Hi,
On some boards, devices consuming a lot of power cannot use a single
regulator, but few of them in parallel to spread the consumption.
In such a case, we must ensure that all these regulators are kept in
sync.
Since this is something that is totally board specific, it should
obviously not be handle by each and every customer drivers that might
be driving a device wired this way on a particular board.
Instead, we implemented a regulator driver that just aggregates
several parent regulators and just forwards the regulators calls to
them.
Let me know what you think,
Maxime
Maxime Ripard (2):
regulator: Add coupled regulator
ARM: sunxi: chip: Add Wifi chip
arch/arm/boot/dts/sun5i-r8-chip.dts | 44 ++++-
drivers/regulator/Kconfig | 7 +
drivers/regulator/Makefile | 1 +
drivers/regulator/coupled-voltage-regulator.c | 241 ++++++++++++++++++++++++++
4 files changed, 292 insertions(+), 1 deletion(-)
create mode 100644 drivers/regulator/coupled-voltage-regulator.c
--
2.6.3
Some boards, in order to power devices that have a quite high power
consumption, wire multiple regulators in parallel.
In such a case, the regulators need to be kept in sync, all of them being
enabled or disabled in parallel.
This also requires to expose only the voltages that are common to all the
regulators.
Eventually support for changing the voltage in parallel should be added
too, possibly with delays between each other to avoid having a too brutal
peak consumption.
Signed-off-by: Maxime Ripard <[email protected]>
---
drivers/regulator/Kconfig | 7 +
drivers/regulator/Makefile | 1 +
drivers/regulator/coupled-voltage-regulator.c | 241 ++++++++++++++++++++++++++
3 files changed, 249 insertions(+)
create mode 100644 drivers/regulator/coupled-voltage-regulator.c
diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index 8df0b0e62976..6ba7bc8fda13 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -35,6 +35,13 @@ config REGULATOR_FIXED_VOLTAGE
useful for systems which use a combination of software
managed regulators and simple non-configurable regulators.
+config REGULATOR_COUPLED_VOLTAGE
+ tristate "Coupled voltage regulator support"
+ help
+ This driver provides support for regulators that are an
+ aggregate of other regulators in the system, and need to
+ keep them all in sync.
+
config REGULATOR_VIRTUAL_CONSUMER
tristate "Virtual regulator consumer support"
help
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 0f8174913c17..c05839257386 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -22,6 +22,7 @@ obj-$(CONFIG_REGULATOR_AS3711) += as3711-regulator.o
obj-$(CONFIG_REGULATOR_AS3722) += as3722-regulator.o
obj-$(CONFIG_REGULATOR_AXP20X) += axp20x-regulator.o
obj-$(CONFIG_REGULATOR_BCM590XX) += bcm590xx-regulator.o
+obj-$(CONFIG_REGULATOR_COUPLED_VOLTAGE) += coupled-voltage-regulator.o
obj-$(CONFIG_REGULATOR_DA903X) += da903x.o
obj-$(CONFIG_REGULATOR_DA9052) += da9052-regulator.o
obj-$(CONFIG_REGULATOR_DA9055) += da9055-regulator.o
diff --git a/drivers/regulator/coupled-voltage-regulator.c b/drivers/regulator/coupled-voltage-regulator.c
new file mode 100644
index 000000000000..dc7aa2aca7e6
--- /dev/null
+++ b/drivers/regulator/coupled-voltage-regulator.c
@@ -0,0 +1,241 @@
+/*
+ * Copyright 2015 Free Electrons
+ * Copyright 2015 NextThing Co.
