -161,10 +160,10 @@ enum msg_end_type {
 };
 
 /**
- * struct tegra_i2c_hw_feature : Different HW support on Tegra
- * @has_continue_xfer_support: Continue transfer supports.
+ * struct tegra_i2c_hw_feature : per hardware generation features
+ * @has_continue_xfer_support: Continue-transfer supported.
  * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer
- *		complete interrupt per packet basis.
+ *		completion interrupt on per packet basis.
  * @has_config_load_reg: Has the config load register to load the new
  *		configuration.
  * @clk_divisor_hs_mode: Clock divisor in HS mode.
@@ -184,7 +183,7 @@ enum msg_end_type {
  * @has_mst_fifo: The I2C controller contains the new MST FIFO interface that
  *		provides additional features and allows for longer messages to
  *		be transferred in one go.
- * @quirks: i2c adapter quirks for limiting write/read transfer size and not
+ * @quirks: I2C adapter quirks for limiting write/read transfer size and not
  *		allowing 0 length transfers.
  * @supports_bus_clear: Bus Clear support to recover from bus hang during
  *		SDA stuck low from device for some unknown reasons.
@@ -247,7 +246,7 @@ struct tegra_i2c_hw_feature {
  * @msg_buf_remaining: size of unsent data in the message buffer
  * @msg_read: identifies read transfers
  * @bus_clk_rate: current I2C bus clock rate
- * @is_multimaster_mode: track if I2C controller is in multi-master mode
+ * @is_multimaster_mode: indicates that I2C controller is in multi-master mode
  * @tx_dma_chan: DMA transmit channel
  * @rx_dma_chan: DMA receive channel
  * @dma_phys: handle to DMA resources
@@ -300,8 +299,8 @@ static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 }
 
 /*
- * i2c_writel and i2c_readl will offset the register if necessary to talk
- * to the I2C block inside the DVC block
+ * If necessary, i2c_writel() and i2c_readl() will offset the register
+ * in order to talk to the I2C block inside the DVC block.
  */
 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
 					unsigned long reg)
@@ -319,7 +318,7 @@ static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
 {
 	writel_relaxed(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 
-	/* Read back register to make sure that register writes completed */
+	/* read back register to make sure that register writes completed */
 	if (reg != I2C_TX_FIFO)
 		readl_relaxed(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 }
@@ -475,7 +474,7 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev)
  * 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
+ * by i2c_readl() and i2c_writel().
  */
 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
 {
@@ -625,7 +624,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 		break;
 	}
 
-	/* Make sure clock divisor programmed correctly */
+	/* make sure clock divisor programmed correctly */
 	clk_divisor = FIELD_PREP(I2C_CLK_DIVISOR_HSMODE,
 				 i2c_dev->hw->clk_divisor_hs_mode) |
 		      FIELD_PREP(I2C_CLK_DIVISOR_STD_FAST_MODE, non_hs_mode);
@@ -638,8 +637,8 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 	}
 
 	/*
-	 * configure setup and hold times only when tsu_thd is non-zero.
-	 * otherwise, preserve the chip default values
+	 * Configure setup and hold times only when tsu_thd is non-zero.
+	 * Otherwise, preserve the chip default values.
 	 */
 	if (i2c_dev->hw->has_interface_timing_reg && tsu_thd)
 		i2c_writel(i2c_dev, tsu_thd, I2C_INTERFACE_TIMING_1);
@@ -683,7 +682,7 @@ static int tegra_i2c_disable_packet_mode(struct tegra_i2c_dev *i2c_dev)
 
 	/*
 	 * NACK interrupt is generated before the I2C controller generates
-	 * the STOP condition on the bus. So wait for 2 clock periods
+	 * the STOP condition on the bus.  So wait for 2 clock periods
 	 * before disabling the controller so that the STOP condition has
 	 * been delivered properly.
 	 */
@@ -705,8 +704,8 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 	u32 val;
 
