[PATCH 0/2] mmc: sdhci: Defer probe if regulators are not registered

[PATCH 0/2] mmc: sdhci: Defer probe if regulators are not registered

[Pavan Kunapuli]

Regulator driver registration may sometimes be done after
mmc driver registration. In such cases, defer mmc probe
to obtain vmmc and vmmcq regulators.
Added vmmc and vmmcq supplies to tegra dt files.

Pavan Kunapuli (2):
  ARM: dt: tegra: Add sdhci regulators
  mmc: sdhci: Defer probe if regulator_get fails

 arch/arm/boot/dts/tegra20-harmony.dts    |   27 ++++++++++++++++++++-
 arch/arm/boot/dts/tegra20-paz00.dts      |   24 +++++++++++++++++++-
 arch/arm/boot/dts/tegra20-seaboard.dts   |   35 ++++++++++++++++++++++++++++-
 arch/arm/boot/dts/tegra20-tamonten.dtsi  |   10 ++++++++
 arch/arm/boot/dts/tegra20-ventana.dts    |   36 ++++++++++++++++++++++++++++-
 arch/arm/boot/dts/tegra20-whistler.dts   |    9 +++++-
 arch/arm/boot/dts/tegra30-cardhu-a02.dts |    2 +
 arch/arm/boot/dts/tegra30-cardhu-a04.dts |    2 +
 arch/arm/boot/dts/tegra30-cardhu.dtsi    |   19 ++++++++++++++-
 drivers/mmc/host/sdhci.c                 |   25 ++++++++++++++++++--
 10 files changed, 176 insertions(+), 13 deletions(-)

[PATCH 1/2] ARM: dt: tegra: Add sdhci regulators

[Pavan Kunapuli]

Adding vmmc and vmmcq supplies for sdhci nodes
in tegra dt files.

Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
---
 arch/arm/boot/dts/tegra20-harmony.dts    |   27 ++++++++++++++++++++-
 arch/arm/boot/dts/tegra20-paz00.dts      |   24 +++++++++++++++++++-
 arch/arm/boot/dts/tegra20-seaboard.dts   |   35 ++++++++++++++++++++++++++++-
 arch/arm/boot/dts/tegra20-tamonten.dtsi  |   10 ++++++++
 arch/arm/boot/dts/tegra20-ventana.dts    |   36 ++++++++++++++++++++++++++++-
 arch/arm/boot/dts/tegra20-whistler.dts   |    9 +++++-
 arch/arm/boot/dts/tegra30-cardhu-a02.dts |    2 +
 arch/arm/boot/dts/tegra30-cardhu-a04.dts |    2 +
 arch/arm/boot/dts/tegra30-cardhu.dtsi    |   19 ++++++++++++++-
 9 files changed, 154 insertions(+), 10 deletions(-)

diff --git a/arch/arm/boot/dts/tegra20-harmony.dts b/arch/arm/boot/dts/tegra20-harmony.dts
index 74b8a47..5b02afe 100644
--- a/arch/arm/boot/dts/tegra20-harmony.dts
+++ b/arch/arm/boot/dts/tegra20-harmony.dts
@@ -419,7 +419,8 @@
 		status = "okay";
 		cd-gpios = <&gpio 69 0>; /* gpio PI5 */
 		wp-gpios = <&gpio 57 0>; /* gpio PH1 */
-		power-gpios = <&gpio 155 0>; /* gpio PT3 */
+		vmmc-supply = <&vddio_sd_reg>;
+		vqmmc-supply = <&vddio_sd_reg>;
 		bus-width = <4>;
 	};
 
@@ -427,7 +428,8 @@
 		status = "okay";
 		cd-gpios = <&gpio 58 0>; /* gpio PH2 */
 		wp-gpios = <&gpio 59 0>; /* gpio PH3 */
-		power-gpios = <&gpio 70 0>; /* gpio PI6 */
+		vmmc-supply = <&vddio_sdmmc_reg>;
+		vqmmc-supply = <&vddio_sdmmc_reg>;
 		bus-width = <8>;
 	};
 
