Re: [PATCH RFC i2c-master] i2c: microchip: pci1xxxx: Add driver for I2C host controller in multifunction endpoint of pci1xxxx switch

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, Aug 23, 2022 at 08:26:03PM +0530, Tharun Kumar P wrote:
> Microchip PCI1XXXX is an unmanaged PCIe3.1a Switch for Consumer,
> Industrial and Automotive applications. This switch has multiple
> downstream ports. In one of the Switch's Downstream port, there
> is a multifunction endpoint for peripherals which includes an I2C
> host controller. The I2C function in the endpoint operates at 100KHz,
> 400KHz and 1 MHz and has buffer depth of 128 bytes.
> This patch provides the I2C controller driver for the I2C endpoint
> of the switch.

...

> @@ -1290,6 +1290,16 @@ config I2C_VIPERBOARD
>  	  River Tech's viperboard.h for detailed meaning
>  	  of the module parameters.
>  
> +config I2C_PCI1XXXX

Looks unsorted.

> +	tristate "PCI1XXXX I2C Host Adapter support"
> +	depends on PCI
> +	help
> +	  Say yes here to enable the I2C Host adapter support for the PCI1xxxx card
> +	  This is a PCI to I2C adapter
> +
> +	  This driver can be built as a module. If so, the module will be
> +	  called as i2c-mchp-pci1xxxx

English grammar and punctuation while keeping lines shorter (~76) please.

...

>  obj-$(CONFIG_I2C_VIPERBOARD)	+= i2c-viperboard.o
> +obj-$(CONFIG_I2C_PCI1XXXX)	+= i2c-mchp-pci1xxxx.o

Why unsorted?

...

> + * Author: Tharun Kumar P <tharunkumar.pasumarthi@microchip.com>
> + *         Kumaravel Thiagarajan <kumaravel.thiagarajan@microchip.com>

Single or many?

...

> +/*SMB register space*/

Style.

...

> +#define SMB_CORE_CTRL_ESO	0x40
> +#define SMB_CORE_CTRL_FW_ACK	0x10

Are they bits or numbers?

...

> +#define SMB_CORE_CMD_READM		0x10
> +#define SMB_CORE_CMD_STOP		0x04
> +#define SMB_CORE_CMD_START		0x01

Ditto.

...

> +#define SMB_CORE_CMD_M_PROCEED	0x02
> +#define SMB_CORE_CMD_M_RUN		0x01

Ditto.

...

> +#define SR_HOLD_TIME_100KHZ		0x85
> +#define SR_HOLD_TIME_400KHZ		0x14
> +#define SR_HOLD_TIME_1000KHZ	0x0B

These has to be decimal, and why the ACPI / DT does not provide them?

Also, do they have units or are they proportional coefficients?

...

> +#define COMPLETION_MDONE	0x40
> +#define COMPLETION_IDLE		0x20
> +#define COMPLETION_MNAKX	0x01

Bits? Same Q for the rest similar stuff.

...

> +#define SMB_IDLE_SCALING_100KHZ		0x03E803C9
> +#define SMB_IDLE_SCALING_400KHZ		0x01F4009D
> +#define SMB_IDLE_SCALING_1000KHZ	0x01F4009D

Shouldn't these magics be decimals?
Ditto for the rest similar stuff.

...

> +#define I2C_DIR_WRITE		0
> +#define I2C_DIR_READ		1

Namespace collision. Doesn't I²C core provide these?

...

> +#define PCI1XXXX_I2C_TIMEOUT	1000

Units? Same to the rest similar cases.

...

> +#define SMBUS_PERI_LOCK		BIT(3)

BIT() out of a sudden. See above.

...

> +/*
> + * struct pci1xxxx_i2c - private structure for the I2C controller

> + *

Redundant blank line.

> + * @adap:	I2C adapter instance
> + * @dev:	pointer to device struct
> + * @i2c_base:	pci base address of the I2C ctrler
> + * @i2c_xfer_done: used for synchronisation between foreground & isr
> + * @freq:	frequency of I2C transfer
> + * @flags:	internal flags to store transfer conditions
> + * @irq:	irq number
> + */

> +

Ditt.

> +struct pci1xxxx_i2c {
> +	struct completion i2c_xfer_done;
> +	bool i2c_xfer_in_progress;
> +	struct i2c_adapter adap;
> +	void __iomem *i2c_base;
> +	u32 freq;
> +	u32 flags;
> +};

I have lack of time to finish review, but you already have enough for the next
version.

...

> +			transferlen = min((u16)(SMBUS_MAST_BUF_MAX_SIZE - 1),
> +					  remainingbytes);

min_t()

...

> +		if (remainingbytes <= transferlen && (i2c->flags &
> +							I2C_FLAGS_STOP))

Strange indentation.

...

> +		/*
> +		 * wait for the DMA_TERM interrupt and if the timer expires, it means
> +		 * the transaction has failed due to some bus lock as we dint get
> +		 * the interrupt
> +		 */

You really have to go through all comments and fix grammar, etc.

...

> +		time_left = wait_for_completion_timeout
> +				(&i2c->i2c_xfer_done, msecs_to_jiffies(PCI1XXXX_I2C_TIMEOUT));

Strange indentation.

...

> +	i2c_del_adapter(&i2c->adap);

Can't you use devm_ variant?

...

> +	pci1xxxx_i2c_shutdown(i2c);

Do you really need this in ->remove()? I would expect something in
the ->suspend() / ->shutdown().

-- 
With Best Regards,
Andy Shevchenko