 	/*
-	 * Catch overflow due to message fully sent
-	 * before the check for RX FIFO availability.
+	 * 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;
@@ -731,8 +730,8 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 	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 there is a partial word at the end of buffer, handle it
+	 * manually to prevent overwriting past the end of buffer.
 	 */
 	if (rx_fifo_avail > 0 && buf_remaining > 0) {
 		/*
@@ -747,7 +746,7 @@ static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 		rx_fifo_avail--;
 	}
 
-	/* RX FIFO must be drained, otherwise it's an Overflow case. */
+	/* RX FIFO must be drained, otherwise it's an Overflow case */
 	if (WARN_ON_ONCE(rx_fifo_avail))
 		return -EINVAL;
 
@@ -773,16 +772,16 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		tx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_TX, val);
 	}
 
-	/* Rounds down to not include partial word at the end of buf */
+	/* rounds down to not include partial word at the end of buffer */
 	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 
-	/* It's very common to have < 4 bytes, so optimize that case. */
+	/* 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
+		 * Update state before writing to FIFO.  If this causes 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
@@ -800,8 +799,8 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 	}
 
 	/*
-	 * 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
+	 * If there is a partial word at the end of buffer, handle it manually
+	 * to prevent reading past the end of buffer, which could cross a page
 	 * boundary and fault.
 	 */
 	if (tx_fifo_avail > 0 && buf_remaining > 0) {
@@ -813,7 +812,7 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 		memcpy(&val, buf, buf_remaining);
 		val = le32_to_cpu(val);
 
-		/* Again update before writing to FIFO to make sure isr sees. */
+		/* again update before writing to FIFO to make sure ISR sees */
 		i2c_dev->msg_buf_remaining = 0;
 		i2c_dev->msg_buf = NULL;
 
@@ -850,7 +849,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	}
 
 	/*
-	 * I2C transfer is terminated during the bus clear so skip
+	 * I2C transfer is terminated during the bus clear, so skip
 	 * processing the other interrupts.
 	 */
 	if (i2c_dev->hw->supports_bus_clear && (status & I2C_INT_BUS_CLR_DONE))
@@ -886,7 +885,8 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	 * During message read XFER_COMPLETE interrupt is triggered prior to
 	 * DMA completion and during message write XFER_COMPLETE interrupt is
 	 * triggered after DMA completion.
-	 * PACKETS_XFER_COMPLETE indicates completion of all bytes of transfer.
+	 *
+	 * PACKETS_XFER_COMPLETE indicates completion of all bytes of transfer,
 	 * so forcing msg_buf_remaining to 0 in DMA mode.
 	 */
 	if (status & I2C_INT_PACKET_XFER_COMPLETE) {
@@ -904,7 +904,7 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	}
 	goto done;
 err:
-	/* An error occurred, mask all interrupts */
+	/* error occurred, mask all interrupts */
 	tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
 		I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
 		I2C_INT_RX_FIFO_DATA_REQ);
@@ -1335,6 +1335,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 		enum msg_end_type end_type = MSG_END_STOP;
 
 		if (i < (num - 1)) {
+			/* check whether follow up message is coming */
 			if (msgs[i + 1].flags & I2C_M_NOSTART)
 				end_type = MSG_END_CONTINUE;
 			else
@@ -1565,7 +1566,6 @@ static const struct tegra_i2c_hw_feature tegra194_i2c_hw = {
 	.has_interface_timing_reg = true,
 };
 
-/* Match table for of_platform binding */
 static const struct of_device_id tegra_i2c_of_match[] = {
 	{ .compatible = "nvidia,tegra194-i2c", .data = &tegra194_i2c_hw, },
 	{ .compatible = "nvidia,tegra186-i2c", .data = &tegra186_i2c_hw, },
@@ -1589,7 +1589,7 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
 	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 */
+		i2c_dev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ;
 
 	multi_mode = of_property_read_bool(np, "multi-master");
 	i2c_dev->is_multimaster_mode = multi_mode;
@@ -1653,11 +1653,13 @@ static int tegra_i2c_init_runtime_pm_and_hardware(struct tegra_i2c_dev *i2c_dev)
 	int ret;
 