@@ -495,6 +497,27 @@
 			gpio = <&gpio 176 0>; /* gpio PW0 */
 			enable-active-high;
 		};
+
+		vddio_sdmmc_reg: regulator@6 {
+			compatible = "regulator-fixed";
+			reg = <6>;
+			regulator-name = "vddio_sdmmc";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			gpio = <&gpio 70 0>; /* gpio PW0 */
+			enable-active-high;
+		};
+
+		vddio_sd_reg: regulator@7 {
+			compatible = "regulator-fixed";
+			reg = <7>;
+			regulator-name = "vddio_sd";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			gpio = <&gpio 155 0>; /* gpio PW0 */
+			enable-active-high;
+		};
+
 	};
 
 	sound {
diff --git a/arch/arm/boot/dts/tegra20-paz00.dts b/arch/arm/boot/dts/tegra20-paz00.dts
index 6a93d14..e161b65 100644
--- a/arch/arm/boot/dts/tegra20-paz00.dts
+++ b/arch/arm/boot/dts/tegra20-paz00.dts
@@ -422,13 +422,17 @@
 		status = "okay";
 		cd-gpios = <&gpio 173 0>; /* gpio PV5 */
 		wp-gpios = <&gpio 57 0>;  /* gpio PH1 */
-		power-gpios = <&gpio 169 0>; /* gpio PV1 */
 		bus-width = <4>;
+		vmmc-supply = <&vddio_sd_reg>;
+		vqmmc-supply = <&vddio_sd_reg>;
+
 	};
 
 	sdhci@c8000600 {
 		status = "okay";
 		bus-width = <8>;
+		vmmc-supply = <&vddio_sdmmc_reg>;
+		vqmmc-supply = <&vddio_sdmmc_reg>;
 	};
 
 	gpio-keys {
@@ -465,6 +469,24 @@
 			regulator-max-microvolt = <5000000>;
 			regulator-always-on;
 		};
+
+		vddio_sd_reg: regulator@1 {
+			compatible = "regulator-fixed";
+			reg = <1>;
+			regulator-name = "vddio_sd";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			enable-active-high;
+			gpio = <&gpio 169 0>; /* gpio PV1 */
+		};
+
+		vddio_sdmmc_reg: regulator@2 {
+			compatible = "regulator-fixed";
+			reg = <2>;
+			regulator-name  = "vddio_sdmmc";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+		};
 	};
 
 	sound {
diff --git a/arch/arm/boot/dts/tegra20-seaboard.dts b/arch/arm/boot/dts/tegra20-seaboard.dts
index eafeca6..1b7d692 100644
--- a/arch/arm/boot/dts/tegra20-seaboard.dts
+++ b/arch/arm/boot/dts/tegra20-seaboard.dts
@@ -450,7 +450,7 @@
 					regulator-always-on;
 				};
 
-				ldo5 {
+				ldo5_reg: ldo5 {
 					regulator-name = "vdd_ldo5,vcore_mmc";
 					regulator-min-microvolt = <2850000>;
 					regulator-max-microvolt = <2850000>;
@@ -565,6 +565,9 @@
 		status = "okay";
 		power-gpios = <&gpio 86 0>; /* gpio PK6 */
 		bus-width = <4>;
+		vmmc-supply = <&vddio_sdmmc_reg>;
+		vqmmc-supply = <&vddio_sdmmc_reg>;
+
 	};
 
 	sdhci@c8000400 {
@@ -573,11 +576,15 @@
 		wp-gpios = <&gpio 57 0>; /* gpio PH1 */
 		power-gpios = <&gpio 70 0>; /* gpio PI6 */
 		bus-width = <4>;
+		vmmc-supply = <&vddio_sd_reg>;
+		vqmmc-supply = <&vddio_sd_reg>;
 	};
 
 	sdhci@c8000600 {
 		status = "okay";
 		bus-width = <8>;
+		vmmc-supply = <&ldo5_reg>;
+		vqmmc-supply = <&vddio_nand_reg>;
 	};
 
 	gpio-keys {
@@ -632,6 +639,32 @@
 			gpio = <&pmic 1 0>;
 			enable-active-high;
 		};
+
+		vddio_sd_reg: regulator@3 {
+			compatible = "regulator-fixed";
+			reg = <3>;
+			regulator-name = "vddio_sd";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			gpio = <&gpio 176 0>; /* gpio PW0 */
+			enable-active-high;
+		};
+
+		vddio_sdmmc_reg: regulator@4 {
+			compatible = "regulator-fixed";
+			reg = <4>;
+			regulator-name = "vddio_sdmmc";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+		};
+
+		vddio_nand_reg: regulator@5 {
+			compatible = "regulator-fixed";
+			reg = <5>;
+			regulator-name = "vddio_nand";
+			regulator-min-microvolt = <1800000>;
+			regulator-max-microvolt = <1800000>;
+		};
 	};
 
