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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: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220618174338.2253021-1-javierm@redhat.com
This commit is contained in:
Javier Martinez Canillas 2022-06-18 19:43:38 +02:00
parent 53618649ca
commit 6fc20a8592
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GPG Key ID: C751E590D63F3D69
1 changed files with 5 additions and 16 deletions
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21
drivers/gpu/drm/solomon/ssd130x-spi.c
View File

@ -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);