[PATCH v1 5/7] i2c: stm32f7: fix configuration of the digital filter

[Patrice CHOTARD]

HI Patrick

On 8/3/21 12:05 PM, Patrice Chotard wrote:
> From: Patrick Delaunay <patrick.delaunay at foss.st.com>
> 
> 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 at foss.st.com>
> Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
> ---
> 
>  drivers/i2c/stm32f7_i2c.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/stm32f7_i2c.c b/drivers/i2c/stm32f7_i2c.c
> index e71a0e0aa3..7e6c65fadc 100644
> --- 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;
> 

Reviewed-by: Patrice Chotard <patrice.chotard at foss.st.com>

Thanks
Patrice