at86rf230: copy pdata to driver allocated space

This patch copies the platform data in driver allocated space at first.
With this change we ensure that we access the allocated platform data as
readonly space.
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/at86rf230.c

@@ -1377,24 +1377,24 @@ static int at86rf230_hw_init(struct at86rf230_local *lp)
 	return at86rf230_write_subreg(lp, SR_SLOTTED_OPERATION, 0);
 }
 
-static struct at86rf230_platform_data *
-at86rf230_get_pdata(struct spi_device *spi)
+static int
+at86rf230_get_pdata(struct spi_device *spi, int *rstn, int *slp_tr)
 {
-	struct at86rf230_platform_data *pdata;
+	struct at86rf230_platform_data *pdata = spi->dev.platform_data;
 
-	if (!IS_ENABLED(CONFIG_OF) || !spi->dev.of_node)
-		return spi->dev.platform_data;
+	if (!IS_ENABLED(CONFIG_OF) || !spi->dev.of_node) {
+		if (!pdata)
+			return -ENOENT;
 
-	pdata = devm_kzalloc(&spi->dev, sizeof(*pdata), GFP_KERNEL);
-	if (!pdata)
-		goto done;
+		*rstn = pdata->rstn;
+		*slp_tr = pdata->slp_tr;
+		return 0;
+	}
 
-	pdata->rstn = of_get_named_gpio(spi->dev.of_node, "reset-gpio", 0);
-	pdata->slp_tr = of_get_named_gpio(spi->dev.of_node, "sleep-gpio", 0);
+	*rstn = of_get_named_gpio(spi->dev.of_node, "reset-gpio", 0);
+	*slp_tr = of_get_named_gpio(spi->dev.of_node, "sleep-gpio", 0);
 
-	spi->dev.platform_data = pdata;
-done:
-	return pdata;
+	return 0;
 }
 
 static int
@@ -1501,43 +1501,42 @@ at86rf230_setup_spi_messages(struct at86rf230_local *lp)
 
 static int at86rf230_probe(struct spi_device *spi)
 {
-	struct at86rf230_platform_data *pdata;
 	struct ieee802154_hw *hw;
 	struct at86rf230_local *lp;
 	unsigned int status;
-	int rc, irq_type;
+	int rc, irq_type, rstn, slp_tr;
 
 	if (!spi->irq) {
 		dev_err(&spi->dev, "no IRQ specified\n");
 		return -EINVAL;
 	}
 
-	pdata = at86rf230_get_pdata(spi);
-	if (!pdata) {
-		dev_err(&spi->dev, "no platform_data\n");
-		return -EINVAL;
+	rc = at86rf230_get_pdata(spi, &rstn, &slp_tr);
+	if (rc < 0) {
+		dev_err(&spi->dev, "failed to parse platform_data: %d\n", rc);
+		return rc;
 	}
 
-	if (gpio_is_valid(pdata->rstn)) {
-		rc = devm_gpio_request_one(&spi->dev, pdata->rstn,
+	if (gpio_is_valid(rstn)) {
+		rc = devm_gpio_request_one(&spi->dev, rstn,
 					   GPIOF_OUT_INIT_HIGH, "rstn");
 		if (rc)
 			return rc;
 	}
 
-	if (gpio_is_valid(pdata->slp_tr)) {
-		rc = devm_gpio_request_one(&spi->dev, pdata->slp_tr,
+	if (gpio_is_valid(slp_tr)) {
+		rc = devm_gpio_request_one(&spi->dev, slp_tr,
 					   GPIOF_OUT_INIT_LOW, "slp_tr");
 		if (rc)
 			return rc;
 	}
 
 	/* Reset */
-	if (gpio_is_valid(pdata->rstn)) {
+	if (gpio_is_valid(rstn)) {
 		udelay(1);
-		gpio_set_value(pdata->rstn, 0);
+		gpio_set_value(rstn, 0);
 		udelay(1);
-		gpio_set_value(pdata->rstn, 1);
+		gpio_set_value(rstn, 1);
 		usleep_range(120, 240);
 	}