[PATCH] w1-gpio: Add GPIO w1 bus master driver
From: Ville Syrjala
Date: Fri Dec 21 2007 - 02:34:28 EST
Add a GPIO 1-wire bus master driver. The driver used the GPIO API to
control the wire and the GPIO pin can be specified using platform data
similar to i2c-gpio. The driver was tested with AT91SAM9260 + DS2401.
Signed-off-by: Ville Syrjala <syrjala@xxxxxx>
---
Documentation/w1/masters/00-INDEX | 2 +
Documentation/w1/masters/w1-gpio | 33 ++++++++++++
drivers/w1/masters/Kconfig | 10 ++++
drivers/w1/masters/Makefile | 1 +
drivers/w1/masters/w1-gpio.c | 100 +++++++++++++++++++++++++++++++++++++
include/linux/w1-gpio.h | 21 ++++++++
6 files changed, 167 insertions(+), 0 deletions(-)
create mode 100644 Documentation/w1/masters/w1-gpio
create mode 100644 drivers/w1/masters/w1-gpio.c
create mode 100644 include/linux/w1-gpio.h
diff --git a/Documentation/w1/masters/00-INDEX b/Documentation/w1/masters/00-INDEX
index 752613c..7b0ceaa 100644
--- a/Documentation/w1/masters/00-INDEX
+++ b/Documentation/w1/masters/00-INDEX
@@ -4,3 +4,5 @@ ds2482
- The Maxim/Dallas Semiconductor DS2482 provides 1-wire busses.
ds2490
- The Maxim/Dallas Semiconductor DS2490 builds USB <-> W1 bridges.
+w1-gpio
+ - GPIO 1-wire bus master driver.
diff --git a/Documentation/w1/masters/w1-gpio b/Documentation/w1/masters/w1-gpio
new file mode 100644
index 0000000..c927139
--- /dev/null
+++ b/Documentation/w1/masters/w1-gpio
@@ -0,0 +1,33 @@
+Kernel driver w1-gpio
+=====================
+
+Author: Ville Syrjala <syrjala@xxxxxx>
+
+
+Description
+-----------
+
+GPIO 1-wire bus master driver. The driver uses the GPIO API to control the
+wire and the GPIO pin can be specified using platform data. The GPIO pin
+must be configured as open-drain.
+
+
+Example (mach-at91)
+-------------------
+
+#include <linux/w1-gpio.h>
+
+static struct w1_gpio_platform_data foo_w1_gpio_pdata = {
+ .pin = AT91_PIN_PB20,
+};
+
+static struct platform_device foo_w1_device = {
+ .name = "w1-gpio",
+ .id = -1,
+ .dev.platform_data = &foo_w1_gpio_pdata,
+};
+
+...
+ at91_set_GPIO_periph(foo_w1_gpio_pdata.pin, 1);
+ at91_set_multi_drive(foo_w1_gpio_pdata.pin, 1);
+ platform_device_register(&foo_w1_device);
diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
index 8236d44..c449309 100644
--- a/drivers/w1/masters/Kconfig
+++ b/drivers/w1/masters/Kconfig
@@ -42,5 +42,15 @@ config W1_MASTER_DS1WM
in HP iPAQ devices like h5xxx, h2200, and ASIC3-based like
hx4700.
+config W1_MASTER_GPIO
+ tristate "GPIO 1-wire busmaster"
+ depends on GENERIC_GPIO
+ help
+ Say Y here if you want to communicate with your 1-wire devices using
+ GPIO pins. This driver uses the GPIO API to control the wire.
+
+ This support is also available as a module. If so, the module
+ will be called w1-gpio.ko.
+
endmenu
diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
index 11551b3..1420b5b 100644
--- a/drivers/w1/masters/Makefile
+++ b/drivers/w1/masters/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_W1_MASTER_MATROX) += matrox_w1.o
obj-$(CONFIG_W1_MASTER_DS2490) += ds2490.o
obj-$(CONFIG_W1_MASTER_DS2482) += ds2482.o
obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o
+obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
new file mode 100644
index 0000000..c5327df
--- /dev/null
+++ b/drivers/w1/masters/w1-gpio.c
@@ -0,0 +1,100 @@
+/*
+ * w1-gpio - GPIO w1 bus master driver
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/w1-gpio.h>
+
+#include "../w1.h"
+#include "../w1_int.h"
+
+#include <asm/gpio.h>
+
+static void w1_gpio_write_bit(void *data, u8 bit)
+{
+ struct w1_gpio_platform_data *pdata = data;
+
+ gpio_set_value(pdata->pin, bit);
+}
+
+static u8 w1_gpio_read_bit(void *data)
+{
+ struct w1_gpio_platform_data *pdata = data;
+
+ return gpio_get_value(pdata->pin);
+}
+
+static int __init w1_gpio_probe(struct platform_device *pdev)
+{
+ struct w1_bus_master *master;
+ struct w1_gpio_platform_data *pdata;
+ int err;
+
+ pdata = pdev->dev.platform_data;
+ if (!pdata)
+ return -ENXIO;
+
+ master = kzalloc(sizeof *master, GFP_KERNEL);
+ if (!master)
+ return -ENOMEM;
+
+ gpio_direction_output(pdata->pin, 1);
+
+ master->data = pdata;
+ master->read_bit = &w1_gpio_read_bit;
+ master->write_bit = &w1_gpio_write_bit;
+
+ err = w1_add_master_device(master);
+ if (err) {
+ kfree(master);
+ return err;
+ }
+
+ platform_set_drvdata(pdev, master);
+
+ return 0;
+}
+
+static int __exit w1_gpio_remove(struct platform_device *pdev)
+{
+ struct w1_bus_master *master = platform_get_drvdata(pdev);
+
+ w1_remove_master_device(master);
+ kfree(master);
+
+ return 0;
+}
+
+static struct platform_driver w1_gpio_driver = {
+ .driver = {
+ .name = "w1-gpio",
+ .owner = THIS_MODULE,
+ },
+ .probe = w1_gpio_probe,
+ .remove = __exit_p(w1_gpio_remove),
+};
+
+static int __init w1_gpio_init(void)
+{
+ return platform_driver_register(&w1_gpio_driver);
+}
+
+static void __exit w1_gpio_exit(void)
+{
+ platform_driver_unregister(&w1_gpio_driver);
+}
+
+module_init(w1_gpio_init);
+module_exit(w1_gpio_exit);
+
+MODULE_DESCRIPTION("GPIO w1 bus master driver");
+MODULE_AUTHOR("Ville Syrjala <syrjala@xxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/w1-gpio.h b/include/linux/w1-gpio.h
new file mode 100644
index 0000000..3b80bb2
--- /dev/null
+++ b/include/linux/w1-gpio.h
@@ -0,0 +1,21 @@
+/*
+ * w1-gpio interface to platform code
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ */
+#ifndef _LINUX_W1_GPIO_H
+#define _LINUX_W1_GPIO_H
+
+/**
+ * struct w1_gpio_platform_data - Platform-dependent data for w1-gpio
+ * @pin: GPIO pin to use
+ */
+struct w1_gpio_platform_data {
+ unsigned int pin;
+};
+
+#endif /* _LINUX_W1_GPIO_H */
--
1.5.2.5
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