Re: [PATCH 1/5] soc: mediatek: Add SMI driver

[Sascha Hauer <s.hauer@pengutronix.de>]

On Fri, Mar 06, 2015 at 06:48:16PM +0800, yong.wu@mediatek.com wrote:
> From: Yong Wu <yong.wu@mediatek.com>
> 
>     This patch add SMI(Smart Multimedia Interface) driver. This driver is
> responsible to enable/disable iommu and control the clocks of each
> local arbiter.
> 
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
>  drivers/soc/mediatek/Kconfig      |   7 ++
>  drivers/soc/mediatek/Makefile     |   1 +
>  drivers/soc/mediatek/mt8173-smi.c | 143 ++++++++++++++++++++++++++++++++++++++
>  include/linux/mtk-smi.h           |  40 +++++++++++

I just posted the power domain driver for prividing the domains this
driver uses. You should base your code on that.

> +#include <linux/mm.h>
> +
> +#define SMI_LARB_MMU_EN                 (0xf00)
> +#define F_SMI_MMU_EN(port)              (1 << (port))
> +
> +struct mtk_smi_larb {
> +	void __iomem *larb_base;
> +	struct clk *larb_clk[3];/* each larb has 3 clk at most */
> +};
> +
> +static const char * const mtk_smi_clk_name[] = {
> +	"larb_sub0", "larb_sub1", "larb_sub2"
> +};
> +
> +static const struct of_device_id mtk_smi_of_ids[] = {
> +	{ .compatible = "mediatek,mt8173-smi-larb",
> +	},

Add a newline after the opening brace.

> +int mtk_smi_config_port(struct platform_device *plarbdev,
> +			unsigned int larbportid)
> +{
> +	struct mtk_smi_larb *larbpriv = dev_get_drvdata(&plarbdev->dev);
> +	int ret;
> +	u32 reg;
> +
> +	ret = mtk_smi_larb_get(plarbdev);
> +	if (ret)
> +		return ret;
> +
> +	reg = readl(larbpriv->larb_base + SMI_LARB_MMU_EN);
> +	reg &= ~F_SMI_MMU_EN(larbportid);
> +	reg |= F_SMI_MMU_EN(larbportid);

This sets the very same bits that are cleared one line above. This is
surely not what you want.

> +	writel(reg, larbpriv->larb_base + SMI_LARB_MMU_EN);
> +
> +	mtk_smi_larb_put(plarbdev);
> +
> +	return 0;
> +}
> +
> +static int mtk_smi_probe(struct platform_device *pdev)
> +{
> +	struct mtk_smi_larb *larbpriv;
> +	struct resource *res;
> +	struct device *dev = &pdev->dev;
> +	unsigned int i;
> +
> +	larbpriv = devm_kzalloc(dev, sizeof(struct mtk_smi_larb), GFP_KERNEL);

sizeof(*larbpriv)

> +	if (!larbpriv)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	larbpriv->larb_base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(larbpriv->larb_base)) {
> +		dev_err(dev, "larbbase %p err\n", larbpriv->larb_base);

You can print an error number with %ld and PTR_ERR(larbpriv->larb_base).
Printing the pointer is not that helpful.

> +/*
> + * Enable iommu for each port, it is only for iommu.
> + *
> + * Returns 0 if successfully, others if failed.
> + */
> +int mtk_smi_config_port(struct platform_device *pdev,
> +			unsigned int larbportid);
> +
> +/*
> + * The multimedia module should call the two function below
> + * which help open/close the clock of the larb.
> + * so the client dtsi should add the larb like "larb = <&larb0>"
> + * to get platform_device.
> + *
> + * mtk_smi_larb_get should be called before the multimedia h/w work.
> + * mtk_smi_larb_put should be called after h/w done.
> + *
> + * Returns 0 if successfully, others if failed.
> + */
> +int mtk_smi_larb_get(struct platform_device *plarbdev);
> +void mtk_smi_larb_put(struct platform_device *plarbdev);

The function documentation usually comes with the definition of a
function, not its declaration.

Sascha

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