 	/*
-	 * VI I2C is in VE power domain which is not always on and not
-	 * an IRQ safe. So, IRQ safe device can't be attached to a non-IRQ
-	 * safe domain as it prevents powering off the PM domain.
-	 * Also, VI I2C device don't need to use runtime IRQ safe as it will
-	 * not be used for atomic transfers.
+	 * VI I2C is in VE power domain which is not always ON and not
+	 * IRQ-safe.  Thus, IRQ-safe device shouldn't be attached to a
+	 * non IRQ-safe domain because this prevents powering off the power
+	 * domain.
+	 *
+	 * VI I2C device shouldn't be marked as IRQ-safe because VI I2C won't
+	 * be used for atomic transfers.
 	 */
 	if (!i2c_dev->is_vi)
 		pm_runtime_irq_safe(i2c_dev->dev);
@@ -1806,9 +1808,8 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 
 	/*
 	 * 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.
+	 * power ON/OFF during of runtime PM resume/suspend, meaning that
+	 * controller needs to be re-initialized after power ON.
 	 */
 	if (i2c_dev->is_vi) {
 		ret = tegra_i2c_init(i2c_dev);
-- 
2.27.0

Re: [PATCH v4 30/31] i2c: tegra: Clean up and improve comments

[Michał Mirosław]

On Sat, Sep 05, 2020 at 11:41:50PM +0300, Dmitry Osipenko wrote:
> Make all comments to be consistent in regards to capitalization and
> punctuation, correct spelling and grammar errors.
[...]
> -	/* Rounds down to not include partial word at the end of buf */
> +	/* rounds down to not include partial word at the end of buffer */
>  	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
>  
> -	/* It's very common to have < 4 bytes, so optimize that case. */
> +	/* 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
> +		 * Update state before writing to FIFO.  If this causes 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
> @@ -800,8 +799,8 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
>  	}

Those first letters don't look consistently capitalized. :-)

Best Regards,
Michał Mirosław

Re: [PATCH v4 30/31] i2c: tegra: Clean up and improve comments

[Dmitry Osipenko]

06.09.2020 01:47, Michał Mirosław пишет:
> On Sat, Sep 05, 2020 at 11:41:50PM +0300, Dmitry Osipenko wrote:
>> Make all comments to be consistent in regards to capitalization and
>> punctuation, correct spelling and grammar errors.
> [...]
>> -	/* Rounds down to not include partial word at the end of buf */
>> +	/* rounds down to not include partial word at the end of buffer */
>>  	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
>>  
>> -	/* It's very common to have < 4 bytes, so optimize that case. */
>> +	/* 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
>> +		 * Update state before writing to FIFO.  If this causes 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
>> @@ -800,8 +799,8 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
>>  	}
> 
> Those first letters don't look consistently capitalized. :-)

In my experience, the more common kernel style is a lowercase for
single-line comments and the opposite for the multi-line comments.
Hence, should be good. If you're meaning something else, then please
clarify.

Re: [PATCH v4 30/31] i2c: tegra: Clean up and improve comments

[Michał Mirosław]

On Sun, Sep 06, 2020 at 01:53:56AM +0300, Dmitry Osipenko wrote:
> 06.09.2020 01:47, Michał Mirosław пишет:
> > On Sat, Sep 05, 2020 at 11:41:50PM +0300, Dmitry Osipenko wrote:
> >> Make all comments to be consistent in regards to capitalization and
> >> punctuation, correct spelling and grammar errors.
> > [...]
> >> -	/* Rounds down to not include partial word at the end of buf */
> >> +	/* rounds down to not include partial word at the end of buffer */
> >>  	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
> >>  
> >> -	/* It's very common to have < 4 bytes, so optimize that case. */
> >> +	/* 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
> >> +		 * Update state before writing to FIFO.  If this causes 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
> >> @@ -800,8 +799,8 @@ static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
> >>  	}
> > 
> > Those first letters don't look consistently capitalized. :-)
> 
> In my experience, the more common kernel style is a lowercase for
> single-line comments and the opposite for the multi-line comments.
> Hence, should be good. If you're meaning something else, then please
> clarify.

I don't have a strong opinion about this, but my preference is: If it's
a full sentence, make it look so.

