* [PATCH 2/2] i2c: designware: allow fine tuning tuning waveform from device tree
2024-02-01 4:46 [PATCH 1/2] dt-bindings: i2c: designware: allow fine tuning tuning waveform from device tree Aahil Awatramani
@ 2024-02-01 4:46 ` Aahil Awatramani
2024-02-01 7:34 ` Krzysztof Kozlowski
2024-02-01 7:33 ` [PATCH 1/2] dt-bindings: " Krzysztof Kozlowski
2024-02-01 11:46 ` Andy Shevchenko
2 siblings, 1 reply; 6+ messages in thread
From: Aahil Awatramani @ 2024-02-01 4:46 UTC (permalink / raw)
To: Aahil Awatramani, David Dillow, Wolfram Sang, Andi Shyti,
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Jarkko Nikula,
Andy Shevchenko, Mika Westerberg, Jan Dabros, linux-i2c,
devicetree, linux-kernel
The Synopsys i2c driver allows a user to override the parameters
controlling the waveform using ACPI; this is useful for fine tuning when
needed to make spec compliance. Extend this support to the device tree to
allow non-ACPI platforms the same capabilities.
Signed-off-by: Aahil Awatramani <aahila@google.com>
---
drivers/i2c/busses/i2c-designware-platdrv.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 855b698e99c0..09c464874fdb 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -132,6 +132,17 @@ static int mscc_twi_set_sda_hold_time(struct dw_i2c_dev *dev)
return 0;
}
+static void i2c_parse_cnt(struct device *dev, char *prop_name, u16 *cnt)
+{
+ u32 tmp_cnt;
+ int ret;
+
+ ret = device_property_read_u32(dev, prop_name, &tmp_cnt);
+ if (ret)
+ return;
+ *cnt = tmp_cnt;
+}
+
static int dw_i2c_of_configure(struct platform_device *pdev)
{
struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
@@ -146,6 +157,15 @@ static int dw_i2c_of_configure(struct platform_device *pdev)
break;
}
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-ss-hcnt", &dev->ss_hcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-ss-lcnt", &dev->ss_lcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-fs-hcnt", &dev->fs_hcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-fs-lcnt", &dev->fs_lcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-fp-hcnt", &dev->fp_hcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-fp-lcnt", &dev->fp_lcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-hs-hcnt", &dev->hs_hcnt);
+ i2c_parse_cnt(&pdev->dev, "i2c-scl-hs-lcnt", &dev->hs_lcnt);
+
return 0;
}
--
2.43.0.429.g432eaa2c6b-goog
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 2/2] i2c: designware: allow fine tuning tuning waveform from device tree
2024-02-01 4:46 ` [PATCH 2/2] " Aahil Awatramani
@ 2024-02-01 7:34 ` Krzysztof Kozlowski
0 siblings, 0 replies; 6+ messages in thread
From: Krzysztof Kozlowski @ 2024-02-01 7:34 UTC (permalink / raw)
To: Aahil Awatramani, David Dillow, Wolfram Sang, Andi Shyti,
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Jarkko Nikula,
Andy Shevchenko, Mika Westerberg, Jan Dabros, linux-i2c,
devicetree, linux-kernel
On 01/02/2024 05:46, Aahil Awatramani wrote:
>
> +static void i2c_parse_cnt(struct device *dev, char *prop_name, u16 *cnt)
> +{
> + u32 tmp_cnt;
> + int ret;
> +
> + ret = device_property_read_u32(dev, prop_name, &tmp_cnt);
> + if (ret)
> + return;
> + *cnt = tmp_cnt;
> +}
> +
> static int dw_i2c_of_configure(struct platform_device *pdev)
> {
> struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
> @@ -146,6 +157,15 @@ static int dw_i2c_of_configure(struct platform_device *pdev)
> break;
> }
>
> + i2c_parse_cnt(&pdev->dev, "i2c-scl-ss-hcnt", &dev->ss_hcnt);
Please post your DTS and post results of testing it against bindings.
