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1 /*
2  * w1-gpio - GPIO w1 bus master driver
3  *
4  * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2
8  * as published by the Free Software Foundation.
9  */
10 
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/slab.h>
15 #include <linux/w1-gpio.h>
16 #include <linux/gpio.h>
17 #include <linux/of_platform.h>
18 #include <linux/of_gpio.h>
19 #include <linux/err.h>
20 #include <linux/of.h>
21 #include <linux/delay.h>
22 
23 #include "../w1.h"
24 #include "../w1_int.h"
25 
w1_gpio_set_pullup(void * data,int delay)26 static u8 w1_gpio_set_pullup(void *data, int delay)
27 {
28 	struct w1_gpio_platform_data *pdata = data;
29 
30 	if (delay) {
31 		pdata->pullup_duration = delay;
32 	} else {
33 		if (pdata->pullup_duration) {
34 			gpio_direction_output(pdata->pin, 1);
35 
36 			msleep(pdata->pullup_duration);
37 
38 			gpio_direction_input(pdata->pin);
39 		}
40 		pdata->pullup_duration = 0;
41 	}
42 
43 	return 0;
44 }
45 
w1_gpio_write_bit_dir(void * data,u8 bit)46 static void w1_gpio_write_bit_dir(void *data, u8 bit)
47 {
48 	struct w1_gpio_platform_data *pdata = data;
49 
50 	if (bit)
51 		gpio_direction_input(pdata->pin);
52 	else
53 		gpio_direction_output(pdata->pin, 0);
54 }
55 
w1_gpio_write_bit_val(void * data,u8 bit)56 static void w1_gpio_write_bit_val(void *data, u8 bit)
57 {
58 	struct w1_gpio_platform_data *pdata = data;
59 
60 	gpio_set_value(pdata->pin, bit);
61 }
62 
w1_gpio_read_bit(void * data)63 static u8 w1_gpio_read_bit(void *data)
64 {
65 	struct w1_gpio_platform_data *pdata = data;
66 
67 	return gpio_get_value(pdata->pin) ? 1 : 0;
68 }
69 
70 #if defined(CONFIG_OF)
71 static const struct of_device_id w1_gpio_dt_ids[] = {
72 	{ .compatible = "w1-gpio" },
73 	{}
74 };
75 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
76 #endif
77 
w1_gpio_probe_dt(struct platform_device * pdev)78 static int w1_gpio_probe_dt(struct platform_device *pdev)
79 {
80 	struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
81 	struct device_node *np = pdev->dev.of_node;
82 	int gpio;
83 
84 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
85 	if (!pdata)
86 		return -ENOMEM;
87 
88 	if (of_get_property(np, "linux,open-drain", NULL))
89 		pdata->is_open_drain = 1;
90 
91 	gpio = of_get_gpio(np, 0);
92 	if (gpio < 0) {
93 		if (gpio != -EPROBE_DEFER)
94 			dev_err(&pdev->dev,
95 					"Failed to parse gpio property for data pin (%d)\n",
96 					gpio);
97 
98 		return gpio;
99 	}
100 	pdata->pin = gpio;
101 
102 	gpio = of_get_gpio(np, 1);
103 	if (gpio == -EPROBE_DEFER)
104 		return gpio;
105 	/* ignore other errors as the pullup gpio is optional */
106 	pdata->ext_pullup_enable_pin = gpio;
107 
108 	pdev->dev.platform_data = pdata;
109 
110 	return 0;
111 }
112 
w1_gpio_probe(struct platform_device * pdev)113 static int w1_gpio_probe(struct platform_device *pdev)
114 {
115 	struct w1_bus_master *master;
116 	struct w1_gpio_platform_data *pdata;
117 	int err;
118 
119 	if (of_have_populated_dt()) {
120 		err = w1_gpio_probe_dt(pdev);
121 		if (err < 0)
122 			return err;
123 	}
124 
125 	pdata = dev_get_platdata(&pdev->dev);
126 
127 	if (!pdata) {
128 		dev_err(&pdev->dev, "No configuration data\n");
129 		return -ENXIO;
130 	}
131 
132 	master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master),
133 			GFP_KERNEL);
134 	if (!master) {
135 		dev_err(&pdev->dev, "Out of memory\n");
136 		return -ENOMEM;
137 	}
138 
139 	err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
140 	if (err) {
141 		dev_err(&pdev->dev, "gpio_request (pin) failed\n");
142 		return err;
143 	}
144 
145 	if (gpio_is_valid(pdata->ext_pullup_enable_pin)) {
146 		err = devm_gpio_request_one(&pdev->dev,
147 				pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW,
148 				"w1 pullup");
149 		if (err < 0) {
150 			dev_err(&pdev->dev, "gpio_request_one "
151 					"(ext_pullup_enable_pin) failed\n");
152 			return err;
153 		}
154 	}
155 
156 	master->data = pdata;
157 	master->read_bit = w1_gpio_read_bit;
158 
159 	if (pdata->is_open_drain) {
160 		gpio_direction_output(pdata->pin, 1);
161 		master->write_bit = w1_gpio_write_bit_val;
162 	} else {
163 		gpio_direction_input(pdata->pin);
164 		master->write_bit = w1_gpio_write_bit_dir;
165 		master->set_pullup = w1_gpio_set_pullup;
166 	}
167 
168 	err = w1_add_master_device(master);
169 	if (err) {
170 		dev_err(&pdev->dev, "w1_add_master device failed\n");
171 		return err;
172 	}
173 
174 	if (pdata->enable_external_pullup)
175 		pdata->enable_external_pullup(1);
176 
177 	if (gpio_is_valid(pdata->ext_pullup_enable_pin))
178 		gpio_set_value(pdata->ext_pullup_enable_pin, 1);
179 
180 	platform_set_drvdata(pdev, master);
181 
182 	return 0;
183 }
184 
w1_gpio_remove(struct platform_device * pdev)185 static int w1_gpio_remove(struct platform_device *pdev)
186 {
187 	struct w1_bus_master *master = platform_get_drvdata(pdev);
188 	struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
189 
190 	if (pdata->enable_external_pullup)
191 		pdata->enable_external_pullup(0);
192 
193 	if (gpio_is_valid(pdata->ext_pullup_enable_pin))
194 		gpio_set_value(pdata->ext_pullup_enable_pin, 0);
195 
196 	w1_remove_master_device(master);
197 
198 	return 0;
199 }
200 
w1_gpio_suspend(struct device * dev)201 static int __maybe_unused w1_gpio_suspend(struct device *dev)
202 {
203 	struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
204 
205 	if (pdata->enable_external_pullup)
206 		pdata->enable_external_pullup(0);
207 
208 	return 0;
209 }
210 
w1_gpio_resume(struct device * dev)211 static int __maybe_unused w1_gpio_resume(struct device *dev)
212 {
213 	struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
214 
215 	if (pdata->enable_external_pullup)
216 		pdata->enable_external_pullup(1);
217 
218 	return 0;
219 }
220 
221 static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume);
222 
223 static struct platform_driver w1_gpio_driver = {
224 	.driver = {
225 		.name	= "w1-gpio",
226 		.pm	= &w1_gpio_pm_ops,
227 		.of_match_table = of_match_ptr(w1_gpio_dt_ids),
228 	},
229 	.probe = w1_gpio_probe,
230 	.remove = w1_gpio_remove,
231 };
232 
233 module_platform_driver(w1_gpio_driver);
234 
235 MODULE_DESCRIPTION("GPIO w1 bus master driver");
236 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
237 MODULE_LICENSE("GPL");
238