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sdhci: avoid changing voltage needlessly

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Because of granularity issues, sometimes we told the hardware to change
to the voltage we were already at. Rework the logic so this doesn't
happen.

Signed-off-by: Pierre Ossman <pierre@ossman.eu>
This commit is contained in:
Pierre Ossman 2009-05-03 20:45:03 +02:00
parent 7ceeb6a40a
commit ae628903ab
2 changed files with 29 additions and 26 deletions
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53
drivers/mmc/host/sdhci.c
View file

@ -1005,12 +1005,34 @@ static void sdhci_set_power(struct sdhci_host *host, unsigned short power)
{
u8 pwr;
if (host->power == power)
if (power == (unsigned short)-1)
pwr = 0;
else {
switch (1 << power) {
case MMC_VDD_165_195:
pwr = SDHCI_POWER_180;
break;
case MMC_VDD_29_30:
case MMC_VDD_30_31:
pwr = SDHCI_POWER_300;
break;
case MMC_VDD_32_33:
case MMC_VDD_33_34:
pwr = SDHCI_POWER_330;
break;
default:
BUG();
}
}
if (host->pwr == pwr)
return;
if (power == (unsigned short)-1) {
host->pwr = pwr;
if (pwr == 0) {
sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
goto out;
return;
}
/*
@ -1020,35 +1042,16 @@ static void sdhci_set_power(struct sdhci_host *host, unsigned short power)
if (!(host->quirks & SDHCI_QUIRK_SINGLE_POWER_WRITE))
sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
pwr = SDHCI_POWER_ON;
switch (1 << power) {
case MMC_VDD_165_195:
pwr |= SDHCI_POWER_180;
break;
case MMC_VDD_29_30:
case MMC_VDD_30_31:
pwr |= SDHCI_POWER_300;
break;
case MMC_VDD_32_33:
case MMC_VDD_33_34:
pwr |= SDHCI_POWER_330;
break;
default:
BUG();
}
/*
* At least the Marvell CaFe chip gets confused if we set the voltage
* and set turn on power at the same time, so set the voltage first.
*/
if ((host->quirks & SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER))
sdhci_writeb(host, pwr & ~SDHCI_POWER_ON, SDHCI_POWER_CONTROL);
sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
pwr |= SDHCI_POWER_ON;
sdhci_writeb(host, pwr, SDHCI_POWER_CONTROL);
out:
host->power = power;
}
/*****************************************************************************\

2
drivers/mmc/host/sdhci.h
View file

@ -255,7 +255,7 @@ struct sdhci_host {
unsigned int timeout_clk; /* Timeout freq (KHz) */
unsigned int clock; /* Current clock (MHz) */
unsigned short power; /* Current voltage */
u8 pwr; /* Current voltage */
struct mmc_request *mrq; /* Current request */
struct mmc_command *cmd; /* Current command */