[v2,05/10] i2c: meson: set clock divider in probe instead of setting it for each transfer

Submitted by Heiner Kallweit on March 9, 2017, 6:42 a.m.

Details

Message ID 5fcfa996-5986-1856-d6f7-a979b7c5d5c9@gmail.com
State Superseded
Headers show

Commit Message

Heiner Kallweit March 9, 2017, 6:42 a.m.
The bus frequency won't change, therefore we can set the clock divider
in probe already and we don't have to set it for each transfer.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
v2:
- no changes
---
 drivers/i2c/busses/i2c-meson.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Comments

Kevin Hilman March 10, 2017, 11:17 p.m.
Heiner Kallweit <hkallweit1@gmail.com> writes:

> The bus frequency won't change, therefore we can set the clock divider
> in probe already and we don't have to set it for each transfer.
>
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - no changes
> ---
>  drivers/i2c/busses/i2c-meson.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
> index a5764be5..594fec22 100644
> --- a/drivers/i2c/busses/i2c-meson.c
> +++ b/drivers/i2c/busses/i2c-meson.c
> @@ -74,7 +74,6 @@ enum {
>   * @error:	Flag set when an error is received
>   * @lock:	To avoid race conditions between irq handler and xfer code
>   * @done:	Completion used to wait for transfer termination
> - * @timings:	Struct including the bus frequency

You just added this field in PATCH 03/10.  Why not do this patch
first, which will simplify the other.

Kevin

>   * @tokens:	Sequence of tokens to be written to the device
>   * @num_tokens:	Number of tokens
>   */
> @@ -93,7 +92,6 @@ struct meson_i2c {
>  
>  	spinlock_t		lock;
>  	struct completion	done;
> -	struct i2c_timings	timings;
>  	u32			tokens[2];
>  	int			num_tokens;
>  };
> @@ -132,12 +130,12 @@ static void meson_i2c_write_tokens(struct meson_i2c *i2c)
>  	writel(i2c->tokens[1], i2c->regs + REG_TOK_LIST1);
>  }
>  
> -static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
> +static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
>  {
>  	unsigned long clk_rate = clk_get_rate(i2c->clk);
>  	unsigned int div;
>  
> -	div = DIV_ROUND_UP(clk_rate, i2c->timings.bus_freq_hz * 4);
> +	div = DIV_ROUND_UP(clk_rate, freq * 4);
>  
>  	/* clock divider has 12 bits */
>  	WARN_ON(div >= (1 << 12));
> @@ -149,7 +147,7 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
>  			   (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
>  
>  	dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__,
> -		clk_rate, i2c->timings.bus_freq_hz, div);
> +		clk_rate, freq, div);
>  }
>  
>  static void meson_i2c_get_data(struct meson_i2c *i2c, char *buf, int len)
> @@ -369,7 +367,6 @@ static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
>  	int i, ret = 0, count = 0;
>  
>  	clk_enable(i2c->clk);
> -	meson_i2c_set_clk_div(i2c);
>  
>  	for (i = 0; i < num; i++) {
>  		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1);
> @@ -396,6 +393,7 @@ static const struct i2c_algorithm meson_i2c_algorithm = {
>  static int meson_i2c_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> +	struct i2c_timings timings;
>  	struct meson_i2c *i2c;
>  	struct resource *mem;
>  	int irq, ret = 0;
> @@ -404,7 +402,7 @@ static int meson_i2c_probe(struct platform_device *pdev)
>  	if (!i2c)
>  		return -ENOMEM;
>  
> -	i2c_parse_fw_timings(&pdev->dev, &i2c->timings, true);
> +	i2c_parse_fw_timings(&pdev->dev, &timings, true);
>  
>  	i2c->dev = &pdev->dev;
>  	platform_set_drvdata(pdev, i2c);
> @@ -462,6 +460,8 @@ static int meson_i2c_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
> +
>  	return 0;
>  }
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Heiner Kallweit March 10, 2017, 11:36 p.m.
Am 11.03.2017 um 00:17 schrieb Kevin Hilman:
> Heiner Kallweit <hkallweit1@gmail.com> writes:
> 
>> The bus frequency won't change, therefore we can set the clock divider
>> in probe already and we don't have to set it for each transfer.
>>
>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>> ---
>> v2:
>> - no changes
>> ---
>>  drivers/i2c/busses/i2c-meson.c | 14 +++++++-------
>>  1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
>> index a5764be5..594fec22 100644
>> --- a/drivers/i2c/busses/i2c-meson.c
>> +++ b/drivers/i2c/busses/i2c-meson.c
>> @@ -74,7 +74,6 @@ enum {
>>   * @error:	Flag set when an error is received
>>   * @lock:	To avoid race conditions between irq handler and xfer code
>>   * @done:	Completion used to wait for transfer termination
>> - * @timings:	Struct including the bus frequency
> 
> You just added this field in PATCH 03/10.  Why not do this patch
> first, which will simplify the other.
> 
Yes, most likely this would be better. Will keep this in mind for the
upcoming v3.

