On 03.10.23, Michael Wu wrote:
> In commit 35eba185fd1a ("i2c: designware: Calculate SCL timing parameter
> for High Speed Mode") the SCL high period count and low period count for
> high speed mode are calculated based on fixed tHIGH = 160 and tLOW = 120.
> However, the set of two fixed values is only applicable to the combination
> of hardware parameters IC_CAP_LOADING is 400 and
> IC_CLK_FREQ_OPTIMIZATION
> is true. Outside of this combination, the SCL frequency may not reach
> 3.4 MHz because the fixed tHIGH and tLOW are not small enough.
>
> Since there are no any registers controlling these two hardware parameters,
> their values can only be declared through the device tree.
>
> v4:
> - yaml: re-formatting two properties' description
> - yaml: enumeriate bus-capacitance-pf
> - yaml: extand an existing example
> - driver: modify the commit description
> - driver: rename "bus-capacitance-pf" to "bus-capacitance-pF"
>
> v3:
> - add vendor prefix on new property name
> - read new properties in i2c_dw_fw_parse_and_configure() directly
> - in i2c_dw_set_timings_master() check dev->bus_capacitance_pf and then
> decide
> t_high and t_low
>
> v2:
> - provide more hardware information in dt-bindings
> - rename "bus-loading" to "bus-capacitance-pf"
> - call new i2c_dw_fw_parse_hw_params() in i2c_dw_fw_parse_and_configure()
> to
> parse hardware parameters from the device tree.
>
> Michael Wu (2):
> dt-bindings: i2c: snps,designware-i2c: declare bus capacitance and clk
> freq optimized
> i2c: dwsignware: determine HS tHIGH and tLOW based on HW parameters
>
> .../bindings/i2c/snps,designware-i2c.yaml | 18 +++++++++++++++
> drivers/i2c/busses/i2c-designware-common.c | 5 ++++
> drivers/i2c/busses/i2c-designware-core.h | 6 +++++
> drivers/i2c/busses/i2c-designware-master.c | 23 +++++++++++++++++--
> 4 files changed, 50 insertions(+), 2 deletions(-)
>
> --
> 2.43.0
Hi Andi,
Please forgive me for my presumption. Regarding this patch, will it be
merged? If not, please kindly provide any suggestions I can make to
improve it.
Sincerely yours,
Michael Wu
