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drivers: i3c: cdns: correct sda push pull hold time

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correct the comments and timing for the sda push-pull hold time
configuration.

Signed-off-by: Ryan McClelland <ryanmcclelland@meta.com>
This commit is contained in:
Ryan McClelland 2024-10-02 16:03:25 -07:00 committed by Anas Nashif
parent 9403b08512
commit 9c48f7eb37
1 changed files with 9 additions and 9 deletions
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18
drivers/i3c/i3c_cdns.c
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@ -472,11 +472,10 @@
#define I3C_BUS_TLOW_OD_MIN_NS 200
/*
* MIPI I3C v1.1.1 Spec defines tsco max as 12ns, but the default for devices is 8ns
* TODO: this should be configurable by the value with in maxRd from the CCC GETMXDS
* for individual devices
* MIPI I3C v1.1.1 Spec defines SDA Signal Data Hold in Push Pull max as the
* minimum of the clock rise and fall time plus 3ns
*/
#define I3C_TSCO_DEFAULT_NS 8
#define I3C_HD_PP_DEFAULT_NS 10
/* Interrupt thresholds. */
/* command response fifo threshold */
@ -3058,16 +3057,18 @@ static enum i3c_bus_mode i3c_bus_mode(const struct i3c_dev_list *dev_list)
/**
* Determine THD_DEL value for CTRL register
*
* Should be MIN(t_cf, t_cr) + 3ns
*
* @param dev Pointer to device driver instance.
*
* @return Value to be written to THD_DEL
*/
static uint8_t cdns_i3c_clk_to_data_turnaround(const struct device *dev)
static uint8_t cdns_i3c_sda_data_hold(const struct device *dev)
{
const struct cdns_i3c_config *config = dev->config;
uint32_t input_clock_frequency = config->input_frequency;
uint8_t thd_delay =
DIV_ROUND_UP(I3C_TSCO_DEFAULT_NS, (NSEC_PER_SEC / input_clock_frequency));
DIV_ROUND_UP(I3C_HD_PP_DEFAULT_NS, (NSEC_PER_SEC / input_clock_frequency));
if (thd_delay > THD_DELAY_MAX) {
thd_delay = THD_DELAY_MAX;
@ -3156,11 +3157,10 @@ static int cdns_i3c_bus_init(const struct device *dev)
ctrl &= ~CTRL_MST_ACK;
/*
* Cadence I3C release r104v1p0 and above support configuration of the clock to data
* turnaround time.
* Cadence I3C release r104v1p0 and above support configuration of the sda data hold time
*/
if (REV_ID_REV(data->hw_cfg.rev_id) >= REV_ID_VERSION(1, 4)) {
ctrl |= CTRL_THD_DELAY(cdns_i3c_clk_to_data_turnaround(dev));
ctrl |= CTRL_THD_DELAY(cdns_i3c_sda_data_hold(dev));
}
/*