[PATCH v6 1/3] iio: imx8qxp-adc: Add driver support for NXP IMX8QXP ADC

[Jonathan Cameron]

On Sat, 25 Sep 2021 10:05:45 +0800
Cai Huoqing <caihuoqing at baidu.com> wrote:

> The NXP i.MX 8QuadXPlus SOC has a new ADC IP, so add
> driver support for this ADC.
> 
> Signed-off-by: Cai Huoqing <caihuoqing at baidu.com>
Hi Cai Huoqing,

Having had a 'final' read through of the driver, I am basically happy
to merge this after Fabio has had time for another look (plus anyone else
who wishes to of course!) 

There were a few minor things inline though that I'll tidy up whilst applying.
If you do a v7 for some other reason please sort these out as well.

Thanks,

Jonathan

...

> +#define IMX8QXP_ADR_ADC_TCTRL(tid)	(0xc0 + tid * 4)
> +#define IMX8QXP_ADR_ADC_CMDH(cid)	(0x100 + cid * 8)
> +#define IMX8QXP_ADR_ADC_CMDL(cid)	(0x104 + cid * 8)

In macros, it is always a good idea to put brackets around
any use of parameters so as to avoid potential odd issues
due to operator precedence.

(0xc0 + (tid) * 4)

> +#define IMX8QXP_ADR_ADC_RESFIFO		0x300
> +#define IMX8QXP_ADR_ADC_TST		0xffc

...

> +
> +struct imx8qxp_adc {
> +	struct device *dev;
> +	void __iomem *regs;
> +	struct clk *clk;
> +	struct clk *ipg_clk;
> +	struct regulator *vref;
> +	struct mutex lock;

A lock should have documentation to identify what it's precise scope is.
I can add

/* Serialise ADC channel reads */
above the lock definition whilst applying if you aren't doing a v7 for
other reasons.

> +	struct completion completion;
> +};
...


> +
> +static irqreturn_t imx8qxp_adc_isr(int irq, void *dev_id)
> +{
> +	struct imx8qxp_adc *adc = dev_id;
> +

Really minor, but the blank line here doesn't help readability much and
is inconsistent with the rest of the driver.  I might remove this whilst
applying if nothing else comes up.

> +	u32 fifo_count;
> +
> +	fifo_count = FIELD_GET(IMX8QXP_ADC_FCTRL_FCOUNT_MASK,
> +			       readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL));
> +
> +	if (fifo_count)
> +		complete(&adc->completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
...