+ *
+ * Author: Maxime Ripard <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <linux/regulator/consumer.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+
+#define COUPLED_REGULATOR_MAX_SUPPLIES 16
+
+struct coupled_regulator {
+ struct regulator **regulators;
+ int n_regulators;
+
+ int *voltages;
+ int n_voltages;
+};
+
+static int coupled_regulator_disable(struct regulator_dev *rdev)
+{
+ struct coupled_regulator *creg = rdev_get_drvdata(rdev);
+ int ret, i;
+
+ for (i = 0; i < creg->n_regulators; i++) {
+ ret = regulator_disable(creg->regulators[i]);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static int coupled_regulator_enable(struct regulator_dev *rdev)
+{
+ struct coupled_regulator *creg = rdev_get_drvdata(rdev);
+ int ret, i;
+
+ for (i = 0; i < creg->n_regulators; i++) {
+ ret = regulator_enable(creg->regulators[i]);
+ if (ret)
+ break;
+ }
+
+ return ret;
+}
+
+static int coupled_regulator_is_enabled(struct regulator_dev *rdev)
+{
+ struct coupled_regulator *creg = rdev_get_drvdata(rdev);
+ int ret = 0, i;
+
+ for (i = 0; i < creg->n_regulators; i++) {
+ ret &= regulator_is_enabled(creg->regulators[i]);
+ if (ret < 0)
+ break;
+ }
+
+ return ret;
+}
+
+static int coupled_regulator_list_voltage(struct regulator_dev *rdev,
+ unsigned int selector)
+{
+ struct coupled_regulator *creg = rdev_get_drvdata(rdev);
+
+ if (selector >= creg->n_voltages)
+ return -EINVAL;
+
+ return creg->voltages[selector];
+}
+
+static struct regulator_ops coupled_regulator_ops = {
+ .enable = coupled_regulator_enable,
+ .disable = coupled_regulator_disable,
+ .is_enabled = coupled_regulator_is_enabled,
+ .list_voltage = coupled_regulator_list_voltage,
+};
+
+static struct regulator_desc coupled_regulator_desc = {
+ .name = "coupled-voltage-regulator",
+ .type = REGULATOR_VOLTAGE,
+ .ops = &coupled_regulator_ops,
+ .owner = THIS_MODULE,
+};
+
+static int coupled_regulator_probe(struct platform_device *pdev)
+{
+ const struct regulator_init_data *init_data;
+ struct coupled_regulator *creg;
+ struct regulator_config config = { };
+ struct regulator_dev *regulator;
+ struct regulator_desc *desc;
+ struct device_node *np = pdev->dev.of_node;
+ int max_voltages, i;
+
+ if (!np) {
+ dev_err(&pdev->dev, "Device Tree node missing\n");
+ return -EINVAL;
+ }
+
+ creg = devm_kzalloc(&pdev->dev, sizeof(*creg), GFP_KERNEL);
+ if (!creg)
+ return -ENOMEM;
+
+ init_data = of_get_regulator_init_data(&pdev->dev, np,
+ &coupled_regulator_desc);
+ if (!init_data)
+ return -ENOMEM;
+
+ config.of_node = np;
+ config.dev = &pdev->dev;
+ config.driver_data = creg;
+ config.init_data = init_data;
+
+ for (i = 0; i < COUPLED_REGULATOR_MAX_SUPPLIES; i++) {
+ char *propname = kasprintf(GFP_KERNEL, "vin%d-supply", i);
+ const void *prop = of_get_property(np, propname, NULL);
+ kfree(propname);
+
+ if (!prop) {
+ creg->n_regulators = i;
+ break;
+ }
+ }
+
+ dev_dbg(&pdev->dev, "Found %d parent regulators\n",
+ creg->n_regulators);
+
+ if (!creg->n_regulators) {
+ dev_err(&pdev->dev, "No parent regulators listed\n");
+ return -EINVAL;
+ }
+
+ creg->regulators = devm_kcalloc(&pdev->dev, creg->n_regulators,
+ sizeof(*creg->regulators), GFP_KERNEL);
+ if (!creg->regulators)
+ return -ENOMEM;
+
+ for (i = 0; i < creg->n_regulators; i++) {
