i2c: stm32f7: fix configuration of the digital filter

The digital filter related computation are present in the driver
however the programming of the filter within the IP is missing.
The maximum value for the DNF is wrong and should be 15 instead of 16.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>

diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c
index e71a0e0..7e6c65f 100644 (file)
--- a/drivers/i2c/stm32f7_i2c.c
+++ b/drivers/i2c/stm32f7_i2c.c
@@ -45,6 +45,8 @@ struct stm32_i2c_regs {
 
 /* STM32 I2C control 1 */
 #define STM32_I2C_CR1_ANFOFF                   BIT(12)
+#define STM32_I2C_CR1_DNF_MASK                 GENMASK(11, 8)
+#define STM32_I2C_CR1_DNF(n)                   (((n) & 0xf) << 8)
 #define STM32_I2C_CR1_ERRIE                    BIT(7)
 #define STM32_I2C_CR1_TCIE                     BIT(6)
 #define STM32_I2C_CR1_STOPIE                   BIT(5)
@@ -106,7 +108,7 @@ struct stm32_i2c_regs {
 #define STM32_I2C_MAX_LEN                      0xff
 
 #define STM32_I2C_DNF_DEFAULT                  0
-#define STM32_I2C_DNF_MAX                      16
+#define STM32_I2C_DNF_MAX                      15
 
 #define STM32_I2C_ANALOG_FILTER_DELAY_MIN      50      /* ns */
 #define STM32_I2C_ANALOG_FILTER_DELAY_MAX      260     /* ns */
@@ -155,7 +157,7 @@ struct stm32_i2c_spec {
  * @clock_src: I2C clock source frequency (Hz)
  * @rise_time: Rise time (ns)
  * @fall_time: Fall time (ns)
- * @dnf: Digital filter coefficient (0-16)
+ * @dnf: value of digital filter to apply
  * @analog_filter: Analog filter delay (On/Off)
  */
 struct stm32_i2c_setup {
@@ -842,6 +844,10 @@ static int stm32_i2c_hw_config(struct stm32_i2c_priv *i2c_priv)
        else
                setbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
 
+       /* Program the Digital Filter */
+       clrsetbits_le32(&regs->cr1, STM32_I2C_CR1_DNF_MASK,
+                       STM32_I2C_CR1_DNF(i2c_priv->setup.dnf));
+
        setbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
 
        return 0;