[PATCH v5 1/3] net: allwinner: reset control support

[Evgeny Boger <boger@wirenboard.com>]

R40 (aka V40/A40i/T3) and A10/A20 share the same EMAC IP.
However, on R40 the EMAC reset needs to be deasserted.

Signed-off-by: Evgeny Boger <boger@wirenboard.com>
---
 drivers/net/ethernet/allwinner/sun4i-emac.c | 64 +++++++++++++++++++--
 1 file changed, 59 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c
index 74635a6fa8ca..56e811b0a279 100644
--- a/drivers/net/ethernet/allwinner/sun4i-emac.c
+++ b/drivers/net/ethernet/allwinner/sun4i-emac.c
@@ -28,6 +28,7 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/phy.h>
+#include <linux/reset.h>
 #include <linux/soc/sunxi/sunxi_sram.h>
 #include <linux/dmaengine.h>
 
@@ -69,6 +70,15 @@ MODULE_PARM_DESC(watchdog, "transmit timeout in milliseconds");
  * devices, EMACA and EMACB.
  */
 
+/**
+ * struct emac_quirks - Differences between SoC variants.
+ *
+ * @has_reset: SoC needs reset deasserted.
+ */
+struct emac_quirks {
+	bool		has_reset;
+};
+
 struct emac_board_info {
 	struct clk		*clk;
 	struct device		*dev;
@@ -85,6 +95,7 @@ struct emac_board_info {
 	unsigned int		link;
 	unsigned int		speed;
 	unsigned int		duplex;
+	struct reset_control	*reset;
 
 	phy_interface_t		phy_interface;
 	struct dma_chan	*rx_chan;
@@ -968,6 +979,7 @@ static int emac_probe(struct platform_device *pdev)
 	struct emac_board_info *db;
 	struct net_device *ndev;
 	int ret = 0;
+	const struct emac_quirks *quirks;
 
 	ndev = alloc_etherdev(sizeof(struct emac_board_info));
 	if (!ndev) {
@@ -986,6 +998,13 @@ static int emac_probe(struct platform_device *pdev)
 
 	spin_lock_init(&db->lock);
 
+	quirks = of_device_get_match_data(&pdev->dev);
+	if (!quirks) {
+		dev_err(&pdev->dev, "Failed to determine the quirks to use\n");
+		ret = -ENODEV;
+		goto out;
+	}
+
 	db->membase = of_iomap(np, 0);
 	if (!db->membase) {
 		dev_err(&pdev->dev, "failed to remap registers\n");
@@ -1002,19 +1021,34 @@ static int emac_probe(struct platform_device *pdev)
 		goto out_iounmap;
 	}
 
+	if (quirks->has_reset) {
+		db->reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+		if (IS_ERR(db->reset)) {
+			dev_err(&pdev->dev, "unable to request reset\n");
+			ret = PTR_ERR(db->reset);
+			goto out_dispose_mapping;
+		}
+
+		ret = reset_control_deassert(db->reset);
+		if (ret) {
+			dev_err(&pdev->dev, "could not deassert EMAC reset\n");
+			goto out_dispose_mapping;
+		}
+	}
+
 	if (emac_configure_dma(db))
 		netdev_info(ndev, "configure dma failed. disable dma.\n");
 
 	db->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(db->clk)) {
 		ret = PTR_ERR(db->clk);
-		goto out_dispose_mapping;
+		goto out_assert_reset;
 	}
 
 	ret = clk_prepare_enable(db->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "Error couldn't enable clock (%d)\n", ret);
-		goto out_dispose_mapping;
+		goto out_assert_reset;
 	}
 
 	ret = sunxi_sram_claim(&pdev->dev);
@@ -1070,6 +1104,8 @@ static int emac_probe(struct platform_device *pdev)
 	sunxi_sram_release(&pdev->dev);
 out_clk_disable_unprepare:
 	clk_disable_unprepare(db->clk);
+out_assert_reset:
+	reset_control_assert(db->reset);
 out_dispose_mapping:
 	irq_dispose_mapping(ndev->irq);
 out_iounmap:
@@ -1095,6 +1131,7 @@ static int emac_remove(struct platform_device *pdev)
 	unregister_netdev(ndev);
 	sunxi_sram_release(&pdev->dev);
 	clk_disable_unprepare(db->clk);
+	reset_control_assert(db->reset);
 	irq_dispose_mapping(ndev->irq);
 	iounmap(db->membase);
 	free_netdev(ndev);
@@ -1126,11 +1163,28 @@ static int emac_resume(struct platform_device *dev)
 	return 0;
 }
 
-static const struct of_device_id emac_of_match[] = {
-	{.compatible = "allwinner,sun4i-a10-emac",},
+static const struct emac_quirks sun4i_a10_emac_quirks = {
+	.has_reset = false,
+};
+
+static const struct emac_quirks sun8i_r40_emac_quirks = {
+	.has_reset = true,
+};
 
+static const struct of_device_id emac_of_match[] = {
+	{
+		.compatible = "allwinner,sun4i-a10-emac",
+		.data = &sun4i_a10_emac_quirks
+	},
+	{
+		.compatible = "allwinner,sun8i-r40-emac",
+		.data = &sun8i_r40_emac_quirks
+	},
 	/* Deprecated */
-	{.compatible = "allwinner,sun4i-emac",},
+	{
+		.compatible = "allwinner,sun4i-emac",
+		.data = &sun4i_a10_emac_quirks
+	},
 	{},
 };
 
-- 
2.25.1