+ char *propname = kasprintf(GFP_KERNEL, "vin%d", i);
+
+ dev_dbg(&pdev->dev, "Trying to get supply %s\n", propname);
+
+ creg->regulators[i] = devm_regulator_get(&pdev->dev, propname);
+ kfree(propname);
+
+ if (IS_ERR(creg->regulators[i])) {
+ dev_err(&pdev->dev, "Couldn't get regulator vin%d\n",
+ i);
+ return PTR_ERR(creg->regulators[i]);
+ }
+ }
+
+ /*
+ * Since we want only to expose voltages that can be set on
+ * all the regulators, we won't have more voltages supported
+ * than the number of voltages supported by the first
+ * regulator in our list
+ */
+ max_voltages = regulator_count_voltages(creg->regulators[0]);
+
+ creg->voltages = devm_kcalloc(&pdev->dev, max_voltages, sizeof(int),
+ GFP_KERNEL);
+
+ /* Build up list of supported voltages */
+ for (i = 0; i < max_voltages; i++) {
+ int voltage = regulator_list_voltage(creg->regulators[0], i);
+ bool usable = true;
+ int j;
+
+ if (voltage <= 0)
+ continue;
+
+ dev_dbg(&pdev->dev, "Checking voltage %d...\n", voltage);
+
+ for (j = 1; j < creg->n_regulators; j++) {
+ if (!regulator_is_supported_voltage(creg->regulators[j],
+ voltage, voltage)) {
+ usable = false;
+ break;
+ }
+ }
+
+ if (usable) {
+ creg->voltages[creg->n_voltages++] = voltage;
+ dev_dbg(&pdev->dev,
+ "Adding voltage %d to the list of supported voltages\n",
+ voltage);
+ }
+ }
+
+ dev_dbg(&pdev->dev, "Supporting %d voltages\n", creg->n_voltages);
+
+ desc = devm_kmemdup(&pdev->dev, &coupled_regulator_desc,
+ sizeof(coupled_regulator_desc), GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+ desc->n_voltages = creg->n_voltages;
+
+ regulator = devm_regulator_register(&pdev->dev, desc, &config);
+ if (IS_ERR(regulator)) {
+ dev_err(&pdev->dev, "Failed to register regulator %s\n",
+ coupled_regulator_desc.name);
+ return PTR_ERR(regulator);
+ }
+
+ return 0;
+}
+
+static struct of_device_id coupled_regulator_of_match[] = {
+ { .compatible = "coupled-voltage-regulator" },
+ { /* Sentinel */ },
+};
+
+static struct platform_driver coupled_regulator_driver = {
+ .probe = coupled_regulator_probe,
+
+ .driver = {
+ .name = "coupled-voltage-regulator",
+ .of_match_table = coupled_regulator_of_match,
+ },
+};
+module_platform_driver(coupled_regulator_driver);
+
+MODULE_AUTHOR("Maxime Ripard <[email protected]>");
+MODULE_DESCRIPTION("Coupled Regulator Driver");
+MODULE_LICENSE("GPL");
--
2.6.3
The CHIP has a WiFi/BT chip on an SDIO bus. That controller is maintained
in reset through a GPIO and uses two independent regulators to be powered
that must be kept in sync.
Model this using an MMC power sequence and a coupled voltage regulator.
Signed-off-by: Maxime Ripard <[email protected]>
---
arch/arm/boot/dts/sun5i-r8-chip.dts | 44 ++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/sun5i-r8-chip.dts b/arch/arm/boot/dts/sun5i-r8-chip.dts
index 530ab28e9ca2..b5ef4eb5b6b4 100644
--- a/arch/arm/boot/dts/sun5i-r8-chip.dts
+++ b/arch/arm/boot/dts/sun5i-r8-chip.dts
@@ -64,6 +64,24 @@
chosen {
stdout-path = "serial0:115200n8";
};
+
+ mmc0_pwrseq: mmc0_pwrseq {
+ compatible = "mmc-pwrseq-simple";
+ pinctrl-names = "default";
+ pinctrl-0 = <&chip_wifi_reg_on_pin>;
+ reset-gpios = <&pio 2 19 GPIO_ACTIVE_LOW>; /* PC19 */
+ };
+
+ /*
+ * Both LDO3 and LDO4 are used in parallel to power up the
+ * WiFi/BT Chip.
