[PATCH v2 1/2] mmc: dw_mmc: Handle late vmmc regulators with EPROBE_DEFER

Doug Anderson
2013-06-07T17:28:46Z

It is possible to specify a regulator that should be turned on when
dw_mmc is probed. At the moment dw_mmc will fail to use the regulator
properly if the regulator probes after dw_mmc. Fix this problem by
honoring EPROBE_DEFER.

At the same time move the regulator code out of the slot init code.
We only specify one regulator for the whole device and other parts of
the code (like suspend/resume) assume that the regulator has only been
enabled once.

Signed-off-by: Doug Anderson <dianders@chromium.org>
---
Changes in v2:
- Avoid hackery to detect regulators that will never show up.
- Move regulator out of slot init--it doesn't belong there.

.../devicetree/bindings/mmc/synopsis-dw-mshc.txt | 4 +++
drivers/mmc/host/dw_mmc.c | 40 ++++++++++++----------
2 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
index 726fd21..d5cc94e 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
@@ -79,6 +82,7 @@ board specific portions as listed below.
broken-cd;
fifo-depth = <0x80>;
card-detect-delay = <200>;
+ vmmc-supply = <&buck8>;

slot@0 {
reg = <0>;
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index bc3a1bc..ab5642d 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1895,7 +1895,7 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
struct mmc_host *mmc;
struct dw_mci_slot *slot;
const struct dw_mci_drv_data *drv_data = host->drv_data;
- int ctrl_id, ret;
+ int ctrl_id;
u8 bus_width;

mmc = mmc_alloc_host(sizeof(struct dw_mci_slot), host->dev);
@@ -1985,19 +1985,6 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
#endif /* CONFIG_MMC_DW_IDMAC */
}

- 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));
- host->vmmc = NULL;
- } else {
- ret = regulator_enable(host->vmmc);
- if (ret) {
- dev_err(host->dev,
- "failed to enable regulator: %d\n", ret);
- goto err_setup_bus;
- }
- }
-
if (dw_mci_get_cd(mmc))
set_bit(DW_MMC_CARD_PRESENT, &slot->flags);
else
@@ -2023,10 +2010,6 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
queue_work(host->card_workqueue, &host->card_work);

return 0;
-
-err_setup_bus:
- mmc_free_host(mmc);
- return -EINVAL;
}

static void dw_mci_cleanup_slot(struct dw_mci_slot *slot, unsigned int id)
@@ -2229,11 +2212,29 @@ int dw_mci_probe(struct dw_mci *host)
}
}

+ host->vmmc = devm_regulator_get(host->dev, "vmmc");
+ if (IS_ERR(host->vmmc)) {
+ ret = PTR_ERR(host->vmmc);
+ if (ret == -EPROBE_DEFER)
+ goto err_clk_ciu;
+
+ dev_info(host->dev, "no vmmc regulator found: %d\n", ret);
+ host->vmmc = NULL;
+ } else {
+ ret = regulator_enable(host->vmmc);
+ if (ret) {
+ if (ret != -EPROBE_DEFER)
+ dev_err(host->dev,
+ "regulator_enable fail: %d\n", ret);
+ goto err_clk_ciu;
+ }
+ }
+
if (!host->bus_hz) {
dev_err(host->dev,
"Platform data must supply bus speed\n");
ret = -ENODEV;
- goto err_clk_ciu;
+ goto err_regulator;
}

host->quirks = host->pdata->quirks;
@@ -2378,6 +2379,7 @@ err_dmaunmap:
if (host->use_dma && host->dma_ops->exit)
host->dma_ops->exit(host);

+err_regulator:
if (host->vmmc)
regulator_disable(host->vmmc);

--
1.8.3