On 20/10/11 09:31, Giuseppe CAVALLARO wrote:
> Hello Adrian
>
> On 10/20/2011 8:22 AM, Adrian Hunter wrote:
>> On 19/10/11 16:45, Giuseppe CAVALLARO wrote:
>>> This patch is to expose the SDCLK frequency in the ios /sys entry.
>>>
>>> For example, if the max clk for a normal speed card is 20MHz
>>> this will be reported in /sys/kernel/debug/mmc0/ios instead of
>>> the real SDCLK frequency (calculated as Baseclock / divisor;
>>> divisor used for programming the Clock Control Register).
>>>
>>> Signed-off-by: Giuseppe Cavallaro <[email protected]>
>>> ---
>>> drivers/mmc/host/sdhci.c | 9 ++++++++-
>>> 1 files changed, 8 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 0e02cc1..6bdf64f 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -1045,6 +1045,7 @@ static void sdhci_set_clock(struct sdhci_host *host,
>>> unsigned int clock)
>>> int div = 0; /* Initialized for compiler warning */
>>> u16 clk = 0;
>>> unsigned long timeout;
>>> + unsigned int new_hc_clock = host->max_clk;
>>>
>>> if (clock == host->clock)
>>> return;
>>> @@ -1134,7 +1135,10 @@ static void sdhci_set_clock(struct sdhci_host *host,
>>> unsigned int clock)
>>> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
>>>
>>> out:
>>> - host->clock = clock;
>>> + if (div)
>>> + new_hc_clock = host->max_clk / div;
>>
>> At this point div is the value written to the register not the
>> divisor
>
> Hmm, you are right. I'll fix it.
>
>>> +
>>> + host->clock = new_hc_clock;
>>> }
>>>
>>> static void sdhci_set_power(struct sdhci_host *host, unsigned short power)
>>> @@ -1293,6 +1297,9 @@ static void sdhci_set_ios(struct mmc_host *mmc,
>>> struct mmc_ios *ios)
>>>
>>> sdhci_set_clock(host, ios->clock);
>>>
>>> + /* Clock provided to the HC */
>>> + ios->clock = host->clock;
>>
>> It would be nicer to keep ios->clock as the target
>> frequency and add a new member to struct mmc_host for
>> the actual frequency.
>
> Why not! I like it. I'll rework the patch and send it again.
> Just a question: do I have to dump both in /sys/.../ios?
> If yes, maybe it's worth using: card_clock and hc_clock as names.
> What do you think?
For me hc_clock is confusing. Potentially the host controller has
lots of clocks e.g. interface clock, functional clock, debounce clock
Also, I would not rename anything. You could add
/sys/kernel/debug/mmcx/actual_clock
or amend /sys/kernel/debug/mmcx/ios e.g.
clock: 26000000 Hz (actual 25000000 Hz)
vdd: 17 (2.9 ~ 3.0 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 0 (legacy)
>
> Regards
> Peppe
>
>>
>>> +
>>> if (ios->power_mode == MMC_POWER_OFF)
>>> sdhci_set_power(host, -1);
>>> else
>>
>>
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
