Re: [LINUX PATCH v9 1/4] Devicetree: Add pl353 smc controller devicetree binding information

From: Miquel Raynal
Date: Thu Jun 07 2018 - 11:42:31 EST


Hi Naga,

On Wed, 6 Jun 2018 13:19:39 +0530, Naga Sureshkumar Relli
<naga.sureshkumar.relli@xxxxxxxxxx> wrote:

> Add pl353 static memory controller devicetree binding information.
>
> Signed-off-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xxxxxxxxxx>
> ---
> Changes in v9:
> - Addressed commens given by Randy Dunlap and Miquel Raynal

Can you please be more specific in your next changelog? I don't
remember what I suggested a few months ago :)

> Changes in v8:
> - None
> Changes in v7:
> - Corrected clocks description
> - prefixed '#' for address and size cells
> Changes in v6:
> - None
> Changes in v5:
> - Removed timing properties
> Changes in v4:
> - none
> Changes in v3:
> - none
> Changes in v2:
> - modified timing binding info as per onfi timing parameters
> - add suffix nano second as timing unit
> - modified the clock names as per the IP spec
> ---
> .../bindings/memory-controllers/pl353-smc.txt | 53 ++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
>
> diff --git a/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt b/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
> new file mode 100644
> index 0000000..551e66b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/memory-controllers/pl353-smc.txt
> @@ -0,0 +1,53 @@
> +Device tree bindings for ARM PL353 static memory controller
> +
> +PL353 static memory controller supports two kinds of memory
> +interfaces.i.e NAND and SRAM/NOR interfaces.
> +The actual devices are instantiated from the child nodes of pl353 smc node.
> +
> +Required properties:
> +- compatible : Should be "arm,pl353-smc-r2p1"

I thing Rob prefers:

- compatible: Must be one of:
* arm, pl353-smc-r2p1

> +- reg : Controller registers map and length.
> +- clock-names : List of input clock names - "ref_clk", "aper_clk"
> + (See clock bindings for details).
> +- clocks : Clock phandles (see clock bindings for details).
> +- address-cells : Address cells, must be 1.
> +- size-cells : Size cells. Must be 1.

Please avoid padding, just this is enough:

- something: And another thing.

> +
> +Child nodes:
> + For NAND the "arm,pl353-nand-r2p1" and for NOR the "cfi-flash" drivers are
> +supported as child nodes.
> +
> +Mandatory timing properties for child nodes:
> +- arm,nand-cycle-t0 : Read cycle time(t_rc).
> +- arm,nand-cycle-t1 : Write cycle time(t_wc).
> +- arm,nand-cycle-t2 : re_n assertion delay(t_rea).
> +- arm,nand-cycle-t3 : we_n de-assertion delay(t_wp).
> +- arm,nand-cycle-t4 : Status read time(t_clr)
> +- arm,nand-cycle-t5 : ID read time(t_ar)
> +- arm,nand-cycle-t6 : busy to re_n(t_rr)

I think this has nothing to do in the DT, you should handle timings
from the ->setup_data_interface() hook. If you need, you may use
different compatibles to distinguish different platform data.

> +
> +for nand partition information please refer the below file

s/nand/NAND/

> +Documentation/devicetree/bindings/mtd/partition.txt
> +
> +Example:
> + pl353smcc_0: pl353smcc@e000e000 {

Why not something more explicit with the '-flash-controller' suffix?

> + compatible = "arm,pl353-smc-r2p1"
> + clock-names = "memclk", "aclk";
> + clocks = <&clkc 11>, <&clkc 44>;
> + reg = <0xe000e000 0x1000>;
> + #address-cells = <1>;
> + #size-cells = <1>;
> + ranges;
> + nand_0: nand@e1000000 {
> + compatible = "arm,pl353-nand-r2p1"

NAND chips do not have their own compatible.

> + reg = <0xe1000000 0x1000000>;
> + arm,nand-cycle-t0 = <0x4>;
> + arm,nand-cycle-t1 = <0x4>;
> + arm,nand-cycle-t2 = <0x1>;
> + arm,nand-cycle-t3 = <0x2>;
> + arm,nand-cycle-t4 = <0x2>;
> + arm,nand-cycle-t5 = <0x2>;
> + arm,nand-cycle-t6 = <0x4>;
> + (...)
> + };
> + };


Thanks,
MiquÃl