Add manual tuning i2c clock timing register support by reading
following properties.
* aspeed,i2c-manual-clk: Enable aspeed i2c clock manual setting
* 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 <potin.lai.pt@xxxxxxxxx>
---
drivers/i2c/busses/i2c-aspeed.c | 57 ++++++++++++++++++++++++++++++++-
1 file changed, 56 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 67e8b97c0c95..64424f377f27 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -60,6 +60,7 @@
#define ASPEED_I2CD_TIME_SCL_LOW_MASK GENMASK(15, 12)
#define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK GENMASK(3, 0)
#define ASPEED_I2CD_TIME_SCL_REG_MAX GENMASK(3, 0)
+#define ASPEED_I2CD_TIME_BASE_DIVISOR_MAX 32768
/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
#define ASPEED_NO_TIMEOUT_CTRL 0
@@ -898,6 +899,57 @@ 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 || divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MAX ||
+ BIT(__fls(divisor)) != divisor) {
+ 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-1) > 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-1) > 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 |= (ilog2(divisor) & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK)
+ | (((clk_high-1) << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
+ & ASPEED_I2CD_TIME_SCL_HIGH_MASK)
+ | (((clk_low-1) << 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 +960,10 @@ 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
