Re: [PATCH 4/5] i2c: qcom-cci: Add OPP table support and enforce FAST_PLUS requirements

Konrad Dybcio
2025-09-04T14:50:16Z

On 9/4/25 4:31 PM, Konrad Dybcio wrote:
> From: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
>
> The CCI clock has voltage requirements, which need to be described
> through an OPP table.
>
> The 1 MHz FAST_PLUS mode requires the CCI core clock runs at 37,5 MHz
> (which is a value common across all SoCs), since it's not possible to
> reach the required timings with the default 19.2 MHz rate.
>
> Address both issues by introducing an OPP table and using it to vote
> for the faster rate.
>
> Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
> ---
> drivers/i2c/busses/i2c-qcom-cci.c | 33 +++++++++++++++++++++++++++++++++
> 1 file changed, 33 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
> index 74fedfdec3ae4e034ec4d946179e963c783b5923..d6192e2a5e3bc4d908cba594d1910a41f3a41e9c 100644
> --- a/drivers/i2c/busses/i2c-qcom-cci.c
> +++ b/drivers/i2c/busses/i2c-qcom-cci.c
> @@ -10,6 +10,7 @@
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_opp.h>
> #include <linux/pm_runtime.h>
>
> #define CCI_HW_VERSION 0x0
> @@ -121,6 +122,7 @@ struct cci_data {
> struct i2c_adapter_quirks quirks;
> u16 queue_size[NUM_QUEUES];
> struct hw_params params[3];
> + bool fast_mode_plus_supported;
> };
>
> struct cci {
> @@ -466,9 +468,22 @@ static const struct i2c_algorithm cci_algo = {
> .functionality = cci_func,
> };
>
> +static unsigned long cci_desired_clk_rate(struct cci *cci)
> +{
> + if (cci->data->fast_mode_plus_supported)
> + return 37500000ULL;
> +
> + return 19200000ULL;

Well this is embarrassing

ULL -> UL

Konrad