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1 From 5edc95eee5ef69d7bfe03eede0e711e8f196dedc Mon Sep 17 00:00:00 2001
2 From: popcornmix <popcornmix@gmail.com>
3 Date: Wed, 8 May 2013 11:46:50 +0100
4 Subject: [PATCH] enabling the realtime clock 1-wire chip DS1307 and 1-wire on
5 GPIO4 (as a module)
6
7 1-wire: Add support for configuring pin for w1-gpio kernel module
8 See: https://github.com/raspberrypi/linux/pull/457
9
10 Add bitbanging pullups, use them for w1-gpio
11
12 Allows parasite power to work, uses module option pullup=1
13
14 bcm2708: Ensure 1-wire pullup is disabled by default, and expose as module parameter
15
16 Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
17
18 w1-gpio: Add gpiopin module parameter and correctly free up gpio pull-up pin, if set
19
20 Signed-off-by: Alex J Lennon <ajlennon@dynamicdevices.co.uk>
21
22 w1-gpio: Sort out the pullup/parasitic power tangle
23 ---
24 drivers/w1/masters/w1-gpio.c | 69 ++++++++++++++++++++++++++++++++++++++++----
25 drivers/w1/w1.h | 6 ++++
26 drivers/w1/w1_int.c | 14 +++++++++
27 drivers/w1/w1_io.c | 18 ++++++++++--
28 include/linux/w1-gpio.h | 1 +
29 5 files changed, 99 insertions(+), 9 deletions(-)
30
31 --- a/drivers/w1/masters/w1-gpio.c
32 +++ b/drivers/w1/masters/w1-gpio.c
33 @@ -23,6 +23,19 @@
34 #include "../w1.h"
35 #include "../w1_int.h"
36
37 +static int w1_gpio_pullup = 0;
38 +static int w1_gpio_pullup_orig = 0;
39 +module_param_named(pullup, w1_gpio_pullup, int, 0);
40 +MODULE_PARM_DESC(pullup, "Enable parasitic power (power on data) mode");
41 +static int w1_gpio_pullup_pin = -1;
42 +static int w1_gpio_pullup_pin_orig = -1;
43 +module_param_named(extpullup, w1_gpio_pullup_pin, int, 0);
44 +MODULE_PARM_DESC(extpullup, "GPIO external pullup pin number");
45 +static int w1_gpio_pin = -1;
46 +static int w1_gpio_pin_orig = -1;
47 +module_param_named(gpiopin, w1_gpio_pin, int, 0);
48 +MODULE_PARM_DESC(gpiopin, "GPIO pin number");
49 +
50 static u8 w1_gpio_set_pullup(void *data, int delay)
51 {
52 struct w1_gpio_platform_data *pdata = data;
53 @@ -67,6 +80,16 @@ static u8 w1_gpio_read_bit(void *data)
54 return gpio_get_value(pdata->pin) ? 1 : 0;
55 }
56
57 +static void w1_gpio_bitbang_pullup(void *data, u8 on)
58 +{
59 + struct w1_gpio_platform_data *pdata = data;
60 +
61 + if (on)
62 + gpio_direction_output(pdata->pin, 1);
63 + else
64 + gpio_direction_input(pdata->pin);
65 +}
66 +
67 #if defined(CONFIG_OF)
68 static const struct of_device_id w1_gpio_dt_ids[] = {
69 { .compatible = "w1-gpio" },
70 @@ -80,6 +103,7 @@ static int w1_gpio_probe_dt(struct platf
71 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev);
72 struct device_node *np = pdev->dev.of_node;
73 int gpio;
74 + u32 value;
75
76 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
77 if (!pdata)
78 @@ -88,6 +112,9 @@ static int w1_gpio_probe_dt(struct platf
79 if (of_get_property(np, "linux,open-drain", NULL))
80 pdata->is_open_drain = 1;
81
82 + if (of_property_read_u32(np, "rpi,parasitic-power", &value) == 0)
83 + pdata->parasitic_power = (value != 0);
84 +
85 gpio = of_get_gpio(np, 0);
86 if (gpio < 0) {
87 if (gpio != -EPROBE_DEFER)
88 @@ -103,7 +130,7 @@ static int w1_gpio_probe_dt(struct platf
89 if (gpio == -EPROBE_DEFER)
90 return gpio;
91 /* ignore other errors as the pullup gpio is optional */
92 - pdata->ext_pullup_enable_pin = gpio;
93 + pdata->ext_pullup_enable_pin = (gpio >= 0) ? gpio : -1;
94
95 pdev->dev.platform_data = pdata;
96
97 @@ -135,6 +162,22 @@ static int w1_gpio_probe(struct platform
98 return -ENOMEM;
99 }
100
101 + w1_gpio_pin_orig = pdata->pin;
102 + w1_gpio_pullup_pin_orig = pdata->ext_pullup_enable_pin;
103 + w1_gpio_pullup_orig = pdata->parasitic_power;
104 +
105 + if(gpio_is_valid(w1_gpio_pin)) {
106 + pdata->pin = w1_gpio_pin;
107 + pdata->ext_pullup_enable_pin = -1;
