| Message ID | 1513636727-4503-1-git-send-email-zjwu@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 19/12/17 00:38, Zhoujie Wu wrote: > According to SD spec 3.00 3.6.1 signal voltage switch > procedure step 6~8, > (6) Set 1.8V Signal Enable in the Host Control 2 register. > (7) Wait 5ms. 1.8V voltage regulator shall be stable within this period. > (8) If 1.8V Signal Enable is cleared by Host Controller, go to step (12). > Host should wait 5ms after set 1.8V signal enable bit in > Host Control 2 register and check if 1.8V is stable or not. > > But current code checks this bit right after set it. > On some platforms with xenon controller found the bit is > cleared right away and host reports "1.8V regulator output > did not became stable" and 5ms delay can help. > > Implement voltage_switch callback for xenon controller to add 5ms > delay to make sure the 1.8V signal enable bit is set by controller. > > Signed-off-by: Zhoujie Wu <zjwu@marvell.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> > --- > v4: move the 5ms delay from sdhci.c to xenon driver. > v3: give more details in comments. > v2: remove undeliverable cc list email. > > drivers/mmc/host/sdhci-xenon.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c > index 0842bbc..4d0791f 100644 > --- a/drivers/mmc/host/sdhci-xenon.c > +++ b/drivers/mmc/host/sdhci-xenon.c > @@ -230,7 +230,14 @@ static void xenon_set_power(struct sdhci_host *host, unsigned char mode, > mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd); > } > > +static void xenon_voltage_switch(struct sdhci_host *host) > +{ > + /* Wait for 5ms after set 1.8V signal enable bit */ > + usleep_range(5000, 5500); > +} > + > static const struct sdhci_ops sdhci_xenon_ops = { > + .voltage_switch = xenon_voltage_switch, > .set_clock = sdhci_set_clock, > .set_power = xenon_set_power, > .set_bus_width = sdhci_set_bus_width, > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 18 December 2017 at 23:38, Zhoujie Wu <zjwu@marvell.com> wrote: > According to SD spec 3.00 3.6.1 signal voltage switch > procedure step 6~8, > (6) Set 1.8V Signal Enable in the Host Control 2 register. > (7) Wait 5ms. 1.8V voltage regulator shall be stable within this period. > (8) If 1.8V Signal Enable is cleared by Host Controller, go to step (12). > Host should wait 5ms after set 1.8V signal enable bit in > Host Control 2 register and check if 1.8V is stable or not. > > But current code checks this bit right after set it. > On some platforms with xenon controller found the bit is > cleared right away and host reports "1.8V regulator output > did not became stable" and 5ms delay can help. > > Implement voltage_switch callback for xenon controller to add 5ms > delay to make sure the 1.8V signal enable bit is set by controller. > > Signed-off-by: Zhoujie Wu <zjwu@marvell.com> Thanks, applied for next! Kind regards Uffe > --- > v4: move the 5ms delay from sdhci.c to xenon driver. > v3: give more details in comments. > v2: remove undeliverable cc list email. > > drivers/mmc/host/sdhci-xenon.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c > index 0842bbc..4d0791f 100644 > --- a/drivers/mmc/host/sdhci-xenon.c > +++ b/drivers/mmc/host/sdhci-xenon.c > @@ -230,7 +230,14 @@ static void xenon_set_power(struct sdhci_host *host, unsigned char mode, > mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd); > } > > +static void xenon_voltage_switch(struct sdhci_host *host) > +{ > + /* Wait for 5ms after set 1.8V signal enable bit */ > + usleep_range(5000, 5500); > +} > + > static const struct sdhci_ops sdhci_xenon_ops = { > + .voltage_switch = xenon_voltage_switch, > .set_clock = sdhci_set_clock, > .set_power = xenon_set_power, > .set_bus_width = sdhci_set_bus_width, > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c index 0842bbc..4d0791f 100644 --- a/drivers/mmc/host/sdhci-xenon.c +++ b/drivers/mmc/host/sdhci-xenon.c @@ -230,7 +230,14 @@ static void xenon_set_power(struct sdhci_host *host, unsigned char mode, mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd); } +static void xenon_voltage_switch(struct sdhci_host *host) +{ + /* Wait for 5ms after set 1.8V signal enable bit */ + usleep_range(5000, 5500); +} + static const struct sdhci_ops sdhci_xenon_ops = { + .voltage_switch = xenon_voltage_switch, .set_clock = sdhci_set_clock, .set_power = xenon_set_power, .set_bus_width = sdhci_set_bus_width,
According to SD spec 3.00 3.6.1 signal voltage switch procedure step 6~8, (6) Set 1.8V Signal Enable in the Host Control 2 register. (7) Wait 5ms. 1.8V voltage regulator shall be stable within this period. (8) If 1.8V Signal Enable is cleared by Host Controller, go to step (12). Host should wait 5ms after set 1.8V signal enable bit in Host Control 2 register and check if 1.8V is stable or not. But current code checks this bit right after set it. On some platforms with xenon controller found the bit is cleared right away and host reports "1.8V regulator output did not became stable" and 5ms delay can help. Implement voltage_switch callback for xenon controller to add 5ms delay to make sure the 1.8V signal enable bit is set by controller. Signed-off-by: Zhoujie Wu <zjwu@marvell.com> --- v4: move the 5ms delay from sdhci.c to xenon driver. v3: give more details in comments. v2: remove undeliverable cc list email. drivers/mmc/host/sdhci-xenon.c | 7 +++++++ 1 file changed, 7 insertions(+)