 	sound {
diff --git a/arch/arm/boot/dts/tegra20-tamonten.dtsi b/arch/arm/boot/dts/tegra20-tamonten.dtsi
index 5b3d8b1..a60e828 100644
--- a/arch/arm/boot/dts/tegra20-tamonten.dtsi
+++ b/arch/arm/boot/dts/tegra20-tamonten.dtsi
@@ -396,6 +396,8 @@
 		wp-gpios = <&gpio 59 0>; /* gpio PH3 */
 		bus-width = <4>;
 		status = "okay";
+		vmmc-supply = <&vddio_sdmmc_reg>;
+		vqmmc-supply = <&vddio_sdmmc_reg>;
 	};
 
 	regulators {
@@ -412,5 +414,13 @@
 			regulator-max-microvolt = <5000000>;
 			regulator-always-on;
 		};
+
+		vddio_sdmmc_reg: regulator@1 {
+			compatible = "regulator-fixed";
+			reg = <1>;
+			regulator-name = "vddio_sdmmc";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+		};
 	};
 };
diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index bec8bb2..0210670 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts
@@ -376,7 +376,7 @@
 					regulator-always-on;
 				};
 
-				ldo5 {
+				ldo5_reg: ldo5 {
 					regulator-name = "vdd_ldo5,vcore_mmc";
 					regulator-min-microvolt = <2850000>;
 					regulator-max-microvolt = <2850000>;
@@ -439,19 +439,24 @@
 		status = "okay";
 		power-gpios = <&gpio 86 0>; /* gpio PK6 */
 		bus-width = <4>;
+		vmmc-supply = <&vddio_sdmmc_reg>;
+		vqmmc-supply = <&vddio_sdmmc_reg>;
 	};
 
 	sdhci@c8000400 {
 		status = "okay";
 		cd-gpios = <&gpio 69 0>; /* gpio PI5 */
 		wp-gpios = <&gpio 57 0>; /* gpio PH1 */
-		power-gpios = <&gpio 70 0>; /* gpio PI6 */
 		bus-width = <4>;
+		vmmc-supply = <&vddio_sd_reg>;
+		vqmmc-supply = <&vddio_sd_reg>;
 	};
 
 	sdhci@c8000600 {
 		status = "okay";
 		bus-width = <8>;
+		vmmc-supply = <&ldo5_reg>;
+		vqmmc-supply = <&vddio_nand_reg>;
 	};
 
 	regulators {
@@ -506,6 +511,33 @@
 			gpio = <&gpio 176 0>; /* gpio PW0 */
 			enable-active-high;
 		};
+
+		vddio_sd_reg: regulator@5 {
+			compatible = "regulator-fixed";
+			reg = <5>;
+			regulator-name = "vddio_sd";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			gpio = <&gpio 70 0>; /* gpio PW0 */
+			enable-active-high;
+		};
+
+		vddio_sdmmc_reg: regulator@6 {
+			compatible = "regulator-fixed";
+			reg = <6>;
+			regulator-name = "vddio_sdmmc";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+		};
+
+		vddio_nand_reg: regulator@7 {
+			compatible = "regulator-fixed";
+			reg = <7>;
+			regulator-name = "vddio_nand";
+			regulator-min-microvolt = <1800000>;
+			regulator-max-microvolt = <1800000>;
+		};
+
 	};
 
 	sound {
diff --git a/arch/arm/boot/dts/tegra20-whistler.dts b/arch/arm/boot/dts/tegra20-whistler.dts
index 94a71c9..bdc4918 100644
--- a/arch/arm/boot/dts/tegra20-whistler.dts
+++ b/arch/arm/boot/dts/tegra20-whistler.dts
@@ -349,7 +349,7 @@
 					regulator-always-on;
 				};
 
-				ldo5 {
+				ldo5_reg: ldo5 {
 					regulator-name = "nvvdd_ldo5,vcore_mmc,avdd_lcd1,vddio_1wire";
 					regulator-min-microvolt = <2800000>;
 					regulator-max-microvolt = <2800000>;
@@ -394,7 +394,7 @@
 					regulator-max-microvolt = <3300000>;
 				};
 
