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SubjectRe: [PATCH v11 1/5] can: m_can: Create a m_can platform framework
Date
On 3/19/19 6:26 PM, Dan Murphy wrote:
> Create a m_can platform framework that peripheral
> devices can register to and use common code and register sets.
> The peripheral devices may provide read/write and configuration
> support of the IP.
>
> Acked-by: Wolfgang Grandegger <wg@grandegger.com>
> Signed-off-by: Dan Murphy <dmurphy@ti.com>

[...]

> -/* m_can private data structure */
> -struct m_can_priv {
> - struct can_priv can; /* must be the first member */
> - struct napi_struct napi;
> - struct net_device *dev;
> - struct device *device;
> - struct clk *hclk;
> - struct clk *cclk;
> - void __iomem *base;
> - u32 irqstatus;
> - int version;
> -
> - /* message ram configuration */
> - void __iomem *mram_base;
> - struct mram_cfg mcfg[MRAM_CFG_NUM];
> -};
> +static u32 m_can_read(struct m_can_priv *priv, enum m_can_reg reg)
> +{
> + if (priv->ops->read_reg)
> + return priv->ops->read_reg(priv, reg);
> + else
> + return -EINVAL;
> +}

How do you plan to check the return value here?
What's the difference between a register value of 0xffffffe9 and
returning -EINVAL?

>
> -static inline u32 m_can_read(const struct m_can_priv *priv, enum m_can_reg reg)
> +static int m_can_write(struct m_can_priv *priv, enum m_can_reg reg, u32 val)
> {
> - return readl(priv->base + reg);
> + if (priv->ops->write_reg)
> + return priv->ops->write_reg(priv, reg, val);
> + else
> + return -EINVAL;
> }

I don't see anyone checking the return value. Better just dereference
the pointer and the kernel will produce a nice backtrace.

Same should be done for all read and write variants.

Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
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