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242 lines
7.5 KiB
242 lines
7.5 KiB
From e172d31b8402f13aed5679cd7023f0c0935aab05 Mon Sep 17 00:00:00 2001
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From: popcornmix <popcornmix@gmail.com>
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Date: Wed, 8 May 2013 11:46:50 +0100
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Subject: [PATCH 060/170] enabling the realtime clock 1-wire chip DS1307 and
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1-wire on GPIO4 (as a module)
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1-wire: Add support for configuring pin for w1-gpio kernel module
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See: https://github.com/raspberrypi/linux/pull/457
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Add bitbanging pullups, use them for w1-gpio
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Allows parasite power to work, uses module option pullup=1
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bcm2708: Ensure 1-wire pullup is disabled by default, and expose as module parameter
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Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
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w1-gpio: Add gpiopin module parameter and correctly free up gpio pull-up pin, if set
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Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
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w1-gpio: Sort out the pullup/parasitic power tangle
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---
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drivers/w1/masters/w1-gpio.c | 69 ++++++++++++++++++++++++++++++++++++++++----
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drivers/w1/w1.h | 6 ++++
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drivers/w1/w1_int.c | 14 +++++++++
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drivers/w1/w1_io.c | 18 ++++++++++--
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include/linux/w1-gpio.h | 1 +
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5 files changed, 99 insertions(+), 9 deletions(-)
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--- a/drivers/w1/masters/w1-gpio.c
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+++ b/drivers/w1/masters/w1-gpio.c
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@@ -23,6 +23,19 @@
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#include "../w1.h"
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#include "../w1_int.h"
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+static int w1_gpio_pullup = 0;
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+static int w1_gpio_pullup_orig = 0;
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+module_param_named(pullup, w1_gpio_pullup, int, 0);
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+MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode");
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+static int w1_gpio_pullup_pin = -1;
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+static int w1_gpio_pullup_pin_orig = -1;
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+module_param_named(extpullup, w1_gpio_pullup_pin, int, 0);
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+MODULE_PARM_DESC(extpullup, "GPIO external pullup pin number");
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+static int w1_gpio_pin = -1;
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+static int w1_gpio_pin_orig = -1;
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+module_param_named(gpiopin, w1_gpio_pin, int, 0);
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+MODULE_PARM_DESC(gpiopin, "GPIO pin number");
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+
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static u8 w1_gpio_set_pullup(void *data, int delay)
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{
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struct w1_gpio_platform_data *pdata = data;
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@@ -67,6 +80,16 @@ static u8 w1_gpio_read_bit(void *data)
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return gpio_get_value(pdata->pin) ? 1 : 0;
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}
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+static void w1_gpio_bitbang_pullup(void *data, u8 on)
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+{
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+ struct w1_gpio_platform_data *pdata = data;
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+
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+ if (on)
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+ gpio_direction_output(pdata->pin, 1);
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+ else
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+ gpio_direction_input(pdata->pin);
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+}
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+
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#if defined(CONFIG_OF)
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static const struct of_device_id w1_gpio_dt_ids[] = {
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{ .compatible = "w1-gpio" },
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@@ -80,6 +103,7 @@ static int w1_gpio_probe_dt(struct platf
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struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
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struct device_node *np = pdev->dev.of_node;
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int gpio;
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+ u32 value;
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata)
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@@ -88,6 +112,9 @@ static int w1_gpio_probe_dt(struct platf
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if (of_get_property(np, "linux,open-drain", NULL))
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pdata->is_open_drain = 1;
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+ if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0)
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+ pdata->parasitic_power = (value != 0);
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+
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gpio = of_get_gpio(np, 0);
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if (gpio < 0) {
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if (gpio != -EPROBE_DEFER)
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@@ -103,7 +130,7 @@ static int w1_gpio_probe_dt(struct platf
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if (gpio == -EPROBE_DEFER)
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return gpio;
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/* ignore other errors as the pullup gpio is optional */
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- pdata->ext_pullup_enable_pin = gpio;
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+ pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1;
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pdev->dev.platform_data = pdata;
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@@ -113,13 +140,15 @@ static int w1_gpio_probe_dt(struct platf
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static int w1_gpio_probe(struct platform_device *pdev)
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{
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struct w1_bus_master *master;
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- struct w1_gpio_platform_data *pdata;
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+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
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int err;
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- if (of_have_populated_dt()) {
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- err = w1_gpio_probe_dt(pdev);
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- if (err < 0)
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- return err;
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+ if(pdata == NULL) {
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+ if (of_have_populated_dt()) {
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+ err = w1_gpio_probe_dt(pdev);
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+ if (err < 0)
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+ return err;
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+ }
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}
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pdata = dev_get_platdata(&pdev->dev);
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@@ -136,6 +165,22 @@ static int w1_gpio_probe(struct platform
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return -ENOMEM;
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}
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+ w1_gpio_pin_orig = pdata->pin;
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+ w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
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+ w1_gpio_pullup_orig = pdata->parasitic_power;
