[PATCH v3 0/2] i2c: designware: Add support for a bus clock

[PATCH v3 0/2] i2c: designware: Add support for a bus clock

[Gareth Williams]

The Synopsys I2C Controller has a bus clock that some SoCs require to access
the registers. This series also details the new clock property in the bindings
documentation.

v3:
 - busclk renamed to pclk.
 - Added comment with dw_i2c_dev struct definition describing pclk.
 - Added enable rollback of first clock if second fails to enable.
 - Changed clocks and clock-names sections to use term "peripheral clock"
   (pclk) instead of "bus clock" (busclk) in dt-bindings documentation.
v2:
 - Use new devm_clk_get_optional() function as it simplifies handling when
   the optional clock is not present.

Phil Edworthy (2):
  dt: snps,designware-i2c: Add clock bindings documentation
  i2c: designware: Add support for a bus clock

 .../devicetree/bindings/i2c/i2c-designware.txt         |  9 +++++++++
 drivers/i2c/busses/i2c-designware-common.c             | 18 ++++++++++++++++--
 drivers/i2c/busses/i2c-designware-core.h               |  2 ++
 drivers/i2c/busses/i2c-designware-platdrv.c            |  5 +++++
 4 files changed, 32 insertions(+), 2 deletions(-)

-- 
2.7.4

[PATCH v3 1/2] dt: snps,designware-i2c: Add clock bindings documentation

[Gareth Williams]

From: Phil Edworthy <phil.edworthy@renesas.com>

The driver requires an undocumented clock property, so detail it.
Add documentation for a separate, optional, bus clock.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

v3:
 - Changed clocks and clock-names sections to use term "peripheral clock"
   (pclk) instead of "bus clock" (busclk).
v2:
 - No changes.
v1:
 - Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index 3e4bcc2..f94aa59 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -6,12 +6,21 @@ Required properties :
                 or "mscc,ocelot-i2c" with "snps,designware-i2c" for fallback
  - reg : Offset and length of the register set for the device
  - interrupts : <IRQ> where IRQ is the interrupt number.
+ - clocks : phandles for the clocks, see the description of clock-names below.
+   The phandle for the "ic_clk" clock is required. The phandle for the "pclk"
+   clock is optional. If a single clock is specified but no clock-name, it is
+   the "ic_clk" clock. If both clocks are listed, the "ic_clk" must be first.
 
 Recommended properties :
 
  - clock-frequency : desired I2C bus clock frequency in Hz.
 
 Optional properties :
+
+ - clock-names : Contains the names of the clocks:
+    "ic_clk", for the core clock used to generate the external I2C clock.
+    "pclk", the peripheral clock, required for register accesses.
+
  - reg : for "mscc,ocelot-i2c", a second register set to configure the SDA hold
    time, named ICPU_CFG:TWI_DELAY in the datasheet.
 
-- 
2.7.4

RE: [PATCH v3 0/2] i2c: designware: Add support for a bus clock

[Gareth Williams]

Sorry, the email below was sent prematurely and will be resent shortly.

-Gareth

> On 20 February 2019 13:26 Gareth Williams wrote:
> The Synopsys I2C Controller has a bus clock that some SoCs require to access
> the registers. This series also details the new clock property in the bindings
> documentation.
>
> v3:
>  - busclk renamed to pclk.
>  - Added comment with dw_i2c_dev struct definition describing pclk.
>  - Added enable rollback of first clock if second fails to enable.
>  - Changed clocks and clock-names sections to use term "peripheral clock"
>    (pclk) instead of "bus clock" (busclk) in dt-bindings documentation.
> v2:
>  - Use new devm_clk_get_optional() function as it simplifies handling when
>    the optional clock is not present.
>
> Phil Edworthy (2):
>   dt: snps,designware-i2c: Add clock bindings documentation
>   i2c: designware: Add support for a bus clock
>
>  .../devicetree/bindings/i2c/i2c-designware.txt         |  9 +++++++++
>  drivers/i2c/busses/i2c-designware-common.c             | 18
> ++++++++++++++++--
>  drivers/i2c/busses/i2c-designware-core.h               |  2 ++
>  drivers/i2c/busses/i2c-designware-platdrv.c            |  5 +++++
>  4 files changed, 32 insertions(+), 2 deletions(-)
>
> --
> 2.7.4



