regulator: Add stub regulator support
Add support for a dummy driver that has an implementation
connected to no real hardware devices. Its purpose is to aid
bringup scenarios by providing clients a regulator interface
that they expect. This driver shouldn't be enabled if a real
device implementation for a particular platform already exists.
Change-Id: Ib83027b4e599ebbc3cb153b2f346bb03495bb746
Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
diff --git a/drivers/regulator/stub-regulator.c b/drivers/regulator/stub-regulator.c
new file mode 100644
index 0000000..afac80a
--- /dev/null
+++ b/drivers/regulator/stub-regulator.c
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/stub-regulator.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define STUB_REGULATOR_MAX_NAME 40
+
+struct regulator_stub {
+ struct regulator_desc rdesc;
+ struct regulator_dev *rdev;
+ int voltage;
+ bool enabled;
+ int mode;
+ int hpm_min_load;
+ int system_uA;
+ char name[STUB_REGULATOR_MAX_NAME];
+};
+
+static int regulator_stub_set_voltage(struct regulator_dev *rdev, int min_uV,
+ int max_uV, unsigned *selector)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ vreg_priv->voltage = min_uV;
+ return 0;
+}
+
+static int regulator_stub_get_voltage(struct regulator_dev *rdev)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ return vreg_priv->voltage;
+}
+
+static int regulator_stub_list_voltage(struct regulator_dev *rdev,
+ unsigned selector)
+{
+ struct regulation_constraints *constraints = rdev->constraints;
+
+ if (selector >= 2)
+ return -EINVAL;
+ else if (selector == 0)
+ return constraints->min_uV;
+ else
+ return constraints->max_uV;
+}
+
+static unsigned int regulator_stub_get_mode(struct regulator_dev *rdev)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ return vreg_priv->mode;
+}
+
+static int regulator_stub_set_mode(struct regulator_dev *rdev,
+ unsigned int mode)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+
+ if (mode != REGULATOR_MODE_NORMAL && mode != REGULATOR_MODE_IDLE) {
+ dev_err(&rdev->dev, "%s: invalid mode requested %u\n",
+ __func__, mode);
+ return -EINVAL;
+ }
+ vreg_priv->mode = mode;
+ return 0;
+}
+
+static unsigned int regulator_stub_get_optimum_mode(struct regulator_dev *rdev,
+ int input_uV, int output_uV, int load_uA)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ unsigned int mode;
+
+ if (load_uA + vreg_priv->system_uA >= vreg_priv->hpm_min_load)
+ mode = REGULATOR_MODE_NORMAL;
+ else
+ mode = REGULATOR_MODE_IDLE;
+
+ return mode;
+}
+
+static int regulator_stub_enable(struct regulator_dev *rdev)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ vreg_priv->enabled = true;
+ return 0;
+}
+
+static int regulator_stub_disable(struct regulator_dev *rdev)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ vreg_priv->enabled = false;
+ return 0;
+}
+
+static int regulator_stub_is_enabled(struct regulator_dev *rdev)
+{
+ struct regulator_stub *vreg_priv = rdev_get_drvdata(rdev);
+ return vreg_priv->enabled;
+}
+
+/* Real regulator operations. */
+static struct regulator_ops regulator_stub_ops = {
+ .enable = regulator_stub_enable,
+ .disable = regulator_stub_disable,
+ .is_enabled = regulator_stub_is_enabled,
+ .set_voltage = regulator_stub_set_voltage,
+ .get_voltage = regulator_stub_get_voltage,
+ .list_voltage = regulator_stub_list_voltage,
+ .set_mode = regulator_stub_set_mode,
+ .get_mode = regulator_stub_get_mode,
+ .get_optimum_mode = regulator_stub_get_optimum_mode,
+};
+
+static void regulator_stub_cleanup(struct regulator_stub *vreg_priv)
+{
+ if (vreg_priv && vreg_priv->rdev)
+ regulator_unregister(vreg_priv->rdev);
+ kfree(vreg_priv);
+}
+
+static int __devinit regulator_stub_probe(struct platform_device *pdev)
+{
+ struct stub_regulator_pdata *vreg_pdata;
+ struct regulator_desc *rdesc;
+ struct regulator_stub *vreg_priv;
+ int rc;
+
+ vreg_pdata = pdev->dev.platform_data;
+ if (!vreg_pdata) {
+ dev_err(&pdev->dev, "%s: no platform data\n", __func__);
+ return -EINVAL;
+ }
+
+ vreg_priv = kzalloc(sizeof(*vreg_priv), GFP_KERNEL);
+ if (!vreg_priv) {
+ dev_err(&pdev->dev, "%s: Unable to allocate memory\n",
+ __func__);
+ return -ENOMEM;
+ }
+ dev_set_drvdata(&pdev->dev, vreg_priv);
+
+ rdesc = &vreg_priv->rdesc;
+ strncpy(vreg_priv->name, vreg_pdata->init_data.constraints.name,
+ STUB_REGULATOR_MAX_NAME);
+ rdesc->name = vreg_priv->name;
+ rdesc->ops = ®ulator_stub_ops;
+
+ /*
+ * Ensure that voltage set points are handled correctly for regulators
+ * which have a specified voltage constraint range, as well as those
+ * that do not.
+ */
+ if (vreg_pdata->init_data.constraints.min_uV == 0 &&
+ vreg_pdata->init_data.constraints.max_uV == 0)
+ rdesc->n_voltages = 0;
+ else
+ rdesc->n_voltages = 2;
+
+ rdesc->id = pdev->id;
+ rdesc->owner = THIS_MODULE;
+ rdesc->type = REGULATOR_VOLTAGE;
+ vreg_priv->system_uA = vreg_pdata->system_uA;
+ vreg_priv->hpm_min_load = vreg_pdata->hpm_min_load;
+
+ vreg_priv->rdev = regulator_register(rdesc, &pdev->dev,
+ &(vreg_pdata->init_data), vreg_priv);
+ if (IS_ERR(vreg_priv->rdev)) {
+ rc = PTR_ERR(vreg_priv->rdev);
+ vreg_priv->rdev = NULL;
+ dev_err(&pdev->dev, "%s: regulator_register failed\n",
+ __func__);
+ goto err_probe;
+ }
+
+ return 0;
+
+err_probe:
+ regulator_stub_cleanup(vreg_priv);
+ return rc;
+}
+
+static int __devexit regulator_stub_remove(struct platform_device *pdev)
+{
+ struct regulator_stub *vreg_priv = dev_get_drvdata(&pdev->dev);
+
+ regulator_stub_cleanup(vreg_priv);
+ return 0;
+}
+
+static struct platform_driver regulator_stub_driver = {
+ .probe = regulator_stub_probe,
+ .remove = __devexit_p(regulator_stub_remove),
+ .driver = {
+ .name = STUB_REGULATOR_DRIVER_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init regulator_stub_init(void)
+{
+ return platform_driver_register(®ulator_stub_driver);
+}
+postcore_initcall(regulator_stub_init);
+
+static void __exit regulator_stub_exit(void)
+{
+ platform_driver_unregister(®ulator_stub_driver);
+}
+module_exit(regulator_stub_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("stub regulator driver");
+MODULE_VERSION("1.0");
+MODULE_ALIAS("platform: " STUB_REGULATOR_DRIVER_NAME);