From 8ceb69e8548f27305e37866ec3b81a79e1402b1a Mon Sep 17 00:00:00 2001 From: Phil Elwell Date: Wed, 4 Feb 2015 12:59:36 +0000 Subject: [PATCH 103/114] w1-gpio: Sort out the pullup/parasitic power tangle --- arch/arm/boot/dts/w1-gpio-overlay.dts | 4 +++- arch/arm/boot/dts/w1-gpio-pullup-overlay.dts | 6 +++-- drivers/w1/masters/w1-gpio.c | 36 ++++++++++++++++++---------- include/linux/w1-gpio.h | 1 + 4 files changed, 32 insertions(+), 15 deletions(-) --- a/arch/arm/boot/dts/w1-gpio-overlay.dts +++ b/arch/arm/boot/dts/w1-gpio-overlay.dts @@ -1,4 +1,4 @@ -// Definitions for lirc-rpi module +// Definitions for w1-gpio module (without external pullup) /dts-v1/; /plugin/; @@ -14,6 +14,7 @@ pinctrl-names = "default"; pinctrl-0 = <&w1_pins>; gpios = <&gpio 4 0>; + rpi,parasitic-power = <0>; status = "okay"; }; }; @@ -33,5 +34,6 @@ __overrides__ { gpiopin = <&w1>,"gpios:4", <&w1_pins>,"brcm,pins:0"; + pullup = <&w1>,"rpi,parasitic-power:0"; }; }; --- a/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts +++ b/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts @@ -1,4 +1,4 @@ -// Definitions for lirc-rpi module +// Definitions for w1-gpio module (with external pullup) /dts-v1/; /plugin/; @@ -14,6 +14,7 @@ pinctrl-names = "default"; pinctrl-0 = <&w1_pins>; gpios = <&gpio 4 0>, <&gpio 5 1>; + rpi,parasitic-power = <0>; status = "okay"; }; }; @@ -33,7 +34,8 @@ __overrides__ { gpiopin = <&w1>,"gpios:4", <&w1_pins>,"brcm,pins:0"; - pullup = <&w1>,"gpios:16", + extpullup = <&w1>,"gpios:16", <&w1_pins>,"brcm,pins:4"; + pullup = <&w1>,"rpi,parasitic-power:0"; }; }; --- a/drivers/w1/masters/w1-gpio.c +++ b/drivers/w1/masters/w1-gpio.c @@ -23,10 +23,14 @@ #include "../w1.h" #include "../w1_int.h" -static int w1_gpio_pullup = -1; -static int w1_gpio_pullup_orig = -1; +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, "GPIO pin pullup number"); +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); @@ -99,6 +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) @@ -107,6 +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) @@ -122,7 +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; @@ -158,17 +166,20 @@ static int w1_gpio_probe(struct platform } w1_gpio_pin_orig = pdata->pin; - w1_gpio_pullup_orig = pdata->ext_pullup_enable_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; } - if(gpio_is_valid(w1_gpio_pullup)) { - pdata->ext_pullup_enable_pin = w1_gpio_pullup; + 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, gpio pullup pin %d\n", pdata->pin, pdata->ext_pullup_enable_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) { @@ -199,10 +210,10 @@ static int w1_gpio_probe(struct platform master->set_pullup = w1_gpio_set_pullup; } - if (gpio_is_valid(w1_gpio_pullup)) { + if (pdata->parasitic_power) { if (pdata->is_open_drain) - printk(KERN_ERR "w1-gpio 'pullup' option " - "doesn't work with open drain GPIO\n"); + 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; } @@ -238,7 +249,8 @@ 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_orig; + pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig; + pdata->parasitic_power = w1_gpio_pullup_orig; return 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;