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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * w1-gpio - GPIO w1 bus master driver
4 *
5 * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
6 */
7
8#include <linux/init.h>
9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/slab.h>
12#include <linux/w1-gpio.h>
13#include <linux/gpio/consumer.h>
14#include <linux/of_platform.h>
15#include <linux/err.h>
16#include <linux/of.h>
17#include <linux/delay.h>
18
19#include <linux/w1.h>
20
21static u8 w1_gpio_set_pullup(void *data, int delay)
22{
23 struct w1_gpio_platform_data *pdata = data;
24
25 if (delay) {
26 pdata->pullup_duration = delay;
27 } else {
28 if (pdata->pullup_duration) {
29 /*
30 * This will OVERRIDE open drain emulation and force-pull
31 * the line high for some time.
32 */
33 gpiod_set_raw_value(pdata->gpiod, 1);
34 msleep(pdata->pullup_duration);
35 /*
36 * This will simply set the line as input since we are doing
37 * open drain emulation in the GPIO library.
38 */
39 gpiod_set_value(pdata->gpiod, 1);
40 }
41 pdata->pullup_duration = 0;
42 }
43
44 return 0;
45}
46
47static void w1_gpio_write_bit(void *data, u8 bit)
48{
49 struct w1_gpio_platform_data *pdata = data;
50
51 gpiod_set_value(pdata->gpiod, bit);
52}
53
54static u8 w1_gpio_read_bit(void *data)
55{
56 struct w1_gpio_platform_data *pdata = data;
57
58 return gpiod_get_value(pdata->gpiod) ? 1 : 0;
59}
60
61#if defined(CONFIG_OF)
62static const struct of_device_id w1_gpio_dt_ids[] = {
63 { .compatible = "w1-gpio" },
64 {}
65};
66MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
67#endif
68
69static int w1_gpio_probe(struct platform_device *pdev)
70{
71 struct w1_bus_master *master;
72 struct w1_gpio_platform_data *pdata;
73 struct device *dev = &pdev->dev;
74 struct device_node *np = dev->of_node;
75 /* Enforce open drain mode by default */
76 enum gpiod_flags gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
77 int err;
78
79 if (of_have_populated_dt()) {
80 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
81 if (!pdata)
82 return -ENOMEM;
83
84 /*
85 * This parameter means that something else than the gpiolib has
86 * already set the line into open drain mode, so we should just
87 * driver it high/low like we are in full control of the line and
88 * open drain will happen transparently.
89 */
90 if (of_get_property(np, "linux,open-drain", NULL))
91 gflags = GPIOD_OUT_LOW;
92
93 pdev->dev.platform_data = pdata;
94 }
95 pdata = dev_get_platdata(dev);
96
97 if (!pdata) {
98 dev_err(dev, "No configuration data\n");
99 return -ENXIO;
100 }
101
102 master = devm_kzalloc(dev, sizeof(struct w1_bus_master),
103 GFP_KERNEL);
104 if (!master) {
105 dev_err(dev, "Out of memory\n");
106 return -ENOMEM;
107 }
108
109 pdata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags);
110 if (IS_ERR(pdata->gpiod)) {
111 dev_err(dev, "gpio_request (pin) failed\n");
112 return PTR_ERR(pdata->gpiod);
113 }
114
115 pdata->pullup_gpiod =
116 devm_gpiod_get_index_optional(dev, NULL, 1, GPIOD_OUT_LOW);
117 if (IS_ERR(pdata->pullup_gpiod)) {
118 dev_err(dev, "gpio_request_one "
119 "(ext_pullup_enable_pin) failed\n");
120 return PTR_ERR(pdata->pullup_gpiod);
121 }
122
123 master->data = pdata;
124 master->read_bit = w1_gpio_read_bit;
125 gpiod_direction_output(pdata->gpiod, 1);
126 master->write_bit = w1_gpio_write_bit;
127
128 /*
129 * If we are using open drain emulation from the GPIO library,
130 * we need to use this pullup function that hammers the line
131 * high using a raw accessor to provide pull-up for the w1
132 * line.
