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[125.228.123.29]) by smtp.gmail.com with ESMTPSA id c10-20020a170902c2ca00b0015e8d4eb207sm8865069pla.81.2022.05.30.04.43.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 May 2022 04:43:39 -0700 (PDT) From: Potin Lai To: Brendan Higgins , Benjamin Herrenschmidt , Joel Stanley , Andrew Jeffery Cc: Patrick Williams , Porin Lai , Porin Lai , linux-i2c@vger.kernel.org, openbmc@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/1] aspeed: i2c: add manual clock setup feature Date: Mon, 30 May 2022 19:40:56 +0800 Message-Id: <20220530114056.8722-1-potin.lai.pt@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Porin Lai Add properties for manual tuning i2c clock timing register. * aspeed,i2c-manual-clk: Enable aspeed i2c clock manual setup * aspeed,i2c-base-clk-div: Base Clock divisor (tBaseClk) * aspeed,i2c-clk-high-cycle: Cycles of clock-high pulse (tClkHigh) * aspeed,i2c-clk-low-cycle: Cycles of clock-low pulse (tClkLow) Signed-off-by: Potin Lai --- drivers/i2c/busses/i2c-aspeed.c | 55 ++++++++++++++++++++++++++++++++- 1 file changed, 54 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 67e8b97c0c95..1f4b5c4b5bf4 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -898,6 +898,56 @@ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) return 0; } +/* precondition: bus.lock has been acquired. */ +static int aspeed_i2c_manual_clk_setup(struct aspeed_i2c_bus *bus) +{ + u32 divisor, clk_high, clk_low, clk_reg_val; + + if (device_property_read_u32(bus->dev, "aspeed,i2c-base-clk-div", + &divisor) != 0) { + dev_err(bus->dev, "Could not read aspeed,i2c-base-clk-div\n"); + return -EINVAL; + } else if (divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) { + dev_err(bus->dev, "Invalid aspeed,i2c-base-clk-div: %u\n", + divisor); + return -EINVAL; + } + + if (device_property_read_u32(bus->dev, "aspeed,i2c-clk-high-cycle", + &clk_high) != 0) { + dev_err(bus->dev, "Could not read aspeed,i2c-clk-high-cycle\n"); + return -EINVAL; + } else if (clk_high > ASPEED_I2CD_TIME_SCL_REG_MAX) { + dev_err(bus->dev, "Invalid aspeed,i2c-clk-high-cycle: %u\n", + clk_high); + return -EINVAL; + } + + if (device_property_read_u32(bus->dev, "aspeed,i2c-clk-low-cycle", + &clk_low) != 0) { + dev_err(bus->dev, "Could not read aspeed,i2c-clk-low-cycle\n"); + return -EINVAL; + } else if (clk_low > ASPEED_I2CD_TIME_SCL_REG_MAX) { + dev_err(bus->dev, "Invalid aspeed,i2c-clk-low-cycle: %u\n", + clk_low); + return -EINVAL; + } + + clk_reg_val = readl(bus->base + ASPEED_I2C_AC_TIMING_REG1); + clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK | + ASPEED_I2CD_TIME_THDSTA_MASK | + ASPEED_I2CD_TIME_TACST_MASK); + clk_reg_val |= (divisor & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) + | ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT) + & ASPEED_I2CD_TIME_SCL_HIGH_MASK) + | ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT) + & ASPEED_I2CD_TIME_SCL_LOW_MASK); + writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1); + writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2); + + return 0; +} + /* precondition: bus.lock has been acquired. */ static int aspeed_i2c_init(struct aspeed_i2c_bus *bus, struct platform_device *pdev) @@ -908,7 +958,10 @@ static int aspeed_i2c_init(struct aspeed_i2c_bus *bus, /* Disable everything. */ writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG); - ret = aspeed_i2c_init_clk(bus); + if (of_property_read_bool(pdev->dev.of_node, "aspeed,i2c-manual-clk")) + ret = aspeed_i2c_manual_clk_setup(bus); + else + ret = aspeed_i2c_init_clk(bus); if (ret < 0) return ret;