From d7a403ac584a5ed4a871c66deeb60fd887074ffc Mon Sep 17 00:00:00 2001 From: popcornmix Date: Wed, 8 May 2013 11:46:50 +0100 Subject: [PATCH] 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 w1-gpio: Add gpiopin module parameter and correctly free up gpio pull-up pin, if set Signed-off-by: Alex J Lennon w1-gpio: Sort out the pullup/parasitic power tangle --- drivers/w1/masters/w1-gpio.c | 69 ++++++++++++++++++++++++++++++++++++++++---- drivers/w1/w1.h | 6 ++++ drivers/w1/w1_int.c | 14 +++++++++ drivers/w1/w1_io.c | 18 ++++++++++-- include/linux/w1-gpio.h | 1 + 5 files changed, 99 insertions(+), 9 deletions(-) --- a/drivers/w1/masters/w1-gpio.c +++ b/drivers/w1/masters/w1-gpio.c @@ -23,6 +23,19 @@ #include "../w1.h" #include "../w1_int.h" +static int w1_gpio_pullup = 0; +static int w1_gpio_pullup_orig = 0; +module_param_named(pullup, w1_gpio_pullup, int, 0); +MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode"); +static int w1_gpio_pullup_pin = -1; +static int w1_gpio_pullup_pin_orig = -1; +module_param_named(extpullup, w1_gpio_pullup_pin, int, 0); +MODULE_PARM_DESC(extpullup, "GPIO external pullup pin 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 +80,16 @@ 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 const struct of_device_id w1_gpio_dt_ids[] = { { .compatible = "w1-gpio" }, @@ -80,6 +103,7 @@ static int w1_gpio_probe_dt(struct platf struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev); struct device_node *np = pdev->dev.of_node; int gpio; + u32 value; pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) @@ -88,6 +112,9 @@ static int w1_gpio_probe_dt(struct platf if (of_get_property(np, "linux,open-drain", NULL)) pdata->is_open_drain = 1; + if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0) + pdata->parasitic_power = (value != 0); + gpio = of_get_gpio(np, 0); if (gpio < 0) { if (gpio != -EPROBE_DEFER) @@ -103,7 +130,7 @@ static int w1_gpio_probe_dt(struct platf if (gpio == -EPROBE_DEFER) return gpio; /* ignore other errors as the pullup gpio is optional */ - pdata->ext_pullup_enable_pin = gpio; + pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1; pdev->dev.platform_data = pdata; @@ -113,13 +140,15 @@ 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 +165,22 @@ static int w1_gpio_probe(struct platform return -ENOMEM; } + w1_gpio_pin_orig = pdata->pin; + w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin; + w1_gpio_pullup_orig = pdata->parasitic_power; + + if(gpio_is_valid(w1_gpio_pin)) { + pdata->pin = w1_gpio_pin; + pdata->ext_pullup_enable_pin = -1; + pdata->parasitic_power = -1; + } + pdata->parasitic_power |= w1_gpio_pullup; + if(gpio_is_valid(w1_gpio_pullup_pin)) { + pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin; + } + + 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); + err = devm_gpio_request(&pdev->dev, pdata->pin, "w1"); if (err) { dev_err(&pdev->dev, "gpio_request (pin) failed\n"); @@ -165,6 +210,14 @@ static int w1_gpio_probe(struct platform master->set_pullup = w1_gpio_set_pullup; } + if (pdata->parasitic_power) { + if (pdata->is_open_drain) + printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) " + "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 +248,10 @@ 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_pin_orig; + pdata->parasitic_power = 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 @@ -122,6 +122,20 @@ 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; } } --- a/include/linux/w1-gpio.h +++ b/include/linux/w1-gpio.h @@ -18,6 +18,7 @@ struct w1_gpio_platform_data { unsigned int pin; unsigned int is_open_drain:1; + unsigned int parasitic_power:1; void (*enable_external_pullup)(int enable); unsigned int ext_pullup_enable_pin; unsigned int pullup_duration;