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authorJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>2012-10-29 14:02:37 +0100
committerSascha Hauer <s.hauer@pengutronix.de>2012-10-29 22:31:18 +0100
commit6cb9aa9202831cc1d0f99f206facd9c19bc1c642 (patch)
tree3ee93a049815d36c7f49846f140ea6dab2c78c42 /drivers/w1
parent6b21594df08f6f569ca86dfb80d03f2d9aa32920 (diff)
downloadbarebox-6cb9aa9202831cc1d0f99f206facd9c19bc1c642.tar.gz
1-wire: add gpio bus
Based on linux implementation. Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/w1')
-rw-r--r--drivers/w1/masters/Kconfig7
-rw-r--r--drivers/w1/masters/Makefile1
-rw-r--r--drivers/w1/masters/w1-gpio.c116
3 files changed, 124 insertions, 0 deletions
diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig
index 86aa8df..e429c14 100644
--- a/drivers/w1/masters/Kconfig
+++ b/drivers/w1/masters/Kconfig
@@ -4,4 +4,11 @@
menu "1-wire Bus Masters"
+config W1_MASTER_GPIO
+ bool "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.
+
endmenu
diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile
index ed1b9d9..84b35bb 100644
--- a/drivers/w1/masters/Makefile
+++ b/drivers/w1/masters/Makefile
@@ -2,3 +2,4 @@
# Makefile for 1-wire bus master drivers.
#
+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..0a3794d
--- /dev/null
+++ b/drivers/w1/masters/w1-gpio.c
@@ -0,0 +1,116 @@
+/*
+ * w1-gpio - GPIO w1 bus master driver
+ *
+ * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
+ * Copyright (c) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * 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 <common.h>
+#include <init.h>
+#include <malloc.h>
+#include <xfuncs.h>
+#include <driver.h>
+#include <linux/w1-gpio.h>
+#include <gpio.h>
+
+#include "../w1.h"
+
+static void w1_gpio_write_bit_dir(struct w1_bus *bus, u8 bit)
+{
+ struct w1_gpio_platform_data *pdata = bus->data;
+
+ if (bit)
+ gpio_direction_input(pdata->pin);
+ else
+ gpio_direction_output(pdata->pin, 0);
+}
+
+static void w1_gpio_write_bit_val(struct w1_bus *bus, u8 bit)
+{
+ struct w1_gpio_platform_data *pdata = bus->data;
+
+ gpio_set_value(pdata->pin, bit);
+}
+
+static u8 w1_gpio_read_bit(struct w1_bus *bus)
+{
+ struct w1_gpio_platform_data *pdata = bus->data;
+
+ return gpio_get_value(pdata->pin) ? 1 : 0;
+}
+
+static int __init w1_gpio_probe(struct device_d *dev)
+{
+ struct w1_bus *master;
+ struct w1_gpio_platform_data *pdata;
+ int err;
+
+ pdata = dev->platform_data;
+
+ if (!pdata)
+ return -ENXIO;
+
+ master = xzalloc(sizeof(struct w1_bus));
+
+ err = gpio_request(pdata->pin, "w1");
+ if (err)
+ goto free_master;
+
+ if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
+ err = gpio_request(pdata->pin, "w1 pullup");
+ if (err < 0)
+ goto free_gpio;
+
+ gpio_direction_output(pdata->pin, 0);
+ }
+
+ 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;
+ }
+
+ master->parent = dev;
+
+ err = w1_bus_register(master);
+ if (err)
+ goto free_gpio_ext_pu;
+
+ if (pdata->enable_external_pullup)
+ pdata->enable_external_pullup(1);
+
+ if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+ gpio_set_value(pdata->ext_pullup_enable_pin, 1);
+
+ return 0;
+
+ free_gpio_ext_pu:
+ if (gpio_is_valid(pdata->ext_pullup_enable_pin))
+ gpio_free(pdata->ext_pullup_enable_pin);
+ free_gpio:
+ gpio_free(pdata->pin);
+ free_master:
+ kfree(master);
+
+ return err;
+}
+
+static struct driver_d w1_gpio_driver = {
+ .name = "w1-gpio",
+ .probe = w1_gpio_probe,
+};
+
+static int __init w1_gpio_init(void)
+{
+ return platform_driver_register(&w1_gpio_driver);
+}
+device_initcall(w1_gpio_init);