Best Regards,
Michał Mirosław

[PATCH v4 31/31] i2c: tegra: Rename couple "ret" variables to "err"

[Dmitry Osipenko]

Rename "ret" variables to "err" in order to make code a bit more
expressive, emphasizing that the returned value is a error code.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index d389ea5813c3..2c84d5848e29 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -935,7 +935,7 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 	unsigned long reg_offset;
 	u32 val, reg, dma_burst;
 	struct dma_chan *chan;
-	int ret;
+	int err;
 
 	if (i2c_dev->hw->has_mst_fifo)
 		reg = I2C_MST_FIFO_CONTROL;
@@ -975,9 +975,9 @@ static void tegra_i2c_config_fifo_trig(struct tegra_i2c_dev *i2c_dev,
 		}
 
 		slv_config.device_fc = true;
-		ret = dmaengine_slave_config(chan, &slv_config);
-		if (ret) {
-			dev_err(i2c_dev->dev, "DMA config failed: %d\n", ret);
+		err = dmaengine_slave_config(chan, &slv_config);
+		if (err) {
+			dev_err(i2c_dev->dev, "DMA config failed: %d\n", err);
 			dev_err(i2c_dev->dev, "falling back to PIO\n");
 			tegra_i2c_release_dma(i2c_dev);
 			i2c_dev->is_curr_dma_xfer = false;
@@ -1584,11 +1584,11 @@ static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
 {
 	struct device_node *np = i2c_dev->dev->of_node;
 	bool multi_mode;
-	int ret;
+	int err;
 
-	ret = of_property_read_u32(np, "clock-frequency",
+	err = of_property_read_u32(np, "clock-frequency",
 				   &i2c_dev->bus_clk_rate);
-	if (ret)
+	if (err)
 		i2c_dev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ;
 
 	multi_mode = of_property_read_bool(np, "multi-master");
@@ -1796,15 +1796,15 @@ static int tegra_i2c_remove(struct platform_device *pdev)
 static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 {
 	struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
-	int ret;
+	int err;
 
-	ret = pinctrl_pm_select_default_state(i2c_dev->dev);
-	if (ret)
-		return ret;
+	err = pinctrl_pm_select_default_state(i2c_dev->dev);
+	if (err)
+		return err;
 
-	ret = clk_bulk_enable(i2c_dev->nclocks, i2c_dev->clocks);
-	if (ret)
-		return ret;
+	err = clk_bulk_enable(i2c_dev->nclocks, i2c_dev->clocks);
+	if (err)
+		return err;
 
 	/*
 	 * VI I2C device is attached to VE power domain which goes through
@@ -1812,8 +1812,8 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 	 * controller needs to be re-initialized after power ON.
 	 */
 	if (i2c_dev->is_vi) {
-		ret = tegra_i2c_init(i2c_dev);
-		if (ret)
+		err = tegra_i2c_init(i2c_dev);
+		if (err)
 			goto disable_clocks;
 	}
 
@@ -1822,7 +1822,7 @@ static int __maybe_unused tegra_i2c_runtime_resume(struct device *dev)
 disable_clocks:
 	clk_bulk_disable(i2c_dev->nclocks, i2c_dev->clocks);
 
-	return ret;
+	return err;
 }
 
 static int __maybe_unused tegra_i2c_runtime_suspend(struct device *dev)
-- 
2.27.0

Re: [PATCH v4 00/31] Improvements for Tegra I2C driver

[Michał Mirosław]

On Sat, Sep 05, 2020 at 11:41:20PM +0300, Dmitry Osipenko wrote:
> Hello!
> 
> This series performs refactoring of the Tegra I2C driver code and hardens
> the atomic-transfer mode.
[...]

Pending comments, all LGTM.

Best Regards,
Michał Mirosław

Re: [PATCH v4 00/31] Improvements for Tegra I2C driver

[Dmitry Osipenko]

06.09.2020 02:16, Michał Mirosław пишет:
> On Sat, Sep 05, 2020 at 11:41:20PM +0300, Dmitry Osipenko wrote:
>> Hello!
>>
>> This series performs refactoring of the Tegra I2C driver code and hardens
>> the atomic-transfer mode.
> [...]
> 
> Pending comments, all LGTM.

Thank you!