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Diffstat (limited to 'Documentation/nfc/nfc-pn544.txt')
-rw-r--r-- | Documentation/nfc/nfc-pn544.txt | 84 |
1 files changed, 1 insertions, 83 deletions
diff --git a/Documentation/nfc/nfc-pn544.txt b/Documentation/nfc/nfc-pn544.txt index 2fcac9f5996e..b36ca14ca2d6 100644 --- a/Documentation/nfc/nfc-pn544.txt +++ b/Documentation/nfc/nfc-pn544.txt | |||
@@ -1,32 +1,15 @@ | |||
1 | Kernel driver for the NXP Semiconductors PN544 Near Field | 1 | Kernel driver for the NXP Semiconductors PN544 Near Field |
2 | Communication chip | 2 | Communication chip |
3 | 3 | ||
4 | Author: Jari Vanhala | ||
5 | Contact: Matti Aaltonen (matti.j.aaltonen at nokia.com) | ||
6 | |||
7 | General | 4 | General |
8 | ------- | 5 | ------- |
9 | 6 | ||
10 | The PN544 is an integrated transmission module for contactless | 7 | The PN544 is an integrated transmission module for contactless |
11 | communication. The driver goes under drives/nfc/ and is compiled as a | 8 | communication. The driver goes under drives/nfc/ and is compiled as a |
12 | module named "pn544". It registers a misc device and creates a device | 9 | module named "pn544". |
13 | file named "/dev/pn544". | ||
14 | 10 | ||
15 | Host Interfaces: I2C, SPI and HSU, this driver supports currently only I2C. | 11 | Host Interfaces: I2C, SPI and HSU, this driver supports currently only I2C. |
16 | 12 | ||
17 | The Interface | ||
18 | ------------- | ||
19 | |||
20 | The driver offers a sysfs interface for a hardware test and an IOCTL | ||
21 | interface for selecting between two operating modes. There are read, | ||
22 | write and poll functions for transferring messages. The two operating | ||
23 | modes are the normal (HCI) mode and the firmware update mode. | ||
24 | |||
25 | PN544 is controlled by sending messages from the userspace to the | ||
26 | chip. The main function of the driver is just to pass those messages | ||
27 | without caring about the message content. | ||
28 | |||
29 | |||
30 | Protocols | 13 | Protocols |
31 | --------- | 14 | --------- |
32 | 15 | ||
@@ -47,68 +30,3 @@ and third (LSB) bytes of the message. The maximum FW message length is | |||
47 | 30 | ||
48 | For the ETSI HCI specification see | 31 | For the ETSI HCI specification see |
49 | http://www.etsi.org/WebSite/Technologies/ProtocolSpecification.aspx | 32 | http://www.etsi.org/WebSite/Technologies/ProtocolSpecification.aspx |
50 | |||
51 | The Hardware Test | ||
52 | ----------------- | ||
53 | |||
54 | The idea of the test is that it can performed by reading from the | ||
55 | corresponding sysfs file. The test is implemented in the board file | ||
56 | and it should test that PN544 can be put into the firmware update | ||
57 | mode. If the test is not implemented the sysfs file does not get | ||
58 | created. | ||
59 | |||
60 | Example: | ||
61 | > cat /sys/module/pn544/drivers/i2c\:pn544/3-002b/nfc_test | ||
62 | 1 | ||
63 | |||
64 | Normal Operation | ||
65 | ---------------- | ||
66 | |||
67 | PN544 is powered up when the device file is opened, otherwise it's | ||
68 | turned off. Only one instance can use the device at a time. | ||
69 | |||
70 | Userspace applications control PN544 with HCI messages. The hardware | ||
71 | sends an interrupt when data is available for reading. Data is | ||
72 | physically read when the read function is called by a userspace | ||
73 | application. Poll() checks the read interrupt state. Configuration and | ||
74 | self testing are also done from the userspace using read and write. | ||
75 | |||
76 | Example platform data: | ||
77 | |||
78 | static int rx71_pn544_nfc_request_resources(struct i2c_client *client) | ||
79 | { | ||
80 | /* Get and setup the HW resources for the device */ | ||
81 | } | ||
82 | |||
83 | static void rx71_pn544_nfc_free_resources(void) | ||
84 | { | ||
85 | /* Release the HW resources */ | ||
86 | } | ||
87 | |||
88 | static void rx71_pn544_nfc_enable(int fw) | ||
89 | { | ||
90 | /* Turn the device on */ | ||
91 | } | ||
92 | |||
93 | static int rx71_pn544_nfc_test(void) | ||
94 | { | ||
95 | /* | ||
96 | * Put the device into the FW update mode | ||
97 | * and then back to the normal mode. | ||
98 | * Check the behavior and return one on success, | ||
99 | * zero on failure. | ||
100 | */ | ||
101 | } | ||
102 | |||
103 | static void rx71_pn544_nfc_disable(void) | ||
104 | { | ||
105 | /* turn the power off */ | ||
106 | } | ||
107 | |||
108 | static struct pn544_nfc_platform_data rx71_nfc_data = { | ||
109 | .request_resources = rx71_pn544_nfc_request_resources, | ||
110 | .free_resources = rx71_pn544_nfc_free_resources, | ||
111 | .enable = rx71_pn544_nfc_enable, | ||
112 | .test = rx71_pn544_nfc_test, | ||
113 | .disable = rx71_pn544_nfc_disable, | ||
114 | }; | ||