[PATCH v3 1/3] net: allwinner: reset control support

[Maxime Ripard]

Hi

On Sun, Nov 21, 2021 at 10:53:35PM +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.

Gated is usually used for clocks, not reset lines, which would usually
be asserted instead.

> Signed-off-by: Evgeny Boger <boger at 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 800ee022388f..16039784f2c6 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"
> @@ -68,6 +69,15 @@ 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;
>  };
> @@ -790,6 +801,7 @@ 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) {
> @@ -808,6 +820,13 @@ 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");
> @@ -824,16 +843,31 @@ 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;
> +		}
> +	}
> +
>  	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);
> @@ -889,6 +923,8 @@ 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:
> @@ -909,6 +945,7 @@ 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);
> @@ -940,11 +977,28 @@ 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 sun4i_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,sun4i-r40-emac",

The R40 is part of the sun8i family

This needs to be updated in your binding and DT patch as well.

Maxime
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