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>

diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 5889a3d133b2af8cf559e074613bf373b7ca8f8f..1d186cd9817b93ae3d19af41a040233bb4dee092 100644 (file)
--- 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 75079fb16f22157c5aa47fffa80b46c092ffa801..ecb786283ffa2e48e6e00aa0c485285e17f3c9cc 100644 (file)
--- 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);
@@ -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;