LinuxLists.cc - [PATCH 1/5] regulator: core: Provide hints to the core about optional supplies

2013-07-30 11:47:05

Subject: [PATCH 1/5] regulator: core: Provide hints to the core about optional supplies

From: Mark Brown <[email protected]>

While the majority of supplies on devices are mandatory and can't be
physically omitted for electrical reasons some devices do have optional
supplies and need to know if they are missing, MMC being the most common
of these.

Currently the core accurately reports all errors when regulators are
requested since it does not know if the supply is one that must be provided
even if by a regulator software does not know about or if it is one that
may genuinely be disconnected. In order to allow this behaviour to be
changed and stub regulators to be provided in the former case add a new
regulator request function regulator_get_optional() which provides a hint
to the core that the regulator may genuinely not be connected.

Currently the implementation is identical to the current behaviour, future
patches will add support in the core for returning stub regulators in the
case where normal regulator_get() fails and the board has requested it.

Signed-off-by: Mark Brown <[email protected]>
---
drivers/regulator/core.c | 59 ++++++++++++++++++++++++++++++++++++++
include/linux/regulator/consumer.h | 18 +++++++++++-
2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 61e4060..f24f401 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1414,6 +1414,65 @@ struct regulator *regulator_get_exclusive(struct device *dev, const char *id)
}
EXPORT_SYMBOL_GPL(regulator_get_exclusive);

+/**
+ * regulator_get_optional - obtain optional access to a regulator.
+ * @dev: device for regulator "consumer"
+ * @id: Supply name or regulator ID.
+ *
+ * Returns a struct regulator corresponding to the regulator producer,
+ * or IS_ERR() condition containing errno. Other consumers will be
+ * unable to obtain this reference is held and the use count for the
+ * regulator will be initialised to reflect the current state of the
+ * regulator.
+ *
+ * This is intended for use by consumers for devices which can have
+ * some supplies unconnected in normal use, such as some MMC devices.
+ * It can allow the regulator core to provide stub supplies for other
+ * supplies requested using normal regulator_get() calls without
+ * disrupting the operation of drivers that can handle absent
+ * supplies.
+ *
+ * Use of supply names configured via regulator_set_device_supply() is
+ * strongly encouraged. It is recommended that the supply name used
+ * should match the name used for the supply and/or the relevant
+ * device pins in the datasheet.
+ */
+struct regulator *regulator_get_optional(struct device *dev, const char *id)
+{
+ return _regulator_get(dev, id, 0);
+}
+EXPORT_SYMBOL_GPL(regulator_get_optional);
+
+/**
+ * devm_regulator_get_optional - Resource managed regulator_get_optional()
+ * @dev: device for regulator "consumer"
+ * @id: Supply name or regulator ID.
+ *
+ * Managed regulator_get_optional(). Regulators returned from this
+ * function are automatically regulator_put() on driver detach. See
+ * regulator_get_optional() for more information.
+ */
+struct regulator *devm_regulator_get_optional(struct device *dev,
+ const char *id)
+{
+ struct regulator **ptr, *regulator;
+
+ ptr = devres_alloc(devm_regulator_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ regulator = regulator_get_optional(dev, id);
+ if (!IS_ERR(regulator)) {
+ *ptr = regulator;
+ devres_add(dev, ptr);
+ } else {
+ devres_free(ptr);
+ }
+
+ return regulator;
+}
+EXPORT_SYMBOL_GPL(devm_regulator_get_optional);
+
/* Locks held by regulator_put() */
static void _regulator_put(struct regulator *regulator)
{
diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h
index 1ccc889..2582e41 100644
--- a/include/linux/regulator/consumer.h
+++ b/include/linux/regulator/consumer.h
@@ -137,6 +137,10 @@ struct regulator *__must_check devm_regulator_get(struct device *dev,
const char *id);
struct regulator *__must_check regulator_get_exclusive(struct device *dev,
const char *id);
+struct regulator *__must_check regulator_get_optional(struct device *dev,
+ const char *id);
+struct regulator *__must_check devm_regulator_get_optional(struct device *dev,
+ const char *id);
void regulator_put(struct regulator *regulator);
void devm_regulator_put(struct regulator *regulator);

@@ -212,14 +216,26 @@ static inline struct regulator *__must_check regulator_get(struct device *dev,
}

static inline struct regulator *__must_check
+devm_regulator_get(struct device *dev, const char *id)
+{
+ return NULL;
+}
+
+static inline struct regulator *__must_check
regulator_get_exclusive(struct device *dev, const char *id)
{
return NULL;
}

