Commit ab714817 authored by Mark A. Greer's avatar Mark A. Greer Committed by Samuel Ortiz

NFC: trf7970a: Handle extra byte in response to Type 5 RMB commands

The current versions of the trf7970a has an erratum where it returns
an extra byte in the response to 'Read Multiple Block' (RMB) commands.
This command is issued to Type 5 tags (i.e., ISO/IEC 15693 tags) by
the neard daemon.

To handle this, define a new Device Tree property,
't5t-rmb-extra-byte-quirk', which indicates that the associated
trf7970a device has this erratum.  The trf7970a device driver
will then ensure that the response length to RMB commands is
reduced by one byte (for devices with the erratum).
Signed-off-by: default avatarMark A. Greer <>
Signed-off-by: default avatarSamuel Ortiz <>
parent d96097e0
......@@ -18,6 +18,9 @@ Optional SoC Specific Properties:
"IRQ Status Read" erratum.
- en2-rf-quirk: Specify that the trf7970a being used has the "EN2 RF"
- t5t-rmb-extra-byte-quirk: Specify that the trf7970a has the erratum
where an extra byte is returned by Read Multiple Block commands issued
to Type 5 tags.
Example (for ARM-based BeagleBone with TRF7970A on SPI1):
......@@ -39,6 +42,7 @@ Example (for ARM-based BeagleBone with TRF7970A on SPI1):
autosuspend-delay = <30000>;
status = "okay";
......@@ -149,6 +149,7 @@
/* Direct commands */
#define TRF7970A_CMD_IDLE 0x00
......@@ -446,6 +447,7 @@ struct trf7970a {
u8 md_rf_tech;
u8 tx_cmd;
bool issue_eof;
bool adjust_resp_len;
int en2_gpio;
int en_gpio;
struct mutex lock;
......@@ -626,6 +628,11 @@ static void trf7970a_send_upstream(struct trf7970a *trf)
trf->aborting = false;
if (trf->adjust_resp_len) {
skb_trim(trf->rx_skb, trf->rx_skb->len - 1);
trf->adjust_resp_len = false;
trf->cb(trf->ddev, trf->cb_arg, trf->rx_skb);
trf->rx_skb = NULL;
......@@ -1429,10 +1436,15 @@ static int trf7970a_per_cmd_config(struct trf7970a *trf, struct sk_buff *skb)
trf->iso_ctrl = iso_ctrl;
if ((trf->framing == NFC_DIGITAL_FRAMING_ISO15693_T5T) &&
trf7970a_is_iso15693_write_or_lock(req[1]) &&
(req[0] & ISO15693_REQ_FLAG_OPTION))
trf->issue_eof = true;
if (trf->framing == NFC_DIGITAL_FRAMING_ISO15693_T5T) {
if (trf7970a_is_iso15693_write_or_lock(req[1]) &&
(req[0] & ISO15693_REQ_FLAG_OPTION))
trf->issue_eof = true;
else if ((trf->quirks &
trf->adjust_resp_len = true;
return 0;
......@@ -1992,6 +2004,9 @@ static int trf7970a_probe(struct spi_device *spi)
return ret;
if (of_property_read_bool(np, "t5t-rmb-extra-byte-quirk"))
trf->quirks |= TRF7970A_QUIRK_T5T_RMB_EXTRA_BYTE;
if (of_property_read_bool(np, "irq-status-read-quirk"))
trf->quirks |= TRF7970A_QUIRK_IRQ_STATUS_READ;
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