Am 01.07.2018 um 13:07 schrieb Andreas F?rber:

[...]

+static int sx1276_probe(struct spi_device *spi)
+{
+	struct net_device *netdev;
+	struct sx1276_priv *priv;
+	int rst, dio[6], ret, model, i;
+	u32 freq_xosc, freq_band;
+	unsigned long long freq_rf;
+	u8 val;
+
+	rst = of_get_named_gpio(spi->dev.of_node, "reset-gpio", 0);
+	if (rst == -ENOENT)
+		dev_warn(&spi->dev, "no reset GPIO available, ignoring");
+
+	for (i = 0; i < 6; i++) {
+		dio[i] = of_get_named_gpio(spi->dev.of_node, "dio-gpios", i);
+		if (dio[i] == -ENOENT)
+			dev_dbg(&spi->dev, "DIO%d not available, ignoring", i);
+		else {
+			ret = gpio_direction_input(dio[i]);
+			if (ret)
+				dev_err(&spi->dev, "couldn't set DIO%d to input", i);
+		}
+	}
+
+	if (gpio_is_valid(rst)) {
+		gpio_set_value(rst, 1);
+		udelay(100);
+		gpio_set_value(rst, 0);
+		msleep(5);
+	}
+
+	spi->bits_per_word = 8;
+	spi_setup(spi);
+
+	ret = sx1276_read_single(spi, REG_VERSION, &val);
+	if (ret) {
+		dev_err(&spi->dev, "version read failed");
+		return ret;
+	}
+
+	if (val == 0x22)
+		model = 1272;
+	else {
+		if (gpio_is_valid(rst)) {
+			gpio_set_value(rst, 0);
+			udelay(100);
+			gpio_set_value(rst, 1);
+			msleep(5);
+		}
+
+		ret = sx1276_read_single(spi, REG_VERSION, &val);
+		if (ret) {
+			dev_err(&spi->dev, "version read failed");
+			return ret;
+		}
+
+		if (val == 0x12)
+			model = 1276;
+		else {
+			dev_err(&spi->dev, "transceiver not recognized (RegVersion = 0x%02x)", (unsigned)val);
+			return -EINVAL;
+		}
+	}

[snip]

To counter my own point, this file of course still has leftover model
detection heuristics; should check for the of_device_id match instead!
SX1272 vs. SX1276 have the reset pin inverted, so - knowing which model
it's supposed to be - we can do the right reset from the start and, if
it doesn't work, report an error to the user.

Also I should update that code to use gpiod, as seen in later patches.

Cheers,
Andreas

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