Subject: Re: [PATCH v4 04/21] PM / devfreq: rockchip-dfi: Add SoC specific init function

From: Jonathan Cameron <[email-masked]>
Date: Tue, 16 May 2023 16:40:17 +0100

On Fri,  5 May 2023 13:38:39 +0200
Sascha Hauer <[email-masked]> wrote:

> Move the RK3399 specifics to a SoC specific init function to make
> the way free for supporting other SoCs later.
> 
> Signed-off-by: Sascha Hauer <[email-masked]>
Hi Sascha,

A few things inline,

Jonathan

> ---
>  drivers/devfreq/event/rockchip-dfi.c | 59 +++++++++++++++++++++-------
>  1 file changed, 44 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> index 47cc9e48dafab..f317d3d063e9c 100644
> --- a/drivers/devfreq/event/rockchip-dfi.c
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -17,6 +17,7 @@
>  #include <linux/slab.h>
>  #include <linux/list.h>
>  #include <linux/of.h>
> +#include <linux/of_device.h>
>  
>  #include <soc/rockchip/rk3399_grf.h>
>  
> @@ -55,27 +56,21 @@ struct rockchip_dfi {
>  	void __iomem *regs;
>  	struct regmap *regmap_pmu;
>  	struct clk *clk;
> +	u32 ddr_type;
>  };
>  
>  static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
>  {
>  	struct rockchip_dfi *dfi = devfreq_event_get_drvdata(edev);
>  	void __iomem *dfi_regs = dfi->regs;
> -	u32 val;
> -	u32 ddr_type;
> -
> -	/* get ddr type */
> -	regmap_read(dfi->regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
> -	ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
> -		    RK3399_PMUGRF_DDRTYPE_MASK;
>  
>  	/* clear DDRMON_CTRL setting */
>  	writel_relaxed(CLR_DDRMON_CTRL, dfi_regs + DDRMON_CTRL);
>  
>  	/* set ddr type to dfi */
> -	if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR3)
> +	if (dfi->ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR3)
>  		writel_relaxed(LPDDR3_EN, dfi_regs + DDRMON_CTRL);
> -	else if (ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR4)
> +	else if (dfi->ddr_type == RK3399_PMUGRF_DDRTYPE_LPDDR4)
>  		writel_relaxed(LPDDR4_EN, dfi_regs + DDRMON_CTRL);
>  
>  	/* enable count, use software mode */
> @@ -167,8 +162,34 @@ static const struct devfreq_event_ops rockchip_dfi_ops = {
>  	.set_event = rockchip_dfi_set_event,
>  };
>  
> +static int rk3399_dfi_init(struct rockchip_dfi *dfi)
> +{
> +	struct regmap *regmap_pmu = dfi->regmap_pmu;
> +	u32 val;
> +
> +	dfi->clk = devm_clk_get(dfi->dev, "pclk_ddr_mon");
> +	if (IS_ERR(dfi->clk))
> +		return dev_err_probe(dfi->dev, PTR_ERR(dfi->clk),
> +				     "Cannot get the clk pclk_ddr_mon\n");
> +
> +	/* get ddr type */
> +	regmap_read(regmap_pmu, RK3399_PMUGRF_OS_REG2, &val);
> +	dfi->ddr_type = (val >> RK3399_PMUGRF_DDRTYPE_SHIFT) &
> +			RK3399_PMUGRF_DDRTYPE_MASK;

I don't suppose you fancy converting whole driver to
FIELD_GET / FIELD_PREP and masks that include the shift? :)
Guess probably not or maybe you do it later in this set.

> +
> +	return 0;
> +};
> +
> +struct rockchip_dfi_devtype_data {
> +	int (*init)(struct rockchip_dfi *dfi);
> +};
> +
> +static struct rockchip_dfi_devtype_data rk3399_devtype_data = {
> +	.init = rk3399_dfi_init,

I guess the 'why' will become apparent later in the set, but at this
stage a callback to get the ddr type would have made more sense and
kept the data local to where it was needed.

> +};
> +
>  static const struct of_device_id rockchip_dfi_id_match[] = {
> -	{ .compatible = "rockchip,rk3399-dfi" },
> +	{ .compatible = "rockchip,rk3399-dfi", .data = &rk3399_devtype_data },
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(of, rockchip_dfi_id_match);
> @@ -179,6 +200,15 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
>  	struct rockchip_dfi *dfi;
>  	struct devfreq_event_desc *desc;
>  	struct device_node *np = pdev->dev.of_node, *node;
> +	const struct of_device_id *of_id;
> +	const struct rockchip_dfi_devtype_data *devtype;
> +	int ret;
> +
> +	of_id = of_match_device(rockchip_dfi_id_match, &pdev->dev);
> +	if (!of_id)
> +		return -ENODEV;
> +
> +	devtype = of_id->data;

device_get_match_data()

or I guess if you really want stick to the of specific form.

of_device_get_match_data()

>  
>  	dfi = devm_kzalloc(dev, sizeof(*dfi), GFP_KERNEL);
>  	if (!dfi)
> @@ -188,11 +218,6 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
>  	if (IS_ERR(dfi->regs))
>  		return PTR_ERR(dfi->regs);
>  
> -	dfi->clk = devm_clk_get(dev, "pclk_ddr_mon");
> -	if (IS_ERR(dfi->clk))
> -		return dev_err_probe(dev, PTR_ERR(dfi->clk),
> -				     "Cannot get the clk pclk_ddr_mon\n");
> -
>  	node = of_parse_phandle(np, "rockchip,pmu", 0);
>  	if (!node)
>  		return dev_err_probe(&pdev->dev, -ENODEV, "Can't find pmu_grf registers\n");
> @@ -208,6 +233,10 @@ static int rockchip_dfi_probe(struct platform_device *pdev)
>  	desc->driver_data = dfi;
>  	desc->name = np->name;
>  
> +	ret = devtype->init(dfi);
> +	if (ret)
> +		return ret;
> +
>  	dfi->edev = devm_devfreq_event_add_edev(&pdev->dev, desc);
>  	if (IS_ERR(dfi->edev)) {
>  		dev_err(&pdev->dev,

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