Unverified Commit 6fc20a85 authored by Javier Martinez Canillas's avatar Javier Martinez Canillas
Browse files

drm/ssd130x: Use new regmap bulk write support to drop custom bus 



Data writes for the ssd130x 4-wire SPI protocol need special handling, due
the Data/Command control (D/C) pin having to be toggled prior to the write.

The regmap API only allowed drivers to provide .reg_{read,write} callbacks
to do per register read/write, but didn't provide a way for drivers to do
the same for bulk read/writes.

For this reason, a custom regmap bus was used by the driver just to define
a bulk write callback that implements the D/C pin toggling. But the regmap
API has been extended to support defining bulk read/write handlers, so the
custom regmap bus is not needed anymore and could just be dropped.

Signed-off-by: default avatarJavier Martinez Canillas <javierm@redhat.com>
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220618174338.2253021-1-javierm@redhat.com
parent 53618649

drivers/gpu/drm/solomon/ssd130x-spi.c

+5 −16
Original line number Diff line number Diff line
@@ -18,11 +18,6 @@ struct ssd130x_spi_transport { 
	struct gpio_desc *dc;

};



static const struct regmap_config ssd130x_spi_regmap_config = {

	.reg_bits = 8,

	.val_bits = 8,

};



/*

 * The regmap bus .write handler, it is just a wrapper around spi_write()

 * but toggling the Data/Command control pin (D/C#). Since for 4-wire SPI
@@ -56,17 +51,12 @@ static int ssd130x_spi_read(void *context, const void *reg, size_t reg_size, 
	return -EOPNOTSUPP;

}



/*

 * A custom bus is needed due the special write that toggles a D/C# pin,

 * another option could be to just have a .reg_write() callback but that

 * will prevent to do data writes in bulk.

 *

 * Once the regmap API is extended to support defining a bulk write handler

 * in the struct regmap_config, this can be simplified and the bus dropped.

 */

static struct regmap_bus regmap_ssd130x_spi_bus = {

static const struct regmap_config ssd130x_spi_regmap_config = {

	.reg_bits = 8,

	.val_bits = 8,

	.write = ssd130x_spi_write,

	.read = ssd130x_spi_read,

	.can_multi_write = true,

};



static int ssd130x_spi_probe(struct spi_device *spi)
@@ -90,8 +80,7 @@ static int ssd130x_spi_probe(struct spi_device *spi) 
	t->spi = spi;

	t->dc = dc;



	regmap = devm_regmap_init(dev, &regmap_ssd130x_spi_bus, t,

				  &ssd130x_spi_regmap_config);

	regmap = devm_regmap_init(dev, NULL, t, &ssd130x_spi_regmap_config);

	if (IS_ERR(regmap))

		return PTR_ERR(regmap);