133 */
134 if (gflags == GPIOD_OUT_LOW_OPEN_DRAIN)
135 master->set_pullup = w1_gpio_set_pullup;
136
137 err = w1_add_master_device(master);
138 if (err) {
139 dev_err(dev, "w1_add_master device failed\n");
140 return err;
141 }
142
143 if (pdata->enable_external_pullup)
144 pdata->enable_external_pullup(1);
145
146 if (pdata->pullup_gpiod)
147 gpiod_set_value(pdata->pullup_gpiod, 1);
148
149 platform_set_drvdata(pdev, master);
150
151 return 0;
152}
153
154static int w1_gpio_remove(struct platform_device *pdev)
155{
156 struct w1_bus_master *master = platform_get_drvdata(pdev);
157 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
158
159 if (pdata->enable_external_pullup)
160 pdata->enable_external_pullup(0);
161
162 if (pdata->pullup_gpiod)
163 gpiod_set_value(pdata->pullup_gpiod, 0);
164
165 w1_remove_master_device(master);
166
167 return 0;
168}
169
170static int __maybe_unused w1_gpio_suspend(struct device *dev)
171{
172 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
173
174 if (pdata->enable_external_pullup)
175 pdata->enable_external_pullup(0);
176
177 return 0;
178}
179
180static int __maybe_unused w1_gpio_resume(struct device *dev)
181{
182 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
183
184 if (pdata->enable_external_pullup)
185 pdata->enable_external_pullup(1);
186
187 return 0;
188}
189
190static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume);
191
192static struct platform_driver w1_gpio_driver = {
193 .driver = {
194 .name = "w1-gpio",
195 .pm = &w1_gpio_pm_ops,
196 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
197 },
198 .probe = w1_gpio_probe,
199 .remove = w1_gpio_remove,
200};
201
202module_platform_driver(w1_gpio_driver);
203
204MODULE_DESCRIPTION("GPIO w1 bus master driver");
205MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
206MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * w1-gpio - GPIO w1 bus master driver
4 *
5 * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi>
6 */
7
8#include <linux/init.h>
9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/slab.h>
12#include <linux/w1-gpio.h>
13#include <linux/gpio/consumer.h>
14#include <linux/of_platform.h>
15#include <linux/err.h>
16#include <linux/of.h>
17#include <linux/delay.h>
18
19#include <linux/w1.h>
20
21static u8 w1_gpio_set_pullup(void *data, int delay)
22{
23 struct w1_gpio_platform_data *pdata = data;
24
25 if (delay) {
26 pdata->pullup_duration = delay;
27 } else {
28 if (pdata->pullup_duration) {
29 /*
30 * This will OVERRIDE open drain emulation and force-pull
31 * the line high for some time.
32 */
33 gpiod_set_raw_value(pdata->gpiod, 1);
34 msleep(pdata->pullup_duration);
35 /*
36 * This will simply set the line as input since we are doing
37 * open drain emulation in the GPIO library.
38 */
39 gpiod_set_value(pdata->gpiod, 1);
40 }
41 pdata->pullup_duration = 0;
42 }
43
44 return 0;
45}
46
47static void w1_gpio_write_bit(void *data, u8 bit)
48{
49 struct w1_gpio_platform_data *pdata = data;
50
51 gpiod_set_value(pdata->gpiod, bit);
52}
53
54static u8 w1_gpio_read_bit(void *data)
55{
56 struct w1_gpio_platform_data *pdata = data;
57
58 return gpiod_get_value(pdata->gpiod) ? 1 : 0;
59}
60
61#if defined(CONFIG_OF)
62static const struct of_device_id w1_gpio_dt_ids[] = {
63 { .compatible = "w1-gpio" },
64 {}
65};
66MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
67#endif
68
69static int w1_gpio_probe(struct platform_device *pdev)
70{
71 struct w1_bus_master *master;
72 struct w1_gpio_platform_data *pdata;
73 struct device *dev = &pdev->dev;
74 struct device_node *np = dev->of_node;
75 /* Enforce open drain mode by default */
76 enum gpiod_flags gflags = GPIOD_OUT_LOW_OPEN_DRAIN;
77 int err;
78
79 if (of_have_populated_dt()) {
80 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
81 if (!pdata)
82 return -ENOMEM;
83
84 /*
85 * This parameter means that something else than the gpiolib has
86 * already set the line into open drain mode, so we should just
87 * driver it high/low like we are in full control of the line and
88 * open drain will happen transparently.
