From bd7d1508a83c544f2d52f668ebabe55c2ea207c5 Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Wed, 8 May 2013 11:46:50 +0100
Subject: [PATCH 021/114] enabling the realtime clock 1-wire chip DS1307 and
1-wire on GPIO4 (as a module)
1-wire: Add support for configuring pin for w1-gpio kernel module
See: https://github.com/raspberrypi/linux/pull/457
Add bitbanging pullups, use them for w1-gpio
Allows parasite power to work, uses module option pullup=1
bcm2708: Ensure 1-wire pullup is disabled by default, and expose as module parameter
Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
w1-gpio: Add gpiopin module parameter and correctly free up gpio pull-up pin, if set
Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
---
arch/arm/mach-bcm2708/bcm2708.c | 29 ++++++++++++++++++++++
drivers/w1/masters/w1-gpio.c | 55 +++++++++++++++++++++++++++++++++++++----
drivers/w1/w1.h | 6 +++++
drivers/w1/w1_int.c | 14 +++++++++++
drivers/w1/w1_io.c | 18 +++++++++++---
5 files changed, 114 insertions(+), 8 deletions(-)
--- a/arch/arm/mach-bcm2708/bcm2708.c
+++ b/arch/arm/mach-bcm2708/bcm2708.c
@@ -32,6 +32,7 @@
#include <linux/io.h>
#include <linux/module.h>
#include <linux/spi/spi.h>
+#include <linux/w1-gpio.h>
#include <linux/version.h>
#include <linux/clkdev.h>
@@ -76,12 +77,19 @@
*/
#define DMA_MASK_BITS_COMMON 32
+// use GPIO 4 for the one-wire GPIO pin, if enabled
+#define W1_GPIO 4
+// ensure one-wire GPIO pullup is disabled by default
+#define W1_PULLUP -1
+
/* command line parameters */
static unsigned boardrev, serial;
static unsigned uart_clock;
static unsigned disk_led_gpio = 16;
static unsigned disk_led_active_low = 1;
static unsigned reboot_part = 0;
+static unsigned w1_gpio_pin = W1_GPIO;
+static unsigned w1_gpio_pullup = W1_PULLUP;
static void __init bcm2708_init_led(void);
@@ -258,6 +266,20 @@ static struct platform_device bcm2708_dm
.num_resources = ARRAY_SIZE(bcm2708_dmaman_resources),
};
+#if defined(CONFIG_W1_MASTER_GPIO) || defined(CONFIG_W1_MASTER_GPIO_MODULE)
+static struct w1_gpio_platform_data w1_gpio_pdata = {
+ .pin = W1_GPIO,
+ .ext_pullup_enable_pin = W1_PULLUP,
+ .is_open_drain = 0,
+};
+
+static struct platform_device w1_device = {
+ .name = "w1-gpio",
+ .id = -1,
+ .dev.platform_data = &w1_gpio_pdata,
+};
+#endif
+
static u64 fb_dmamask = DMA_BIT_MASK(DMA_MASK_BITS_COMMON);
static struct platform_device bcm2708_fb_device = {
@@ -652,6 +674,11 @@ void __init bcm2708_init(void)
#ifdef CONFIG_BCM2708_GPIO
bcm_register_device(&bcm2708_gpio_device);
#endif
+#if defined(CONFIG_W1_MASTER_GPIO) || defined(CONFIG_W1_MASTER_GPIO_MODULE)
+ w1_gpio_pdata.pin = w1_gpio_pin;
+ w1_gpio_pdata.ext_pullup_enable_pin = w1_gpio_pullup;
+ platform_device_register(&w1_device);
+#endif
bcm_register_device(&bcm2708_systemtimer_device);
bcm_register_device(&bcm2708_fb_device);
bcm_register_device(&bcm2708_usb_device);
@@ -853,3 +880,5 @@ module_param(uart_clock, uint, 0644);
module_param(disk_led_gpio, uint, 0644);
module_param(disk_led_active_low, uint, 0644);
module_param(reboot_part, uint, 0644);
+module_param(w1_gpio_pin, uint, 0644);
+module_param(w1_gpio_pullup, uint, 0644);
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -23,6 +23,15 @@
#include "../w1.h"
#include "../w1_int.h"
+static int w1_gpio_pullup = -1;
+static int w1_gpio_pullup_orig = -1;
+module_param_named(pullup, w1_gpio_pullup, int, 0);
+MODULE_PARM_DESC(pullup, "GPIO pin pullup number");
+static int w1_gpio_pin = -1;
+static int w1_gpio_pin_orig = -1;
+module_param_named(gpiopin, w1_gpio_pin, int, 0);
+MODULE_PARM_DESC(gpiopin, "GPIO pin number");
+
static u8 w1_gpio_set_pullup(void *data, int delay)
{
struct w1_gpio_platform_data *pdata = data;
@@ -67,6 +76,16 @@ static u8 w1_gpio_read_bit(void *data)
return gpio_get_value(pdata->pin) ? 1 : 0;
}
+static void w1_gpio_bitbang_pullup(void *data, u8 on)
