1 // SPDX-License-Identifier: GPL-2.0-only
3  * w1-gpio - GPIO w1 bus master driver
12 #include <linux/w1-gpio.h>
17 #include <linux/delay.h>
21 static u8 w1_gpio_set_pullup(void *data, int delay)  in w1_gpio_set_pullup()  argument
25 	if (delay) {  in w1_gpio_set_pullup()
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()
31 			 * the line high for some time.  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()
36 			 * This will simply set the line as input since we are doing  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()
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()
87 		 * driver it high/low like we are in full control of the line and  in w1_gpio_probe()
90 		if (of_get_property(np, "linux,open-drain", NULL))  in w1_gpio_probe()
93 		pdev->dev.platform_data = pdata;  in w1_gpio_probe()
99 		return -ENXIO;  in w1_gpio_probe()
106 		return -ENOMEM;  in w1_gpio_probe()
109 	pdata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags);  in w1_gpio_probe()
110 	if (IS_ERR(pdata->gpiod)) {  in w1_gpio_probe()
112 		return PTR_ERR(pdata->gpiod);  in w1_gpio_probe()
115 	pdata->pullup_gpiod =  in w1_gpio_probe()
117 	if (IS_ERR(pdata->pullup_gpiod)) {  in w1_gpio_probe()
120 		return PTR_ERR(pdata->pullup_gpiod);  in w1_gpio_probe()
123 	master->data = pdata;  in w1_gpio_probe()
124 	master->read_bit = w1_gpio_read_bit;  in w1_gpio_probe()
125 	gpiod_direction_output(pdata->gpiod, 1);  in w1_gpio_probe()
126 	master->write_bit = w1_gpio_write_bit;  in w1_gpio_probe()
130 	 * we need to use this pullup function that hammers the line  in w1_gpio_probe()
131 	 * high using a raw accessor to provide pull-up for the w1  in w1_gpio_probe()
132 	 * line.  in w1_gpio_probe()
135 		master->set_pullup = w1_gpio_set_pullup;  in w1_gpio_probe()
143 	if (pdata->enable_external_pullup)  in w1_gpio_probe()
144 		pdata->enable_external_pullup(1);  in w1_gpio_probe()
146 	if (pdata->pullup_gpiod)  in w1_gpio_probe()
147 		gpiod_set_value(pdata->pullup_gpiod, 1);  in w1_gpio_probe()
157 	struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);  in w1_gpio_remove()
159 	if (pdata->enable_external_pullup)  in w1_gpio_remove()
160 		pdata->enable_external_pullup(0);  in w1_gpio_remove()
162 	if (pdata->pullup_gpiod)  in w1_gpio_remove()
163 		gpiod_set_value(pdata->pullup_gpiod, 0);  in w1_gpio_remove()
174 	if (pdata->enable_external_pullup)  in w1_gpio_suspend()
175 		pdata->enable_external_pullup(0);  in w1_gpio_suspend()
184 	if (pdata->enable_external_pullup)  in w1_gpio_resume()
185 		pdata->enable_external_pullup(1);  in w1_gpio_resume()
194 		.name	= "w1-gpio",