diff options
Diffstat (limited to 'drivers/w1/masters/w1-gpio.c')
| -rw-r--r-- | drivers/w1/masters/w1-gpio.c | 69 |
1 files changed, 63 insertions, 6 deletions
diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c index a373ae69d9f6..080e5976e2a6 100644 --- 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 platform_device *pdev) 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 platform_device *pdev) 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 platform_device *pdev) 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 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) - 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_device *pdev) 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_device *pdev) 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 platform_device *pdev) 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; } |