[PATCH v3 1/3] NFC: trf7970a: add device tree option for 27MHz clock
From: Geoff Lansberry <hidden>
Date: 2016-12-22 04:19:00
Also in:
linux-wireless, lkml, netdev
Subsystem:
networking drivers, nfc subsystem, open firmware and flattened device tree bindings, the rest, ti trf7970a nfc driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Heidelberg, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds, Mark Greer
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. Signed-off-by: Geoff Lansberry <redacted> --- .../devicetree/bindings/net/nfc/trf7970a.txt | 2 + drivers/nfc/trf7970a.c | 50 +++++++++++++++++----- 2 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 32b35a0..8b01fc81 100644
--- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
+++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt@@ -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"; }; };
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index 26c9dbb..b1cd4ef 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c@@ -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);
@@ -1987,6 +2005,7 @@ 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");
@@ -2043,6 +2062,15 @@ static int trf7970a_probe(struct spi_device *spi) return ret; } + 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;
--
2.7.4
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