Re: [PATCH 1/7] mmc: dw_mmc: lookup for optional biu and ciu clocks
From: Thomas Abraham
Date: Thu May 10 2012 - 05:11:10 EST
On 2 May 2012 14:47, Will Newton <will.newton@xxxxxxxxx> wrote:
> On Wed, May 2, 2012 at 6:07 AM, Thomas Abraham
> <thomas.abraham@xxxxxxxxxx> wrote:
>> Some platforms allow for clock gating and control of bus interface unit clock
>> and card interface unit clock. Add support for clock lookup of optional biu
>> and ciu clocks for clock gating and clock speed determination.
>>
>> Signed-off-by: Abhilash Kesavan <a.kesavan@xxxxxxxxxxx>
>> Signed-off-by: Thomas Abraham <thomas.abraham@xxxxxxxxxx>
>> ---
>> drivers/mmc/host/dw_mmc.c | 35 +++++++++++++++++++++++++++++++----
>> include/linux/mmc/dw_mmc.h | 4 ++++
>> 2 files changed, 35 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 1532357..036846f 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -1938,19 +1938,35 @@ int dw_mci_probe(struct dw_mci *host)
>> return -ENODEV;
>> }
>>
>> - if (!host->pdata->bus_hz) {
>> + host->biu_clk = clk_get(&host->dev, "biu");
>> + if (IS_ERR(host->biu_clk))
>> + dev_info(&host->dev, "biu clock not available\n");
>> + else
>> + clk_enable(host->biu_clk);
>> +
>> + host->ciu_clk = clk_get(&host->dev, "ciu");
>> + if (IS_ERR(host->ciu_clk))
>> + dev_info(&host->dev, "ciu clock not available\n");
>
> Should these printks be at debug level? I'm not 100% sure either way
> but it could be a little noisy on systems that do not use these
> clocks.
Right. I will change dev_info to dev_dbg.
>
>> + else
>> + clk_enable(host->ciu_clk);
>> +
>> + if (IS_ERR(host->ciu_clk))
>> + host->bus_hz = host->pdata->bus_hz;
>> + else
>> + host->bus_hz = clk_get_rate(host->ciu_clk);
>> +
>> + if (!host->bus_hz) {
>> dev_err(&host->dev,
>> "Platform data must supply bus speed\n");
>> - return -ENODEV;
>> + ret = -ENODEV;
>> + goto err_clk;
>> }
>>
>> - host->bus_hz = host->pdata->bus_hz;
>> host->quirks = host->pdata->quirks;
>>
>> spin_lock_init(&host->lock);
>> INIT_LIST_HEAD(&host->queue);
>>
>> -
>> host->dma_ops = host->pdata->dma_ops;
>> dw_mci_init_dma(host);
>>
>> @@ -2095,6 +2111,13 @@ err_dmaunmap:
>> regulator_disable(host->vmmc);
>> regulator_put(host->vmmc);
>> }
>> + kfree(host);
>> +
>> +err_clk:
>> + clk_disable(host->ciu_clk);
>> + clk_disable(host->biu_clk);
>> + clk_put(host->ciu_clk);
>> + clk_put(host->biu_clk);
>
> Are these calls safe, or do we need to check IS_ERR as above?
The clk_disable is safe on Samsung platforms but it cannot be assumed
for other platforms. So, the IS_ERR check will be added before
clk_disable. clk_put will not need the IS_ERR check. Thanks for
pointing this out.
>
>> return ret;
>> }
>> EXPORT_SYMBOL(dw_mci_probe);
>> @@ -2128,6 +2151,10 @@ void dw_mci_remove(struct dw_mci *host)
>> regulator_put(host->vmmc);
>> }
>>
>> + clk_disable(host->ciu_clk);
>> + clk_disable(host->biu_clk);
>> + clk_put(host->ciu_clk);
>> + clk_put(host->biu_clk);
>
> Likewise.
Yes, will be fixed.
Thanks,
Thomas.
[...]
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