-				ldo12 {
+				ldo12_reg: ldo12 {
 					regulator-name = "nvvdd_ldo12,vddio_sdio";
 					regulator-min-microvolt = <2800000>;
 					regulator-max-microvolt = <2800000>;
@@ -496,11 +496,16 @@
 		status = "okay";
 		wp-gpios = <&gpio 173 0>; /* gpio PV5 */
 		bus-width = <8>;
+		vmmc-supply = <&ldo12_reg>;
+		vqmmc-supply = <&ldo12_reg>;
 	};
 
 	sdhci@c8000600 {
 		status = "okay";
 		bus-width = <8>;
+		vmmc-supply = <&ldo5_reg>;
+		vqmmc-supply = <&ldo5_reg>;
+
 	};
 
 	regulators {
diff --git a/arch/arm/boot/dts/tegra30-cardhu-a02.dts b/arch/arm/boot/dts/tegra30-cardhu-a02.dts
index adc88aa..697effa 100644
--- a/arch/arm/boot/dts/tegra30-cardhu-a02.dts
+++ b/arch/arm/boot/dts/tegra30-cardhu-a02.dts
@@ -88,6 +88,8 @@
 		status = "okay";
 		power-gpios = <&gpio 28 0>; /* gpio PD4 */
 		bus-width = <4>;
+		vmmc-supply = <&vio_reg>;
+		vqmmc-supply = <&vio_reg>;
 	};
 };
 
diff --git a/arch/arm/boot/dts/tegra30-cardhu-a04.dts b/arch/arm/boot/dts/tegra30-cardhu-a04.dts
index 08163e1..ee4820a 100644
--- a/arch/arm/boot/dts/tegra30-cardhu-a04.dts
+++ b/arch/arm/boot/dts/tegra30-cardhu-a04.dts
@@ -100,5 +100,7 @@
 		status = "okay";
 		power-gpios = <&gpio 27 0>; /* gpio PD3 */
 		bus-width = <4>;
+		vmmc-supply = <&vio_reg>;
+		vqmmc-supply = <&vio_reg>;
 	};
 };
diff --git a/arch/arm/boot/dts/tegra30-cardhu.dtsi b/arch/arm/boot/dts/tegra30-cardhu.dtsi
index b245e6c..fbf0fae 100644
--- a/arch/arm/boot/dts/tegra30-cardhu.dtsi
+++ b/arch/arm/boot/dts/tegra30-cardhu.dtsi
@@ -247,7 +247,7 @@
 
 				ldo5_reg: ldo5 {
 					regulator-name = "vddio_sdmmc,avdd_vdac";
-					regulator-min-microvolt = <3300000>;
+					regulator-min-microvolt = <1800000>;
 					regulator-max-microvolt = <3300000>;
 					regulator-always-on;
 				};
@@ -290,13 +290,16 @@
 		status = "okay";
 		cd-gpios = <&gpio 69 0>; /* gpio PI5 */
 		wp-gpios = <&gpio 155 0>; /* gpio PT3 */
-		power-gpios = <&gpio 31 0>; /* gpio PD7 */
 		bus-width = <4>;
+		vmmc-supply = <&sdcard_3v3_reg>;
+		vqmmc-supply = <&ldo5_reg>;
 	};
 
 	sdhci@78000600 {
 		status = "okay";
 		bus-width = <8>;
+		vmmc-supply = <&emmc_3v3_reg>;
+		vqmmc-supply = <&vio_reg>;
 	};
 
 	regulators {
@@ -451,6 +454,18 @@
 			gpio-open-drain;
 			vin-supply = <&vdd_5v0_reg>;
 		};
+
+		sdcard_3v3_reg: regulator@13 {
+			compatible = "regulator-fixed";
+			reg = <13>;
+			regulator-name = "sdcard_3v3";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			enable-active-high;
+			gpio = <&gpio 31 0>; /* GPIO PD7 */
+			vin-supply = <&sys_3v3_reg>;
+		};
+
 	};
 
 	sound {
-- 
1.7.1.1

[PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Pavan Kunapuli]

vmmc and vqmmc regulators control the voltage to
the host and device. Defer the probe if either of
them is not registered.

Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
---
 drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
 1 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7922adb..925c403 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
 	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
 		mmc->caps |= MMC_CAP_NEEDS_POLL;
 
-	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
+	/*
+	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
+	 * vqmmc regulator should be present. If it's not present,
+	 * assume the regulator driver registration is not yet done and
+	 * defer the probe.
+	 */
 	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
 	if (IS_ERR(host->vqmmc)) {
-		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
+		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
 		host->vqmmc = NULL;
+		return -EPROBE_DEFER;
 	}
 	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
 		regulator_enable(host->vqmmc);
@@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
 
 	ocr_avail = 0;
 
+	/*
+	 * vmmc regulator should be present. If it's not present,
+	 * assume the regulator driver registration is not yet done
+	 * and defer the probe.
+	 */
 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
 	if (IS_ERR(host->vmmc)) {
-		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
+		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
 		host->vmmc = NULL;
+		ret = -EPROBE_DEFER;
+		goto vmmc_err;
 	} else
 		regulator_enable(host->vmmc);
 