+{
+ struct w1_gpio_platform_data *pdata = data;
+
+ if (on)
+ gpio_direction_output(pdata->pin, 1);
+ else
+ gpio_direction_input(pdata->pin);
+}
+
#if defined(CONFIG_OF)
static struct of_device_id w1_gpio_dt_ids[] = {
{ .compatible = "w1-gpio" },
@@ -113,13 +132,15 @@ static int w1_gpio_probe_dt(struct platf
static int w1_gpio_probe(struct platform_device *pdev)
{
struct w1_bus_master *master;
- struct w1_gpio_platform_data *pdata;
+ struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
int err;
- if (of_have_populated_dt()) {
- err = w1_gpio_probe_dt(pdev);
- if (err < 0)
- return err;
+ if(pdata == NULL) {
+ if (of_have_populated_dt()) {
+ err = w1_gpio_probe_dt(pdev);
+ if (err < 0)
+ return err;
+ }
}
pdata = dev_get_platdata(&pdev->dev);
@@ -136,6 +157,19 @@ static int w1_gpio_probe(struct platform
return -ENOMEM;
}
+ w1_gpio_pin_orig = pdata->pin;
+ w1_gpio_pullup_orig = pdata->ext_pullup_enable_pin;
+
+ if(gpio_is_valid(w1_gpio_pin)) {
+ pdata->pin = w1_gpio_pin;
+ pdata->ext_pullup_enable_pin = -1;
+ }
+ if(gpio_is_valid(w1_gpio_pullup)) {
+ pdata->ext_pullup_enable_pin = w1_gpio_pullup;
+ }
+
+ dev_info(&pdev->dev, "gpio pin %d, gpio pullup pin %d\n", pdata->pin, pdata->ext_pullup_enable_pin);
+
err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
if (err) {
dev_err(&pdev->dev, "gpio_request (pin) failed\n");
@@ -165,6 +199,14 @@ static int w1_gpio_probe(struct platform
master->set_pullup = w1_gpio_set_pullup;
}
+ if (gpio_is_valid(w1_gpio_pullup)) {
+ if (pdata->is_open_drain)
+ printk(KERN_ERR "w1-gpio 'pullup' option "
+ "doesn't work with open drain GPIO\n");
+ else
+ master->bitbang_pullup = w1_gpio_bitbang_pullup;
+ }
+
err = w1_add_master_device(master);
if (err) {
dev_err(&pdev->dev, "w1_add_master device failed\n");
@@ -195,6 +237,9 @@ static int w1_gpio_remove(struct platfor
w1_remove_master_device(master);
+ pdata->pin = w1_gpio_pin_orig;
+ pdata->ext_pullup_enable_pin = w1_gpio_pullup_orig;
+
return 0;
}
--- a/drivers/w1/w1.h
+++ b/drivers/w1/w1.h
@@ -171,6 +171,12 @@ struct w1_bus_master
u8 (*set_pullup)(void *, int);
+ /**
+ * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
+ * @return -1=Error, 0=completed
+ */
+ void (*bitbang_pullup) (void *, u8);
+
void (*search)(void *, struct w1_master *,
u8, w1_slave_found_callback);
};
--- a/drivers/w1/w1_int.c
+++ b/drivers/w1/w1_int.c
@@ -123,6 +123,20 @@ int w1_add_master_device(struct w1_bus_m
return(-EINVAL);
}
+ /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
+ * and takes care of timing itself */
+ if (!master->write_byte && !master->touch_bit && master->set_pullup) {
+ printk(KERN_ERR "w1_add_master_device: set_pullup requires "
+ "write_byte or touch_bit, disabling\n");
+ master->set_pullup = NULL;
+ }
+
+ if (master->set_pullup && master->bitbang_pullup) {
+ printk(KERN_ERR "w1_add_master_device: set_pullup should not "
+ "be set when bitbang_pullup is used, disabling\n");
+ master->set_pullup = NULL;
+ }
+
/* Lock until the device is added (or not) to w1_masters. */
mutex_lock(&w1_mlock);
/* Search for the first available id (starting at 1). */
--- a/drivers/w1/w1_io.c
+++ b/drivers/w1/w1_io.c
@@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
static void w1_post_write(struct w1_master *dev)
{
if (dev->pullup_duration) {
- if (dev->enable_pullup && dev->bus_master->set_pullup)
- dev->bus_master->set_pullup(dev->bus_master->data, 0);
- else
+ if (dev->enable_pullup) {
+ if (dev->bus_master->set_pullup) {
+ dev->bus_master->set_pullup(dev->
+ bus_master->data,
+ 0);
+ } else if (dev->bus_master->bitbang_pullup) {
+ dev->bus_master->
+ bitbang_pullup(dev->bus_master->data, 1);
msleep(dev->pullup_duration);
+ dev->bus_master->
+ bitbang_pullup(dev->bus_master->data, 0);
+ }
+ } else {
+ msleep(dev->pullup_duration);
+ }
+
dev->pullup_duration = 0;
}
}