On 2016年11月25日 18:25, Philipp Zabel wrote:
Am Donnerstag, den 24.11.2016, 18:20 +0800 schrieb zhangfei:
On 2016年11月24日 17:50, Philipp Zabel wrote:
Am Donnerstag, den 24.11.2016, 17:40 +0800 schrieb zhangfei:
On 2016年11月24日 17:26, Philipp Zabel wrote:
Am Mittwoch, den 23.11.2016, 16:07 +0800 schrieb Zhangfei Gao:
Add DT bindings documentation for hi3660 SoC reset controller.
Signed-off-by: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
---
.../bindings/reset/hisilicon,hi3660-reset.txt | 51 ++++++++++++++++++++++
1 file changed, 51 insertions(+)
create mode 100644 Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
diff --git a/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
new file mode 100644
index 0000000..250daf2
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
@@ -0,0 +1,51 @@
+Hisilicon System Reset Controller
+======================================
+
+Please also refer to reset.txt in this directory for common reset
+controller binding usage.
+
+The reset controller registers are part of the system-ctl block on
+hi3660 SoC.
+
+Required properties:
+- compatible: should be
+ "hisilicon,hi3660-reset"
+- #reset-cells: 1, see below
+- hisi,rst-syscon: phandle of the reset's syscon.
+- hisi,reset-bits: Contains the reset control register information
+ Should contain 2 cells for each reset exposed to
+ consumers, defined as:
+ Cell #1 : offset from the syscon register base
+ Cell #2 : bits position of the control register
+
+Example:
+ iomcu: iomcu@ffd7e000 {
+ compatible = "hisilicon,hi3660-iomcu", "syscon";
+ reg = <0x0 0xffd7e000 0x0 0x1000>;
+ };
+
+ iomcu_rst: iomcu_rst_controller {
This should be
iomcu_rst: reset-controller {
+ compatible = "hisilicon,hi3660-reset";
+ #reset-cells = <1>;
+ hisi,rst-syscon = <&iomcu>;
+ hisi,reset-bits = <0x20 0x8 /* 0: i2c0 */
+ 0x20 0x10 /* 1: i2c1 */
+ 0x20 0x20 /* 2: i2c2 */
+ 0x20 0x8000000>; /* 3: i2c6 */
+ };
The reset lines are controlled through iomcu bits, is there a reason not
to put the iomcu_rst node inside the iomcu node? That way the
hisi,rst-syscon property could be removed and the syscon could be
retrieved via the reset-controller parent node.
iomcu is common registers, controls clock and reset, etc.
So we use syscon, without mapping the registers everywhere.
It is common case in hisilicon, same in hi6220.
Also the #clock-cells and #reset-cells can not be put in the same node,
if they are both using probe, since reset_probe will not be called.
So we use hisi,rst-syscon as a general solution.
What I meant is this:
iomcu: iomcu@ffd7e000 {
compatible = "hisilicon,hi3660-iomcu", "syscon", "simple-mfd";
reg = <0x0 0xffd7e000 0x0 0x1000>;
#clock-cells = <1>;
In my test, if there add #clock-cells = <1>, reset_probe will not be
called any more.
Since clk_probe is called first.
No matter iomcu_rst is child node or not.
I don't understand this, does the clock driver bind to the iomcu node
using CLK_OF_DECLARE_DRIVER(..., "hisilicon,hi3660-iomcu", ...)?
This method:CLK_OF_DECLARE_DRIVER is not prefered in clock,
and we have to use probe instead, to make all driver build as modules as
possible.
For example hi3660.
static struct platform_driver hi3660_clk_driver = {
.probe = hi3660_clk_probe,
.driver = {
.name = "hi3660-clk",
.of_match_table = hi3660_clk_match_table,
},
};
static int __init hi3660_clk_init(void)
{
return platform_driver_register(&hi3660_clk_driver);
}
core_initcall(hi3660_clk_init);
And many examples in drivers/clock, just
#grep -rn probe drivers/clk/
drivers/clk/clk-axm5516.c:587: .probe = axmclk_probe,
If the parent node happen to be clock, and set
#clock-cells = <1>;
Then clock_probe/hi3660_clk_probe will be called first.
But reset_probe will not be called any more.
Thanks
My comment was based only on this reset binding documentation and the
example DT snippet. Could you point me to the clock driver probe code
and show me a more complete part of the hi3660 device tree?
regards
Philipp
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