linux-kernel - Re: [PATCH] clk: keystone: syscon-clk: Do not use syscon helper to build regmap

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Message-ID: <20250123200209.lqdap6jdzz4ud37f@riveter>
Date: Thu, 23 Jan 2025 14:02:09 -0600
From: Nishanth Menon <nm@...com>
To: Andrew Davis <afd@...com>, Stephen Boyd <sboyd@...nel.org>
CC: Vignesh Raghavendra <vigneshr@...com>,
        Santosh Shilimkar
	<ssantosh@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen
 Boyd <sboyd@...nel.org>, <linux-kernel@...r.kernel.org>,
        <linux-clk@...r.kernel.org>, "Rob Herring (Arm)" <robh@...nel.org>,
        Lee Jones
	<lee@...nel.org>
Subject: Re: [PATCH] clk: keystone: syscon-clk: Do not use syscon helper to
 build regmap

On 12:19-20250123, Andrew Davis wrote:
> The syscon helper device_node_to_regmap() is used to fetch a regmap
> registered to a device node. It also currently creates this regmap
> if the node did not already have a regmap associated with it. This
> should only be used on "syscon" nodes. This driver is not such a
> device and instead uses device_node_to_regmap() on its own node as
> a hacky way to create a regmap for itself.
> 
> This will not work going forward and so we should create our regmap
> the normal way by defining our regmap_config, fetching our memory
> resource, then using the normal regmap_init_mmio() function.
> 
> Signed-off-by: Andrew Davis <afd@...com>

Tested-by: Nishanth Menon <nm@...com>

Could we get this routed to master as fixes asap please to get a sane 6.14?

This is part of the fixes TI K3 platforms boot issues reported in
https://lore.kernel.org/all/b2413460-ec8b-4c77-99b8-4c32b262439a@ti.com/

on the latest linus master v6.13-5001-gd0d106a2bd21 + linux
next-20250123

Total set of patches tested with:
https://lore.kernel.org/all/20250119182121.3956546-1-vaishnav.a@ti.com/
https://lore.kernel.org/r/20250123181726.597144-1-afd@ti.com
https://lore.kernel.org/r/20250123181913.597304-1-afd@ti.com
https://lore.kernel.org/r/20250123182059.597491-1-afd@ti.com
https://lore.kernel.org/r/20250123182234.597665-1-afd@ti.com


Cc Rob and Lee

> ---
>  drivers/clk/keystone/syscon-clk.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/keystone/syscon-clk.c b/drivers/clk/keystone/syscon-clk.c
> index 935d9a2d8c2b3..073c2ebcdf6af 100644
> --- a/drivers/clk/keystone/syscon-clk.c
> +++ b/drivers/clk/keystone/syscon-clk.c
> @@ -105,6 +105,12 @@ static struct clk_hw
>  	return &priv->hw;
>  }
>  
> +static const struct regmap_config ti_syscon_regmap_cfg = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +};
> +
>  static int ti_syscon_gate_clk_probe(struct platform_device *pdev)
>  {
>  	const struct ti_syscon_gate_clk_data *data, *p;
> @@ -113,12 +119,18 @@ static int ti_syscon_gate_clk_probe(struct platform_device *pdev)
>  	int num_clks, num_parents, i;
>  	const char *parent_name;
>  	struct regmap *regmap;
> +	void __iomem *base;
>  
>  	data = device_get_match_data(dev);
>  	if (!data)
>  		return -EINVAL;
>  
> -	regmap = device_node_to_regmap(dev->of_node);
> +	base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(base))
> +		return dev_err_probe(dev, PTR_ERR(base),
> +				     "failed to get base memory resource\n");
> +
> +	regmap = regmap_init_mmio(dev, base, &ti_syscon_regmap_cfg);
>  	if (IS_ERR(regmap))
>  		return dev_err_probe(dev, PTR_ERR(regmap),
>  				     "failed to get regmap\n");
> -- 
> 2.39.2
> 

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D