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path: root/drivers/nfc/trf7970a.c
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Diffstat (limited to 'drivers/nfc/trf7970a.c')
-rw-r--r--drivers/nfc/trf7970a.c91
1 files changed, 80 insertions, 11 deletions
diff --git a/drivers/nfc/trf7970a.c b/drivers/nfc/trf7970a.c
index 9e1a34e23af2..d17c701c7888 100644
--- a/drivers/nfc/trf7970a.c
+++ b/drivers/nfc/trf7970a.c
@@ -272,12 +272,18 @@
#define TRF7970A_MODULATOR_EN_OOK BIT(6)
#define TRF7970A_MODULATOR_27MHZ BIT(7)
+#define TRF7970A_RX_GAIN_REDUCTION_MAX_DB 15
+#define TRF7970A_RX_GAIN_REDUCTION_DB_PER_LSB 5
#define TRF7970A_RX_SPECIAL_SETTINGS_NO_LIM BIT(0)
#define TRF7970A_RX_SPECIAL_SETTINGS_AGCR BIT(1)
-#define TRF7970A_RX_SPECIAL_SETTINGS_GD_0DB (0x0 << 2)
-#define TRF7970A_RX_SPECIAL_SETTINGS_GD_5DB (0x1 << 2)
-#define TRF7970A_RX_SPECIAL_SETTINGS_GD_10DB (0x2 << 2)
-#define TRF7970A_RX_SPECIAL_SETTINGS_GD_15DB (0x3 << 2)
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT 2
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_MAX (0x3)
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_MASK (TRF7970A_RX_SPECIAL_SETTINGS_GD_MAX << \
+ TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT)
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_0DB (0x0 << TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT)
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_5DB (0x1 << TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT)
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_10DB (0x2 << TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT)
+#define TRF7970A_RX_SPECIAL_SETTINGS_GD_15DB (0x3 << TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT)
#define TRF7970A_RX_SPECIAL_SETTINGS_HBT BIT(4)
#define TRF7970A_RX_SPECIAL_SETTINGS_M848 BIT(5)
#define TRF7970A_RX_SPECIAL_SETTINGS_C424 BIT(6)
@@ -452,6 +458,8 @@ struct trf7970a {
unsigned int timeout;
bool ignore_timeout;
struct delayed_work timeout_work;
+ u8 rx_gain_reduction;
+ bool custom_rx_gain_reduction;
};
static int trf7970a_cmd(struct trf7970a *trf, u8 opcode)
@@ -551,6 +559,41 @@ static int trf7970a_read_irqstatus(struct trf7970a *trf, u8 *status)
return ret;
}
+static int trf7970a_update_rx_gain_reduction(struct trf7970a *trf)
+{
+ int ret = 0;
+ u8 reg;
+
+ if (!trf->custom_rx_gain_reduction)
+ return 0;
+
+ ret = trf7970a_read(trf, TRF7970A_RX_SPECIAL_SETTINGS, &reg);
+ if (ret)
+ return ret;
+ reg &= ~(TRF7970A_RX_SPECIAL_SETTINGS_GD_MASK);
+ reg |= trf->rx_gain_reduction;
+
+ ret = trf7970a_write(trf, TRF7970A_RX_SPECIAL_SETTINGS, reg);
+
+ return ret;
+}
+
+static int trf7970a_update_iso_ctrl_register(struct trf7970a *trf, u8 iso_ctrl)
+{
+ int ret;
+
+ ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
+ if (ret)
+ return ret;
+ /*
+ * Every time the ISO_CTRL register is written, the RX special setting register is reset by
+ * the chip. When a custom gain reguduction is required, it should be rewritten now.
