Re: [PATCH 1/2] net: allwinner: reset control support
From: Maxime Ripard <hidden>
Date: 2021-03-08 13:37:15
Also in:
linux-arm-kernel, lkml
Hi, On Sun, Mar 07, 2021 at 06:13:51AM +0300, Evgeny Boger wrote:
R40 (aka V40/A40i/T3) and A10/A20 share the same EMAC IP. However, on R40 the EMAC is gated by default. Signed-off-by: Evgeny Boger <redacted>
On which device was it tested?
quoted hunk ↗ jump to hunk
--- drivers/net/ethernet/allwinner/sun4i-emac.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-)diff --git a/drivers/net/ethernet/allwinner/sun4i-emac.c b/drivers/net/ethernet/allwinner/sun4i-emac.c index 5ed80d9a6b9f..c0ae06dd922c 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 "sun4i-emac.h"@@ -85,6 +86,7 @@ struct emac_board_info { unsigned int link; unsigned int speed; unsigned int duplex; + struct reset_control *reset;
You should align this with the rest of the other fields
quoted hunk ↗ jump to hunk
phy_interface_t phy_interface; };@@ -791,6 +793,7 @@ static int emac_probe(struct platform_device *pdev) struct net_device *ndev; int ret = 0; const char *mac_addr; + struct reset_control *reset; ndev = alloc_etherdev(sizeof(struct emac_board_info)); if (!ndev) {@@ -852,6 +855,19 @@ static int emac_probe(struct platform_device *pdev) goto out_release_sram; } + reset = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL); + if (IS_ERR(reset)) { + dev_err(&pdev->dev, "unable to request reset\n"); + ret = -ENODEV; + goto out_release_sram; + }
Judging from your commit log, it's not really optional for the R40. The way we usually deal with this is to have a structure associated with a new compatible and have a flag tell if that compatible requires a reset line or not. The dt binding should also be amended to allow the reset property
+ db->reset = reset;
+ ret = reset_control_deassert(db->reset);
+ if (ret) {
+ dev_err(&pdev->dev, "could not deassert EMAC reset\n");
+ goto out_release_sram;
+ }
+The programming guidelines in the datasheet ask that the reset line must be deasserted before the clock in enabled. Maxime
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