+ */
+ vcc_wifi: wifi_reg {
+ compatible = "coupled-voltage-regulator";
+ regulator-name = "vcc-wifi";
+ vin0-supply = <®_ldo3>;
+ vin1-supply = <®_ldo4>;
+ };
};
&codec {
@@ -113,10 +131,15 @@
};
};
+&mmc0_pins_a {
+ allwinner,pull = <SUN4I_PINCTRL_PULL_UP>;
+};
+
&mmc0 {
pinctrl-names = "default";
pinctrl-0 = <&mmc0_pins_a>;
- vmmc-supply = <®_vcc3v3>;
+ vmmc-supply = <&vcc_wifi>;
+ mmc-pwrseq = <&mmc0_pwrseq>;
bus-width = <4>;
non-removable;
status = "okay";
@@ -138,6 +161,13 @@
allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
};
+ chip_wifi_reg_on_pin: chip_wifi_reg_on_pin@0 {
+ allwinner,pins = "PC19";
+ allwinner,function = "gpio_out";
+ allwinner,drive = <SUN4I_PINCTRL_10_MA>;
+ allwinner,pull = <SUN4I_PINCTRL_NO_PULL>;
+ };
+
chip_id_det_pin: chip_id_det_pin@0 {
allwinner,pins = "PG2";
allwinner,function = "gpio_in";
@@ -171,6 +201,18 @@
regulator-always-on;
};
+®_ldo3 {
+ regulator-min-microvolt = <3300000>;
+ regulator-max-microvolt = <3300000>;
+ regulator-name = "vcc-wifi-1";
+};
+
+®_ldo4 {
+ regulator-min-microvolt = <3300000>;
+ regulator-max-microvolt = <3300000>;
+ regulator-name = "vcc-wifi-2";
+};
+
®_ldo5 {
regulator-min-microvolt = <1800000>;
regulator-max-microvolt = <1800000>;
--
2.6.3
On Mon, Nov 30, 2015 at 04:29:05PM +0100, Maxime Ripard wrote:
> +static struct of_device_id coupled_regulator_of_match[] = {
> + { .compatible = "coupled-voltage-regulator" },
> + { /* Sentinel */ },
> +};
This defines a device tree binding but does not document it -
doucmentation is mandatory for all new device tree bindings.
On 30 November 2015 at 08:29, Maxime Ripard
<[email protected]> wrote:
> Some boards, in order to power devices that have a quite high power
> consumption, wire multiple regulators in parallel.
>
> In such a case, the regulators need to be kept in sync, all of them being
> enabled or disabled in parallel.
>
> This also requires to expose only the voltages that are common to all the
> regulators.
>
> Eventually support for changing the voltage in parallel should be added
> too, possibly with delays between each other to avoid having a too brutal
> peak consumption.
>
> Signed-off-by: Maxime Ripard <[email protected]>
> ---
> drivers/regulator/Kconfig | 7 +
> drivers/regulator/Makefile | 1 +
> drivers/regulator/coupled-voltage-regulator.c | 241 ++++++++++++++++++++++++++
> 3 files changed, 249 insertions(+)
> create mode 100644 drivers/regulator/coupled-voltage-regulator.c
>
> diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
> index 8df0b0e62976..6ba7bc8fda13 100644
> --- a/drivers/regulator/Kconfig
> +++ b/drivers/regulator/Kconfig
> @@ -35,6 +35,13 @@ config REGULATOR_FIXED_VOLTAGE
> useful for systems which use a combination of software
> managed regulators and simple non-configurable regulators.
>
> +config REGULATOR_COUPLED_VOLTAGE
> + tristate "Coupled voltage regulator support"
> + help
> + This driver provides support for regulators that are an
> + aggregate of other regulators in the system, and need to
> + keep them all in sync.
> +
> config REGULATOR_VIRTUAL_CONSUMER
> tristate "Virtual regulator consumer support"
> help
> diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
> index 0f8174913c17..c05839257386 100644
> --- a/drivers/regulator/Makefile
> +++ b/drivers/regulator/Makefile
> @@ -22,6 +22,7 @@ obj-$(CONFIG_REGULATOR_AS3711) += as3711-regulator.o
> obj-$(CONFIG_REGULATOR_AS3722) += as3722-regulator.o
> obj-$(CONFIG_REGULATOR_AXP20X) += axp20x-regulator.o
> obj-$(CONFIG_REGULATOR_BCM590XX) += bcm590xx-regulator.o
> +obj-$(CONFIG_REGULATOR_COUPLED_VOLTAGE) += coupled-voltage-regulator.o
> obj-$(CONFIG_REGULATOR_DA903X) += da903x.o
> obj-$(CONFIG_REGULATOR_DA9052) += da9052-regulator.o
> obj-$(CONFIG_REGULATOR_DA9055) += da9055-regulator.o
> diff --git a/drivers/regulator/coupled-voltage-regulator.c b/drivers/regulator/coupled-voltage-regulator.c
> new file mode 100644
> index 000000000000..dc7aa2aca7e6
> --- /dev/null
> +++ b/drivers/regulator/coupled-voltage-regulator.c
> @@ -0,0 +1,241 @@
> +/*
> + * Copyright 2015 Free Electrons
> + * Copyright 2015 NextThing Co.
