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);
___
devicetree-discuss mailing list
devicetree-discuss@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/devicetree-discuss