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authorVille Syrjala <syrjala@sci.fi>2008-02-06 01:39:01 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-06 10:41:15 -0800
commitad8dc96e3b2c3e28854e0de4ab49351ed547b30c (patch)
tree6faab05e76206f130333ccff4c080600ed00d332 /drivers/w1/masters/w1-gpio.c
parent4cdf854f7d60498bbda436068a118b95059b244b (diff)
downloadop-kernel-dev-ad8dc96e3b2c3e28854e0de4ab49351ed547b30c.zip
op-kernel-dev-ad8dc96e3b2c3e28854e0de4ab49351ed547b30c.tar.gz
w1-gpio: add GPIO w1 bus master driver
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@sci.fi> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/w1/masters/w1-gpio.c')
-rw-r--r--drivers/w1/masters/w1-gpio.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
new file mode 100644
index 0000000..9e1138a
--- /dev/null
+++ b/drivers/w1/masters/w1-gpio.c
@@ -0,0 +1,124 @@
+/*
+ * w1-gpio - GPIO w1 bus master driver
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
+ *
+ * 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_dir(void *data, u8 bit)
+{
+ struct w1_gpio_platform_data *pdata = data;
+
+ if (bit)
+ gpio_direction_input(pdata->pin);
+ else
+ gpio_direction_output(pdata->pin, 0);
+}
+
+static void w1_gpio_write_bit_val(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 = pdev->dev.platform_data;
+ int err;
+
+ if (!pdata)
+ return -ENXIO;
+
+ master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL);
+ if (!master)
+ return -ENOMEM;
+
+ err = gpio_request(pdata->pin, "w1");
+ if (err)
+ goto free_master;
+
+ master->data = pdata;
+ master->read_bit = w1_gpio_read_bit;
+
+ if (pdata->is_open_drain) {
+ gpio_direction_output(pdata->pin, 1);
+ master->write_bit = w1_gpio_write_bit_val;
+ } else {
+ gpio_direction_input(pdata->pin);
+ master->write_bit = w1_gpio_write_bit_dir;
+ }
+
+ err = w1_add_master_device(master);
+ if (err)
+ goto free_gpio;
+
+ platform_set_drvdata(pdev, master);
+
+ return 0;
+
+ free_gpio:
+ gpio_free(pdata->pin);
+ free_master:
+ kfree(master);
+
+ return err;
+}
+
+static int __exit w1_gpio_remove(struct platform_device *pdev)
+{
+ struct w1_bus_master *master = platform_get_drvdata(pdev);
+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+
+ w1_remove_master_device(master);
+ gpio_free(pdata->pin);
+ kfree(master);
+
+ return 0;
+}
+
+static struct platform_driver w1_gpio_driver = {
+ .driver = {
+ .name = "w1-gpio",
+ .owner = THIS_MODULE,
+ },
+ .remove = __exit_p(w1_gpio_remove),
+};
+
+static int __init w1_gpio_init(void)
+{
+ return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe);
+}
+
+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@sci.fi>");
+MODULE_LICENSE("GPL");
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