Re: [PATCH v2 18/20] mmc: sdio: enable a default power off mode of the card
On Thu, Jul 22, 2010 at 2:35 PM, Roger Quadros roger.quad...@nokia.com wrote: On 07/21/2010 08:33 PM, ext Ohad Ben-Cohen wrote: Add support for an SDIO device to stay powered off even without the presence of an SDIO function driver. A host should explicitly ask for it by means of MMC_CAP_DONT_POWER_CARD, and the SDIO function driver should know it needs to call sdio_claim_power before accessing the device. Signed-off-by: Ohad Ben-Coheno...@wizery.com Shouldn't this be the default behaviour? If there is no function driver for any of the functions of the card, then sdio core shold power off the card. I don't see a need for a special capability flag for this. in fact MMC_CAP_DONT_POWER_CARD does not seem like an mmc host's capability Totally agree. I didn't want to change the current behavior of the cards/funcs so I looked for a way to explicitly power down only specific cards. Alternatively we could power down all cards at the end mmc_attach_sdio, and then power them up selectively in sdio_bus_probe, just before calling probe. If the probe succeeds, the function driver takes over. If the probe fails, we can power them down again. Is that what you meant ? This would work both if the sdio function driver is already loaded, or will only be loaded at a later time. But I'm not too fond of the extra power on/off cycles that it will introduce for each card.. Thanks, Ohad. flag, it seems more like a request from the board to keep the card powered off. regards, -roger -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 18/20] mmc: sdio: enable a default power off mode of the card
On Sun, 25 Jul 2010, Ohad Ben-Cohen wrote: On Thu, Jul 22, 2010 at 2:35 PM, Roger Quadros roger.quad...@nokia.com wrote: On 07/21/2010 08:33 PM, ext Ohad Ben-Cohen wrote: Add support for an SDIO device to stay powered off even without the presence of an SDIO function driver. A host should explicitly ask for it by means of MMC_CAP_DONT_POWER_CARD, and the SDIO function driver should know it needs to call sdio_claim_power before accessing the device. Signed-off-by: Ohad Ben-Coheno...@wizery.com Shouldn't this be the default behaviour? If there is no function driver for any of the functions of the card, then sdio core shold power off the card. I don't see a need for a special capability flag for this. in fact MMC_CAP_DONT_POWER_CARD does not seem like an mmc host's capability Totally agree. I didn't want to change the current behavior of the cards/funcs so I looked for a way to explicitly power down only specific cards. Alternatively we could power down all cards at the end mmc_attach_sdio, and then power them up selectively in sdio_bus_probe, just before calling probe. If the probe succeeds, the function driver takes over. If the probe fails, we can power them down again. Exactly! Is that what you meant ? This would work both if the sdio function driver is already loaded, or will only be loaded at a later time. But I'm not too fond of the extra power on/off cycles that it will introduce for each card.. This is still way better than introducing knowledge about specific cards in the host drivers. Nicolas -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 18/20] mmc: sdio: enable a default power off mode of the card
On Sun, Jul 25, 2010 at 4:56 PM, Nicolas Pitre n...@fluxnic.net wrote: On Sun, 25 Jul 2010, Ohad Ben-Cohen wrote: On Thu, Jul 22, 2010 at 2:35 PM, Roger Quadros roger.quad...@nokia.com wrote: On 07/21/2010 08:33 PM, ext Ohad Ben-Cohen wrote: Add support for an SDIO device to stay powered off even without the presence of an SDIO function driver. A host should explicitly ask for it by means of MMC_CAP_DONT_POWER_CARD, and the SDIO function driver should know it needs to call sdio_claim_power before accessing the device. Signed-off-by: Ohad Ben-Coheno...@wizery.com Shouldn't this be the default behaviour? If there is no function driver for any of the functions of the card, then sdio core shold power off the card. I don't see a need for a special capability flag for this. in fact MMC_CAP_DONT_POWER_CARD does not seem like an mmc host's capability Totally agree. I didn't want to change the current behavior of the cards/funcs so I looked for a way to explicitly power down only specific cards. Alternatively we could power down all cards at the end mmc_attach_sdio, and then power them up selectively in sdio_bus_probe, just before calling probe. If the probe succeeds, the function driver takes over. If the probe fails, we can power them down again. Exactly! Ok, v3 is on the way :) (featuring no special host CAP, fix locking issues, and power down unclaimed cards also on resume) -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v2 18/20] mmc: sdio: enable a default power off mode of the card
On 07/21/2010 08:33 PM, ext Ohad Ben-Cohen wrote: Add support for an SDIO device to stay powered off even without the presence of an SDIO function driver. A host should explicitly ask for it by means of MMC_CAP_DONT_POWER_CARD, and the SDIO function driver should know it needs to call sdio_claim_power before accessing the device. Signed-off-by: Ohad Ben-Coheno...@wizery.com Shouldn't this be the default behaviour? If there is no function driver for any of the functions of the card, then sdio core shold power off the card. I don't see a need for a special capability flag for this. in fact MMC_CAP_DONT_POWER_CARD does not seem like an mmc host's capability flag, it seems more like a request from the board to keep the card powered off. regards, -roger -- To unsubscribe from this list: send the line unsubscribe linux-omap in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[PATCH v2 18/20] mmc: sdio: enable a default power off mode of the card
Add support for an SDIO device to stay powered off even without
the presence of an SDIO function driver. A host should explicitly
ask for it by means of MMC_CAP_DONT_POWER_CARD, and the SDIO
function driver should know it needs to call sdio_claim_power
before accessing the device.
Signed-off-by: Ohad Ben-Cohen o...@wizery.com
---
drivers/mmc/core/sdio.c | 15 +--
include/linux/mmc/host.h |1 +
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index 5c0fbfa..164353f 100644
--- a/drivers/mmc/core/sdio.c
+++ b/drivers/mmc/core/sdio.c
@@ -80,8 +80,9 @@ static int sdio_init_func(struct mmc_card *card, unsigned int
fn)
return ret;
/* For each SDIO function initialized, increase the power claim
-* reference count of the card */
- atomic_inc(card-power_claims);
+* reference count of the card, unless explicitly requested not to */
+ if (!(card-host-caps MMC_CAP_DONT_POWER_CARD))
+ atomic_inc(card-power_claims);
return 0;
@@ -607,6 +608,16 @@ int mmc_attach_sdio(struct mmc_host *host, u32 ocr)
mmc_release_host(host);
/*
+* If power is not required for this card, power it off.
+* The sdio function will need to call sdio_claim_power.
+*/
+ if (!atomic_read(card-power_claims)) {
+ pr_info(%s: power is not claimed, releasing\n,
+ mmc_hostname(host));
+ mmc_release_power(host);
+ }
+
+ /*
* First add the card to the driver model...
*/
err = mmc_add_card(host-card);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 3675d58..756cf38 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -155,6 +155,7 @@ struct mmc_host {
#define MMC_CAP_DISABLE(1 7)/* Can the host be
disabled */
#define MMC_CAP_NONREMOVABLE (1 8)/* Nonremovable e.g. eMMC */
#define MMC_CAP_WAIT_WHILE_BUSY(1 9)/* Waits while card is
busy */
+#define MMC_CAP_DONT_POWER_CARD(1 10) /* Keep the card
powered off */
mmc_pm_flag_t pm_caps;/* supported pm features */
--
1.7.0.4
--
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