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+
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+ if(gpio_is_valid(w1_gpio_pin)) {
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+ pdata->pin = w1_gpio_pin;
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+ pdata->ext_pullup_enable_pin = -1;
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+ pdata->parasitic_power = -1;
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+ }
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+ pdata->parasitic_power |= w1_gpio_pullup;
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+ if(gpio_is_valid(w1_gpio_pullup_pin)) {
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+ pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
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+ }
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+
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+ dev_info(&pdev->dev, "gpio pin %d, external pullup pin %d, parasitic power %d\n", pdata->pin, pdata->ext_pullup_enable_pin, pdata->parasitic_power);
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+
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err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
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if (err) {
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dev_err(&pdev->dev, "gpio_request (pin) failed\n");
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@@ -165,6 +210,14 @@ static int w1_gpio_probe(struct platform
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master->set_pullup = w1_gpio_set_pullup;
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}
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+ if (pdata->parasitic_power) {
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+ if (pdata->is_open_drain)
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+ printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
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+ "option doesn't work with open drain GPIO\n");
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+ else
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+ master->bitbang_pullup = w1_gpio_bitbang_pullup;
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+ }
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+
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err = w1_add_master_device(master);
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if (err) {
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dev_err(&pdev->dev, "w1_add_master device failed\n");
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@@ -195,6 +248,10 @@ static int w1_gpio_remove(struct platfor
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w1_remove_master_device(master);
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+ pdata->pin = w1_gpio_pin_orig;
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+ pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
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+ pdata->parasitic_power = w1_gpio_pullup_orig;
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+
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return 0;
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}
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--- a/drivers/w1/w1.h
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+++ b/drivers/w1/w1.h
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@@ -171,6 +171,12 @@ struct w1_bus_master
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u8 (*set_pullup)(void *, int);
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+ /**
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+ * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
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+ * @return -1=Error, 0=completed
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+ */
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+ void (*bitbang_pullup) (void *, u8);
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+
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void (*search)(void *, struct w1_master *,
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u8, w1_slave_found_callback);
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};
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--- a/drivers/w1/w1_int.c
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+++ b/drivers/w1/w1_int.c
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@@ -122,6 +122,20 @@ int w1_add_master_device(struct w1_bus_m
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return(-EINVAL);
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}
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+ /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
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+ * and takes care of timing itself */
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+ if (!master->write_byte && !master->touch_bit && master->set_pullup) {
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+ printk(KERN_ERR "w1_add_master_device: set_pullup requires "
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+ "write_byte or touch_bit, disabling\n");
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+ master->set_pullup = NULL;
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+ }
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+
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+ if (master->set_pullup && master->bitbang_pullup) {
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+ printk(KERN_ERR "w1_add_master_device: set_pullup should not "
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+ "be set when bitbang_pullup is used, disabling\n");
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+ master->set_pullup = NULL;
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+ }
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+
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/* Lock until the device is added (or not) to w1_masters. */
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mutex_lock(&w1_mlock);
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/* Search for the first available id (starting at 1). */
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--- a/drivers/w1/w1_io.c
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+++ b/drivers/w1/w1_io.c
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@@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
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static void w1_post_write(struct w1_master *dev)
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{
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if (dev->pullup_duration) {
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- if (dev->enable_pullup && dev->bus_master->set_pullup)
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- dev->bus_master->set_pullup(dev->bus_master->data, 0);
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- else
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+ if (dev->enable_pullup) {
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+ if (dev->bus_master->set_pullup) {
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+ dev->bus_master->set_pullup(dev->
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+ bus_master->data,
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+ 0);
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+ } else if (dev->bus_master->bitbang_pullup) {
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+ dev->bus_master->
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+ bitbang_pullup(dev->bus_master->data, 1);
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msleep(dev->pullup_duration);
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+ dev->bus_master->
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+ bitbang_pullup(dev->bus_master->data, 0);
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+ }
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+ } else {
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+ msleep(dev->pullup_duration);
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+ }
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+
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dev->pullup_duration = 0;
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}
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}
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--- a/include/linux/w1-gpio.h
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+++ b/include/linux/w1-gpio.h
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@@ -18,6 +18,7 @@
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struct w1_gpio_platform_data {
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unsigned int pin;
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unsigned int is_open_drain:1;
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+ unsigned int parasitic_power:1;
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void (*enable_external_pullup)(int enable);
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unsigned int ext_pullup_enable_pin;
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unsigned int pullup_duration;
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