@@ -3121,7 +3134,13 @@ reset:
 untasklet:
 	tasklet_kill(&host->card_tasklet);
 	tasklet_kill(&host->finish_tasklet);
+vmmc_err:
+	if (host->vqmmc) {
+		if (regulator_is_enabled(host->vqmmc))
+			regulator_disable(host->vqmmc);
 
+		regulator_put(host->vqmmc);
+	}
 	return ret;
 }
 
-- 
1.7.1.1

[PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Pavan Kunapuli]

vmmc and vqmmc regulators control the voltage to
the host and device. Defer the probe if either of
them is not registered.

Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
---
 drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
 1 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7922adb..925c403 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
 	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
 		mmc->caps |= MMC_CAP_NEEDS_POLL;
 
-	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
+	/*
+	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
+	 * vqmmc regulator should be present. If it's not present,
+	 * assume the regulator driver registration is not yet done and
+	 * defer the probe.
+	 */
 	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
 	if (IS_ERR(host->vqmmc)) {
-		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
+		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
 		host->vqmmc = NULL;
+		return -EPROBE_DEFER;
 	}
 	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
 		regulator_enable(host->vqmmc);
@@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
 
 	ocr_avail = 0;
 
+	/*
+	 * vmmc regulator should be present. If it's not present,
+	 * assume the regulator driver registration is not yet done
+	 * and defer the probe.
+	 */
 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
 	if (IS_ERR(host->vmmc)) {
-		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
+		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
 		host->vmmc = NULL;
+		ret = -EPROBE_DEFER;
+		goto vmmc_err;
 	} else
 		regulator_enable(host->vmmc);
 
@@ -3121,7 +3134,13 @@ reset:
 untasklet:
 	tasklet_kill(&host->card_tasklet);
 	tasklet_kill(&host->finish_tasklet);
+vmmc_err:
+	if (host->vqmmc) {
+		if (regulator_is_enabled(host->vqmmc))
+			regulator_disable(host->vqmmc);
 
+		regulator_put(host->vqmmc);
+	}
 	return ret;
 }
 
-- 
1.7.1.1

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Lucas Stach]

Am Dienstag, den 23.10.2012, 12:49 +0530 schrieb Pavan Kunapuli:
> vmmc and vqmmc regulators control the voltage to
> the host and device. Defer the probe if either of
> them is not registered.
> 
Does this work with boards where we don't have any MMC supplies? Or are
we just deferring the probe indefinitely there?

For boards that power MMC unconditionally, are we supposed to add dummy
regulators to make them work with this patchset?

> Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
> ---
>  drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
>  1 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
>  		mmc->caps |= MMC_CAP_NEEDS_POLL;
>  
> -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> +	/*
> +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> +	 * vqmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done and
> +	 * defer the probe.
> +	 */
>  	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
>  	if (IS_ERR(host->vqmmc)) {
> -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
>  		host->vqmmc = NULL;
> +		return -EPROBE_DEFER;
>  	}
>  	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
>  		regulator_enable(host->vqmmc);
> @@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  
>  	ocr_avail = 0;
>  
> +	/*
> +	 * vmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done
> +	 * and defer the probe.
> +	 */
>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
>  	if (IS_ERR(host->vmmc)) {
> -		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
>  		host->vmmc = NULL;
> +		ret = -EPROBE_DEFER;
> +		goto vmmc_err;
>  	} else
>  		regulator_enable(host->vmmc);
>  
> @@ -3121,7 +3134,13 @@ reset:
>  untasklet:
>  	tasklet_kill(&host->card_tasklet);
>  	tasklet_kill(&host->finish_tasklet);
> +vmmc_err:
> +	if (host->vqmmc) {
> +		if (regulator_is_enabled(host->vqmmc))
> +			regulator_disable(host->vqmmc);
>  
> +		regulator_put(host->vqmmc);
> +	}
>  	return ret;
>  }
>  

RE: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Pavan Kunapuli]

>> Does this work with boards where we don't have any MMC supplies? Or are we just deferring the probe indefinitely there?
The probe will be deferred indefinitely.

>> For boards that power MMC unconditionally, are we supposed to add dummy regulators to make them work with this patchset?
Yes. We need to add dummy regulators for boards that power MMC unconditionally. I am not sure if there is any other solution other than using deferred probe that would guarantee regulators availability.

