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Mon, 11 Apr 2016 12:57:59 +0900 (KST) From: Chanwoo Choi To: myungjoo.ham@samsung.com, kyungmin.park@samsung.com, k.kozlowski@samsung.com, kgene@kernel.org, s.nawrocki@samsung.com, tomasz.figa@gmail.com Subject: [PATCH v9 02/20] PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver Date: Mon, 11 Apr 2016 12:57:40 +0900 Message-id: <1460347078-15175-3-git-send-email-cw00.choi@samsung.com> X-Mailer: git-send-email 1.8.0 In-reply-to: <1460347078-15175-1-git-send-email-cw00.choi@samsung.com> References: <1460347078-15175-1-git-send-email-cw00.choi@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrNIsWRmVeSWpSXmKPExsWyRsSkQPeEAne4wb1TLBbXvzxntZh/5Byr Rf+bhawW516tZLSYdH8Ci8XrF4YW/Y9fM1ucbXrDbrHp8TVWi8u75rBZfO49wmgx4/w+Jot1 G2+xW9y+zGvx8sgPRoul1y8yWdxuXMFmMWH6WhaLM6cvsVq07j3CbnH4TTurRdvqD6wWq3b9 YXQQ91gzbw2jR0tzD5vH5b5eJo9bd+o9ds66y+6xcvkXNo9NqzrZPDYvqff4d4zdY8vVdhaP vi2rGD0+b5IL4InisklJzcksSy3St0vgynh95CRTwRyFiu2rpjM1MC6Q6mLk5JAQMJHY++Ea E4QtJnHh3nq2LkYuDiGBFYwS/xv/s8EU9b7ZA5WYxSjx+8pjVgjnC6PEirVrwNrZBLQk9r+4 AVYlIjCVUeLzqTYWEIdZ4AizxNSNN8CqhAWyJba8nM8KYrMIqEqc+fidHcTmFXCV2H6whRli n5zEhz2PwOKcAm4Sn9a3A9VzAK1zlXj2uQ5kpoTAEQ6JV4sPQM0RkPg2+RALSI2EgKzEpgNQ YyQlDq64wTKBUXgBI8MqRtHUguSC4qT0ImO94sTc4tK8dL3k/NxNjMA4Pv3vWf8OxrsHrA8x CnAwKvHwOlzjChdiTSwrrsw9xGgKtGEis5Rocj4wWeSVxBsamxlZmJqYGhuZW5opifMulPoZ LCSQnliSmp2aWpBaFF9UmpNafIiRiYNTqoHR8m9p0ratMeeyc/Jyj904eyy0td5Z0+qoch7f g5gt6Tfu10axXfV3b18qUrdrknBBUsu2qZNL/620iP69qOn1rPw/Pub99rpMuY2mZRavDqfG CokHhfR35sw48WqXmvDlL7x1YY9DmZ6d27PzodFzlzUWNfxVvExTT5Qb+m5xy5vI+u/2Rx8l luKMREMt5qLiRACf1gQT3gIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprBKsWRmVeSWpSXmKPExsVy+t9jQd3jCtzhBosnWVlc//Kc1WL+kXOs Fv1vFrJanHu1ktFi0v0JLBavXxha9D9+zWxxtukNu8Wmx9dYLS7vmsNm8bn3CKPFjPP7mCzW bbzFbnH7Mq/FyyM/GC2WXr/IZHG7cQWbxYTpa1kszpy+xGrRuvcIu8XhN+2sFm2rP7BarNr1 h9FB3GPNvDWMHi3NPWwel/t6mTxu3an32DnrLrvHyuVf2Dw2repk89i8pN7j3zF2jy1X21k8 +rasYvT4vEkugCeqgdEmIzUxJbVIITUvOT8lMy/dVsk7ON453tTMwFDX0NLCXEkhLzE31VbJ xSdA1y0zB+hrJYWyxJxSoFBAYnGxkr4dpgmhIW66FjCNEbq+IUFwPUYGaCBhDWPG6yMnmQrm KFRsXzWdqYFxgVQXIyeHhICJRO+bPWwQtpjEhXvrgWwuDiGBWYwSv688ZoVwvjBKrFi7hgmk ik1AS2L/ixtgVSICUxklPp9qYwFxmAWOMEtM3XgDrEpYIFtiy8v5rCA2i4CqxJmP39lBbF4B V4ntB1uYIfbJSXzY8wgszingJvFpfTtQPQfQOleJZ5/rJjDyLmBkWMUokVqQXFCclJ5rlJda rlecmFtcmpeul5yfu4kRnCqeSe9gPLzL/RCjAAejEg/vi8tc4UKsiWXFlbmHGCU4mJVEeB/I cocL8aYkVlalFuXHF5XmpBYfYjQFumsis5Rocj4wjeWVxBsam5gZWRqZG1oYGZsrifM+/r8u TEggPbEkNTs1tSC1CKaPiYNTqoGxzqrQjKFDjvmu2dMPvSzFRheu3d3+uyJbf+PyycGBiW+1 0u7Pkvuf82yj2a6/j++fmPXbLCiAPXgZG+8Nx3Avvrt/lwmWfr7d5iIlslJhN7PD6WVP185P vcEdJ7Nsx4RDKq//L7pzooR3Xu5Bi4dH5m9tXX7w/vEpW0Wk/9foPVr9QPXoB+XZ15RYijMS DbWYi4oTAdfOcLcrAwAA DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160410_205825_522981_E7C82607 X-CRM114-Status: GOOD ( 16.20 ) X-Spam-Score: -7.9 (-------) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, inki.dae@samsung.com, linux-samsung-soc@vger.kernel.org, linux@arm.linux.org.uk, cw00.choi@samsung.com, pawel.moll@arm.com, ijc+devicetree@hellion.org.uk, linux.amoon@gmail.com, linux-pm@vger.kernel.org, rjw@rjwysocki.net, linux-kernel@vger.kernel.org, m.reichl@fivetechno.de, tjakobi@math.uni-bielefeld.de, devicetree@vger.kernel.org, robh+dt@kernel.org, galak@codeaurora.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-3.