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Thu, 31 Mar 2016 18:06:06 +0900 (KST) From: Chanwoo Choi To: myungjoo.ham@samsung.com, kyungmin.park@samsung.com, k.kozlowski@samsung.com, kgene@kernel.org Subject: [PATCH v7 02/20] PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver Date: Thu, 31 Mar 2016 18:05:47 +0900 Message-id: <1459415165-32613-3-git-send-email-cw00.choi@samsung.com> X-Mailer: git-send-email 1.8.0 In-reply-to: <1459415165-32613-1-git-send-email-cw00.choi@samsung.com> References: <1459415165-32613-1-git-send-email-cw00.choi@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrHIsWRmVeSWpSXmKPExsWyRsSkULf+xZ8wgz1n2C2uf3nOajH/yDlW i/43C1ktzr1ayWgx6f4EFovXLwwt+h+/ZrY42/SG3WLT42usFpd3zWGz+Nx7hNFixvl9TBbr Nt5it7h9mdfi5ZEfjBZLr19ksrjduILNYsL0tSwWZ05fYrVo3XuE3aJt9QdWB1GPNfPWMHq0 NPeweVzu62XyuHWn3mPnrLvsHiuXf2Hz2LSqk81j85J6j3/H2D22XG1n8ejbsorR4/MmuQCe KC6blNSczLLUIn27BK6M10dOMhXMUajYvmo6UwPjAqkuRg4OCQETiUMzcroYOYFMMYkL99az gdhCAisYJSb3ZkPETSQWHPwIFOcCis9ilHi64hIrhPOFUeLOtu2sIFVsAloS+1/cAOsWEUiR ePzwJFgHs8ARZompG28wgSSEBbIlFt9YDWazCKhKHG6+DdbAK+Aq8at5HxPEOjmJD3sesYPY nAJuEvfn32eGOMlV4tCSV1A1azkktm8sgJgjIPFt8iEWiG9kJTYdYIYokZQ4uOIGywRG4QWM DKsYRVMLkguKk9KLjPSKE3OLS/PS9ZLzczcxAqP19L9nfTsYbx6wPsQowMGoxMOrkfYnTIg1 say4MvcQoynQhonMUqLJ+cCUkFcSb2hsZmRhamJqbGRuaaYkzpsg9TNYSCA9sSQ1OzW1ILUo vqg0J7X4ECMTB6dUA2N89HcpuRWB88+KWLbMDdwVYCW01s/ny+nfF3+WX7i9cZfAU7sCnuKL 4lt+CRy9JvDQ8mI9q/2zNT/SK7s++nbPThN8ZhSy3f/PZgmGis8slhITNK71nxMxutd/8Y7k Qfe1z68cdb0y0TTtgVfIsV3vJK+vs03c/HfOA/2Tp5Wc+KaWLIjzcopXYinOSDTUYi4qTgQA pDuffNECAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuplleLIzCtJLcpLzFFi42I5/e+xoG79iz9hBj+rLa5/ec5qMf/IOVaL /jcLWS3OvVrJaDHp/gQWi9cvDC36H79mtjjb9IbdYtPja6wWl3fNYbP43HuE0WLG+X1MFus2 3mK3uH2Z1+LlkR+MFkuvX2SyuN24gs1iwvS1LBZnTl9itWjde4Tdom31B1YHUY8189YwerQ0 97B5XO7rZfK4dafeY+esu+weK5d/YfPYtKqTzWPzknqPf8fYPbZcbWfx6NuyitHj8ya5AJ6o BkabjNTElNQihdS85PyUzLx0WyXv4HjneFMzA0NdQ0sLcyWFvMTcVFslF58AXbfMHKBXlRTK EnNKgUIBicXFSvp2mCaEhrjpWsA0Ruj6hgTB9RgZoIGENYwZr4+cZCqYo1CxfdV0pgbGBVJd jJwcEgImEgsOfmSDsMUkLtxbD2RzcQgJzGKUeLriEiuE84VR4s627awgVWwCWhL7X9wA6xAR SJF4/PAkWAezwBFmiakbbzCBJIQFsiUW31gNZrMIqEocbr4N1sAr4Crxq3kfE8Q6OYkPex6x g9icAm4S9+ffZwaxhYBqDi15xTSBkXcBI8MqRonUguSC4qT0XMO81HK94sTc4tK8dL3k/NxN jOCk8ExqB+PBXe6HGAU4GJV4eC8k/wkTYk0sK67MPcQowcGsJML79wpQiDclsbIqtSg/vqg0 J7X4EKMp0GETmaVEk/OBCSuvJN7Q2MTMyNLI3NDCyNhcSZz38f91YUIC6YklqdmpqQWpRTB9 TBycUg2Mhj0X+Wc6pFit48oRrzKbt2CWytVV+W0Ze39OC/yve8fMY7amxpuiy033XOLSm/XT D2tN+l+5UtrIznGKZYVgz8Igb4ODV3anu/VvYdvg+Dp829rQxA9PvW0fhN3YUF/0f3Xpmp02 hjL9L83fyM976jfhv1v+zw0rT1l/r3Yo1FRRTk1dvIRfiaU4I9FQi7moOBEA+HnbGyADAAA= 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-20160331_020631_638696_4CCD946B X-CRM114-Status: GOOD ( 16.40 ) 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=-5.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, 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"; + };