> Kevin
> 
>>   * @tokens:	Sequence of tokens to be written to the device
>>   * @num_tokens:	Number of tokens
>>   */
>> @@ -93,7 +92,6 @@ struct meson_i2c {
>>  
>>  	spinlock_t		lock;
>>  	struct completion	done;
>> -	struct i2c_timings	timings;
>>  	u32			tokens[2];
>>  	int			num_tokens;
>>  };
>> @@ -132,12 +130,12 @@ static void meson_i2c_write_tokens(struct meson_i2c *i2c)
>>  	writel(i2c->tokens[1], i2c->regs + REG_TOK_LIST1);
>>  }
>>  
>> -static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
>> +static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
>>  {
>>  	unsigned long clk_rate = clk_get_rate(i2c->clk);
>>  	unsigned int div;
>>  
>> -	div = DIV_ROUND_UP(clk_rate, i2c->timings.bus_freq_hz * 4);
>> +	div = DIV_ROUND_UP(clk_rate, freq * 4);
>>  
>>  	/* clock divider has 12 bits */
>>  	WARN_ON(div >= (1 << 12));
>> @@ -149,7 +147,7 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
>>  			   (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
>>  
>>  	dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__,
>> -		clk_rate, i2c->timings.bus_freq_hz, div);
>> +		clk_rate, freq, div);
>>  }
>>  
>>  static void meson_i2c_get_data(struct meson_i2c *i2c, char *buf, int len)
>> @@ -369,7 +367,6 @@ static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
>>  	int i, ret = 0, count = 0;
>>  
>>  	clk_enable(i2c->clk);
>> -	meson_i2c_set_clk_div(i2c);
>>  
>>  	for (i = 0; i < num; i++) {
>>  		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1);
>> @@ -396,6 +393,7 @@ static const struct i2c_algorithm meson_i2c_algorithm = {
>>  static int meson_i2c_probe(struct platform_device *pdev)
>>  {
>>  	struct device_node *np = pdev->dev.of_node;
>> +	struct i2c_timings timings;
>>  	struct meson_i2c *i2c;
>>  	struct resource *mem;
>>  	int irq, ret = 0;
>> @@ -404,7 +402,7 @@ static int meson_i2c_probe(struct platform_device *pdev)
>>  	if (!i2c)
>>  		return -ENOMEM;
>>  
>> -	i2c_parse_fw_timings(&pdev->dev, &i2c->timings, true);
>> +	i2c_parse_fw_timings(&pdev->dev, &timings, true);
>>  
>>  	i2c->dev = &pdev->dev;
>>  	platform_set_drvdata(pdev, i2c);
>> @@ -462,6 +460,8 @@ static int meson_i2c_probe(struct platform_device *pdev)
>>  		return ret;
>>  	}
>>  
>> +	meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
>> +
>>  	return 0;
>>  }
> 

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Patch hide | download patch | download mbox

diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c
index a5764be5..594fec22 100644
--- a/drivers/i2c/busses/i2c-meson.c
+++ b/drivers/i2c/busses/i2c-meson.c
@@ -74,7 +74,6 @@  enum {
  * @error:	Flag set when an error is received
  * @lock:	To avoid race conditions between irq handler and xfer code
  * @done:	Completion used to wait for transfer termination
- * @timings:	Struct including the bus frequency
  * @tokens:	Sequence of tokens to be written to the device
  * @num_tokens:	Number of tokens
  */
@@ -93,7 +92,6 @@  struct meson_i2c {
 
 	spinlock_t		lock;
 	struct completion	done;
-	struct i2c_timings	timings;
 	u32			tokens[2];
 	int			num_tokens;
 };
@@ -132,12 +130,12 @@  static void meson_i2c_write_tokens(struct meson_i2c *i2c)
 	writel(i2c->tokens[1], i2c->regs + REG_TOK_LIST1);
 }
 
-static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
+static void meson_i2c_set_clk_div(struct meson_i2c *i2c, unsigned int freq)
 {
 	unsigned long clk_rate = clk_get_rate(i2c->clk);
 	unsigned int div;
 
-	div = DIV_ROUND_UP(clk_rate, i2c->timings.bus_freq_hz * 4);
+	div = DIV_ROUND_UP(clk_rate, freq * 4);
 
 	/* clock divider has 12 bits */
 	WARN_ON(div >= (1 << 12));
@@ -149,7 +147,7 @@  static void meson_i2c_set_clk_div(struct meson_i2c *i2c)
 			   (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT);
 
 	dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__,
-		clk_rate, i2c->timings.bus_freq_hz, div);
+		clk_rate, freq, div);
 }
 
 static void meson_i2c_get_data(struct meson_i2c *i2c, char *buf, int len)
@@ -369,7 +367,6 @@  static int meson_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 	int i, ret = 0, count = 0;
 
 	clk_enable(i2c->clk);
-	meson_i2c_set_clk_div(i2c);
 
 	for (i = 0; i < num; i++) {
 		ret = meson_i2c_xfer_msg(i2c, msgs + i, i == num - 1);
@@ -396,6 +393,7 @@  static const struct i2c_algorithm meson_i2c_algorithm = {
 static int meson_i2c_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
+	struct i2c_timings timings;
 	struct meson_i2c *i2c;
 	struct resource *mem;
 	int irq, ret = 0;
@@ -404,7 +402,7 @@  static int meson_i2c_probe(struct platform_device *pdev)
 	if (!i2c)
 		return -ENOMEM;
 
-	i2c_parse_fw_timings(&pdev->dev, &i2c->timings, true);
+	i2c_parse_fw_timings(&pdev->dev, &timings, true);
 
 	i2c->dev = &pdev->dev;
 	platform_set_drvdata(pdev, i2c);
@@ -462,6 +460,8 @@  static int meson_i2c_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	meson_i2c_set_clk_div(i2c, timings.bus_freq_hz);
+
 	return 0;
 }