linux-kernel - [PATCH v4 03/15] dt-bindings: devfreq: rk3399

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Message-Id: <20220308110825.v4.3.I9341269171c114d0e04e41d48037fd32816e2d8c@changeid>
Date:   Tue,  8 Mar 2022 11:08:49 -0800
From:   Brian Norris <briannorris@...omium.org>
To:     MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Heiko Stuebner <heiko@...ech.de>
Cc:     Derek Basehore <dbasehore@...omium.org>,
        devicetree@...r.kernel.org, linux-rockchip@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Lin Huang <hl@...k-chips.com>,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
        Brian Norris <briannorris@...omium.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Subject: [PATCH v4 03/15] dt-bindings: devfreq: rk3399_dmc: Fix Hz units

The driver and all downstream device trees [1] are using Hz units, but
the document claims MHz. DRAM frequency for these systems can't possibly
exceed 2^32-1 Hz, so the choice of unit doesn't really matter than much.

Rather than add unnecessary risk in getting the units wrong, let's just
go with the unofficial convention and make the docs match reality.

A sub-1MHz frequency is extremely unlikely, so include a minimum in the
schema, to help catch anybody who might have believed this was MHz.

[1] And notably, also those trying to upstream them:
https://lore.kernel.org/lkml/20210308233858.24741-3-daniel.lezcano@linaro.org/

Signed-off-by: Brian Norris <briannorris@...omium.org>
Reviewed-by: Rob Herring <robh@...nel.org>
Acked-by: Chanwoo Choi <cw00.choi@...sung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
---

(no changes since v3)

Changes in v3:
 * Add Reviewed-by, Acked-by

 .../rockchip,rk3399-dmc.yaml                  | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/memory-controllers/rockchip,rk3399-dmc.yaml b/Documentation/devicetree/bindings/memory-controllers/rockchip,rk3399-dmc.yaml
index 356bbe5db383..96efb23cfc0f 100644
--- a/Documentation/devicetree/bindings/memory-controllers/rockchip,rk3399-dmc.yaml
+++ b/Documentation/devicetree/bindings/memory-controllers/rockchip,rk3399-dmc.yaml
@@ -115,11 +115,11 @@ properties:
 
   rockchip,ddr3_odt_dis_freq:
     $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1000000  # In case anyone thought this was MHz.
     description:
       When the DRAM type is DDR3, this parameter defines the ODT disable
-      frequency in MHz (Mega Hz). When the DDR frequency is less then
-      ddr3_odt_dis_freq, the ODT on the DRAM side and controller side are both
-      disabled.
+      frequency in Hz. When the DDR frequency is less then ddr3_odt_dis_freq,
+      the ODT on the DRAM side and controller side are both disabled.
 
   rockchip,ddr3_drv:
     deprecated: true
@@ -163,11 +163,11 @@ properties:
 
   rockchip,lpddr3_odt_dis_freq:
     $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1000000  # In case anyone thought this was MHz.
     description:
       When the DRAM type is LPDDR3, this parameter defines then ODT disable
-      frequency in MHz (Mega Hz). When DDR frequency is less then
-      ddr3_odt_dis_freq, the ODT on the DRAM side and controller side are both
-      disabled.
+      frequency in Hz. When DDR frequency is less then ddr3_odt_dis_freq, the
+      ODT on the DRAM side and controller side are both disabled.
 
   rockchip,lpddr3_drv:
     deprecated: true
@@ -210,11 +210,11 @@ properties:
 
   rockchip,lpddr4_odt_dis_freq:
     $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1000000  # In case anyone thought this was MHz.
     description:
       When the DRAM type is LPDDR4, this parameter defines the ODT disable
-      frequency in MHz (Mega Hz). When the DDR frequency is less then
-      ddr3_odt_dis_freq, the ODT on the DRAM side and controller side are both
-      disabled.
+      frequency in Hz. When the DDR frequency is less then ddr3_odt_dis_freq,
+      the ODT on the DRAM side and controller side are both disabled.
 
   rockchip,lpddr4_drv:
     deprecated: true
@@ -300,7 +300,7 @@ examples:
       rockchip,sr_mc_gate_idle = <0x3>;
       rockchip,srpd_lite_idle = <0x4>;
       rockchip,standby_idle = <0x2000>;
-      rockchip,ddr3_odt_dis_freq = <333>;
-      rockchip,lpddr3_odt_dis_freq = <333>;
-      rockchip,lpddr4_odt_dis_freq = <333>;
+      rockchip,ddr3_odt_dis_freq = <333000000>;
+      rockchip,lpddr3_odt_dis_freq = <333000000>;
+      rockchip,lpddr4_odt_dis_freq = <333000000>;
     };
-- 
2.35.1.616.g0bdcbb4464-goog