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: Javier Martinez Canillas javierm@redhat.com ---
This patch depends on the following regmap fixes:
https://lkml.org/lkml/2022/6/16/198
drivers/gpu/drm/solomon/ssd130x-spi.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-)
diff --git a/drivers/gpu/drm/solomon/ssd130x-spi.c b/drivers/gpu/drm/solomon/ssd130x-spi.c index 43722adab1f8..72f066ccd2d9 100644 --- a/drivers/gpu/drm/solomon/ssd130x-spi.c +++ b/drivers/gpu/drm/solomon/ssd130x-spi.c @@ -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, ®map_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);