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From: Philipp Zabel <p.zabel@pengutronix.de>
To: "Paweł Anikiel" <pan@semihalf.com>,
	miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
	robh+dt@kernel.org, arnd@arndb.de, olof@lixom.net,
	soc@kernel.org, dinguyen@kernel.org
Cc: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
	 linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,  tn@semihalf.com,
	ka@semihalf.com, jam@semihalf.com
Subject: Re: [PATCH 3/3] reset: socfpga: add empty driver allowing consumers to probe
Date: Tue, 05 Oct 2021 11:34:07 +0200	[thread overview]
Message-ID: <ce254cc123f2809976c2f2404941a9074c458309.camel@pengutronix.de> (raw)
Message-ID: <20211005093407.6FCAsOZYukqdChGyMhvCtKU-0iQe1qmWgVVlQSxU-40@z> (raw)
In-Reply-To: <20210920124141.1166544-4-pan@semihalf.com>

Hi Paweł,

On Mon, 2021-09-20 at 14:41 +0200, Paweł Anikiel wrote:
> The early reset driver doesn't ever probe, which causes consuming
> devices to be unable to probe. Add an empty driver to set this device
> as available, allowing consumers to probe.
> 
> Signed-off-by: Paweł Anikiel <pan@semihalf.com>
> ---
>  drivers/reset/reset-socfpga.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/reset/reset-socfpga.c b/drivers/reset/reset-socfpga.c
> index 2a72f861f798..8c6492e5693c 100644
> --- a/drivers/reset/reset-socfpga.c
> +++ b/drivers/reset/reset-socfpga.c
> @@ -92,3 +92,29 @@ void __init socfpga_reset_init(void)
>  	for_each_matching_node(np, socfpga_early_reset_dt_ids)
>  		a10_reset_init(np);
>  }
> +
> +/*
> + * The early driver is problematic, because it doesn't register
> + * itself as a driver. This causes certain device links to prevent
> + * consumer devices from probing. The hacky solution is to register
> + * an empty driver, whose only job is to attach itself to the reset
> + * manager and call probe.
> + */
> +static const struct of_device_id socfpga_reset_dt_ids[] = {
> +	{ .compatible = "altr,rst-mgr", },
> +	{ /* sentinel */ },
> +};
> +
> +static int reset_simple_probe(struct platform_device *pdev)
> +{
> +	return 0;
> +}
> +
> +static struct platform_driver reset_socfpga_driver = {
> +	.probe	= reset_simple_probe,
> +	.driver = {
> +		.name		= "socfpga-reset",
> +		.of_match_table	= socfpga_reset_dt_ids,
> +	},
> +};
> +builtin_platform_driver(reset_socfpga_driver);

If we can just let devlink delay all consumers until the empty driver is
probed, does the reset controller have to be registered early at all?

regards
Philipp

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID
From: Philipp Zabel <p.zabel@pengutronix.de>
To: "Paweł Anikiel" <pan@semihalf.com>,
	miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com,
	robh+dt@kernel.org, arnd@arndb.de, olof@lixom.net,
	soc@kernel.org, dinguyen@kernel.org
Cc: linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, tn@semihalf.com,
	ka@semihalf.com, jam@semihalf.com
Subject: Re: [PATCH 3/3] reset: socfpga: add empty driver allowing consumers to probe
Date: Tue, 05 Oct 2021 11:34:07 +0200	[thread overview]
Message-ID: <ce254cc123f2809976c2f2404941a9074c458309.camel@pengutronix.de> (raw)
Message-ID: <20211005093407.jXvLQu5OcoRL3lRP0fcKpgsQUsFgeDRX8K6hMlOWhmM@z> (raw)
In-Reply-To: <20210920124141.1166544-4-pan@semihalf.com>