89 */
90 if (of_get_property(np, "linux,open-drain", NULL))
91 gflags = GPIOD_OUT_LOW;
92
93 pdev->dev.platform_data = pdata;
94 }
95 pdata = dev_get_platdata(dev);
96
97 if (!pdata) {
98 dev_err(dev, "No configuration data\n");
99 return -ENXIO;
100 }
101
102 master = devm_kzalloc(dev, sizeof(struct w1_bus_master),
103 GFP_KERNEL);
104 if (!master) {
105 dev_err(dev, "Out of memory\n");
106 return -ENOMEM;
107 }
108
109 pdata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags);
110 if (IS_ERR(pdata->gpiod)) {
111 dev_err(dev, "gpio_request (pin) failed\n");
112 return PTR_ERR(pdata->gpiod);
113 }
114
115 pdata->pullup_gpiod =
116 devm_gpiod_get_index_optional(dev, NULL, 1, GPIOD_OUT_LOW);
117 if (IS_ERR(pdata->pullup_gpiod)) {
118 dev_err(dev, "gpio_request_one "
119 "(ext_pullup_enable_pin) failed\n");
120 return PTR_ERR(pdata->pullup_gpiod);
121 }
122
123 master->data = pdata;
124 master->read_bit = w1_gpio_read_bit;
125 gpiod_direction_output(pdata->gpiod, 1);
126 master->write_bit = w1_gpio_write_bit;
127
128 /*
129 * If we are using open drain emulation from the GPIO library,
130 * we need to use this pullup function that hammers the line
131 * high using a raw accessor to provide pull-up for the w1
132 * line.
133 */
134 if (gflags == GPIOD_OUT_LOW_OPEN_DRAIN)
135 master->set_pullup = w1_gpio_set_pullup;
136
137 err = w1_add_master_device(master);
138 if (err) {
139 dev_err(dev, "w1_add_master device failed\n");
140 return err;
141 }
142
143 if (pdata->enable_external_pullup)
144 pdata->enable_external_pullup(1);
145
146 if (pdata->pullup_gpiod)
147 gpiod_set_value(pdata->pullup_gpiod, 1);
148
149 platform_set_drvdata(pdev, master);
150
151 return 0;
152}
153
154static int w1_gpio_remove(struct platform_device *pdev)
155{
156 struct w1_bus_master *master = platform_get_drvdata(pdev);
157 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
158
159 if (pdata->enable_external_pullup)
160 pdata->enable_external_pullup(0);
161
162 if (pdata->pullup_gpiod)
163 gpiod_set_value(pdata->pullup_gpiod, 0);
164
165 w1_remove_master_device(master);
166
167 return 0;
168}
169
170static int __maybe_unused w1_gpio_suspend(struct device *dev)
171{
172 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
173
174 if (pdata->enable_external_pullup)
175 pdata->enable_external_pullup(0);
176
177 return 0;
178}
179
180static int __maybe_unused w1_gpio_resume(struct device *dev)
181{
182 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev);
183
184 if (pdata->enable_external_pullup)
185 pdata->enable_external_pullup(1);
186
187 return 0;
188}
189
190static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume);
191
192static struct platform_driver w1_gpio_driver = {
193 .driver = {
194 .name = "w1-gpio",
195 .pm = &w1_gpio_pm_ops,
196 .of_match_table = of_match_ptr(w1_gpio_dt_ids),
197 },
198 .probe = w1_gpio_probe,
199 .remove = w1_gpio_remove,
200};
201
202module_platform_driver(w1_gpio_driver);
203
204MODULE_DESCRIPTION("GPIO w1 bus master driver");
205MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>");
206MODULE_LICENSE("GPL");