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Re: [PATCH v3 1/2] dt: snps,designware-i2c: Add clock bindings documentation

[Wolfram Sang]

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On Wed, Feb 20, 2019 at 03:50:02PM +0000, Gareth Williams wrote:
> From: Phil Edworthy <phil.edworthy@renesas.com>
> 
> The driver requires an undocumented clock property, so detail it.
> Add documentation for a separate, optional, bus clock.
> 
> Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

Looks good to me:

Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Let's see what the designware maintainers have to say.

> 
> v3:
>  - Changed clocks and clock-names sections to use term "peripheral clock"
>    (pclk) instead of "bus clock" (busclk).
> v2:
>  - No changes.
> v1:
>  - Reviewed-by: Rob Herring <robh@kernel.org>
> ---
>  Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> index 3e4bcc2..f94aa59 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> @@ -6,12 +6,21 @@ Required properties :
>                  or "mscc,ocelot-i2c" with "snps,designware-i2c" for fallback
>   - reg : Offset and length of the register set for the device
>   - interrupts : <IRQ> where IRQ is the interrupt number.
> + - clocks : phandles for the clocks, see the description of clock-names below.
> +   The phandle for the "ic_clk" clock is required. The phandle for the "pclk"
> +   clock is optional. If a single clock is specified but no clock-name, it is
> +   the "ic_clk" clock. If both clocks are listed, the "ic_clk" must be first.
>  
>  Recommended properties :
>  
>   - clock-frequency : desired I2C bus clock frequency in Hz.
>  
>  Optional properties :
> +
> + - clock-names : Contains the names of the clocks:
> +    "ic_clk", for the core clock used to generate the external I2C clock.
> +    "pclk", the peripheral clock, required for register accesses.
> +
>   - reg : for "mscc,ocelot-i2c", a second register set to configure the SDA hold
>     time, named ICPU_CFG:TWI_DELAY in the datasheet.
>  
> -- 
> 2.7.4
> 

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[PATCH v3 1/2] dt: snps,designware-i2c: Add clock bindings documentation

[Gareth Williams]

From: Phil Edworthy <phil.edworthy@renesas.com>

The driver requires an undocumented clock property, so detail it.
Add documentation for a separate, optional, bus clock.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>

v3:
 - Changed clocks and clock-names sections to use term "peripheral clock"
   (pclk) instead of "bus clock" (busclk).
v2:
 - No changes.
v1:
 - Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index 3e4bcc2..f94aa59 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -6,12 +6,21 @@ Required properties :
                 or "mscc,ocelot-i2c" with "snps,designware-i2c" for fallback
  - reg : Offset and length of the register set for the device
  - interrupts : <IRQ> where IRQ is the interrupt number.
+ - clocks : phandles for the clocks, see the description of clock-names below.
+   The phandle for the "ic_clk" clock is required. The phandle for the "pclk"
+   clock is optional. If a single clock is specified but no clock-name, it is
+   the "ic_clk" clock. If both clocks are listed, the "ic_clk" must be first.
 
 Recommended properties :
 
  - clock-frequency : desired I2C bus clock frequency in Hz.
 
 Optional properties :
+
+ - clock-names : Contains the names of the clocks:
+    "ic_clk", for the core clock used to generate the external I2C clock.
+    "pclk", the peripheral clock, required for register accesses.
+
  - reg : for "mscc,ocelot-i2c", a second register set to configure the SDA hold
    time, named ICPU_CFG:TWI_DELAY in the datasheet.
 
-- 
2.7.4