Hi Paweł,

On Mon, 2021-09-20 at 14:41 +0200, Paweł Anikiel wrote:
> The early reset driver doesn't ever probe, which causes consuming
> devices to be unable to probe. Add an empty driver to set this device
> as available, allowing consumers to probe.
> 
> Signed-off-by: Paweł Anikiel <pan@semihalf.com>
> ---
>  drivers/reset/reset-socfpga.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/reset/reset-socfpga.c b/drivers/reset/reset-socfpga.c
> index 2a72f861f798..8c6492e5693c 100644
> --- a/drivers/reset/reset-socfpga.c
> +++ b/drivers/reset/reset-socfpga.c
> @@ -92,3 +92,29 @@ void __init socfpga_reset_init(void)
>  	for_each_matching_node(np, socfpga_early_reset_dt_ids)
>  		a10_reset_init(np);
>  }
> +
> +/*
> + * The early driver is problematic, because it doesn't register
> + * itself as a driver. This causes certain device links to prevent
> + * consumer devices from probing. The hacky solution is to register
> + * an empty driver, whose only job is to attach itself to the reset
> + * manager and call probe.
> + */
> +static const struct of_device_id socfpga_reset_dt_ids[] = {
> +	{ .compatible = "altr,rst-mgr", },
> +	{ /* sentinel */ },
> +};
> +
> +static int reset_simple_probe(struct platform_device *pdev)
> +{
> +	return 0;
> +}
> +
> +static struct platform_driver reset_socfpga_driver = {
> +	.probe	= reset_simple_probe,
> +	.driver = {
> +		.name		= "socfpga-reset",
> +		.of_match_table	= socfpga_reset_dt_ids,
> +	},
> +};
> +builtin_platform_driver(reset_socfpga_driver);

If we can just let devlink delay all consumers until the empty driver is
probed, does the reset controller have to be registered early at all?

regards
Philipp

  reply	other threads:[~2021-10-05  9:36 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20210920124138.7Rv4Bat-mDXSJL5_d7ykDRJFDCAMP3dSiZm0nDPMaDU@z>
2021-09-20 12:41 ` [PATCH 0/3] Add support for the Mercury+ AA1 module Paweł Anikiel
     [not found]   ` <20210920124139.jQM-Tqzr63A2Hs1WHPqhhGaUuJiNYaCWKRl5YiR4iTA@z>
2021-09-20 12:41     ` [PATCH 1/3] dt-bindings: mtd: spi-nor: add n25q00 schema Paweł Anikiel
     [not found]       ` <20210923165648.FCg577uaG9fWz1MINUjzq_6XdotxOakHUOjndV9cMBM@z>
2021-09-23 16:56         ` Rob Herring
2021-09-23 16:56           ` Rob Herring
     [not found]       ` <20210923185904.twJ5GB7t8omyZ7RKqA5bcaS2QzsOxfghoI6XXJrCzfc@z>
2021-09-23 18:59         ` Pratyush Yadav
     [not found]           ` <20211005115906.sVeqCk7Lbj-UbEQBqo8aQDAVjC_bmmDQ6QaO3ChH2n4@z>
2021-10-05 11:59             ` Tudor.Ambarus
2021-10-05 11:59               ` Tudor.Ambarus
     [not found]   ` <20210920124140.RZTw5kTlMXDVKDMnzhD0FZ5oHIQ_cZ6kTSSrKdQw9WU@z>
2021-09-20 12:41     ` [PATCH 2/3] dts: socfpga: Add Mercury+ AA1 devicetree Paweł Anikiel
     [not found]   ` <20210920124141.dOhXof_mbq7fNGtevvmYnhhpG15cTTgPtsQcSOqhER8@z>
2021-09-20 12:41     ` [PATCH 3/3] reset: socfpga: add empty driver allowing consumers to probe Paweł Anikiel
     [not found]       ` <20211005093407.6FCAsOZYukqdChGyMhvCtKU-0iQe1qmWgVVlQSxU-40@z>
2021-10-05  9:34         ` Philipp Zabel [this message]
2021-10-05  9:34           ` Philipp Zabel
     [not found]           ` <20211005111205.yhacoo2AdAdnUkQ86NaPU0ASEexP3rjoqfZSlZF-dlI@z>
2021-10-05 11:12             ` Paweł Anikiel
     [not found]               ` <20211005102225.PzZXA7w0Qn5d_3_cHQbe86EPWtaa_CBoQpc89EEeouA@z>
2021-10-05 10:22                 ` Philipp Zabel
2021-10-05 10:22                   ` Philipp Zabel
2021-10-05 10:22                   ` Philipp Zabel
2021-10-05 11:12               ` Paweł Anikiel
2021-10-05 11:12               ` Paweł Anikiel
     [not found]   ` <20210920124140.u56dOOGofORjfYeTSsKGqD2HNw-7gu5UqvN2ocHwr-g@z>
     [not found]     ` <20210923165624.wCIpZMuEaOTqgzTIVio-auukBwIkYM1Ik1HRSlI8hTg@z>
2021-09-23 16:56       ` [PATCH 2/3] dts: socfpga: Add Mercury+ AA1 devicetree Rob Herring

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