On 9/26/2024 3:58 PM, Vladimir Zapolskiy wrote:
> Hello Manikanta.
>
> On 9/26/24 06:43, Manikanta Mylavarapu wrote:
>> In existing socs, I2C serial engine is sourced from XO (19.2MHz).
>> Where as in IPQ5424, I2C serial engine is sourced from GPLL0 (32MHz).
>>
>> The existing map table is based on 19.2MHz. This patch incorporate
>> the clock map table to derive the SCL clock from the 32MHz source
>> clock frequency.
>>
>> Signed-off-by: Manikanta Mylavarapu <quic_mmanikan@xxxxxxxxxxx>
>> ---
>> Changes in v2:
>> - Dropped IPQ5424 from the commit title
>> - Added else part to assign geni_i2c_clk_map_19p2mhz to itr
>> - Dropped MHZ macro and used HZ_PER_MHZ macro
>> - Expanded SE to serial engine
>> - Added the reason for 32MHz clock in commit message
>>
>> drivers/i2c/busses/i2c-qcom-geni.c | 19 ++++++++++++++++---
>> 1 file changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
>> index 212336f724a6..22f2a0d83641 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -16,6 +16,7 @@
>> #include <linux/pm_runtime.h>
>> #include <linux/soc/qcom/geni-se.h>
>> #include <linux/spinlock.h>
>> +#include <linux/units.h>
>> #define SE_I2C_TX_TRANS_LEN 0x26c
>> #define SE_I2C_RX_TRANS_LEN 0x270
>> @@ -146,18 +147,30 @@ struct geni_i2c_clk_fld {
>> * clk_freq_out = t / t_cycle
>> * source_clock = 19.2 MHz
>> */
>> -static const struct geni_i2c_clk_fld geni_i2c_clk_map[] = {
>> +static const struct geni_i2c_clk_fld geni_i2c_clk_map_19p2mhz[] = {
>> {KHZ(100), 7, 10, 11, 26},
>> {KHZ(400), 2, 5, 12, 24},
>> {KHZ(1000), 1, 3, 9, 18},
>> };
>> +/* source_clock = 32 MHz */
>> +static const struct geni_i2c_clk_fld geni_i2c_clk_map_32mhz[] = {
>> + {KHZ(100), 7, 14, 18, 40},
>> + {KHZ(400), 4, 3, 11, 20},
>> + {KHZ(1000), 4, 3, 6, 15},
>> +};
>
> Please double check the values.
>
> This is what I get:
> * for 100KHz: 32000000 / (40 * 7) ~ 114286, apparently 32000000 / (40 * 8) would
> be a better fit, however it's unclear what would be proper t_high / t_low values,
> * for 400KHz: it seems good,
> * for 1000KHz: 32000000 / (15 * 4) ~ 533333, which is almost 1/2 of the wanted
> bus frequency, so this one looks very wrong.
>
> Do you have any ideas how to get better bus frequency settings?
>
Thanks for pointing this out.
I will double check and get back with the proper data.
Thanks & Regards,
Manikanta.
