diff mbox series

[v2,1/2] dt: snps,designware-i2c: Add clock bindings documentation

Message ID 1550589042-11096-2-git-send-email-gareth.williams.jx@renesas.com
State Superseded
Headers show
Series dt: i2c: Add support for bus clock | expand

Commit Message

Gareth Williams Feb. 19, 2019, 3:10 p.m. UTC 
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>
Signed-off-by: Gareth Williams <gareth.williams.jx@renesas.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
v2:
 - No changes.
---
 Documentation/devicetree/bindings/i2c/i2c-designware.txt | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Wolfram Sang Feb. 19, 2019, 8:23 p.m. UTC | #1 
On Tue, Feb 19, 2019 at 03:10:41PM +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.

Is it named "bus clock" in the datasheets? If so, then be it, but if
possible, I'd avoid this term because it is ambigious (Is it the I2C bus
or the interconnect bus or...?). pclk sounds more precise to me.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index 3e4bcc2..822ebce 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 "bus"
+   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.
+    "bus", the bus clock, sometimes described as pclk, 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.