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Diffstat (limited to 'Documentation/nfc/nfc-pn544.txt')
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diff --git a/Documentation/nfc/nfc-pn544.txt b/Documentation/nfc/nfc-pn544.txt deleted file mode 100644 index 2fcac9f5996..00000000000 --- a/Documentation/nfc/nfc-pn544.txt +++ /dev/null @@ -1,114 +0,0 @@ -Kernel driver for the NXP Semiconductors PN544 Near Field -Communication chip - -Author: Jari Vanhala -Contact: Matti Aaltonen (matti.j.aaltonen at nokia.com) - -General -------- - -The PN544 is an integrated transmission module for contactless -communication. The driver goes under drives/nfc/ and is compiled as a -module named "pn544". It registers a misc device and creates a device -file named "/dev/pn544". - -Host Interfaces: I2C, SPI and HSU, this driver supports currently only I2C. - -The Interface -------------- - -The driver offers a sysfs interface for a hardware test and an IOCTL -interface for selecting between two operating modes. There are read, -write and poll functions for transferring messages. The two operating -modes are the normal (HCI) mode and the firmware update mode. - -PN544 is controlled by sending messages from the userspace to the -chip. The main function of the driver is just to pass those messages -without caring about the message content. - - -Protocols ---------- - -In the normal (HCI) mode and in the firmware update mode read and -write functions behave a bit differently because the message formats -or the protocols are different. - -In the normal (HCI) mode the protocol used is derived from the ETSI -HCI specification. The firmware is updated using a specific protocol, -which is different from HCI. - -HCI messages consist of an eight bit header and the message body. The -header contains the message length. Maximum size for an HCI message is -33. In HCI mode sent messages are tested for a correct -checksum. Firmware update messages have the length in the second (MSB) -and third (LSB) bytes of the message. The maximum FW message length is -1024 bytes. - -For the ETSI HCI specification see -http://www.etsi.org/WebSite/Technologies/ProtocolSpecification.aspx - -The Hardware Test ------------------ - -The idea of the test is that it can performed by reading from the -corresponding sysfs file. The test is implemented in the board file -and it should test that PN544 can be put into the firmware update -mode. If the test is not implemented the sysfs file does not get -created. - -Example: -> cat /sys/module/pn544/drivers/i2c\:pn544/3-002b/nfc_test -1 - -Normal Operation ----------------- - -PN544 is powered up when the device file is opened, otherwise it's -turned off. Only one instance can use the device at a time. - -Userspace applications control PN544 with HCI messages. The hardware -sends an interrupt when data is available for reading. Data is -physically read when the read function is called by a userspace -application. Poll() checks the read interrupt state. Configuration and -self testing are also done from the userspace using read and write. - -Example platform data: - -static int rx71_pn544_nfc_request_resources(struct i2c_client *client) -{ - /* Get and setup the HW resources for the device */ -} - -static void rx71_pn544_nfc_free_resources(void) -{ - /* Release the HW resources */ -} - -static void rx71_pn544_nfc_enable(int fw) -{ - /* Turn the device on */ -} - -static int rx71_pn544_nfc_test(void) -{ - /* - * Put the device into the FW update mode - * and then back to the normal mode. - * Check the behavior and return one on success, - * zero on failure. - */ -} - -static void rx71_pn544_nfc_disable(void) -{ - /* turn the power off */ -} - -static struct pn544_nfc_platform_data rx71_nfc_data = { - .request_resources = rx71_pn544_nfc_request_resources, - .free_resources = rx71_pn544_nfc_free_resources, - .enable = rx71_pn544_nfc_enable, - .test = rx71_pn544_nfc_test, - .disable = rx71_pn544_nfc_disable, -}; |