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
26static 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
46static 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
56static 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
63static 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)
71static const struct of_device_id w1_gpio_dt_ids[] = {
72	{ .compatible = "w1-gpio" },
73	{}
74};
75MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
76#endif
77
78static 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
113static 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
185static 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
201#ifdef CONFIG_PM
202
203static int w1_gpio_suspend(struct platform_device *pdev, pm_message_t state)
204{
205	struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
206
207	if (pdata->enable_external_pullup)
208		pdata->enable_external_pullup(0);
209
210	return 0;
211}
212
213static int w1_gpio_resume(struct platform_device *pdev)
214{
215	struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
216
217	if (pdata->enable_external_pullup)
218		pdata->enable_external_pullup(1);
219
220	return 0;
221}
222
223#else
224#define w1_gpio_suspend	NULL
225#define w1_gpio_resume	NULL
226#endif
227
228static struct platform_driver w1_gpio_driver = {
229	.driver = {
230		.name	= "w1-gpio",
231		.of_match_table = of_match_ptr(w1_gpio_dt_ids),
232	},
233	.probe = w1_gpio_probe,
234	.remove	= w1_gpio_remove,
235	.suspend = w1_gpio_suspend,
236	.resume = w1_gpio_resume,
237};
238
239module_platform_driver(w1_gpio_driver);
240
241MODULE_DESCRIPTION("GPIO w1 bus master driver");
242MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
243MODULE_LICENSE("GPL");
244