[PATCH 3/7] mmc: msm_sdhci: handle bulk clock initialization error

[Neil Armstrong]

On 07/04/2025 11:02, neil.armstrong at linaro.org wrote:
> On 07/04/2025 10:19, Jorge Ramirez-Ortiz wrote:
>> Some boards do not require all clocks to be available (i.e:
>> dragonboard820c).
> 
> Can you specify which clock isn't available ? Because we have clk-stub for that

Enable:
CONFIG_CLK_STUB=y

and change this:
diff --git a/drivers/clk/clk-stub.c b/drivers/clk/clk-stub.c
index 343fa5cd3fe..c14f5b6e1a6 100644
--- a/drivers/clk/clk-stub.c
+++ b/drivers/clk/clk-stub.c
@@ -14,7 +14,7 @@
  static const struct udevice_id nop_parent_ids[] = {
         { .compatible = "qcom,rpm-proc" },
         { .compatible = "qcom,glink-rpm" },
-       { .compatible = "qcom,rpm-sm6115" },
+       { .compatible = "qcom,glink-smd-rpm" },
         { }
  };

And clk_get_bulk() should work!

Neil

> 
> Thanks,
> Neil
> 
>>
>> This change provides a fallback to the core clock when the bulk cant be
>> retrived.
>>
>> Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez at oss.qualcomm.com>
>> ---
>>   drivers/mmc/msm_sdhci.c | 27 +++++++++++++++++++++++++--
>>   1 file changed, 25 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mmc/msm_sdhci.c b/drivers/mmc/msm_sdhci.c
>> index 27bb7052fca..8081330bd25 100644
>> --- a/drivers/mmc/msm_sdhci.c
>> +++ b/drivers/mmc/msm_sdhci.c
>> @@ -9,6 +9,7 @@
>>   #include <clk.h>
>>   #include <dm.h>
>> +#include <dm/devres.h>
>>   #include <malloc.h>
>>   #include <sdhci.h>
>>   #include <wait_bit.h>
>> @@ -56,6 +57,17 @@ struct msm_sdhc_variant_info {
>>   DECLARE_GLOBAL_DATA_PTR;
>> +static int get_core_clock(struct udevice *dev, struct clk_bulk *bulk)
>> +{
>> +    bulk->count = 1;
>> +
>> +    bulk->clks = devm_kcalloc(dev, 1, sizeof(struct clk), GFP_KERNEL);
>> +    if (!bulk->clks)
>> +        return -ENOMEM;
>> +
>> +    return clk_get_by_name(dev, "core", &bulk->clks[0]);
>> +}
>> +
>>   static int msm_sdc_clk_init(struct udevice *dev)
>>   {
>>       struct msm_sdhc *prv = dev_get_priv(dev);
>> @@ -73,8 +85,15 @@ static int msm_sdc_clk_init(struct udevice *dev)
>>       ret = clk_get_bulk(dev, &prv->clks);
>>       if (ret) {
>> -        log_warning("Couldn't get mmc clocks: %d\n", ret);
>> -        return ret;
>> +        log_warning("Bulk clocks not available (%d), trying core clock\n", ret);
>> +
>> +        /* Sometimes not all clocks are needed - chainloading uboot */
>> +        ret = get_core_clock(dev, &prv->clks);
>> +        if (ret) {
>> +            log_warning("Core clock not available:(%d)\n", ret);
>> +            return ret;
>> +        }
>> +        n_clks = 1;
>>       }
>>       ret = clk_enable_bulk(&prv->clks);
>> @@ -83,6 +102,9 @@ static int msm_sdc_clk_init(struct udevice *dev)
>>           return ret;
>>       }
>> +    if (n_clks == 1)
>> +        goto set_rate;
>> +
>>       /* If clock-names is unspecified, then the first clock is the core clock */
>>       if (!ofnode_get_property(node, "clock-names", &n_clks)) {
>>           if (!clk_set_rate(&prv->clks.clks[0], clk_rate)) {
>> @@ -105,6 +127,7 @@ static int msm_sdc_clk_init(struct udevice *dev)
>>           return -EINVAL;
>>       }
>> +set_rate:
>>       /* The clock is already enabled by the clk_bulk above */
>>       clk_rate = clk_set_rate(&prv->clks.clks[i], clk_rate);
>>       /* If we get a rate of 0 then something has probably gone wrong. */
>