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] dt-bindings: i2c: designware: allow fine tuning tuning waveform from device tree
2024-02-01 4:46 [PATCH 1/2] dt-bindings: i2c: designware: allow fine tuning tuning waveform from device tree Aahil Awatramani
2024-02-01 4:46 ` [PATCH 2/2] " Aahil Awatramani
@ 2024-02-01 7:33 ` Krzysztof Kozlowski
2024-02-01 11:46 ` Andy Shevchenko
2 siblings, 0 replies; 6+ messages in thread
From: Krzysztof Kozlowski @ 2024-02-01 7:33 UTC (permalink / raw)
To: Aahil Awatramani, David Dillow, Wolfram Sang, Andi Shyti,
Rob Herring, Krzysztof Kozlowski, Conor Dooley, Jarkko Nikula,
Andy Shevchenko, Mika Westerberg, Jan Dabros, linux-i2c,
devicetree, linux-kernel
On 01/02/2024 05:46, Aahil Awatramani wrote:
> The Synopsys i2c driver allows a user to override the parameters
Driver? That already suggests it is not suitable for binding...
> controlling the waveform using ACPI; this is useful for fine tuning when
> needed to make spec compliance. Extend this support to the device tree to
> allow non-ACPI platforms the same capabilities.
>
> Signed-off-by: Aahil Awatramani <aahila@google.com>
> ---
> Documentation/devicetree/bindings/i2c/i2c.txt | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
> index fc3dd7ec0445..3c33c36571f9 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c.txt
> @@ -45,6 +45,24 @@ wants to support one of the below features, it should adapt these bindings.
> Number of nanoseconds the SCL signal takes to rise; t(r) in the I2C
> specification.
>
> +- i2c-scl-ss-hcnt
> + HCNT value for standard speed mode in I2C Controller.
I have no clue what is HCNT, so I expect you to help us understand what
is this and why this is suitable for DT. Your reference to driver
suggests it is not suitable for DT.
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] dt-bindings: i2c: designware: allow fine tuning tuning waveform from device tree
2024-02-01 4:46 [PATCH 1/2] dt-bindings: i2c: designware: allow fine tuning tuning waveform from device tree Aahil Awatramani
2024-02-01 4:46 ` [PATCH 2/2] " Aahil Awatramani
2024-02-01 7:33 ` [PATCH 1/2] dt-bindings: " Krzysztof Kozlowski
@ 2024-02-01 11:46 ` Andy Shevchenko
2024-02-09 21:05 ` Aahil Awatramani
2 siblings, 1 reply; 6+ messages in thread
From: Andy Shevchenko @ 2024-02-01 11:46 UTC (permalink / raw)
To: Aahil Awatramani
Cc: David Dillow, Wolfram Sang, Andi Shyti, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Jarkko Nikula, Mika Westerberg,
Jan Dabros, linux-i2c, devicetree, linux-kernel
On Thu, Feb 01, 2024 at 04:46:22AM +0000, Aahil Awatramani wrote:
> The Synopsys i2c driver allows a user to override the parameters
> controlling the waveform using ACPI; this is useful for fine tuning when
> needed to make spec compliance. Extend this support to the device tree to
> allow non-ACPI platforms the same capabilities.
DT has different counters from which one should derive these ones.
Can you explain why existing bindings may _not_ be utilised?
Without this very justification, NAK.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] dt-bindings: i2c: designware: allow fine tuning tuning waveform from device tree
2024-02-01 11:46 ` Andy Shevchenko
@ 2024-02-09 21:05 ` Aahil Awatramani
0 siblings, 0 replies; 6+ messages in thread
From: Aahil Awatramani @ 2024-02-09 21:05 UTC (permalink / raw)
To: Andy Shevchenko
Cc: David Dillow, Wolfram Sang, Andi Shyti, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Jarkko Nikula, Mika Westerberg,
Jan Dabros, linux-i2c, devicetree, linux-kernel
Thank you Andy and Krzysztof,
I think you are right and I can use the other DT counter, I am
currently trying to test if they work for me.
Best,
Aahil
On Thu, Feb 1, 2024 at 3:49 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Thu, Feb 01, 2024 at 04:46:22AM +0000, Aahil Awatramani wrote:
> > The Synopsys i2c driver allows a user to override the parameters
> > controlling the waveform using ACPI; this is useful for fine tuning when
> > needed to make spec compliance. Extend this support to the device tree to
> > allow non-ACPI platforms the same capabilities.
>
> DT has different counters from which one should derive these ones.
> Can you explain why existing bindings may _not_ be utilised?
>
> Without this very justification, NAK.
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread