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NFC: trf7970a: add device tree option for 27MHz clock 

The TRF7970A has configuration options to support hardware designs
which use a 27.12MHz clock. This commit adds a device tree option
'clock-frequency' to support configuring the this chip for default
13.56MHz clock or the optional 27.12MHz clock.

Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Geoff Lansberry <geoff@kuvee.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Geoff Lansberry 2016-12-21 23:18:32 -05:00 committed by Samuel Ortiz
parent 2891f2d5c1
commit 837eb4d21e
2 changed files with 41 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/devicetree/bindings/net/nfc/trf7970a.txt
View File

@ -21,6 +21,7 @@ Optional SoC Specific Properties:
- 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.
- clock-frequency: Set to specify that the input frequency to the trf7970a is 13560000Hz or 27120000Hz
Example (for ARM-based BeagleBone with TRF7970A on SPI1):
@ -43,6 +44,7 @@ Example (for ARM-based BeagleBone with TRF7970A on SPI1):
irq-status-read-quirk;
en2-rf-quirk;
t5t-rmb-extra-byte-quirk;
clock-frequency = <27120000>;
status = "okay";
};
};

50
drivers/nfc/trf7970a.c
View File

@ -124,6 +124,9 @@
NFC_PROTO_ISO15693_MASK | NFC_PROTO_NFC_DEP_MASK)
#define TRF7970A_AUTOSUSPEND_DELAY 30000 /* 30 seconds */
#define TRF7970A_13MHZ_CLOCK_FREQUENCY 13560000
#define TRF7970A_27MHZ_CLOCK_FREQUENCY 27120000
#define TRF7970A_RX_SKB_ALLOC_SIZE 256
@ -1056,12 +1059,11 @@ static int trf7970a_init(struct trf7970a *trf)
trf->chip_status_ctrl &= ~TRF7970A_CHIP_STATUS_RF_ON;
ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL, 0);
ret = trf7970a_write(trf, TRF7970A_MODULATOR_SYS_CLK_CTRL,
trf->modulator_sys_clk_ctrl);
if (ret)
goto err_out;
trf->modulator_sys_clk_ctrl = 0;
ret = trf7970a_write(trf, TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS,
TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLH_96 |
TRF7970A_ADJUTABLE_FIFO_IRQ_LEVELS_WLL_32);
@ -1181,27 +1183,37 @@ static int trf7970a_in_config_rf_tech(struct trf7970a *trf, int tech)
switch (tech) {
case NFC_DIGITAL_RF_TECH_106A:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443A_106;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_OOK;
trf->guard_time = TRF7970A_GUARD_TIME_NFCA;
break;
case NFC_DIGITAL_RF_TECH_106B:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_14443B_106;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_ASK10;
trf->guard_time = TRF7970A_GUARD_TIME_NFCB;
break;
case NFC_DIGITAL_RF_TECH_212F:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_FELICA_212;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_ASK10;
trf->guard_time = TRF7970A_GUARD_TIME_NFCF;
break;
case NFC_DIGITAL_RF_TECH_424F:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_FELICA_424;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_ASK10;
trf->guard_time = TRF7970A_GUARD_TIME_NFCF;
break;
case NFC_DIGITAL_RF_TECH_ISO15693:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_15693_SGL_1OF4_2648;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_OOK;
trf->guard_time = TRF7970A_GUARD_TIME_15693;
break;
default:
@ -1571,17 +1583,23 @@ static int trf7970a_tg_config_rf_tech(struct trf7970a *trf, int tech)
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE |
TRF7970A_ISO_CTRL_NFC_CE |
TRF7970A_ISO_CTRL_NFC_CE_14443A;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_OOK;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_OOK;
break;
case NFC_DIGITAL_RF_TECH_212F:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE |
TRF7970A_ISO_CTRL_NFC_NFCF_212;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_ASK10;
break;
case NFC_DIGITAL_RF_TECH_424F:
trf->iso_ctrl_tech = TRF7970A_ISO_CTRL_NFC_NFC_CE_MODE |
TRF7970A_ISO_CTRL_NFC_NFCF_424;
trf->modulator_sys_clk_ctrl = TRF7970A_MODULATOR_DEPTH_ASK10;
trf->modulator_sys_clk_ctrl =
(trf->modulator_sys_clk_ctrl & 0xf8) |
TRF7970A_MODULATOR_DEPTH_ASK10;
break;
default:
dev_dbg(trf->dev, "Unsupported rf technology: %d\n", tech);
@ -1990,6 +2008,7 @@ static int trf7970a_probe(struct spi_device *spi)
struct device_node *np = spi->dev.of_node;
struct trf7970a *trf;
int uvolts, autosuspend_delay, ret;
u32 clk_freq = TRF7970A_13MHZ_CLOCK_FREQUENCY;
if (!np) {
dev_err(&spi->dev, "No Device Tree entry\n");
@ -2045,6 +2064,15 @@ static int trf7970a_probe(struct spi_device *spi)
}
}
of_property_read_u32(np, "clock-frequency", &clk_freq);
if ((clk_freq != TRF7970A_27MHZ_CLOCK_FREQUENCY) ||
(clk_freq != TRF7970A_13MHZ_CLOCK_FREQUENCY)) {
dev_err(trf->dev,
"clock-frequency (%u Hz) unsupported\n",
clk_freq);
return -EINVAL;
}
if (of_property_read_bool(np, "en2-rf-quirk"))
trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW;