Re: [PATCH 1/2] mmc: dw_mmc: Handle late vmmc regulator with EPROBE_DEFER
Hi Doug,
On Thursday 06 of June 2013 21:46:45 Doug Anderson wrote:
It is possible to specify a regulator that should be turned on when
dw_mmc is probed. This regulator is optional, though a warning will
be printed if it's missing. The fact that the regulator is optional
means that (at the moment) it's not possible to use a regulator that
probes _after_ dw_mmc.
Fix this limitation by adding the ability to make vmmc required. If a
vmmc-supply is specified in the device tree we'll assume that vmmc is
required.
This interesting case makes me think that regulator core should
differentiate between regulator lookup failure due to no lookup specified
and due to the regulator specified in lookup being unavailable, returning
appropriate (different) error codes.
CCing Mark and Liam.
Best regards,
Tomasz
Signed-off-by: Doug Anderson diand...@chromium.org
---
.../devicetree/bindings/mmc/synopsis-dw-mshc.txt | 3 +++
drivers/mmc/host/dw_mmc.c | 22
-- include/linux/mmc/dw_mmc.h
| 3 +++
3 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt index
726fd21..b09d2d0 100644
--- a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
+++ b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
@@ -55,6 +55,9 @@ Optional properties:
* broken-cd: as documented in mmc core bindings.
+* vmmc-supply: The phandle to the regulator to use for vmmc. If this
is + specified we'll defer probe until we can find this regulator. +
Aliases:
- All the MSHC controller nodes should be represented in the aliases
node using diff --git a/drivers/mmc/host/dw_mmc.c
b/drivers/mmc/host/dw_mmc.c index bc3a1bc..d3a0f8a 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1987,8 +1987,17 @@ static int dw_mci_init_slot(struct dw_mci *host,
unsigned int id)
host-vmmc = devm_regulator_get(mmc_dev(mmc), vmmc);
if (IS_ERR(host-vmmc)) {
- pr_info(%s: no vmmc regulator found\n,
mmc_hostname(mmc));
+ ret = PTR_ERR(host-vmmc);
host-vmmc = NULL;
+
+ if (host-pdata-vmmc_required) {
+ if (ret != -EPROBE_DEFER)
+ pr_err(%s: vmmc required: %d\n,
+ mmc_hostname(mmc), ret);
+ goto err_setup_bus;
+ }
+ pr_info(%s: no vmmc regulator found %d\n,
mmc_hostname(mmc),
+ ret);
} else {
ret = regulator_enable(host-vmmc);
if (ret) {
@@ -2026,7 +2035,7 @@ static int dw_mci_init_slot(struct dw_mci *host,
unsigned int id)
err_setup_bus:
mmc_free_host(mmc);
- return -EINVAL;
+ return ret;
}
static void dw_mci_cleanup_slot(struct dw_mci_slot *slot, unsigned int
id) @@ -2162,6 +2171,13 @@ static struct dw_mci_board
*dw_mci_parse_dt(struct dw_mci *host) if (of_find_property(np,
enable-sdio-wakeup, NULL))
pdata-pm_caps |= MMC_PM_WAKE_SDIO_IRQ;
+ /*
+ * If vmmc is directly specified in the device tree then we'll
assume
+ * it's required and honor EPROBE_DEFER so it can show up late.
+ */
+ if (of_find_property(np, vmmc-supply, NULL))
+ pdata-vmmc_required = 1;
+
return pdata;
}
@@ -2352,6 +2368,8 @@ int dw_mci_probe(struct dw_mci *host)
/* We need at least one slot to succeed */
for (i = 0; i host-num_slots; i++) {
ret = dw_mci_init_slot(host, i);
+ if (ret == -EPROBE_DEFER)
+ goto err_workqueue;
if (ret)
dev_dbg(host-dev, slot %d init failed\n, i);
else
diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
index 198f0fa..e84d288 100644
--- a/include/linux/mmc/dw_mmc.h
+++ b/include/linux/mmc/dw_mmc.h
@@ -244,6 +244,9 @@ struct dw_mci_board {
/* delay in mS before detecting cards after interrupt */
u32 detect_delay_ms;
+ /* If true then we won't probe until vmmc is available */
+ bool vmmc_required;
+
int (*init)(u32 slot_id, irq_handler_t , void *);
int (*get_ro)(u32 slot_id);
int (*get_cd)(u32 slot_id);
___
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Re: [PATCH 1/2] mmc: dw_mmc: Handle late vmmc regulator with EPROBE_DEFER
On Fri, Jun 07, 2013 at 12:19:58PM +0200, Tomasz Figa wrote: On Thursday 06 of June 2013 21:46:45 Doug Anderson wrote: dw_mmc is probed. This regulator is optional, though a warning will be printed if it's missing. The fact that the regulator is optional means that (at the moment) it's not possible to use a regulator that probes _after_ dw_mmc. Fix this limitation by adding the ability to make vmmc required. If a vmmc-supply is specified in the device tree we'll assume that vmmc is required. This interesting case makes me think that regulator core should differentiate between regulator lookup failure due to no lookup specified and due to the regulator specified in lookup being unavailable, returning appropriate (different) error codes. It does exactly that in so far as it can - you get -ENODEV if there's definitely no supply and -EPROBE_DEFER otherwise. signature.asc Description: Digital signature ___ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss
Re: [PATCH 1/2] mmc: dw_mmc: Handle late vmmc regulator with EPROBE_DEFER
On Friday 07 of June 2013 11:24:04 Mark Brown wrote: On Fri, Jun 07, 2013 at 12:19:58PM +0200, Tomasz Figa wrote: On Thursday 06 of June 2013 21:46:45 Doug Anderson wrote: dw_mmc is probed. This regulator is optional, though a warning will be printed if it's missing. The fact that the regulator is optional means that (at the moment) it's not possible to use a regulator that probes _after_ dw_mmc. Fix this limitation by adding the ability to make vmmc required. If a vmmc-supply is specified in the device tree we'll assume that vmmc is required. This interesting case makes me think that regulator core should differentiate between regulator lookup failure due to no lookup specified and due to the regulator specified in lookup being unavailable, returning appropriate (different) error codes. It does exactly that in so far as it can - you get -ENODEV if there's definitely no supply and -EPROBE_DEFER otherwise. Oh, right, thanks. I somehow felt that it should be doing this already, but I was looking at 3.9 on Free Electron's LXR. It does so since commit 1e4b545cdd regulator: core: return err value for regulator_get if there is no DT binding so I think this patch should be reworked to check the returned error code instead. Best regards, Tomasz ___ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss
Re: [PATCH 1/2] mmc: dw_mmc: Handle late vmmc regulator with EPROBE_DEFER
Tomasz / Mark, On Fri, Jun 7, 2013 at 3:30 AM, Tomasz Figa tomasz.f...@gmail.com wrote: On Friday 07 of June 2013 11:24:04 Mark Brown wrote: On Fri, Jun 07, 2013 at 12:19:58PM +0200, Tomasz Figa wrote: This interesting case makes me think that regulator core should differentiate between regulator lookup failure due to no lookup specified and due to the regulator specified in lookup being unavailable, returning appropriate (different) error codes. It does exactly that in so far as it can - you get -ENODEV if there's definitely no supply and -EPROBE_DEFER otherwise. Oh, right, thanks. I somehow felt that it should be doing this already, but I was looking at 3.9 on Free Electron's LXR. It does so since commit 1e4b545cdd regulator: core: return err value for regulator_get if there is no DT binding Thanks, this is much cleaner. That's what I get for doing the majority of my work on 3.8 at the moment. :-P I will rework the patch and send it out again. -Doug ___ devicetree-discuss mailing list devicetree-discuss@lists.ozlabs.org https://lists.ozlabs.org/listinfo/devicetree-discuss