-----Original Message-----
From: Lucas Stach [mailto:dev@lynxeye.de] 
Sent: 23 October 2012 13:27
To: Pavan Kunapuli
Cc: swarren@wwwdotorg.org; linux@arm.linux.org.uk; cjb@laptop.org; linux-tegra@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; linux-mmc@vger.kernel.org
Subject: Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

Am Dienstag, den 23.10.2012, 12:49 +0530 schrieb Pavan Kunapuli:
> vmmc and vqmmc regulators control the voltage to the host and device. 
> Defer the probe if either of them is not registered.
> 
Does this work with boards where we don't have any MMC supplies? Or are we just deferring the probe indefinitely there?

For boards that power MMC unconditionally, are we supposed to add dummy regulators to make them work with this patchset?

> Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
> ---
>  drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
>  1 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 
> 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
>  		mmc->caps |= MMC_CAP_NEEDS_POLL;
>  
> -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> +	/*
> +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> +	 * vqmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done and
> +	 * defer the probe.
> +	 */
>  	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
>  	if (IS_ERR(host->vqmmc)) {
> -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
>  		host->vqmmc = NULL;
> +		return -EPROBE_DEFER;
>  	}
>  	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
>  		regulator_enable(host->vqmmc);
> @@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  
>  	ocr_avail = 0;
>  
> +	/*
> +	 * vmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done
> +	 * and defer the probe.
> +	 */
>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
>  	if (IS_ERR(host->vmmc)) {
> -		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
>  		host->vmmc = NULL;
> +		ret = -EPROBE_DEFER;
> +		goto vmmc_err;
>  	} else
>  		regulator_enable(host->vmmc);
>  
> @@ -3121,7 +3134,13 @@ reset:
>  untasklet:
>  	tasklet_kill(&host->card_tasklet);
>  	tasklet_kill(&host->finish_tasklet);
> +vmmc_err:
> +	if (host->vqmmc) {
> +		if (regulator_is_enabled(host->vqmmc))
> +			regulator_disable(host->vqmmc);
>  
> +		regulator_put(host->vqmmc);
> +	}
>  	return ret;
>  }
>  

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Jaehoon Chung]

I didn't understand why defer the probe?
I think that some board can't control vqmmc or vmmc.

Best Regards,
Jaehoon Chung
On 10/23/2012 04:18 PM, Pavan Kunapuli wrote:
> vmmc and vqmmc regulators control the voltage to
> the host and device. Defer the probe if either of
> them is not registered.
> 
> Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
> ---
>  drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
>  1 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
>  		mmc->caps |= MMC_CAP_NEEDS_POLL;
>  
> -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> +	/*
> +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> +	 * vqmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done and
> +	 * defer the probe.
> +	 */
>  	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
>  	if (IS_ERR(host->vqmmc)) {
> -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
>  		host->vqmmc = NULL;
> +		return -EPROBE_DEFER;
>  	}
>  	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
>  		regulator_enable(host->vqmmc);
> @@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  
>  	ocr_avail = 0;
>  
> +	/*
> +	 * vmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done
> +	 * and defer the probe.
> +	 */
>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
>  	if (IS_ERR(host->vmmc)) {
> -		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
>  		host->vmmc = NULL;
> +		ret = -EPROBE_DEFER;
> +		goto vmmc_err;
>  	} else
>  		regulator_enable(host->vmmc);
>  
> @@ -3121,7 +3134,13 @@ reset:
>  untasklet:
>  	tasklet_kill(&host->card_tasklet);
>  	tasklet_kill(&host->finish_tasklet);
> +vmmc_err:
> +	if (host->vqmmc) {
> +		if (regulator_is_enabled(host->vqmmc))
> +			regulator_disable(host->vqmmc);
>  
> +		regulator_put(host->vqmmc);
> +	}
>  	return ret;
>  }
>  
> 

RE: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Pavan Kunapuli]

For platforms where the board can control vmmc or vqmmc, if the regulator supplies registration is not done before sdhci probe, deferring sdhci probe would ensure that the regulators are available the next time around. For platforms where the board can't control vmmc or vqmmc, we can have a dummy regulator to make sure probe will never get deferred.

-----Original Message-----
From: Jaehoon Chung [mailto:jh80.chung@samsung.com] 
Sent: 23 October 2012 15:41
To: Pavan Kunapuli
Cc: swarren@wwwdotorg.org; linux@arm.linux.org.uk; cjb@laptop.org; linux-kernel@vger.kernel.org; linux-mmc@vger.kernel.org
Subject: Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

I didn't understand why defer the probe?
I think that some board can't control vqmmc or vmmc.

