commit 6bbb14f018d4e7f958bcdc04b92be412601c44f6
author Patrick Delaunay <patrick.delaunay@foss.st.com> Tue Aug 03 12:05:13 2021 +0200
committer Patrice Chotard <patrice.chotard@foss.st.com> Fri Oct 08 08:42:40 2021 +0200
tree 26a7b3b9fda32b59da1ce6b36a9b70790438eeed
parent 09599998919c6eab26c3dfd0fcd2f8a6a07cf75d

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>

drivers/i2c/stm32f7_i2c.c

diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c
index e71a0e0..7e6c65f 100644
--- a/drivers/i2c/stm32f7_i2c.c
+++ b/drivers/i2c/stm32f7_i2c.c
@@ -45,6 +45,8 @@
 
 /* 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 @@
 #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 @@
  * @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 @@
 	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;