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[125.228.123.29]) by smtp.gmail.com with ESMTPSA id d15-20020aa797af000000b0051bbc198f3fsm12560272pfq.13.2022.06.07.09.39.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Jun 2022 09:39:36 -0700 (PDT) From: Potin Lai To: Brendan Higgins , Benjamin Herrenschmidt , Joel Stanley , Andrew Jeffery , Rob Herring , Rayn Chen Cc: Patrick Williams , Potin Lai , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, Potin Lai Subject: [PATCH v3 1/2] aspeed: i2c: add clock duty cycle property Date: Wed, 8 Jun 2022 00:37:02 +0800 Message-Id: <20220607163703.26355-2-potin.lai.pt@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220607163703.26355-1-potin.lai.pt@gmail.com> References: <20220607163703.26355-1-potin.lai.pt@gmail.com> X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Introduce i2c-clk-duty-cycle property for setting a minimum clock high percentage. This driver calculate clk_high and clk_low with giving duty cycle. If it could not find a suit clk_high and clk_low, it apply default duty cycle 50%. Signed-off-by: Potin Lai --- drivers/i2c/busses/i2c-aspeed.c | 56 ++++++++++++++++++++++++++------- 1 file changed, 45 insertions(+), 11 deletions(-) diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c index 67e8b97c0c95..825d23f79be7 100644 --- a/drivers/i2c/busses/i2c-aspeed.c +++ b/drivers/i2c/busses/i2c-aspeed.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -27,6 +28,8 @@ #include #include +#define DEFAULT_I2C_CLK_DUTY_CYCLE 50 + /* I2C Register */ #define ASPEED_I2C_FUN_CTRL_REG 0x00 #define ASPEED_I2C_AC_TIMING_REG1 0x04 @@ -149,9 +152,11 @@ struct aspeed_i2c_bus { spinlock_t lock; struct completion cmd_complete; u32 (*get_clk_reg_val)(struct device *dev, - u32 divisor); + u32 divisor, + u32 duty_cycle); unsigned long parent_clk_frequency; u32 bus_frequency; + u32 duty_cycle; /* Transaction state. */ enum aspeed_i2c_master_state master_state; struct i2c_msg *msgs; @@ -798,9 +803,11 @@ static const struct i2c_algorithm aspeed_i2c_algo = { static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, u32 clk_high_low_mask, - u32 divisor) + u32 divisor, + u32 duty_cycle) { u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp; + u32 tmp_base_clk_divisor; /* * SCL_high and SCL_low represent a value 1 greater than what is stored @@ -842,10 +849,32 @@ static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, "clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n", divisor, (1 << base_clk_divisor) * clk_high_low_max); } else { - tmp = (divisor + (1 << base_clk_divisor) - 1) + for (tmp_base_clk_divisor = base_clk_divisor; + tmp_base_clk_divisor <= ASPEED_I2CD_TIME_BASE_DIVISOR_MASK; + tmp_base_clk_divisor++) { + /* calculate clk_high and clk_low with duty cycle */ + tmp = (divisor + (1 << tmp_base_clk_divisor) - 1) + >> tmp_base_clk_divisor; + + clk_high = DIV_ROUND_UP(tmp * duty_cycle, 100); + clk_low = tmp - clk_high; + + if (max(clk_high, clk_low) <= (clk_high_low_mask + 1)) + break; + } + + if (tmp_base_clk_divisor <= ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) + base_clk_divisor = tmp_base_clk_divisor; + else { + dev_err(dev, + "could not find clk_high and clk_low with duty cycle %u%%\n, recalculate with base_clk_divisor %u and duty_cycle 50%%", + duty_cycle, base_clk_divisor); + duty_cycle = 50; + tmp = (divisor + (1 << base_clk_divisor) - 1) >> base_clk_divisor; - clk_low = tmp / 2; - clk_high = tmp - clk_low; + clk_high = DIV_ROUND_UP(tmp * duty_cycle, 100); + clk_low = tmp - clk_high; + } if (clk_high) clk_high--; @@ -863,22 +892,22 @@ static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK); } -static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor) +static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor, u32 duty_cycle) { /* * clk_high and clk_low are each 3 bits wide, so each can hold a max * value of 8 giving a clk_high_low_max of 16. */ - return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor); + return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor, duty_cycle); } -static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor) +static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor, u32 duty_cycle) { /* * clk_high and clk_low are each 4 bits wide, so each can hold a max * value of 16 giving a clk_high_low_max of 32. */ - return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor); + return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor, duty_cycle); } /* precondition: bus.lock has been acquired. */ @@ -891,7 +920,7 @@ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK | ASPEED_I2CD_TIME_THDSTA_MASK | ASPEED_I2CD_TIME_TACST_MASK); - clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor); + clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor, bus->duty_cycle); writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1); writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2); @@ -1009,11 +1038,16 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ; } + ret = of_property_read_u32(pdev->dev.of_node, + "i2c-clk-duty-cycle-min", &bus->duty_cycle); + if (ret < 0 || !bus->duty_cycle || bus->duty_cycle > 100) + bus->duty_cycle = DEFAULT_I2C_CLK_DUTY_CYCLE; + match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node); if (!match) bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val; else - bus->get_clk_reg_val = (u32 (*)(struct device *, u32)) + bus->get_clk_reg_val = (u32 (*)(struct device *, u32, u32)) match->data; /* Initialize the I2C adapter */