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SubjectRe: [PATCH v5 08/11] i2c: designware: Convert driver to using regmap API
On Wed, May 27, 2020 at 06:30:43PM +0300, Serge Semin wrote:
> Seeing the DW I2C driver is using flags-based accessors with two
> conditional clauses it would be better to replace them with the regmap
> API IO methods and to initialize the regmap object with read/write
> callbacks specific to the controller registers map implementation. This
> will be also handy for the drivers with non-standard registers mapping
> (like an embedded into the Baikal-T1 System Controller DW I2C block, which
> glue-driver is a part of this series).
>
> As before the driver tries to detect the mapping setup at probe stage and
> creates a regmap object accordingly, which will be used by the rest of the
> code to correctly access the controller registers. In two places it was
> appropriate to convert the hand-written read-modify-write and
> read-poll-loop design patterns to the corresponding regmap API
> ready-to-use methods.
>
> Note the regmap IO methods return value is checked only at the probe
> stage. The rest of the code won't do this because basically we have
> MMIO-based regmap so non of the read/write methods can fail (this also
> won't be needed for the Baikal-T1-specific I2C controller).

...

> + struct regmap_config map_cfg = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> + .disable_locking = true,
> + .reg_read = dw_reg_read,
> + .reg_write = dw_reg_write,

> + .max_register = DW_IC_COMP_TYPE

Perhaps leave comma here as well.

> + };

...

> + /*
> + * Note we'll check the return value of the regmap IO accessors only
> + * at the probe stage. The rest of the code won't do this because
> + * basically we have MMIO-based regmap so non of the read/write methods
> + * can fail.
> + */
> + dev->map = devm_regmap_init(dev->dev, NULL, dev, &map_cfg);
> + if (IS_ERR(dev->map)) {
> + dev_err(dev->dev, "Failed to init the registers map\n");

> + return PTR_ERR(dev->map);
> + }
> +
> return 0;

return PTR_ERR_OR_ZERO(dev->map);

--
With Best Regards,
Andy Shevchenko


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