path: root/Documentation/nfc
diff options
authorSamuel Ortiz <>2013-01-10 01:25:04 +0100
committerSamuel Ortiz <>2013-01-10 01:27:46 +0100
commit1353a10c474d1c6895051d33eefeb93542015008 (patch)
tree075dfaf046d609116be95ab6ff1b7c3c3714fe3a /Documentation/nfc
parent8a0ecfe74b3692258311d084d31613516828905f (diff)
NFC: Update pn544 documentation
The pn544 driver no longer has a /dev/pn544 interface nor a sysfs one. Reported-by: Marcel Holtmann <> Signed-off-by: Samuel Ortiz <>
Diffstat (limited to 'Documentation/nfc')
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 @@
Kernel driver for the NXP Semiconductors PN544 Near Field
Communication chip
-Author: Jari Vanhala
-Contact: Matti Aaltonen (matti.j.aaltonen at
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".
+module named "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.
@@ -47,68 +30,3 @@ and third (LSB) bytes of the message. The maximum FW message length is
For the ETSI HCI specification see
-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
-> cat /sys/module/pn544/drivers/i2c\:pn544/3-002b/nfc_test
-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,