167 lines
5.4 KiB
Diff
167 lines
5.4 KiB
Diff
From 8ceb69e8548f27305e37866ec3b81a79e1402b1a Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Wed, 4 Feb 2015 12:59:36 +0000
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Subject: [PATCH 103/114] w1-gpio: Sort out the pullup/parasitic power tangle
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---
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arch/arm/boot/dts/w1-gpio-overlay.dts | 4 +++-
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arch/arm/boot/dts/w1-gpio-pullup-overlay.dts | 6 +++--
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drivers/w1/masters/w1-gpio.c | 36 ++++++++++++++++++----------
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include/linux/w1-gpio.h | 1 +
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4 files changed, 32 insertions(+), 15 deletions(-)
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--- a/arch/arm/boot/dts/w1-gpio-overlay.dts
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+++ b/arch/arm/boot/dts/w1-gpio-overlay.dts
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@@ -1,4 +1,4 @@
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-// Definitions for lirc-rpi module
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+// Definitions for w1-gpio module (without external pullup)
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/dts-v1/;
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/plugin/;
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@@ -14,6 +14,7 @@
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pinctrl-names = "default";
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pinctrl-0 = <&w1_pins>;
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gpios = <&gpio 4 0>;
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+ rpi,parasitic-power = <0>;
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status = "okay";
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};
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};
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@@ -33,5 +34,6 @@
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__overrides__ {
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gpiopin = <&w1>,"gpios:4",
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<&w1_pins>,"brcm,pins:0";
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+ pullup = <&w1>,"rpi,parasitic-power:0";
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};
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};
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--- a/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts
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+++ b/arch/arm/boot/dts/w1-gpio-pullup-overlay.dts
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@@ -1,4 +1,4 @@
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-// Definitions for lirc-rpi module
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+// Definitions for w1-gpio module (with external pullup)
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/dts-v1/;
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/plugin/;
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@@ -14,6 +14,7 @@
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pinctrl-names = "default";
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pinctrl-0 = <&w1_pins>;
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gpios = <&gpio 4 0>, <&gpio 5 1>;
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+ rpi,parasitic-power = <0>;
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status = "okay";
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};
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};
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@@ -33,7 +34,8 @@
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__overrides__ {
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gpiopin = <&w1>,"gpios:4",
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<&w1_pins>,"brcm,pins:0";
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- pullup = <&w1>,"gpios:16",
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+ extpullup = <&w1>,"gpios:16",
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<&w1_pins>,"brcm,pins:4";
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+ pullup = <&w1>,"rpi,parasitic-power:0";
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};
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};
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--- a/drivers/w1/masters/w1-gpio.c
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+++ b/drivers/w1/masters/w1-gpio.c
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@@ -23,10 +23,14 @@
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#include "../w1.h"
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#include "../w1_int.h"
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-static int w1_gpio_pullup = -1;
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-static int w1_gpio_pullup_orig = -1;
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+static int w1_gpio_pullup = 0;
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+static int w1_gpio_pullup_orig = 0;
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module_param_named(pullup, w1_gpio_pullup, int, 0);
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-MODULE_PARM_DESC(pullup, "GPIO pin pullup number");
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+MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode");
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+static int w1_gpio_pullup_pin = -1;
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+static int w1_gpio_pullup_pin_orig = -1;
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+module_param_named(extpullup, w1_gpio_pullup_pin, int, 0);
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+MODULE_PARM_DESC(extpullup, "GPIO external pullup pin number");
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static int w1_gpio_pin = -1;
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static int w1_gpio_pin_orig = -1;
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module_param_named(gpiopin, w1_gpio_pin, int, 0);
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@@ -99,6 +103,7 @@ static int w1_gpio_probe_dt(struct platf
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struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
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struct device_node *np = pdev->dev.of_node;
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int gpio;
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+ u32 value;
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata)
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@@ -107,6 +112,9 @@ static int w1_gpio_probe_dt(struct platf
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if (of_get_property(np, "linux,open-drain", NULL))
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pdata->is_open_drain = 1;
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+ if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0)
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+ pdata->parasitic_power = (value != 0);
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+
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gpio = of_get_gpio(np, 0);
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if (gpio < 0) {
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if (gpio != -EPROBE_DEFER)
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@@ -122,7 +130,7 @@ static int w1_gpio_probe_dt(struct platf
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if (gpio == -EPROBE_DEFER)
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return gpio;
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/* ignore other errors as the pullup gpio is optional */
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- pdata->ext_pullup_enable_pin = gpio;
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+ pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1;
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pdev->dev.platform_data = pdata;
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@@ -158,17 +166,20 @@ static int w1_gpio_probe(struct platform
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}
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w1_gpio_pin_orig = pdata->pin;
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- w1_gpio_pullup_orig = pdata->ext_pullup_enable_pin;
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+ w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
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+ w1_gpio_pullup_orig = pdata->parasitic_power;
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if(gpio_is_valid(w1_gpio_pin)) {
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pdata->pin = w1_gpio_pin;
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pdata->ext_pullup_enable_pin = -1;
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+ pdata->parasitic_power = -1;
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}
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- if(gpio_is_valid(w1_gpio_pullup)) {
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- pdata->ext_pullup_enable_pin = w1_gpio_pullup;
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+ pdata->parasitic_power |= w1_gpio_pullup;
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+ if(gpio_is_valid(w1_gpio_pullup_pin)) {
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+ pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
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}
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- dev_info(&pdev->dev, "gpio pin %d, gpio pullup pin %d\n", pdata->pin, pdata->ext_pullup_enable_pin);
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+ 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);
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err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
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if (err) {
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@@ -199,10 +210,10 @@ static int w1_gpio_probe(struct platform
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master->set_pullup = w1_gpio_set_pullup;
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}
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- if (gpio_is_valid(w1_gpio_pullup)) {
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+ if (pdata->parasitic_power) {
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if (pdata->is_open_drain)
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- printk(KERN_ERR "w1-gpio 'pullup' option "
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- "doesn't work with open drain GPIO\n");
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+ printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
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+ "option doesn't work with open drain GPIO\n");
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else
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master->bitbang_pullup = w1_gpio_bitbang_pullup;
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}
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@@ -238,7 +249,8 @@ static int w1_gpio_remove(struct platfor
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w1_remove_master_device(master);
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pdata->pin = w1_gpio_pin_orig;
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- pdata->ext_pullup_enable_pin = w1_gpio_pullup_orig;
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+ pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
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+ pdata->parasitic_power = w1_gpio_pullup_orig;
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return 0;
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}
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--- a/include/linux/w1-gpio.h
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+++ b/include/linux/w1-gpio.h
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@@ -18,6 +18,7 @@
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struct w1_gpio_platform_data {
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unsigned int pin;
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unsigned int is_open_drain:1;
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+ unsigned int parasitic_power:1;
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void (*enable_external_pullup)(int enable);
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unsigned int ext_pullup_enable_pin;
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unsigned int pullup_duration;
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