> + *
> + * Author: Maxime Ripard <[email protected]>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of the
> + * License, or (at your option) any later version.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include <linux/regulator/consumer.h>
> +#include <linux/regulator/driver.h>
> +#include <linux/regulator/of_regulator.h>
> +
> +#define COUPLED_REGULATOR_MAX_SUPPLIES 16
> +
> +struct coupled_regulator {
> + struct regulator **regulators;
> + int n_regulators;
> +
Extra line.
> + int *voltages;
> + int n_voltages;
> +};
This new structure needs documentation.
> +
> +static int coupled_regulator_disable(struct regulator_dev *rdev)
> +{
> + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> + int ret, i;
> +
> + for (i = 0; i < creg->n_regulators; i++) {
> + ret = regulator_disable(creg->regulators[i]);
> + if (ret)
> + break;
> + }
> +
> + return ret;
> +}
What happens to the other regulators when an element of the chain
fails to disable? Should they be powered on again?
> +
> +static int coupled_regulator_enable(struct regulator_dev *rdev)
> +{
> + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> + int ret, i;
> +
> + for (i = 0; i < creg->n_regulators; i++) {
> + ret = regulator_enable(creg->regulators[i]);
> + if (ret)
> + break;
> + }
> +
> + return ret;
> +}
Same thing here - shouldn't the previously enabled regulators be
switched off when one fails to come on? It might be worth documenting
the behaviour being enacted.
> +
> +static int coupled_regulator_is_enabled(struct regulator_dev *rdev)
> +{
> + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> + int ret = 0, i;
> +
> + for (i = 0; i < creg->n_regulators; i++) {
> + ret &= regulator_is_enabled(creg->regulators[i]);
Why is the '&=' here? Since it is set to '0' from the start, won't it
always clear all the bits in a potential error return code? Apologies
if I'm missing something.
> + if (ret < 0)
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static int coupled_regulator_list_voltage(struct regulator_dev *rdev,
> + unsigned int selector)
> +{
> + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> +
> + if (selector >= creg->n_voltages)
> + return -EINVAL;
> +
> + return creg->voltages[selector];
> +}
> +
> +static struct regulator_ops coupled_regulator_ops = {
> + .enable = coupled_regulator_enable,
> + .disable = coupled_regulator_disable,
> + .is_enabled = coupled_regulator_is_enabled,
> + .list_voltage = coupled_regulator_list_voltage,
> +};
> +
> +static struct regulator_desc coupled_regulator_desc = {
> + .name = "coupled-voltage-regulator",
> + .type = REGULATOR_VOLTAGE,
> + .ops = &coupled_regulator_ops,
> + .owner = THIS_MODULE,
> +};
> +
> +static int coupled_regulator_probe(struct platform_device *pdev)
> +{
> + const struct regulator_init_data *init_data;
> + struct coupled_regulator *creg;
> + struct regulator_config config = { };
> + struct regulator_dev *regulator;
> + struct regulator_desc *desc;
> + struct device_node *np = pdev->dev.of_node;
> + int max_voltages, i;
> +
> + if (!np) {
> + dev_err(&pdev->dev, "Device Tree node missing\n");
> + return -EINVAL;
> + }
> +
> + creg = devm_kzalloc(&pdev->dev, sizeof(*creg), GFP_KERNEL);
> + if (!creg)
> + return -ENOMEM;
> +
> + init_data = of_get_regulator_init_data(&pdev->dev, np,
> + &coupled_regulator_desc);
> + if (!init_data)
> + return -ENOMEM;
> +
> + config.of_node = np;
> + config.dev = &pdev->dev;
> + config.driver_data = creg;
> + config.init_data = init_data;
