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

Sascha Hauer
2015-03-09T11:03:46Z

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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