Best Regards,
Jaehoon Chung
On 10/23/2012 04:18 PM, Pavan Kunapuli wrote:
> vmmc and vqmmc regulators control the voltage to the host and device. 
> Defer the probe if either of them is not registered.
> 
> Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
> ---
>  drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
>  1 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 
> 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
>  		mmc->caps |= MMC_CAP_NEEDS_POLL;
>  
> -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> +	/*
> +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> +	 * vqmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done and
> +	 * defer the probe.
> +	 */
>  	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
>  	if (IS_ERR(host->vqmmc)) {
> -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
>  		host->vqmmc = NULL;
> +		return -EPROBE_DEFER;
>  	}
>  	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
>  		regulator_enable(host->vqmmc);
> @@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  
>  	ocr_avail = 0;
>  
> +	/*
> +	 * vmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done
> +	 * and defer the probe.
> +	 */
>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
>  	if (IS_ERR(host->vmmc)) {
> -		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
>  		host->vmmc = NULL;
> +		ret = -EPROBE_DEFER;
> +		goto vmmc_err;
>  	} else
>  		regulator_enable(host->vmmc);
>  
> @@ -3121,7 +3134,13 @@ reset:
>  untasklet:
>  	tasklet_kill(&host->card_tasklet);
>  	tasklet_kill(&host->finish_tasklet);
> +vmmc_err:
> +	if (host->vqmmc) {
> +		if (regulator_is_enabled(host->vqmmc))
> +			regulator_disable(host->vqmmc);
>  
> +		regulator_put(host->vqmmc);
> +	}
>  	return ret;
>  }
>  
> 

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Philip Rakity]

On 23 Oct 2012, at 09:19, Pavan Kunapuli <pkunapuli-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> wrote:

> vmmc and vqmmc regulators control the voltage to
> the host and device. Defer the probe if either of
> them is not registered.
> 
> Signed-off-by: Pavan Kunapuli <pkunapuli-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
> drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
> 1 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
> 	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
> 		mmc->caps |= MMC_CAP_NEEDS_POLL;
> 
> -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> +	/*
> +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> +	 * vqmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done and
> +	 * defer the probe.
> +	 */
> 	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
> 	if (IS_ERR(host->vqmmc)) {
> -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> 		host->vqmmc = NULL;
> +		return -EPROBE_DEFER;

Some systems exist where vmmc regulator exists and vqmmc regulator does not.  The vmmc regular is fixed at 3.3v.  
Deferring the probe will cause issues.

> 	}
> 	else if (regulator_is_supported_voltage(host->vqmmc, 1800000, 1800000))
> 		regulator_enable(host->vqmmc);
> @@ -2903,10 +2909,17 @@ int sdhci_add_host(struct sdhci_host *host)
> 
> 	ocr_avail = 0;
> 
> +	/*
> +	 * vmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done
> +	 * and defer the probe.
> +	 */
> 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
> 	if (IS_ERR(host->vmmc)) {
> -		pr_info("%s: no vmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vmmc regulator found\n", mmc_hostname(mmc));
> 		host->vmmc = NULL;
> +		ret = -EPROBE_DEFER;
> +		goto vmmc_err;
> 	} else
> 		regulator_enable(host->vmmc);
> 
> @@ -3121,7 +3134,13 @@ reset:
> untasklet:
> 	tasklet_kill(&host->card_tasklet);
> 	tasklet_kill(&host->finish_tasklet);
> +vmmc_err:
> +	if (host->vqmmc) {
> +		if (regulator_is_enabled(host->vqmmc))
> +			regulator_disable(host->vqmmc);
> 
> +		regulator_put(host->vqmmc);
> +	}
> 	return ret;
> }
> 
> -- 
> 1.7.1.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Russell King - ARM Linux]

On Tue, Oct 23, 2012 at 03:21:58PM +0200, Philip Rakity wrote:
> On 23 Oct 2012, at 09:19, Pavan Kunapuli <pkunapuli-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> wrote:
> > -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> > +	/*
> > +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> > +	 * vqmmc regulator should be present. If it's not present,
> > +	 * assume the regulator driver registration is not yet done and
> > +	 * defer the probe.
> > +	 */
> > 	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
> > 	if (IS_ERR(host->vqmmc)) {
> > -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> > +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> > 		host->vqmmc = NULL;
> > +		return -EPROBE_DEFER;
> 
> Some systems exist where vmmc regulator exists and vqmmc regulator does not.  The vmmc regular is fixed at 3.3v.  
> Deferring the probe will cause issues.