> +
> + for (i = 0; i < COUPLED_REGULATOR_MAX_SUPPLIES; i++) {
> + char *propname = kasprintf(GFP_KERNEL, "vin%d-supply", i);
> + const void *prop = of_get_property(np, propname, NULL);
> + kfree(propname);
> +
> + if (!prop) {
> + creg->n_regulators = i;
> + break;
> + }
> + }
> +
> + dev_dbg(&pdev->dev, "Found %d parent regulators\n",
> + creg->n_regulators);
> +
> + if (!creg->n_regulators) {
> + dev_err(&pdev->dev, "No parent regulators listed\n");
> + return -EINVAL;
> + }
> +
> + creg->regulators = devm_kcalloc(&pdev->dev, creg->n_regulators,
> + sizeof(*creg->regulators), GFP_KERNEL);
> + if (!creg->regulators)
> + return -ENOMEM;
> +
> + for (i = 0; i < creg->n_regulators; i++) {
> + char *propname = kasprintf(GFP_KERNEL, "vin%d", i);
> +
> + dev_dbg(&pdev->dev, "Trying to get supply %s\n", propname);
> +
> + creg->regulators[i] = devm_regulator_get(&pdev->dev, propname);
> + kfree(propname);
> +
> + if (IS_ERR(creg->regulators[i])) {
> + dev_err(&pdev->dev, "Couldn't get regulator vin%d\n",
> + i);
> + return PTR_ERR(creg->regulators[i]);
> + }
> + }
> +
> + /*
> + * Since we want only to expose voltages that can be set on
> + * all the regulators, we won't have more voltages supported
> + * than the number of voltages supported by the first
> + * regulator in our list
> + */
> + max_voltages = regulator_count_voltages(creg->regulators[0]);
> +
> + creg->voltages = devm_kcalloc(&pdev->dev, max_voltages, sizeof(int),
> + GFP_KERNEL);
> +
> + /* Build up list of supported voltages */
> + for (i = 0; i < max_voltages; i++) {
> + int voltage = regulator_list_voltage(creg->regulators[0], i);
> + bool usable = true;
> + int j;
> +
> + if (voltage <= 0)
> + continue;
> +
> + dev_dbg(&pdev->dev, "Checking voltage %d...\n", voltage);
> +
> + for (j = 1; j < creg->n_regulators; j++) {
> + if (!regulator_is_supported_voltage(creg->regulators[j],
> + voltage, voltage)) {
> + usable = false;
> + break;
> + }
> + }
> +
> + if (usable) {
> + creg->voltages[creg->n_voltages++] = voltage;
> + dev_dbg(&pdev->dev,
> + "Adding voltage %d to the list of supported voltages\n",
> + voltage);
> + }
> + }
> +
> + dev_dbg(&pdev->dev, "Supporting %d voltages\n", creg->n_voltages);
> +
> + desc = devm_kmemdup(&pdev->dev, &coupled_regulator_desc,
> + sizeof(coupled_regulator_desc), GFP_KERNEL);
> + if (!desc)
> + return -ENOMEM;
> + desc->n_voltages = creg->n_voltages;
> +
> + regulator = devm_regulator_register(&pdev->dev, desc, &config);
> + if (IS_ERR(regulator)) {
> + dev_err(&pdev->dev, "Failed to register regulator %s\n",
> + coupled_regulator_desc.name);
> + return PTR_ERR(regulator);
> + }
> +
> + return 0;
> +}
> +
> +static struct of_device_id coupled_regulator_of_match[] = {
> + { .compatible = "coupled-voltage-regulator" },
> + { /* Sentinel */ },
> +};
> +
> +static struct platform_driver coupled_regulator_driver = {
> + .probe = coupled_regulator_probe,
> +
> + .driver = {
> + .name = "coupled-voltage-regulator",
> + .of_match_table = coupled_regulator_of_match,
> + },
> +};
> +module_platform_driver(coupled_regulator_driver);
> +
> +MODULE_AUTHOR("Maxime Ripard <[email protected]>");
> +MODULE_DESCRIPTION("Coupled Regulator Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.6.3
>
> --
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Hello Maxime,
On Mon, Nov 30, 2015 at 12:29 PM, Maxime Ripard
<[email protected]> wrote:
[snip]
>
> +config REGULATOR_COUPLED_VOLTAGE
Shouldn't this depend on OF?
