Signed-off-by: Geoff Lansberry <ge...@kuvee.com>
---
 .../devicetree/bindings/net/nfc/trf7970a.txt       |  2 ++
 drivers/nfc/trf7970a.c                             | 33 ++++++++++++++++++++--
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt 
b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
index 32b35a0..09c5056 100644
--- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
+++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
@@ -7,6 +7,7 @@ Required properties:
 - interrupts: A single interrupt specifier.
 - ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
   TRF7970A.
+- ti,ss-gpio: GPIO entry used for active low SS (spi slave select) on the 
TRF7970A
 - vin-supply: Regulator for supply voltage to VIN pin
 
 Optional SoC Specific Properties:
@@ -37,6 +38,7 @@ Example (for ARM-based BeagleBone with TRF7970A on SPI1):
                interrupts = <14 0>;
                ti,enable-gpios = <&gpio2 2 GPIO_ACTIVE_LOW>,
                                  <&gpio2 5 GPIO_ACTIVE_LOW>;
+               ti,ss-gpio = <&gpio2 4 GPIO_ACTIVE_HIGH>;
                vin-supply = <&ldo3_reg>;
                vin-voltage-override = <5000000>;
                autosuspend-delay = <30000>;
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index 10842b7..2c3530a 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -450,6 +450,7 @@ struct trf7970a {
        bool                            adjust_resp_len;
        int                             en2_gpio;
        int                             en_gpio;
+       int                             ss_gpio;
        struct mutex                    lock;
        unsigned int                    timeout;
        bool                            ignore_timeout;
@@ -462,9 +463,11 @@ static int trf7970a_cmd(struct trf7970a *trf, u8 opcode)
        u8 cmd = TRF7970A_CMD_BIT_CTRL | TRF7970A_CMD_BIT_OPCODE(opcode);
        int ret;
 
+       gpio_set_value(trf->ss_gpio, 0);
        dev_dbg(trf->dev, "cmd: 0x%x\n", cmd);
 
        ret = spi_write(trf->spi, &cmd, 1);
+       gpio_set_value(trf->ss_gpio, 1);
        if (ret)
                dev_err(trf->dev, "%s - cmd: 0x%x, ret: %d\n", __func__, cmd,
                                ret);
@@ -476,7 +479,9 @@ static int trf7970a_read(struct trf7970a *trf, u8 reg, u8 
*val)
        u8 addr = TRF7970A_CMD_BIT_RW | reg;
        int ret;
 
+       gpio_set_value(trf->ss_gpio, 0);
        ret = spi_write_then_read(trf->spi, &addr, 1, val, 1);
+       gpio_set_value(trf->ss_gpio, 1);
        if (ret)
                dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr,
                                ret);
@@ -493,6 +498,7 @@ static int trf7970a_read_cont(struct trf7970a *trf, u8 reg, 
u8 *buf, size_t len)
        struct spi_message m;
        int ret;
 
+       gpio_set_value(trf->ss_gpio, 0);
        dev_dbg(trf->dev, "read_cont(0x%x, %zd)\n", addr, len);
 
        spi_message_init(&m);
@@ -508,6 +514,7 @@ static int trf7970a_read_cont(struct trf7970a *trf, u8 reg, 
u8 *buf, size_t len)
        spi_message_add_tail(&t[1], &m);
 
        ret = spi_sync(trf->spi, &m);
+       gpio_set_value(trf->ss_gpio, 1);
        if (ret)
                dev_err(trf->dev, "%s - addr: 0x%x, ret: %d\n", __func__, addr,
                                ret);
@@ -519,9 +526,11 @@ static int trf7970a_write(struct trf7970a *trf, u8 reg, u8 
val)
        u8 buf[2] = { reg, val };
        int ret;
 
