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SubjectRe: [PATCH v2 5/5] gpio: pca953x: Add support for PCAL6534
On Tue, Sep 06, 2022 at 09:28:19AM +0100, Martyn Welch wrote:
> From: Martyn Welch <martyn.welch@collabora.com>
>
> Add support for the NXP PCAL6534. This device is broadly a 34-bit version
> of the PCAL6524. However, whilst the registers are broadly what you'd
> expect for a 34-bit version of the PCAL6524, the spacing of the registers
> has been compacted. This has the unfortunate effect of breaking the bit
> shift based mechanism that is employed to work out register locations used
> by the other chips supported by this driver. To accommodate ths, callback
> functions have been added to allow alterate implementations of
> pca953x_recalc_addr() and pca953x_check_register() for the PCAL6534.


This looks much cleaner!

...

> @@ -107,6 +109,7 @@ static const struct i2c_device_id pca953x_id[] = {
> { "tca9539", 16 | PCA953X_TYPE | PCA_INT, },
> { "tca9554", 8 | PCA953X_TYPE | PCA_INT, },
> { "xra1202", 8 | PCA953X_TYPE },
> +
> { }

Missed Diodes?

> };
> MODULE_DEVICE_TABLE(i2c, pca953x_id);

...

> + u8 (*recalc_addr)(struct pca953x_chip *chip, int reg , int off);
> + bool (*check_reg)(struct pca953x_chip *chip, unsigned int reg,
> + u32 checkbank);

I would think of splitting this change. Like in a separate patch you simply
create this interface and only add what you need in the next one.

...

> +static bool pcal6534_check_register(struct pca953x_chip *chip, unsigned int reg,
> + u32 checkbank)
> +{
> + int bank;
> + int offset;
> +
> + if (reg > 0x2f) {

I guess code read and generation wise the

if (reg >= 0x30) {

is slightly better.

> + /*
> + * Reserved block between 14h and 2Fh does not align on
> + * expected bank boundaries like other devices.
> + */
> + int temp = reg - 0x30;
> +
> + bank = temp / NBANK(chip);
> + offset = temp - (bank * NBANK(chip));

Parentheses are not needed fur multiplication, but if you insist...

> + bank += 8;

> + } else if (reg > 0x53) {

In the similar way...

> + /* Handle lack of reserved registers after output port
> + * configuration register to form a bank.
> + */

Comment style

/*
* Handle...
*/

> + int temp = reg - 0x54;
> +
> + bank = temp / NBANK(chip);
> + offset = temp - (bank * NBANK(chip));
> + bank += 16;
> + } else {
> + bank = reg / NBANK(chip);
> + offset = reg - (bank * NBANK(chip));
> + }
> +
> + /* Register is not in the matching bank. */
> + if (!(BIT(bank) & checkbank))
> + return false;
> +
> + /* Register is not within allowed range of bank. */
> + if (offset >= NBANK(chip))
> + return false;
> +
> + return true;
> +}

...

> - u8 regaddr = pinctrl | addr | (off / BANK_SZ);
>
> - return regaddr;
> + return pinctrl | addr | (off / BANK_SZ);

Stray change, or anything I have missed?

...

> +/* The PCAL6534 and compatible chips have altered bank alignment that doesn't
> + * fit within the bit shifting scheme used for other devices.
> + */

Comment style.

...

> @@ -1240,6 +1335,7 @@ static const struct of_device_id pca953x_dt_ids[] = {
>
> { .compatible = "nxp,pcal6416", .data = OF_953X(16, PCA_LATCH_INT), },
> { .compatible = "nxp,pcal6524", .data = OF_953X(24, PCA_LATCH_INT), },
> + { .compatible = "nxp,pcal6534", .data = OF_653X(34, PCA_LATCH_INT), },
> { .compatible = "nxp,pcal9535", .data = OF_953X(16, PCA_LATCH_INT), },
> { .compatible = "nxp,pcal9554b", .data = OF_953X( 8, PCA_LATCH_INT), },
> { .compatible = "nxp,pcal9555a", .data = OF_953X(16, PCA_LATCH_INT), },

Do you decide to drop Diodes compatible from the code?

--
With Best Regards,
Andy Shevchenko


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