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Fri, 08 Apr 2016 13:25:11 +0900 (KST) From: Chanwoo Choi To: myungjoo.ham@samsung.com, kyungmin.park@samsung.com, k.kozlowski@samsung.com, kgene@kernel.org Subject: [PATCH v8 02/20] PM / devfreq: exynos: Add documentation for generic exynos bus frequency driver Date: Fri, 08 Apr 2016 13:24:51 +0900 Message-id: <1460089509-16260-3-git-send-email-cw00.choi@samsung.com> X-Mailer: git-send-email 1.8.0 In-reply-to: <1460089509-16260-1-git-send-email-cw00.choi@samsung.com> References: <1460089509-16260-1-git-send-email-cw00.choi@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrAIsWRmVeSWpSXmKPExsWyRsSkWHe5EXu4wdLXlhbXvzxntZh/5Byr Rf+bhawW516tZLSYdH8Ci8XrF4YW/Y9fM1ucbXrDbrHp8TVWi8u75rBZfO49wmgx4/w+Jot1 G2+xW9y+zGvx8sgPRoul1y8yWdxuXMFmMWH6WhaLM6cvsVq07j3CbtG2+gOrg6jHmnlrGD1a mnvYPC739TJ53LpT77Fz1l12j5XLv7B5bFrVyeaxeUm9x79j7B5brrazePRtWcXo8XmTXABP FJdNSmpOZllqkb5dAlfG6yMnmQrmKFRsXzWdqYFxgVQXIyeHhICJxO6e00wQtpjEhXvr2boY uTiEBFYwStzp/M8IU/RiwkyoxCxGibltv5ggnC+MEl8OXmADqWIT0JLY/+IGmC0ikCLx+OFJ sA5mgSPMElM33gDbISyQLXFg3QegsRwcLAKqEn0fzEHCvAKuEnNWrGeG2CYn8WHPI3YQm1PA TWLylUlgcSGgmhubpzODzJQQ2MIhcWHPXrAiFgEBiW+TD7GAzJQQkJXYdABqjqTEwRU3WCYw Ci9gZFjFKJpakFxQnJReZKRXnJhbXJqXrpecn7uJERixp/8969vBePOA9SFGAQ5GJR7eC+/Z woVYE8uKK3MPMZoCbZjILCWanA9MC3kl8YbGZkYWpiamxkbmlmZK4rwJUj+DhQTSE0tSs1NT C1KL4otKc1KLDzEycXBKNTBmL9792dDd80rkXeaMlPObuwX6P/fLH4q/YKTiJ/XlA/exvXv+ caSc9UsqOiqdHCPg56fAIn0+K7eornVbe3VANR9LPbvvXE3nq+KHJq8PVvVd/Iuf8bP6jp7D zZ/WN62d/76P8f22rtOtMRVZwid1JsTxz9F2XmP8RnLz9z2nw1RTu+Pm9CuxFGckGmoxFxUn AgBKuvZJ0wIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuplleLIzCtJLcpLzFFi42I5/e+xoO5yI/Zwg4OzjSyuf3nOajH/yDlW i/43C1ktzr1ayWgx6f4EFovXLwwt+h+/ZrY42/SG3WLT42usFpd3zWGz+Nx7hNFixvl9TBbr Nt5it7h9mdfi5ZEfjBZLr19ksrjduILNYsL0tSwWZ05fYrVo3XuE3aJt9QdWB1GPNfPWMHq0 NPeweVzu62XyuHWn3mPnrLvsHiuXf2Hz2LSqk81j85J6j3/H2D22XG1n8ejbsorR4/MmuQCe qAZGm4zUxJTUIoXUvOT8lMy8dFsl7+B453hTMwNDXUNLC3MlhbzE3FRbJRefAF23zBygX5UU yhJzSoFCAYnFxUr6dpgmhIa46VrANEbo+oYEwfUYGaCBhDWMGa+PnGQqmKNQsX3VdKYGxgVS XYycHBICJhIvJsxkg7DFJC7cWw9kc3EICcxilJjb9osJwvnCKPHl4AWwKjYBLYn9L26A2SIC KRKPH54E62AWOMIsMXXjDSaQhLBAtsSBdR8Yuxg5OFgEVCX6PpiDhHkFXCXmrFjPDLFNTuLD nkfsIDangJvE5CuTwOJCQDU3Nk9nnsDIu4CRYRWjRGpBckFxUnquUV5quV5xYm5xaV66XnJ+ 7iZGcFJ4Jr2D8fAu90OMAhyMSjy8F96zhQuxJpYVV+YeYpTgYFYS4XXVZw8X4k1JrKxKLcqP LyrNSS0+xGgKdNdEZinR5HxgwsoriTc0NjEzsjQyN7QwMjZXEud9/H9dmJBAemJJanZqakFq EUwfEwenVAOj9cw9hu8F2Df9al4grRLY+TBLQHE15/81bEu27Dv8727vrvs6Rzl6a8t8zkV5 /vFfMW/WSf33D6/vPv93UcOrZcdPuu9IXZTdaVT8t09fZS9bwDL5SdqRTKr7Joi0nF76iXf6 gW9NJoWif++Zrq5vKT4mnizk0K8cc8ZVMVDBS5vhr2QK9283JZbijERDLeai4kQArfpWOiAD AAA= 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-20160407_212535_455970_CD9349E9 X-CRM114-Status: GOOD ( 15.72 ) 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"; + };