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RDNS_NONE,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch adds the documentation for generic exynos bus frequency driver. Signed-off-by: Chanwoo Choi Reviewed-by: Krzysztof Kozlowski Signed-off-by: MyungJoo Ham --- .../devicetree/bindings/devfreq/exynos-bus.txt | 95 ++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 Documentation/devicetree/bindings/devfreq/exynos-bus.txt diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt new file mode 100644 index 000000000000..78171b918e3f --- /dev/null +++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt @@ -0,0 +1,95 @@ +* Generic Exynos Bus frequency device + +The Samsung Exynos SoC has many buses for data transfer between DRAM +and sub-blocks in SoC. Most Exynos SoCs share the common architecture +for buses. Generally, each bus of Exynos SoC includes a source clock +and a power line, which are able to change the clock frequency +of the bus in runtime. To monitor the usage of each bus in runtime, +the driver uses the PPMU (Platform Performance Monitoring Unit), which +is able to measure the current load of sub-blocks. + +There are a little different composition among Exynos SoC because each Exynos +SoC has different sub-blocks. Therefore, shch difference should be specified +in devicetree file instead of each device driver. In result, this driver +is able to support the bus frequency for all Exynos SoCs. + +Required properties for bus device: +- compatible: Should be "samsung,exynos-bus". +- clock-names : the name of clock used by the bus, "bus". +- clocks : phandles for clock specified in "clock-names" property. +- operating-points-v2: the OPP table including frequency/voltage information + to support DVFS (Dynamic Voltage/Frequency Scaling) feature. +- vdd-supply: the regulator to provide the buses with the voltage. +- devfreq-events: the devfreq-event device to monitor the current utilization + of buses. + +Optional properties for bus device: +- exynos,saturation-ratio: the percentage value which is used to calibrate + the performance count against total cycle count. +- exynos,voltage-tolerance: the percentage value for bus voltage tolerance + which is used to calculate the max voltage. + +Example1: + Show the AXI buses of Exynos3250 SoC. Exynos3250 divides the buses to + power line (regulator). The MIF (Memory Interface) AXI bus is used to + transfer data between DRAM and CPU and uses the VDD_MIF regualtor. + + - power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block + + - MIF bus's frequency/voltage table + ----------------------- + |Lv| Freq | Voltage | + ----------------------- + |L1| 50000 |800000 | + |L2| 100000 |800000 | + |L3| 134000 |800000 | + |L4| 200000 |825000 | + |L5| 400000 |875000 | + ----------------------- + +Example2 : + The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi + is listed below: + + bus_dmc: bus_dmc { + compatible = "samsung,exynos-bus"; + clocks = <&cmu_dmc CLK_DIV_DMC>; + clock-names = "bus"; + operating-points-v2 = <&bus_dmc_opp_table>; + status = "disabled"; + }; + + bus_dmc_opp_table: opp_table1 { + compatible = "operating-points-v2"; + opp-shared; + + opp@50000000 { + opp-hz = /bits/ 64 <50000000>; + opp-microvolt = <800000>; + }; + opp@100000000 { + opp-hz = /bits/ 64 <100000000>; + opp-microvolt = <800000>; + }; + opp@134000000 { + opp-hz = /bits/ 64 <134000000>; + opp-microvolt = <800000>; + }; + opp@200000000 { + opp-hz = /bits/ 64 <200000000>; + opp-microvolt = <825000>; + }; + opp@400000000 { + opp-hz = /bits/ 64 <400000000>; + opp-microvolt = <875000>; + }; + }; + + Usage case to handle the frequency and voltage of bus on runtime + in exynos3250-rinato.dts is listed below: + + &bus_dmc { + devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>; + vdd-supply = <&buck1_reg>; /* VDD_MIF */ + status = "okay"; + };