That's one of the issues of deferred probing: you don't know if one of the
_get() functions failed because it just isn't present, or whether it's
failed because it hasn't been registered yet.

The two conditions are indistinguishable from the driver point of view.

The solution to it is to ensure that those drivers where hardware resource
X is optional provide a dummy resource to the driver when the hardware
resource is not available.  That means, as far as the driver is concerned,
that it will always expect to get a full set of resources whether or not
the hardware has them.

If drivers care about such stuff, then we should have xxx_is_dummy()
functions (eg, clk_is_dummy(clk)) which return TRUE when the hardware
resource is not available.  (which we could use NULL to indicate and
would be in keeping with the specified IS_ERR() usage of these APIs.)

Re: [PATCH 1/2] ARM: dt: tegra: Add sdhci regulators

[Stephen Warren]

On 10/23/2012 01:18 AM, Pavan Kunapuli wrote:
> Adding vmmc and vmmcq supplies for sdhci nodes
> in tegra dt files.

As I already mentioned downstream, this patch is invalid because it will
cause runtime failures if applied before the second patch in this
series. Please see the more detailed explanation I sent downstream.

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Stephen Warren]

On 10/23/2012 01:18 AM, Pavan Kunapuli wrote:
> vmmc and vqmmc regulators control the voltage to
> the host and device. Defer the probe if either of
> them is not registered.
> 
> Signed-off-by: Pavan Kunapuli <pkunapuli@nvidia.com>
> ---
>  drivers/mmc/host/sdhci.c |   25 ++++++++++++++++++++++---
>  1 files changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7922adb..925c403 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2844,11 +2844,17 @@ int sdhci_add_host(struct sdhci_host *host)
>  	    !(host->mmc->caps & MMC_CAP_NONREMOVABLE))
>  		mmc->caps |= MMC_CAP_NEEDS_POLL;
>  
> -	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
> +	/*
> +	 * If vqmmc regulator and no 1.8V signalling, then there's no UHS.
> +	 * vqmmc regulator should be present. If it's not present,
> +	 * assume the regulator driver registration is not yet done and
> +	 * defer the probe.
> +	 */
>  	host->vqmmc = regulator_get(mmc_dev(mmc), "vqmmc");
>  	if (IS_ERR(host->vqmmc)) {
> -		pr_info("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
> +		pr_err("%s: no vqmmc regulator found\n", mmc_hostname(mmc));
>  		host->vqmmc = NULL;
> +		return -EPROBE_DEFER;
>  	}

Right now, the regulator is optional, and any failure to acquire the
regulator is just ignored.

Instead, I think the behaviour we want is:

Attempt to get regulator.
1) If no error -> OK
2) If deferred probe error -> return -EPROBE_DEFER
3) If any other error -> ignore it

Assuming that regulator_get() can explicitly detect and return the
difference between cases (1) and (2) above. If it can't, it seems like
it should be able to.

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Stephen Warren]

On 10/23/2012 01:57 AM, Lucas Stach wrote:
> Am Dienstag, den 23.10.2012, 12:49 +0530 schrieb Pavan Kunapuli:
>> vmmc and vqmmc regulators control the voltage to
>> the host and device. Defer the probe if either of
>> them is not registered.
>
> Does this work with boards where we don't have any MMC supplies? Or are
> we just deferring the probe indefinitely there?
> 
> For boards that power MMC unconditionally, are we supposed to add dummy
> regulators to make them work with this patchset?

I believe that dummy (fixed) regulators are supposed to be provided in
all cases where the platform doesn't actually have one. The fact that
everything worked OK without them before this patch was most likely a
mistake/accident.

Re: [PATCH 2/2] mmc: sdhci: Defer probe if regulator_get fails

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 714 bytes --]

On Tue, Oct 23, 2012 at 10:29:41AM -0600, Stephen Warren wrote:
> On 10/23/2012 01:57 AM, Lucas Stach wrote:

> > Does this work with boards where we don't have any MMC supplies? Or are
> > we just deferring the probe indefinitely there?

> > For boards that power MMC unconditionally, are we supposed to add dummy
> > regulators to make them work with this patchset?

> I believe that dummy (fixed) regulators are supposed to be provided in
> all cases where the platform doesn't actually have one. The fact that
> everything worked OK without them before this patch was most likely a
> mistake/accident.

That's the general idea; clearly there *are* supplies here, they're just
not software controlled supplies.

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