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Message-ID: <20141211215944.4127.4186.stgit@notabene.brown>
Date: Fri, 12 Dec 2014 08:59:44 +1100
From: NeilBrown <neilb@...e.de>
To: Grant Likely <grant.likely@...aro.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Mark Rutland <mark.rutland@....com>,
Jiri Slaby <jslaby@...e.cz>
Cc: devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] TTY: add slave driver to power-on device via a
regulator.
The regulator is identified in devicetree as 'vdd-supply'
Signed-off-by: NeilBrown <neilb@...e.de>
---
.../devicetree/bindings/serial/slave-reg.txt | 18 ++++
drivers/tty/Kconfig | 2
drivers/tty/Makefile | 1
drivers/tty/slaves/Kconfig | 12 ++
drivers/tty/slaves/Makefile | 2
drivers/tty/slaves/tty-reg.c | 102 ++++++++++++++++++++
6 files changed, 137 insertions(+)
create mode 100644 Documentation/devicetree/bindings/serial/slave-reg.txt
create mode 100644 drivers/tty/slaves/Kconfig
create mode 100644 drivers/tty/slaves/Makefile
create mode 100644 drivers/tty/slaves/tty-reg.c
diff --git a/Documentation/devicetree/bindings/serial/slave-reg.txt b/Documentation/devicetree/bindings/serial/slave-reg.txt
new file mode 100644
index 000000000000..7896bce8dfe4
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/slave-reg.txt
@@ -0,0 +1,18 @@
+Regulator powered UART-attached device
+
+Required properties:
+- compatible: "tty,regulator"
+- vdd-supply: regulator to power the device
+
+
+This is listed as a child node of a UART. When the
+UART is opened, the device is powered.
+
+Example:
+
+&uart1 {
+ bluetooth {
+ compatible = "tty,regulator";
+ vdd-supply = <&vaux4>;
+ };
+};
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index b24aa010f68c..ea3383c71701 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -419,4 +419,6 @@ config DA_CONSOLE
help
This enables a console on a Dash channel.
+source drivers/tty/slaves/Kconfig
+
endif # TTY
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
index 58ad1c05b7f8..45957d671e33 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_R3964) += n_r3964.o
obj-y += vt/
obj-$(CONFIG_HVC_DRIVER) += hvc/
obj-y += serial/
+obj-$(CONFIG_TTY_SLAVE) += slaves/
# tty drivers
obj-$(CONFIG_AMIGA_BUILTIN_SERIAL) += amiserial.o
diff --git a/drivers/tty/slaves/Kconfig b/drivers/tty/slaves/Kconfig
new file mode 100644
index 000000000000..2dd1acf80f8c
--- /dev/null
+++ b/drivers/tty/slaves/Kconfig
@@ -0,0 +1,12 @@
+menuconfig TTY_SLAVE
+ bool "TTY slave devices"
+ help
+ Devices which attach via a uart, but need extra
+ driver support for power management etc.
+
+if TTY_SLAVE
+
+config TTY_SLAVE_REGULATOR
+ tristate "TTY slave device powered by regulator"
+
+endif
diff --git a/drivers/tty/slaves/Makefile b/drivers/tty/slaves/Makefile
new file mode 100644
index 000000000000..e636bf49f1cc
--- /dev/null
+++ b/drivers/tty/slaves/Makefile
@@ -0,0 +1,2 @@
+
+obj-$(CONFIG_TTY_SLAVE_REGULATOR) += tty-reg.o
diff --git a/drivers/tty/slaves/tty-reg.c b/drivers/tty/slaves/tty-reg.c
new file mode 100644
index 000000000000..613f8b10967c
--- /dev/null
+++ b/drivers/tty/slaves/tty-reg.c
@@ -0,0 +1,102 @@
+/*
+ * tty-reg:
+ * Support for any device which needs a regulator turned on
+ * when a tty is opened.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/regulator/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/tty.h>
+
+struct tty_reg_data {
+ struct regulator *reg;
+ bool reg_enabled;
+};
+
+static int tty_reg_runtime_resume(struct device *slave)
+{
+ struct tty_reg_data *data = dev_get_drvdata(slave);
+ if (!data->reg_enabled &&
+ regulator_enable(data->reg) == 0) {
+ dev_dbg(slave, "power on\n");
+ data->reg_enabled = true;
+ }
+ return 0;
+}
+
+static int tty_reg_runtime_suspend(struct device *slave)
+{
+ struct tty_reg_data *data = dev_get_drvdata(slave);
+
+ if (data->reg_enabled &&
+ regulator_disable(data->reg) == 0) {
+ dev_dbg(slave, "power off\n");
+ data->reg_enabled = false;
+ }
+ return 0;
+}
+
+static int tty_reg_probe(struct platform_device *pdev)
+{
+ struct tty_reg_data *data;
+ struct regulator *reg;
+ int err;
+
+ err = -ENODEV;
+ if (pdev->dev.parent == NULL)
+ goto out;
+ reg = devm_regulator_get(&pdev->dev, "vdd");
+ err = PTR_ERR(reg);
+ if (IS_ERR(reg))
+ goto out;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+ err = -ENOMEM;
+ if (!data)
+ goto out;
+ data->reg = reg;
+ data->reg_enabled = false;
+ pm_runtime_enable(&pdev->dev);
+ platform_set_drvdata(pdev, data);
+ err = 0;
+out:
+ return err;
+}
+
+static struct of_device_id tty_reg_dt_ids[] = {
+ { .compatible = "tty,regulator", },
+ {}
+};
+
+static const struct dev_pm_ops tty_reg_pm_ops = {
+ SET_RUNTIME_PM_OPS(tty_reg_runtime_suspend,
+ tty_reg_runtime_resume, NULL)
+};
+
+static struct platform_driver tty_reg_driver = {
+ .driver.name = "tty-regulator",
+ .driver.owner = THIS_MODULE,
+ .driver.of_match_table = tty_reg_dt_ids,
+ .driver.pm = &tty_reg_pm_ops,
+ .probe = tty_reg_probe,
+};
+
+static int __init tty_reg_init(void)
+{
+ return platform_driver_register(&tty_reg_driver);
+}
+module_init(tty_reg_init);
+
+static void __exit tty_reg_exit(void)
+{
+ platform_driver_unregister(&tty_reg_driver);
+}
+module_exit(tty_reg_exit);
+
+MODULE_AUTHOR("NeilBrown <neilb@...e.de>");
+MODULE_DESCRIPTION("Serial port device which requires a regulator when open.");
+MODULE_LICENSE("GPL v2");
--
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