| Message ID | 20241003111525.779410-1-michael.wu@kneron.us |
|---|---|
| Headers | show |
| Series | Compute HS HCNT and LCNT based on HW parameters | expand |
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
Hi Michael, > 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 merged to i2c/i2c-host. Thanks, Andi
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(-)