linux-kernel - Re: [PATCH 3/3] clk: samsung: add Exynos ACPM clock driver

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Message-ID: <e17ea82b-fb3e-45d2-a168-3b917816fe7b@kernel.org>
Date: Sun, 24 Aug 2025 19:10:26 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Tudor Ambarus <tudor.ambarus@...aro.org>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Peter Griffin <peter.griffin@...aro.org>,
 André Draszik <andre.draszik@...aro.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>,
 Sylwester Nawrocki <s.nawrocki@...sung.com>,
 Chanwoo Choi <cw00.choi@...sung.com>
Cc: linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
 devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 linux-clk@...r.kernel.org, willmcvicker@...gle.com, kernel-team@...roid.com
Subject: Re: [PATCH 3/3] clk: samsung: add Exynos ACPM clock driver

On 19/08/2025 13:45, Tudor Ambarus wrote:
> +
> +static int acpm_clk_set_rate(struct clk_hw *hw, unsigned long rate,
> +			     unsigned long parent_rate)
> +{
> +	struct acpm_clk *clk = to_acpm_clk(hw);
> +
> +	return clk->handle->ops.dvfs_ops.set_rate(clk->handle,
> +					clk->acpm_chan_id, clk->id, rate);
> +}
> +
> +static const struct clk_ops acpm_clk_ops = {
> +	.recalc_rate = acpm_clk_recalc_rate,
> +	.round_rate = acpm_clk_round_rate,

This should be determine_rate. Check recent patchset from Brian Masney.
I applied the samsung bits from it to samsung soc tree.

...

> +
> +static int __init acpm_clk_probe(struct platform_device *pdev)

module probe for sure should not be __init.

> +{
> +	const struct acpm_clk_match_data *match_data;
> +	const struct acpm_handle *acpm_handle;
> +	struct clk_hw_onecell_data *clk_data;
> +	struct clk_hw **hws;
> +	struct device *dev = &pdev->dev;
> +	struct acpm_clk *aclks;
> +	unsigned int acpm_chan_id;
> +	int i, err, count;
> +
> +	acpm_handle = devm_acpm_get_by_node(dev, dev->parent->of_node);
> +	if (IS_ERR(acpm_handle))
> +		return dev_err_probe(dev, PTR_ERR(acpm_handle),
> +				     "Failed to get acpm handle.\n");
> +
> +	match_data = of_device_get_match_data(dev);
> +	if (!match_data)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Failed to get match data.\n");
> +
> +	count = match_data->nr_clks;
> +	acpm_chan_id = match_data->acpm_chan_id;
> +
> +	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, count),
> +				GFP_KERNEL);
> +	if (!clk_data)
> +		return -ENOMEM;
> +
> +	clk_data->num = count;
> +	hws = clk_data->hws;
> +
> +	aclks = devm_kcalloc(dev, count, sizeof(*aclks), GFP_KERNEL);
> +	if (!aclks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < count; i++) {
> +		const struct acpm_clk_variant *variant = &match_data->clks[i];
> +		struct acpm_clk *aclk = &aclks[i];
> +
> +		hws[i] = &aclk->hw;
> +
> +		aclk->id = variant->id;
> +		aclk->handle = acpm_handle;
> +		aclk->acpm_chan_id = acpm_chan_id;
> +
> +		err = acpm_clk_ops_init(dev, aclk, variant->name);
> +		if (err)
> +			return dev_err_probe(dev, err,
> +					     "Failed to register clock.\n");
> +	}
> +
> +	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
> +					   clk_data);
> +}
> +
> +#define ACPM_CLK(_id, cname)					\
> +	{							\
> +		.id		= _id,				\
> +		.name		= cname,			\
> +	}
> +
> +static const struct acpm_clk_variant gs101_acpm_clks[] __initconst = {

This goes to top of the file, after struct declarations.

> +	ACPM_CLK(CLK_ACPM_DVFS_MIF, "mif"),
> +	ACPM_CLK(CLK_ACPM_DVFS_INT, "int"),
> +	ACPM_CLK(CLK_ACPM_DVFS_CPUCL0, "cpucl0"),
> +	ACPM_CLK(CLK_ACPM_DVFS_CPUCL1, "cpucl1"),
> +	ACPM_CLK(CLK_ACPM_DVFS_CPUCL2, "cpucl2"),
> +	ACPM_CLK(CLK_ACPM_DVFS_G3D, "g3d"),
> +	ACPM_CLK(CLK_ACPM_DVFS_G3DL2, "g3dl2"),
> +	ACPM_CLK(CLK_ACPM_DVFS_TPU, "tpu"),
> +	ACPM_CLK(CLK_ACPM_DVFS_INTCAM, "intcam"),
> +	ACPM_CLK(CLK_ACPM_DVFS_TNR, "tnr"),
> +	ACPM_CLK(CLK_ACPM_DVFS_CAM, "cam"),
> +	ACPM_CLK(CLK_ACPM_DVFS_MFC, "mfc"),
> +	ACPM_CLK(CLK_ACPM_DVFS_DISP, "disp"),
> +	ACPM_CLK(CLK_ACPM_DVFS_BO, "b0"),
> +};
> +
> +static const struct acpm_clk_match_data acpm_clk_gs101 __initconst = {

Are you going to have more of such clk_match_data? More variants?

> +	.clks = gs101_acpm_clks,
> +	.nr_clks = ARRAY_SIZE(gs101_acpm_clks),
> +	.acpm_chan_id = 0,
> +};
> +
> +static const struct of_device_id acpm_clk_ids[] __initconst = {
> +	{
> +		.compatible = "google,gs101-acpm-dvfs-clocks",
> +		.data =  &acpm_clk_gs101,
> +	},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, acpm_clk_ids);
> +
> +static struct platform_driver acpm_clk_driver __refdata = {

__refdata feels wrong here. There is a long standing issue with Samsung
clock drivers - I sent a patchset for that but it did failed testing.

But your code is even simpler - no CLK_OFDECLARE - so why is this refdata?


Best regards,
Krzysztof