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SubjectRe: [PATCH 3/5] i2c: stm32f7: add support for DNF i2c-digital-filter binding
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Hello all

Looks good to me

Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@foss.st.com>

Regards

On 2/5/21 9:51 AM, Alain Volmat wrote:
> Add the support for the i2c-digital-filter binding, allowing to enable
> the digital filter via the device-tree and indicate its value in the DT.
>
> Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
> ---
> drivers/i2c/busses/i2c-stm32f7.c | 27 ++++++++++++++++-----------
> 1 file changed, 16 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index 0c539fea2754..f77cd6512a86 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -222,7 +222,6 @@ struct stm32f7_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)
> * @fmp_clr_offset: Fast Mode Plus clear register offset from set register
> */
> struct stm32f7_i2c_setup {
> @@ -230,7 +229,6 @@ struct stm32f7_i2c_setup {
> u32 clock_src;
> u32 rise_time;
> u32 fall_time;
> - u8 dnf;
> u32 fmp_clr_offset;
> };
>
> @@ -310,6 +308,8 @@ struct stm32f7_i2c_msg {
> * @smbus_mode: states that the controller is configured in SMBus mode
> * @host_notify_client: SMBus host-notify client
> * @analog_filter: boolean to indicate enabling of the analog filter
> + * @dnf_dt: value of digital filter requested via dt
> + * @dnf: value of digital filter to apply
> */
> struct stm32f7_i2c_dev {
> struct i2c_adapter adap;
> @@ -339,6 +339,8 @@ struct stm32f7_i2c_dev {
> bool smbus_mode;
> struct i2c_client *host_notify_client;
> bool analog_filter;
> + u32 dnf_dt;
> + u32 dnf;
> };
>
> /*
> @@ -384,13 +386,11 @@ static struct stm32f7_i2c_spec stm32f7_i2c_specs[] = {
> static const struct stm32f7_i2c_setup stm32f7_setup = {
> .rise_time = STM32F7_I2C_RISE_TIME_DEFAULT,
> .fall_time = STM32F7_I2C_FALL_TIME_DEFAULT,
> - .dnf = STM32F7_I2C_DNF_DEFAULT,
> };
>
> static const struct stm32f7_i2c_setup stm32mp15_setup = {
> .rise_time = STM32F7_I2C_RISE_TIME_DEFAULT,
> .fall_time = STM32F7_I2C_FALL_TIME_DEFAULT,
> - .dnf = STM32F7_I2C_DNF_DEFAULT,
> .fmp_clr_offset = 0x40,
> };
>
> @@ -459,10 +459,11 @@ static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
> return -EINVAL;
> }
>
> - if (setup->dnf > STM32F7_I2C_DNF_MAX) {
> + i2c_dev->dnf = DIV_ROUND_CLOSEST(i2c_dev->dnf_dt, i2cclk);
> + if (i2c_dev->dnf > STM32F7_I2C_DNF_MAX) {
> dev_err(i2c_dev->dev,
> "DNF out of bound %d/%d\n",
> - setup->dnf, STM32F7_I2C_DNF_MAX);
> + i2c_dev->dnf * i2cclk, STM32F7_I2C_DNF_MAX * i2cclk);
> return -EINVAL;
> }
>
> @@ -473,13 +474,13 @@ static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
> af_delay_max =
> (i2c_dev->analog_filter ?
> STM32F7_I2C_ANALOG_FILTER_DELAY_MAX : 0);
> - dnf_delay = setup->dnf * i2cclk;
> + dnf_delay = i2c_dev->dnf * i2cclk;
>
> sdadel_min = specs->hddat_min + setup->fall_time -
> - af_delay_min - (setup->dnf + 3) * i2cclk;
> + af_delay_min - (i2c_dev->dnf + 3) * i2cclk;
>
> sdadel_max = specs->vddat_max - setup->rise_time -
> - af_delay_max - (setup->dnf + 4) * i2cclk;
> + af_delay_max - (i2c_dev->dnf + 4) * i2cclk;
>
> scldel_min = setup->rise_time + specs->sudat_min;
>
> @@ -645,6 +646,7 @@ static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
> setup->speed_freq = t->bus_freq_hz;
> i2c_dev->setup.rise_time = t->scl_rise_ns;
> i2c_dev->setup.fall_time = t->scl_fall_ns;
> + i2c_dev->dnf_dt = t->digital_filter_width_ns;
> setup->clock_src = clk_get_rate(i2c_dev->clk);
>
> if (!setup->clock_src) {
> @@ -652,6 +654,9 @@ static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
> return -EINVAL;
> }
>
> + if (!of_property_read_bool(i2c_dev->dev->of_node, "i2c-digital-filter"))
> + i2c_dev->dnf_dt = STM32F7_I2C_DNF_DEFAULT;
> +
> do {
> ret = stm32f7_i2c_compute_timing(i2c_dev, setup,
> &i2c_dev->timing);
> @@ -681,7 +686,7 @@ static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
> dev_dbg(i2c_dev->dev, "I2C Rise(%i) and Fall(%i) Time\n",
> setup->rise_time, setup->fall_time);
> dev_dbg(i2c_dev->dev, "I2C Analog Filter(%s), DNF(%i)\n",
> - (i2c_dev->analog_filter ? "On" : "Off"), setup->dnf);
> + (i2c_dev->analog_filter ? "On" : "Off"), i2c_dev->dnf);
>
> i2c_dev->bus_rate = setup->speed_freq;
>
> @@ -732,7 +737,7 @@ static void stm32f7_i2c_hw_config(struct stm32f7_i2c_dev *i2c_dev)
> stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1,
> STM32F7_I2C_CR1_DNF_MASK);
> stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
> - STM32F7_I2C_CR1_DNF(i2c_dev->setup.dnf));
> + STM32F7_I2C_CR1_DNF(i2c_dev->dnf));
>
> stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
> STM32F7_I2C_CR1_PE);
>

--
--
~ Py MORDRET
--

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