On Mon, May 30, 2022 at 07:40:56PM +0800, Potin Lai wrote:
> From: Porin Lai <potin.lai.pt@xxxxxxxxx>
>
> 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)
Do we need to add these to
Documentation/devicetree/bindings/i2c/aspeed,i2c.yaml ?
>
> Signed-off-by: Potin Lai <potin.lai.pt@xxxxxxxxx>
> ---
> 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;
>
> --
> 2.17.1
>
--
Patrick Williams
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