> + tristate "Coupled voltage regulator support"
the Kconfig symbol is tristate so the driver can be built as a module...
> +
> +static struct of_device_id coupled_regulator_of_match[] = {
> + { .compatible = "coupled-voltage-regulator" },
> + { /* Sentinel */ },
> +};
> +
...but the driver is missing a MODULE_DEVICE_TABLE(of, ...) so module
autoloading won't work.
Best regards,
Javier
Hi Mathieu,
On Mon, Nov 30, 2015 at 10:17:45AM -0700, Mathieu Poirier wrote:
> On 30 November 2015 at 08:29, Maxime Ripard
> <[email protected]> wrote:
> > Some boards, in order to power devices that have a quite high power
> > consumption, wire multiple regulators in parallel.
> >
> > In such a case, the regulators need to be kept in sync, all of them being
> > enabled or disabled in parallel.
> >
> > This also requires to expose only the voltages that are common to all the
> > regulators.
> >
> > Eventually support for changing the voltage in parallel should be added
> > too, possibly with delays between each other to avoid having a too brutal
> > peak consumption.
> >
> > Signed-off-by: Maxime Ripard <[email protected]>
> > ---
> > drivers/regulator/Kconfig | 7 +
> > drivers/regulator/Makefile | 1 +
> > drivers/regulator/coupled-voltage-regulator.c | 241 ++++++++++++++++++++++++++
> > 3 files changed, 249 insertions(+)
> > create mode 100644 drivers/regulator/coupled-voltage-regulator.c
> >
> > diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
> > index 8df0b0e62976..6ba7bc8fda13 100644
> > --- a/drivers/regulator/Kconfig
> > +++ b/drivers/regulator/Kconfig
> > @@ -35,6 +35,13 @@ config REGULATOR_FIXED_VOLTAGE
> > useful for systems which use a combination of software
> > managed regulators and simple non-configurable regulators.
> >
> > +config REGULATOR_COUPLED_VOLTAGE
> > + tristate "Coupled voltage regulator support"
> > + help
> > + This driver provides support for regulators that are an
> > + aggregate of other regulators in the system, and need to
> > + keep them all in sync.
> > +
> > config REGULATOR_VIRTUAL_CONSUMER
> > tristate "Virtual regulator consumer support"
> > help
> > diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
> > index 0f8174913c17..c05839257386 100644
> > --- a/drivers/regulator/Makefile
> > +++ b/drivers/regulator/Makefile
> > @@ -22,6 +22,7 @@ obj-$(CONFIG_REGULATOR_AS3711) += as3711-regulator.o
> > obj-$(CONFIG_REGULATOR_AS3722) += as3722-regulator.o
> > obj-$(CONFIG_REGULATOR_AXP20X) += axp20x-regulator.o
> > obj-$(CONFIG_REGULATOR_BCM590XX) += bcm590xx-regulator.o
> > +obj-$(CONFIG_REGULATOR_COUPLED_VOLTAGE) += coupled-voltage-regulator.o
> > obj-$(CONFIG_REGULATOR_DA903X) += da903x.o
> > obj-$(CONFIG_REGULATOR_DA9052) += da9052-regulator.o
> > obj-$(CONFIG_REGULATOR_DA9055) += da9055-regulator.o
> > diff --git a/drivers/regulator/coupled-voltage-regulator.c b/drivers/regulator/coupled-voltage-regulator.c
> > new file mode 100644
> > index 000000000000..dc7aa2aca7e6
> > --- /dev/null
> > +++ b/drivers/regulator/coupled-voltage-regulator.c
> > @@ -0,0 +1,241 @@
> > +/*
> > + * Copyright 2015 Free Electrons
> > + * Copyright 2015 NextThing Co.
