From 9c50f6318fdf116e5abaeb05bffa0b65e48ba259 Mon Sep 17 00:00:00 2001 From: popcornmix Date: Wed, 8 May 2013 11:46:50 +0100 Subject: [PATCH 031/121] 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 --- arch/arm/mach-bcm2708/bcm2708.c | 29 +++++++++++++++++ arch/arm/mach-bcm2709/bcm2709.c | 29 +++++++++++++++++ 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 + 7 files changed, 157 insertions(+), 9 deletions(-) --- a/arch/arm/mach-bcm2708/bcm2708.c +++ b/arch/arm/mach-bcm2708/bcm2708.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -77,12 +78,19 @@ */ #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 = UART0_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 bool vc_i2c_override = false; static unsigned use_dt = 0; @@ -303,6 +311,20 @@ static struct platform_device bcm2708_dm .num_resources = ARRAY_SIZE(bcm2708_dmaengine_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 = { @@ -729,6 +751,11 @@ void __init bcm2708_init(void) #ifdef CONFIG_BCM2708_GPIO bcm_register_device_dt(&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; + bcm_register_device_dt(&w1_device); +#endif bcm_register_device_dt(&bcm2708_fb_device); bcm_register_device_dt(&bcm2708_usb_device); @@ -942,5 +969,7 @@ 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); module_param(vc_i2c_override, bool, 0644); MODULE_PARM_DESC(vc_i2c_override, "Allow the use of VC's I2C peripheral."); --- a/arch/arm/mach-bcm2709/bcm2709.c +++ b/arch/arm/mach-bcm2709/bcm2709.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include @@ -79,12 +80,19 @@ */ #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 = UART0_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 bool vc_i2c_override = false; static unsigned use_dt = 0; @@ -313,6 +321,20 @@ static struct platform_device bcm2708_dm .num_resources = ARRAY_SIZE(bcm2708_dmaengine_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 = { @@ -749,6 +771,11 @@ void __init bcm2709_init(void) #ifdef CONFIG_BCM2708_GPIO bcm_register_device_dt(&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; + bcm_register_device_dt(&w1_device); +#endif bcm_register_device_dt(&bcm2708_fb_device); bcm_register_device_dt(&bcm2708_usb_device); @@ -1110,5 +1137,7 @@ 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); module_param(vc_i2c_override, bool, 0644); MODULE_PARM_DESC(vc_i2c_override, "Allow the use of VC's I2C peripheral."); --- 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 @@ -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; } } --- 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;