diff mbox series

[v7,32/34] i2c: tegra: Clean up and improve comments

Message ID 20200908224006.25636-33-digetx@gmail.com
State New
Headers show
Series Improvements for Tegra I2C driver | expand

Checks

Context Check Description
tagr/GVS success 1124251
tagr/GVS pending 1124251
tagr/GVS success 1122533
tagr/GVS pending 1122533
tagr/GVS-1122491 fail None
tagr/GVS-1122491 pending None

Commit Message

Dmitry Osipenko Sept. 8, 2020, 10:40 p.m. UTC
Make all comments to be consistent in regards to capitalization and
punctuation, correct spelling and grammar errors, improve wording.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/i2c/busses/i2c-tegra.c | 88 ++++++++++++++++++----------------
 1 file changed, 47 insertions(+), 41 deletions(-)

Comments

Thierry Reding Sept. 17, 2020, 12:32 p.m. UTC | #1
On Wed, Sep 09, 2020 at 01:40:04AM +0300, Dmitry Osipenko wrote:
> Make all comments to be consistent in regards to capitalization and
> punctuation, correct spelling and grammar errors, improve wording.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 88 ++++++++++++++++++----------------
>  1 file changed, 47 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
> index 558b1f2934a0..31fbc6181dd5 100644
> --- a/drivers/i2c/busses/i2c-tegra.c
> +++ b/drivers/i2c/busses/i2c-tegra.c
> @@ -136,7 +136,7 @@
>  /* configuration load timeout in microseconds */
>  #define I2C_CONFIG_LOAD_TIMEOUT			1000000
>  
> -/* Packet header size in bytes */
> +/* packet header size in bytes */
>  #define I2C_PACKET_HEADER_SIZE			12
>  
>  /*
> @@ -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

I think that space before ':' can go away. Although that's preexisting,
so could also be a separate patch, I guess.

> + * @has_continue_xfer_support: Continue-transfer supported.

This isn't a proper sentence, so I don't think it should have a
full-stop. And it shouldn't start with an uppercase letter, either.

>   * @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.
> @@ -245,7 +244,7 @@ struct tegra_i2c_hw_feature {
>   * @msg_err: error code for completed message
>   * @msg_buf: pointer to current message data
>   * @msg_buf_remaining: size of unsent data in the message buffer
> - * @msg_read: identifies read transfers
> + * @msg_read: indicates read direction of a transfer

Hm... "read" is the "direction". Perhaps "indicates the direction of a
transfer"? Or perhaps "indicates that the transfer is a read access"?

[...]
> @@ -1797,9 +1804,8 @@ 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

s/during of runtime PM/during runtime PM/

Thierry
Dmitry Osipenko Sept. 17, 2020, 3:02 p.m. UTC | #2
17.09.2020 15:32, Thierry Reding пишет:
...
>>  /**
>> - * 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
> 
> I think that space before ':' can go away. Although that's preexisting,
> so could also be a separate patch, I guess.

I haven't even noticed that!
Dmitry Osipenko Sept. 17, 2020, 3:17 p.m. UTC | #3
17.09.2020 18:02, Dmitry Osipenko пишет:
> 17.09.2020 15:32, Thierry Reding пишет:
> ...
>>>  /**
>>> - * 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
>>
>> I think that space before ':' can go away. Although that's preexisting,
>> so could also be a separate patch, I guess.
> 
> I haven't even noticed that!
> 

Wait, that ':' is used only for the struct description, hence it
actually looks natural in the code.
Thierry Reding Sept. 21, 2020, 10:20 a.m. UTC | #4
On Wed, 09 Sep 2020 01:40:04 +0300, Dmitry Osipenko wrote:
> Make all comments to be consistent in regards to capitalization and
> punctuation, correct spelling and grammar errors, improve wording.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 88 ++++++++++++++++++----------------
>  1 file changed, 47 insertions(+), 41 deletions(-)

Tested-by: Thierry Reding <treding@nvidia.com>
Thierry Reding Sept. 21, 2020, 11:43 a.m. UTC | #5
On Thu, Sep 17, 2020 at 06:17:39PM +0300, Dmitry Osipenko wrote:
> 17.09.2020 18:02, Dmitry Osipenko пишет:
> > 17.09.2020 15:32, Thierry Reding пишет:
> > ...
> >>>  /**
> >>> - * 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
> >>
> >> I think that space before ':' can go away. Although that's preexisting,
> >> so could also be a separate patch, I guess.
> > 
> > I haven't even noticed that!
> > 
> 
> Wait, that ':' is used only for the struct description, hence it
> actually looks natural in the code.