+ */
+ ret = trf7970a_update_rx_gain_reduction(trf);
+
+ return ret;
+}
+
static int trf7970a_read_target_proto(struct trf7970a *trf, u8 *target_proto)
{
int ret;
@@ -930,8 +973,7 @@ static irqreturn_t trf7970a_irq(int irq, void *dev_id)
}
if (iso_ctrl != trf->iso_ctrl) {
- ret = trf7970a_write(trf, TRF7970A_ISO_CTRL,
- iso_ctrl);
+ ret = trf7970a_update_iso_ctrl_register(trf, iso_ctrl);
if (ret)
goto err_unlock_exit;
@@ -1035,6 +1077,11 @@ static int trf7970a_init(struct trf7970a *trf)
if (ret)
goto err_out;
+ /* Set the gain reduction after soft init */
+ ret = trf7970a_update_rx_gain_reduction(trf);
+ if (ret)
+ goto err_out;
+
ret = trf7970a_cmd(trf, TRF7970A_CMD_IDLE);
if (ret)
goto err_out;
@@ -1309,7 +1356,7 @@ static int trf7970a_in_config_framing(struct trf7970a *trf, int framing)
}
if (iso_ctrl != trf->iso_ctrl) {
- ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
+ ret = trf7970a_update_iso_ctrl_register(trf, iso_ctrl);
if (ret)
return ret;
@@ -1441,7 +1488,7 @@ static int trf7970a_per_cmd_config(struct trf7970a *trf,
}
if (iso_ctrl != trf->iso_ctrl) {
- ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
+ ret = trf7970a_update_iso_ctrl_register(trf, iso_ctrl);
if (ret)
return ret;
@@ -1605,8 +1652,7 @@ static int trf7970a_tg_config_rf_tech(struct trf7970a *trf, int tech)
*/
if ((trf->framing == NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED) &&
(trf->iso_ctrl_tech != trf->iso_ctrl)) {
- ret = trf7970a_write(trf, TRF7970A_ISO_CTRL,
- trf->iso_ctrl_tech);
+ ret = trf7970a_update_iso_ctrl_register(trf, trf->iso_ctrl_tech);
trf->iso_ctrl = trf->iso_ctrl_tech;
}
@@ -1654,7 +1700,7 @@ static int trf7970a_tg_config_framing(struct trf7970a *trf, int framing)
trf->framing = framing;
if (iso_ctrl != trf->iso_ctrl) {
- ret = trf7970a_write(trf, TRF7970A_ISO_CTRL, iso_ctrl);
+ ret = trf7970a_update_iso_ctrl_register(trf, iso_ctrl);
if (ret)
return ret;
@@ -1755,6 +1801,10 @@ static int _trf7970a_tg_listen(struct nfc_digital_dev *ddev, u16 timeout,
if (ret)
goto out_err;
+ ret = trf7970a_update_rx_gain_reduction(trf);
+ if (ret)
+ goto out_err;
+
ret = trf7970a_write(trf, TRF7970A_REG_IO_CTRL,
trf->io_ctrl | TRF7970A_REG_IO_CTRL_VRS(0x1));
if (ret)
@@ -1945,6 +1995,10 @@ static int trf7970a_startup(struct trf7970a *trf)
if (ret)
return ret;
+ ret = trf7970a_update_rx_gain_reduction(trf);
+ if (ret)
+ return ret;
+
pm_runtime_set_active(trf->dev);
pm_runtime_enable(trf->dev);
pm_runtime_mark_last_busy(trf->dev);
@@ -1993,6 +2047,7 @@ static int trf7970a_probe(struct spi_device *spi)
struct trf7970a *trf;
int uvolts, autosuspend_delay, ret;
u32 clk_freq = TRF7970A_13MHZ_CLOCK_FREQUENCY;
+ u32 rx_gain_reduction_db;
if (!np) {
dev_err(&spi->dev, "No Device Tree entry\n");
@@ -2054,6 +2109,20 @@ static int trf7970a_probe(struct spi_device *spi)
trf->modulator_sys_clk_ctrl = 0;
}
+ if (of_property_read_u32(np, "ti,rx-gain-reduction-db", &rx_gain_reduction_db) == 0) {
+ if (rx_gain_reduction_db > TRF7970A_RX_GAIN_REDUCTION_MAX_DB) {
+ dev_warn(trf->dev, "RX Gain reduction too high. Ignored\n");
+ } else if ((rx_gain_reduction_db % TRF7970A_RX_GAIN_REDUCTION_DB_PER_LSB)) {
+ dev_warn(trf->dev, "RX Gain must be set in 5 dB increments. Ignored\n");
+ } else {
+ dev_dbg(trf->dev, "RX gain set to -%udB\n", rx_gain_reduction_db);
+ trf->rx_gain_reduction = ((rx_gain_reduction_db /
+ TRF7970A_RX_GAIN_REDUCTION_DB_PER_LSB) <<
+ TRF7970A_RX_SPECIAL_SETTINGS_GD_SHIFT);
+ trf->custom_rx_gain_reduction = true;
+ }
+ }
+
ret = devm_request_threaded_irq(trf->dev, spi->irq, NULL,
trf7970a_irq,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
generated by cgit (git 2.34.1) at 2025-07-31 21:50:06 +0000