mrf24j40: add csma params support

This patch adds supports to change the CSMA parameters. The datasheet
doesn't say anything about max_be value. Seems not configurable and we
assume the 802.15.4 default. But this value must exists because there is
a min_be value.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/net/ieee802154/mrf24j40.c

@@ -776,6 +776,21 @@ static int mrf24j40_handle_rx(struct mrf24j40 *devrec)
 	return spi_async(devrec->spi, &devrec->rx_msg);
 }
 
+static int
+mrf24j40_csma_params(struct ieee802154_hw *hw, u8 min_be, u8 max_be,
+		     u8 retries)
+{
+	struct mrf24j40 *devrec = hw->priv;
+	u8 val;
+
+	/* min_be */
+	val = min_be << 3;
+	/* csma backoffs */
+	val |= retries;
+
+	return regmap_update_bits(devrec->regmap_short, REG_TXMCR, 0x1f, val);
+}
+
 static const struct ieee802154_ops mrf24j40_ops = {
 	.owner = THIS_MODULE,
 	.xmit_async = mrf24j40_tx,
@@ -784,6 +799,7 @@ static const struct ieee802154_ops mrf24j40_ops = {
 	.stop = mrf24j40_stop,
 	.set_channel = mrf24j40_set_channel,
 	.set_hw_addr_filt = mrf24j40_filter,
+	.set_csma_params = mrf24j40_csma_params,
 };
 
 static void mrf24j40_intstat_complete(void *context)
@@ -979,6 +995,14 @@ static void  mrf24j40_phy_setup(struct mrf24j40 *devrec)
 {
 	ieee802154_random_extended_addr(&devrec->hw->phy->perm_extended_addr);
 	devrec->hw->phy->current_channel = 11;
+
+	/* mrf24j40 supports max_minbe 0 - 3 */
+	devrec->hw->phy->supported.max_minbe = 3;
+	/* datasheet doesn't say anything about max_be, but we have min_be
+	 * So we assume the max_be default.
+	 */
+	devrec->hw->phy->supported.min_maxbe = 5;
+	devrec->hw->phy->supported.max_maxbe = 5;
 }
 
 static int mrf24j40_probe(struct spi_device *spi)
@@ -1001,7 +1025,8 @@ static int mrf24j40_probe(struct spi_device *spi)
 	devrec->hw = hw;
 	devrec->hw->parent = &spi->dev;
 	devrec->hw->phy->supported.channels[0] = CHANNEL_MASK;
-	devrec->hw->flags = IEEE802154_HW_TX_OMIT_CKSUM | IEEE802154_HW_AFILT;
+	devrec->hw->flags = IEEE802154_HW_TX_OMIT_CKSUM | IEEE802154_HW_AFILT |
+			    IEEE802154_HW_CSMA_PARAMS;
 
 	mrf24j40_setup_tx_spi_messages(devrec);
 	mrf24j40_setup_rx_spi_messages(devrec);