1 // SPDX-License-Identifier: GPL-2.0-only
3  * w1-gpio - GPIO w1 bus master driver
12 #include <linux/w1-gpio.h>
13 #include <linux/gpio/consumer.h>
26 		pdata->pullup_duration = delay;  in w1_gpio_set_pullup()
28 		if (pdata->pullup_duration) {  in w1_gpio_set_pullup()
30 			 * This will OVERRIDE open drain emulation and force-pull  in w1_gpio_set_pullup()
33 			gpiod_set_raw_value(pdata->gpiod, 1);  in w1_gpio_set_pullup()
34 			msleep(pdata->pullup_duration);  in w1_gpio_set_pullup()
37 			 * open drain emulation in the GPIO library.  in w1_gpio_set_pullup()
39 			gpiod_set_value(pdata->gpiod, 1);  in w1_gpio_set_pullup()
41 		pdata->pullup_duration = 0;  in w1_gpio_set_pullup()
51 	gpiod_set_value(pdata->gpiod, bit);  in w1_gpio_write_bit()
58 	return gpiod_get_value(pdata->gpiod) ? 1 : 0;  in w1_gpio_read_bit()
63 	{ .compatible = "w1-gpio" },
73 	struct device *dev = &pdev->dev;  in w1_gpio_probe()
74 	struct device_node *np = dev->of_node;  in w1_gpio_probe()
75 	/* Enforce open drain mode by default */  in w1_gpio_probe()
80 		pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);  in w1_gpio_probe()
82 			return -ENOMEM;  in w1_gpio_probe()
86 		 * already set the line into open drain mode, so we should just  in w1_gpio_probe()
88 		 * open drain will happen transparently.  in w1_gpio_probe()
90 		if (of_property_present(np, "linux,open-drain"))  in w1_gpio_probe()
93 		pdev->dev.platform_data = pdata;  in w1_gpio_probe()
99 		return -ENXIO;  in w1_gpio_probe()
105 		return -ENOMEM;  in w1_gpio_probe()
107 	pdata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags);  in w1_gpio_probe()
108 	if (IS_ERR(pdata->gpiod)) {  in w1_gpio_probe()
110 		return PTR_ERR(pdata->gpiod);  in w1_gpio_probe()
113 	pdata->pullup_gpiod =  in w1_gpio_probe()
115 	if (IS_ERR(pdata->pullup_gpiod)) {  in w1_gpio_probe()
118 		return PTR_ERR(pdata->pullup_gpiod);  in w1_gpio_probe()
121 	master->data = pdata;  in w1_gpio_probe()
122 	master->read_bit = w1_gpio_read_bit;  in w1_gpio_probe()
123 	gpiod_direction_output(pdata->gpiod, 1);  in w1_gpio_probe()
124 	master->write_bit = w1_gpio_write_bit;  in w1_gpio_probe()
127 	 * If we are using open drain emulation from the GPIO library,  in w1_gpio_probe()
129 	 * high using a raw accessor to provide pull-up for the w1  in w1_gpio_probe()
133 		master->set_pullup = w1_gpio_set_pullup;  in w1_gpio_probe()
141 	if (pdata->enable_external_pullup)  in w1_gpio_probe()
142 		pdata->enable_external_pullup(1);  in w1_gpio_probe()
144 	if (pdata->pullup_gpiod)  in w1_gpio_probe()
145 		gpiod_set_value(pdata->pullup_gpiod, 1);  in w1_gpio_probe()
155 	struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);  in w1_gpio_remove()
157 	if (pdata->enable_external_pullup)  in w1_gpio_remove()
158 		pdata->enable_external_pullup(0);  in w1_gpio_remove()
160 	if (pdata->pullup_gpiod)  in w1_gpio_remove()
161 		gpiod_set_value(pdata->pullup_gpiod, 0);  in w1_gpio_remove()
172 	if (pdata->enable_external_pullup)  in w1_gpio_suspend()
173 		pdata->enable_external_pullup(0);  in w1_gpio_suspend()
182 	if (pdata->enable_external_pullup)  in w1_gpio_resume()
183 		pdata->enable_external_pullup(1);  in w1_gpio_resume()
192 		.name	= "w1-gpio",
202 MODULE_DESCRIPTION("GPIO w1 bus master driver");