+static inline struct regulator *__must_check
+regulator_get_optional(struct device *dev, const char *id)
+{
+ return NULL;
+}
+

static inline struct regulator *__must_check
-devm_regulator_get(struct device *dev, const char *id)
+devm_regulator_get_optional(struct device *dev, const char *id)
{
return NULL;
}
--
1.8.3.2

2013-07-30 11:46:44

by Mark Brown

[permalink] [raw]

Subject: [PATCH 2/5] mmc: core: Indicate that vmmcq may be absent

From: Mark Brown <[email protected]>

Use regulator_get_optional() to tell the core that requests for the vmmcq
regulator can fail in a real system.

Signed-off-by: Mark Brown <[email protected]>
---
drivers/mmc/core/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 49a5bca..5d08855 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -1313,7 +1313,7 @@ int mmc_regulator_get_supply(struct mmc_host *mmc)

supply = devm_regulator_get(dev, "vmmc");
mmc->supply.vmmc = supply;
- mmc->supply.vqmmc = devm_regulator_get(dev, "vqmmc");
+ mmc->supply.vqmmc = devm_regulator_get_optional(dev, "vqmmc");

if (IS_ERR(supply))
return PTR_ERR(supply);
--
1.8.3.2

2013-07-30 11:46:47

by Mark Brown

[permalink] [raw]

Subject: [PATCH 4/5] mmc: dw_mmc: Indicate that regulators may be absent

2013-07-30 11:47:11

by Mark Brown

[permalink] [raw]

Subject: [PATCH 5/5] mmc: pxamci: Indicate that regulators may be absent

2013-07-30 11:47:47

by Mark Brown

[permalink] [raw]

Subject: [PATCH 3/5] mmc: sdhci: Indicate that regulators may be absent

From: Mark Brown <[email protected]>

Use regulator_get_optional() to tell the core that requests for regulators
can fail in a real system.

Signed-off-by: Mark Brown <[email protected]>
---
drivers/mmc/host/sdhci.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index a78bd4f..dd2c083 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2966,7 +2966,7 @@ int sdhci_add_host(struct sdhci_host *host)
mmc->caps |= MMC_CAP_NEEDS_POLL;

/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
- host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
+ host->vqmmc = regulator_get_optional(mmc_dev(mmc), "vqmmc");
if (IS_ERR_OR_NULL(host->vqmmc)) {
if (PTR_ERR(host->vqmmc) < 0) {
pr_info("%s: no vqmmc regulator found\n",
@@ -3042,7 +3042,7 @@ int sdhci_add_host(struct sdhci_host *host)

ocr_avail = 0;

- host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
+ host->vmmc = regulator_get_optional(mmc_dev(mmc), "vmmc");
if (IS_ERR_OR_NULL(host->vmmc)) {
if (PTR_ERR(host->vmmc) < 0) {
pr_info("%s: no vmmc regulator found\n",
--
1.8.3.2

2013-07-30 13:33:34

by Seungwon Jeon

[permalink] [raw]

Subject: RE: [PATCH 4/5] mmc: dw_mmc: Indicate that regulators may be absent

On Tue, July 30, 2013, Mark Brown wrote:
> From: Mark Brown <[email protected]>
>
> Use regulator_get_optional() to tell the core that requests for regulators
> can fail in a real system.
>
> Signed-off-by: Mark Brown <[email protected]>
Acked-by: Seungwon Jeon <[email protected]>

Thanks,
Seungwon Jeon

2013-07-31 03:29:23

by Jaehoon Chung

[permalink] [raw]

Subject: Re: [PATCH 4/5] mmc: dw_mmc: Indicate that regulators may be absent

Acked-by: Jaehoon Chung <[email protected]>

Best Regards,
Jaehoon Chung

On 07/30/2013 10:33 PM, Seungwon Jeon wrote:
> On Tue, July 30, 2013, Mark Brown wrote:
>> From: Mark Brown <[email protected]>
>>
>> Use regulator_get_optional() to tell the core that requests for regulators
>> can fail in a real system.
>>
>> Signed-off-by: Mark Brown <[email protected]>
> Acked-by: Seungwon Jeon <[email protected]>
>
> Thanks,
> Seungwon Jeon
>
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