Re: [PATCH 1/2] net: allwinner: reset control support

Hi, thank you for your review!


3/8/21 4:36 PM, Maxime Ripard пишет:

Hi,

On Sun, Mar 07, 2021 at 06:13:51AM +0300, Evgeny Boger wrote:

quoted

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?

It's custom-made Allwinner A40i device with two IP101GRI PHYs in MII mode.

quoted

---
  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

  
  	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

got it

quoted

+	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.

right, found it at section 3.3.2.6, thanks

Maxime

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