Am Mittwoch, den 14.08.2013, 16:48 +0800 schrieb Nicolin Chen:
Hi Sascha,
On Wed, Aug 14, 2013 at 09:50:17AM +0200, Sascha Hauer wrote:
- tx-clksrc-names : The names for all available clock sources for tx, which
- is also being listed in SoC reference manual, ClkSrc_Sel bit of SPDIF_SRPC.
- And the name list would be different between different SoC. Use 'null' for
- those unlisted names, and the max number of tx-clksrc-names should be 8.
- rx-clksrc-names : The names for all available clock sources for rx, which
- is also being listed in SoC reference manual, TxClk_Source bit of SPDIF_STC.
- And the name list would be different between different SoC. Use 'null' for
- those unlisted names, and the max number of rx-clksrc-names should be 16.
+Optional properties:
- rx-clksrc-lock: This is a boolean property. If present, ClkSrc_Sel bit
- of SPDIF_SRPC would be set a clock source that cares DPLL locked condition.
+Example1:
+spdif: spdif@02004000 {
- clocks = <&clks 197>;
- clock-names = "core";
- rx-clksrc-lock;
- rx-clksrc-names =
"lock.ext", "lock.spdif", "lock.asrc","lock.spdif_ext", "lock.esai", "ext","spdif", "asrc", "spdif_ext", "esai","lock.mlb", "lock.mlb_phy", "mlb","mlb_phy";- tx-clksrc-names =
"xtal", "spdif", "asrc", "spdif_ext","esai", "ipg", "mlb", "mlb_phy";I had a hard time understanding what you are doing here.
With this the clk names in arch/arm/mach-imx/clk-imx6q.c become an API between the Kernel and the devicetree. Don't do that.
There is a standardized devicetree binding for clocks. Use it.
I think I should first explain to you what this part is doing: The driver needs to set Clk_source bit for TX/RX to select the clock from a clock mux. The names listed above are those of the clocks connecting to the mux, while they are not only internal clocks which're included in clk-imx6q.c but also external ones, an on-board external osc for example.
The driver does get the clock by using the standard DT binding, see the 'clocks = <&clks 197>' above, and then compare this obtained clock->name with the name list to decide which value should be set to the Clk_source bit.
================================================================== ClkSrc_Sel from i.MX6Q reference manual:
Clock source selection, all other settings not shown are reserved: 0000 if (DPLL Locked) SPDIF_RxClk else extal 0001 if (DPLL Locked) SPDIF_RxClk else spdif_clk 0010 if (DPLL Locked) SPDIF_RxClk else asrc_clk 0011 if (DPLL Locked) SPDIF_RxClk else spdif_extclk 0100 if (DPLL Locked) SPDIF_Rxclk else esai_hckt 0101 extal_clk 0110 spdif_clk 0111 asrc_clk 1000 spdif_extclk 1001 esai_hckt 1010 if (DPLL Locked) SPDIF_RxClk else mlb_clk ==================================================================
==================================================================
From i.MX53 reference manual:
0000 if (DPLL Locked) SPDIF_RxClk else extal 0001 if (DPLL Locked) SPDIF_RxClk else spdif_clk 0011 if (DPLL Locked) SPDIF_RxClk else asrc_clk 0100 if (DPLL Locked) SPDIF_Rxclk else esai_hckt 0101 extal_clk 0110 spdif_clk 1000 asrc_clk 1001 esai_hckt 1010 if (DPLL Locked) SPDIF_RxClk else mlb_clk 1011 if (DPLL Locked) SPDIF_RxClk else camp_clk 1100 mkb_clk 1101 camp_clk ==================================================================
To me this looks like the device tree should just contain the list of unique clock inputs using phandles. /* for i.MX6Q: */ clocks = <&...>; clock-names = "xtal", "spdif", "asrc", "spdif_ext", "esai", "mlb";
/* for i.MX53: */ clocks = <&...>; clock-names = "xtal", "spdif", "asrc", "esai", "mlb", "camp";
The driver could contain this list of named inputs to the multiplexer and the DPLL locking information for each SoC version. The per-clock DPLL locking bit shouldn't be in the device tree at all.
So the name list here basically is not being used to obtain a clock like what standardized DT binding does but to provide the driver a full list to look up which value should be exactly used according to the obtained clock.
I think I should revise the binding doc for these two lists. It might be hard to explain within that kinda short paragraph.
Surely, if I misunderstand your point, please correct me. And if you have any sage idea, please guide me.
regards Philipp