108 + pdata->parasitic_power = -1;
109 + }
110 + pdata->parasitic_power |= w1_gpio_pullup;
111 + if(gpio_is_valid(w1_gpio_pullup_pin)) {
112 + pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin;
113 + }
114 +
115 + dev_info(&pdev->dev, "gpio pin %d, external pullup pin %d, parasitic power %d\n", pdata->pin, pdata->ext_pullup_enable_pin, pdata->parasitic_power);
116 +
117 err = devm_gpio_request(&pdev->dev, pdata->pin, "w1");
118 if (err) {
119 dev_err(&pdev->dev, "gpio_request (pin) failed\n");
120 @@ -164,6 +207,14 @@ static int w1_gpio_probe(struct platform
121 master->set_pullup = w1_gpio_set_pullup;
122 }
123
124 + if (pdata->parasitic_power) {
125 + if (pdata->is_open_drain)
126 + printk(KERN_ERR "w1-gpio 'pullup'(parasitic power) "
127 + "option doesn't work with open drain GPIO\n");
128 + else
129 + master->bitbang_pullup = w1_gpio_bitbang_pullup;
130 + }
131 +
132 err = w1_add_master_device(master);
133 if (err) {
134 dev_err(&pdev->dev, "w1_add_master device failed\n");
135 @@ -194,6 +245,10 @@ static int w1_gpio_remove(struct platfor
136
137 w1_remove_master_device(master);
138
139 + pdata->pin = w1_gpio_pin_orig;
140 + pdata->ext_pullup_enable_pin = w1_gpio_pullup_pin_orig;
141 + pdata->parasitic_power = w1_gpio_pullup_orig;
142 +
143 return 0;
144 }
145
146 --- a/drivers/w1/w1.h
147 +++ b/drivers/w1/w1.h
148 @@ -173,6 +173,12 @@ struct w1_bus_master
149
150 u8 (*set_pullup)(void *, int);
151
152 + /**
153 + * Turns the pullup on/off in bitbanging mode, takes an on/off argument.
154 + * @return -1=Error, 0=completed
155 + */
156 + void (*bitbang_pullup) (void *, u8);
157 +
158 void (*search)(void *, struct w1_master *,
159 u8, w1_slave_found_callback);
160 };
161 --- a/drivers/w1/w1_int.c
162 +++ b/drivers/w1/w1_int.c
163 @@ -122,6 +122,20 @@ int w1_add_master_device(struct w1_bus_m
164 return(-EINVAL);
165 }
166
167 + /* bitbanging hardware uses bitbang_pullup, other hardware uses set_pullup
168 + * and takes care of timing itself */
169 + if (!master->write_byte && !master->touch_bit && master->set_pullup) {
170 + printk(KERN_ERR "w1_add_master_device: set_pullup requires "
171 + "write_byte or touch_bit, disabling\n");
172 + master->set_pullup = NULL;
173 + }
174 +
175 + if (master->set_pullup && master->bitbang_pullup) {
176 + printk(KERN_ERR "w1_add_master_device: set_pullup should not "
177 + "be set when bitbang_pullup is used, disabling\n");
178 + master->set_pullup = NULL;
179 + }
180 +
181 /* Lock until the device is added (or not) to w1_masters. */
182 mutex_lock(&w1_mlock);
183 /* Search for the first available id (starting at 1). */
184 --- a/drivers/w1/w1_io.c
185 +++ b/drivers/w1/w1_io.c
186 @@ -134,10 +134,22 @@ static void w1_pre_write(struct w1_maste
187 static void w1_post_write(struct w1_master *dev)
188 {
189 if (dev->pullup_duration) {
190 - if (dev->enable_pullup && dev->bus_master->set_pullup)
191 - dev->bus_master->set_pullup(dev->bus_master->data, 0);
192 - else
193 + if (dev->enable_pullup) {
194 + if (dev->bus_master->set_pullup) {
195 + dev->bus_master->set_pullup(dev->
196 + bus_master->data,
197 + 0);
198 + } else if (dev->bus_master->bitbang_pullup) {
199 + dev->bus_master->
200 + bitbang_pullup(dev->bus_master->data, 1);
201 msleep(dev->pullup_duration);
202 + dev->bus_master->
203 + bitbang_pullup(dev->bus_master->data, 0);
204 + }
205 + } else {
206 + msleep(dev->pullup_duration);
207 + }
208 +
209 dev->pullup_duration = 0;
210 }
211 }
212 --- a/include/linux/w1-gpio.h
213 +++ b/include/linux/w1-gpio.h
214 @@ -18,6 +18,7 @@
215 struct w1_gpio_platform_data {
216 unsigned int pin;
217 unsigned int is_open_drain:1;
218 + unsigned int parasitic_power:1;
219 void (*enable_external_pullup)(int enable);
220 unsigned int ext_pullup_enable_pin;
221 unsigned int pullup_duration;
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