> > + *
> > + * Author: Maxime Ripard <[email protected]>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License as
> > + * published by the Free Software Foundation; either version 2 of the
> > + * License, or (at your option) any later version.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/regulator/driver.h>
> > +#include <linux/regulator/of_regulator.h>
> > +
> > +#define COUPLED_REGULATOR_MAX_SUPPLIES 16
> > +
> > +struct coupled_regulator {
> > + struct regulator **regulators;
> > + int n_regulators;
> > +
>
> Extra line.
>
> > + int *voltages;
> > + int n_voltages;
> > +};
>
> This new structure needs documentation.
Ack.
> > +
> > +static int coupled_regulator_disable(struct regulator_dev *rdev)
> > +{
> > + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> > + int ret, i;
> > +
> > + for (i = 0; i < creg->n_regulators; i++) {
> > + ret = regulator_disable(creg->regulators[i]);
> > + if (ret)
> > + break;
> > + }
> > +
> > + return ret;
> > +}
>
> What happens to the other regulators when an element of the chain
> fails to disable? Should they be powered on again?
>
> > +
> > +static int coupled_regulator_enable(struct regulator_dev *rdev)
> > +{
> > + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> > + int ret, i;
> > +
> > + for (i = 0; i < creg->n_regulators; i++) {
> > + ret = regulator_enable(creg->regulators[i]);
> > + if (ret)
> > + break;
> > + }
> > +
> > + return ret;
> > +}
>
> Same thing here - shouldn't the previously enabled regulators be
> switched off when one fails to come on? It might be worth documenting
> the behaviour being enacted.
That's actually a very good question, and I don't have a good answer
to it. I guess the safest approach would be to roll back and do the
opposite operation on the one we previously enabled / disabled.
I wonder whether it might damage the hardware or not though.
Mark?
> > +
> > +static int coupled_regulator_is_enabled(struct regulator_dev *rdev)
> > +{
> > + struct coupled_regulator *creg = rdev_get_drvdata(rdev);
> > + int ret = 0, i;
> > +
> > + for (i = 0; i < creg->n_regulators; i++) {
> > + ret &= regulator_is_enabled(creg->regulators[i]);
>
> Why is the '&=' here? Since it is set to '0' from the start, won't it
> always clear all the bits in a potential error return code? Apologies
> if I'm missing something.
It was supposed to be a bitwise or, and not an and, sorry.
But your comment on the error code that might be altered is still
valid though, I'll rework that part.
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
On Tue, Dec 01, 2015 at 03:04:36PM +0100, Maxime Ripard wrote:
> On Mon, Nov 30, 2015 at 10:17:45AM -0700, Mathieu Poirier wrote:
> > On 30 November 2015 at 08:29, Maxime Ripard
> > > + for (i = 0; i < creg->n_regulators; i++) {
> > > + ret = regulator_disable(creg->regulators[i]);
> > > + if (ret)
> > > + break;
> > > + }
> > What happens to the other regulators when an element of the chain
> > fails to disable? Should they be powered on again?
> That's actually a very good question, and I don't have a good answer
> to it. I guess the safest approach would be to roll back and do the
> opposite operation on the one we previously enabled / disabled.
> I wonder whether it might damage the hardware or not though.
> Mark?
Yeah, I'd expect us to try to unwind everything - presumably if the
supplies are partially enabled we'll not be able to satisfy the power
demands of whatever is connected (otherwise why would you create such an
innovative hardware design?) and it'll also mean that the refcounting
will be off if we ever try to do anything with the supply again.
Hi Javier,
On Mon, Nov 30, 2015 at 04:06:14PM -0300, Javier Martinez Canillas wrote:
> Hello Maxime,
>
> On Mon, Nov 30, 2015 at 12:29 PM, Maxime Ripard
> <[email protected]> wrote:
>
> [snip]
>
> >
> > +config REGULATOR_COUPLED_VOLTAGE
>
> Shouldn't this depend on OF?
>
> > + tristate "Coupled voltage regulator support"
>
> the Kconfig symbol is tristate so the driver can be built as a module...
>
> > +
> > +static struct of_device_id coupled_regulator_of_match[] = {
> > + { .compatible = "coupled-voltage-regulator" },
> > + { /* Sentinel */ },
> > +};
> > +
>
> ...but the driver is missing a MODULE_DEVICE_TABLE(of, ...) so module
> autoloading won't work.
You're right, it will be in the v2.
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com