From 370acd9248703fb8531cd87982fb02dcce32a2b4 Mon Sep 17 00:00:00 2001 From: popcornmix Date: Wed, 8 May 2013 11:46:50 +0100 Subject: [PATCH 19/54] 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 --- arch/arm/mach-bcm2708/bcm2708.c | 29 +++++++++++++++++++++ drivers/w1/masters/w1-gpio.c | 57 ++++++++++++++++++++++++++++++++++++----- drivers/w1/w1.h | 6 +++++ drivers/w1/w1_int.c | 14 ++++++++++ drivers/w1/w1_io.c | 18 ++++++++++--- 5 files changed, 115 insertions(+), 9 deletions(-) diff --git a/arch/arm/mach-bcm2708/bcm2708.c b/arch/arm/mach-bcm2708/bcm2708.c index e892006..221d145 100644 --- a/arch/arm/mach-bcm2708/bcm2708.c +++ b/arch/arm/mach-bcm2708/bcm2708.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include @@ -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_dmaman_device = { .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 = { @@ -680,6 +702,11 @@ 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); @@ -883,3 +910,5 @@ 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); diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c index 9709b8b..b10f9c9 100644 --- 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" }, @@ -102,14 +121,16 @@ static int w1_gpio_probe_dt(struct platform_device *pdev) 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) { - dev_err(&pdev->dev, "Failed to parse DT\n"); - return err; + if(pdata == NULL) { + if (of_have_populated_dt()) { + err = w1_gpio_probe_dt(pdev); + if (err < 0) { + dev_err(&pdev->dev, "Failed to parse DT\n"); + return err; + } } } @@ -127,6 +148,19 @@ static int w1_gpio_probe(struct platform_device *pdev) 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"); @@ -156,6 +190,14 @@ static int w1_gpio_probe(struct platform_device *pdev) 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"); @@ -186,6 +228,9 @@ static int w1_gpio_remove(struct platform_device *pdev) w1_remove_master_device(master); + pdata->pin = w1_gpio_pin_orig; + pdata->ext_pullup_enable_pin = w1_gpio_pullup_orig; + return 0; } diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h index ca8081a..3392959 100644 --- 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. */ diff --git a/drivers/w1/w1_int.c b/drivers/w1/w1_int.c index 590bd8a..a4d69b6 100644 --- a/drivers/w1/w1_int.c +++ b/drivers/w1/w1_int.c @@ -118,6 +118,20 @@ int w1_add_master_device(struct w1_bus_master *master) 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). */ diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c index e10acc2..667fdd5 100644 --- a/drivers/w1/w1_io.c +++ b/drivers/w1/w1_io.c @@ -127,10 +127,22 @@ static void w1_pre_write(struct w1_master *dev) 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; } } -- 1.9.1