+       gpio_set_value(trf->ss_gpio, 0);
        dev_dbg(trf->dev, "write(0x%x): 0x%x\n", reg, val);
 
        ret = spi_write(trf->spi, buf, 2);
+       gpio_set_value(trf->ss_gpio, 1);
        if (ret)
                dev_err(trf->dev, "%s - write: 0x%x 0x%x, ret: %d\n", __func__,
                                buf[0], buf[1], ret);
@@ -535,6 +544,7 @@ static int trf7970a_read_irqstatus(struct trf7970a *trf, u8 
*status)
        u8 buf[2];
        u8 addr;
 
+       gpio_set_value(trf->ss_gpio, 0);
        addr = TRF7970A_IRQ_STATUS | TRF7970A_CMD_BIT_RW;
 
        if (trf->quirks & TRF7970A_QUIRK_IRQ_STATUS_READ) {
@@ -544,6 +554,7 @@ static int trf7970a_read_irqstatus(struct trf7970a *trf, u8 
*status)
                ret = spi_write_then_read(trf->spi, &addr, 1, buf, 1);
        }
 
+       gpio_set_value(trf->ss_gpio, 1);
        if (ret)
                dev_err(trf->dev, "%s - irqstatus: Status read failed: %d\n",
                                __func__, ret);
@@ -559,6 +570,7 @@ static int trf7970a_read_target_proto(struct trf7970a *trf, 
u8 *target_proto)
        u8 buf[2];
        u8 addr;
 
+       gpio_set_value(trf->ss_gpio, 0);
        addr = TRF79070A_NFC_TARGET_PROTOCOL | TRF7970A_CMD_BIT_RW |
                TRF7970A_CMD_BIT_CONTINUOUS;
 
@@ -569,6 +581,7 @@ static int trf7970a_read_target_proto(struct trf7970a *trf, 
u8 *target_proto)
        else
                *target_proto = buf[0];
 
+       gpio_set_value(trf->ss_gpio, 1);
        return ret;
 }
 
@@ -663,6 +676,7 @@ static int trf7970a_transmit(struct trf7970a *trf, struct 
sk_buff *skb,
        print_hex_dump_debug("trf7970a tx data: ", DUMP_PREFIX_NONE,
                        16, 1, skb->data, len, false);
 
+       gpio_set_value(trf->ss_gpio, 0);
        spi_message_init(&m);
 
        memset(&t, 0, sizeof(t));
@@ -679,7 +693,7 @@ static int trf7970a_transmit(struct trf7970a *trf, struct 
sk_buff *skb,
        if (ret) {
                dev_err(trf->dev, "%s - Can't send tx data: %d\n", __func__,
                                ret);
-               return ret;
+               goto out_err;
        }
 
        skb_pull(skb, len);
@@ -706,7 +720,9 @@ static int trf7970a_transmit(struct trf7970a *trf, struct 
sk_buff *skb,
 
        schedule_delayed_work(&trf->timeout_work, msecs_to_jiffies(timeout));
 
-       return 0;
+out_err:
+       gpio_set_value(trf->ss_gpio, 1);
+       return ret;
 }
 
 static void trf7970a_fill_fifo(struct trf7970a *trf)
@@ -2039,6 +2055,19 @@ static int trf7970a_probe(struct spi_device *spi)
                return ret;
        }
 
+       trf->ss_gpio = of_get_named_gpio(np, "ti,ss-gpio", 0);
+       if (!gpio_is_valid(trf->ss_gpio)) {
+               dev_err(trf->dev, "No SS GPIO property\n");
+               return trf->ss_gpio;
+       }
+
+       ret = devm_gpio_request_one(trf->dev, trf->ss_gpio,
+                       GPIOF_DIR_OUT | GPIOF_INIT_HIGH, "trf7970a SS");
+       if (ret) {
+               dev_err(trf->dev, "Can't request SS GPIO: %d\n", ret);
+               return ret;
+       }
+
        if (of_property_read_bool(np, "en2-rf-quirk"))
                trf->quirks |= TRF7970A_QUIRK_EN2_MUST_STAY_LOW;
 
-- 
1.9.1

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