diff options
Diffstat (limited to 'target/linux/brcm2708/patches-3.10/0055-Add-bitbanging-pullups-use-them-for-w1-gpio.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-3.10/0055-Add-bitbanging-pullups-use-them-for-w1-gpio.patch | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-3.10/0055-Add-bitbanging-pullups-use-them-for-w1-gpio.patch b/target/linux/brcm2708/patches-3.10/0055-Add-bitbanging-pullups-use-them-for-w1-gpio.patch new file mode 100644 index 0000000000..f71bc9ffe0 --- /dev/null +++ b/target/linux/brcm2708/patches-3.10/0055-Add-bitbanging-pullups-use-them-for-w1-gpio.patch @@ -0,0 +1,130 @@ +From 28ca85a46bbdae4152b48a669872ac205d053856 Mon Sep 17 00:00:00 2001 +From: popcornmix <popcornmix@gmail.com> +Date: Wed, 1 May 2013 21:14:28 +0100 +Subject: [PATCH 055/174] Add bitbanging pullups, use them for w1-gpio + +Allows parasite power to work, uses module option pullup=1 +--- + drivers/w1/masters/w1-gpio.c | 20 ++++++++++++++++++++ + drivers/w1/w1.h | 6 ++++++ + drivers/w1/w1_int.c | 16 +++++++++------- + drivers/w1/w1_io.c | 18 +++++++++++++++--- + 4 files changed, 50 insertions(+), 10 deletions(-) + +--- a/drivers/w1/masters/w1-gpio.c ++++ b/drivers/w1/masters/w1-gpio.c +@@ -23,6 +23,9 @@ + #include "../w1.h" + #include "../w1_int.h" + ++static int w1_gpio_pullup = 0; ++module_param_named(pullup, w1_gpio_pullup, int, 0); ++ + static void w1_gpio_write_bit_dir(void *data, u8 bit) + { + struct w1_gpio_platform_data *pdata = data; +@@ -47,6 +50,16 @@ 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" }, +@@ -133,6 +146,13 @@ static int w1_gpio_probe(struct platform + master->write_bit = w1_gpio_write_bit_dir; + } + ++ if (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"); +--- a/drivers/w1/w1.h ++++ b/drivers/w1/w1.h +@@ -148,6 +148,12 @@ 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); ++ + /** Really nice hardware can handles the different types of ROM search + * w1_master* is passed to the slave found callback. + */ +--- a/drivers/w1/w1_int.c ++++ b/drivers/w1/w1_int.c +@@ -117,19 +117,21 @@ int w1_add_master_device(struct w1_bus_m + printk(KERN_ERR "w1_add_master_device: invalid function set\n"); + return(-EINVAL); + } +- /* While it would be electrically possible to make a device that +- * generated a strong pullup in bit bang mode, only hardware that +- * controls 1-wire time frames are even expected to support a strong +- * pullup. w1_io.c would need to support calling set_pullup before +- * the last write_bit operation of a w1_write_8 which it currently +- * doesn't. +- */ ++ ++ /* 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 +@@ -127,10 +127,22 @@ 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; + } + } |