What makes the struct description different from the field descriptions?
A description list is basically:

  <term>: <description>

And it doesn't matter what exactly <term> is.

Thierry
Thierry Reding Sept. 21, 2020, 11:44 a.m. UTC | #6
On Mon, Sep 21, 2020 at 01:43:20PM +0200, Thierry Reding wrote:
> On Thu, Sep 17, 2020 at 06:17:39PM +0300, Dmitry Osipenko wrote:
> > 17.09.2020 18:02, Dmitry Osipenko пишет:
> > > 17.09.2020 15:32, Thierry Reding пишет:
> > > ...
> > >>>  /**
> > >>> - * 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
> > >>
> > >> I think that space before ':' can go away. Although that's preexisting,
> > >> so could also be a separate patch, I guess.
> > > 
> > > I haven't even noticed that!
> > > 
> > 
> > Wait, that ':' is used only for the struct description, hence it
> > actually looks natural in the code.
> 
> What makes the struct description different from the field descriptions?
> A description list is basically:
> 
>   <term>: <description>
> 
> And it doesn't matter what exactly <term> is.

Anyway, like I said, this is preexisting, so we can always fix that up
in another patch:

Reviewed-by: Thierry Reding <treding@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 558b1f2934a0..31fbc6181dd5 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -136,7 +136,7 @@ 
 /* configuration load timeout in microseconds */
 #define I2C_CONFIG_LOAD_TIMEOUT			1000000
 
-/* Packet header size in bytes */
+/* packet header size in bytes */
 #define I2C_PACKET_HEADER_SIZE			12
 
 /*
@@ -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.
@@ -245,7 +244,7 @@  struct tegra_i2c_hw_feature {
  * @msg_err: error code for completed message
  * @msg_buf: pointer to current message data
  * @msg_buf_remaining: size of unsent data in the message buffer
- * @msg_read: identifies read transfers
+ * @msg_read: indicates read direction of a transfer
  * @bus_clk_rate: current I2C bus clock rate
  * @multimaster_mode: indicates that I2C controller is in multi-master mode
  * @tx_dma_chan: DMA transmit channel
@@ -306,8 +305,8 @@  static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, u32 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 u32 tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev, u32 reg)
 {
@@ -322,7 +321,7 @@  static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val, u32 reg)
 {
 	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));
 }
@@ -474,7 +473,7 @@  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)
 {
@@ -632,7 +631,7 @@  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);
@@ -645,8 +644,8 @@  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);
@@ -690,7 +689,7 @@  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.
 	 */
@@ -711,8 +710,8 @@  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;
@@ -725,7 +724,7 @@  static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 		rx_fifo_avail = FIELD_GET(I2C_FIFO_STATUS_RX, val);
 	}
 
-	/* Rounds down to not include partial word at the end of buf */
+	/* round down to exclude partial word at the end of buffer */
 	words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 	if (words_to_transfer > rx_fifo_avail)
 		words_to_transfer = rx_fifo_avail;
@@ -737,8 +736,8 @@  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) {
 		/*
@@ -778,10 +777,15 @@  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 */
+	/* round down to exclude 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. */
+	/*
+	 * This hunk pushes 4 bytes at a time into the TX FIFO.
+	 *
+	 * It's very common to have < 4 bytes, hence there is no word
+	 * to push if we have less than 4 bytes to transfer.
+	 */
 	if (words_to_transfer) {
 		if (words_to_transfer > tx_fifo_avail)
 			words_to_transfer = tx_fifo_avail;
@@ -805,8 +809,8 @@  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) {
@@ -854,7 +858,7 @@  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))
@@ -890,7 +894,8 @@  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) {
@@ -908,7 +913,7 @@  static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 	}
 	goto done;
 err:
-	/* An error occurred, mask all interrupts */
+	/* mask all interrupts on error */
 	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);
@@ -1337,6 +1342,7 @@  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
@@ -1566,7 +1572,6 @@  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, },
@@ -1590,7 +1595,7 @@  static void tegra_i2c_parse_dt(struct tegra_i2c_dev *i2c_dev)
 	err = of_property_read_u32(np, "clock-frequency",
 				   &i2c_dev->bus_clk_rate);
 	if (err)
-		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->multimaster_mode = multi_mode;
@@ -1722,11 +1727,13 @@  static int tegra_i2c_probe(struct platform_device *pdev)
 		goto release_clocks;
 
 	/*
-	 * 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);
@@ -1797,9 +1804,8 @@  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) {
 		err = tegra_i2c_init(i2c_dev);