Commit d23d4d4d authored by Noralf Trønnes's avatar Noralf Trønnes
Browse files

drm/tinydrm: Move tinydrm_spi_transfer() 



This is only used by mipi-dbi drivers so move it there.

The reason this isn't moved to the SPI subsystem is that it will in a
later patch pass a dummy rx buffer for SPI controllers that need this.
Low memory boards (64MB) can run into a problem allocating such a "large"
contiguous buffer on every transfer after a long up time.
This leaves a very specific use case, so we'll keep the function here.
mipi-dbi will first go through a refactoring though, before this will
be done.

Remove SPI todo entry now that we're done with the tinydrm.ko SPI code.

v2: Drop moving the mipi_dbi_spi_init() declaration (Sam)

Cc: David Lechner <david@lechnology.com>
Reviewed-by: default avatarSam Ravnborg <sam@ravnborg.org>
Acked-by: default avatar: David Lechner <david@lechnology.com>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-8-noralf@tronnes.org
parent 083a6c23

Documentation/gpu/tinydrm.rst

+0 −3
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@@ -11,9 +11,6 @@ Helpers 
.. kernel-doc:: include/drm/tinydrm/tinydrm-helpers.h

   :internal:



.. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c

   :export:



.. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c

   :export:

Documentation/gpu/todo.rst

+0 −3
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@@ -443,9 +443,6 @@ tinydrm 
Tinydrm is the helper driver for really simple fb drivers. The goal is to make

those drivers as simple as possible, so lots of room for refactoring:



- spi helpers, probably best put into spi core/helper code. Thierry said

  the spi maintainer is fast&reactive, so shouldn't be a big issue.



- extract the mipi-dbi helper (well, the non-tinydrm specific parts at

  least) into a separate helper, like we have for mipi-dsi already. Or follow

  one of the ideas for having a shared dsi/dbi helper, abstracting away the

drivers/gpu/drm/tinydrm/core/Makefile

+1 −1
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# SPDX-License-Identifier: GPL-2.0-only

tinydrm-y := tinydrm-pipe.o tinydrm-helpers.o

tinydrm-y := tinydrm-pipe.o



obj-$(CONFIG_DRM_TINYDRM) += tinydrm.o

drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c

deleted100644 → 0
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// SPDX-License-Identifier: GPL-2.0-or-later

/*

 * Copyright (C) 2016 Noralf Trønnes

 */



#include <linux/backlight.h>

#include <linux/dma-buf.h>

#include <linux/module.h>

#include <linux/pm.h>

#include <linux/spi/spi.h>

#include <linux/swab.h>



#include <drm/drm_device.h>

#include <drm/drm_drv.h>

#include <drm/drm_fourcc.h>

#include <drm/drm_framebuffer.h>

#include <drm/drm_print.h>

#include <drm/drm_rect.h>

#include <drm/tinydrm/tinydrm-helpers.h>



#if IS_ENABLED(CONFIG_SPI)



/**

 * tinydrm_spi_transfer - SPI transfer helper

 * @spi: SPI device

 * @speed_hz: Override speed (optional)

 * @bpw: Bits per word

 * @buf: Buffer to transfer

 * @len: Buffer length

 *

 * This SPI transfer helper breaks up the transfer of @buf into chunks which

 * the SPI controller driver can handle.

 *

 * Returns:

 * Zero on success, negative error code on failure.

 */

int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz,

			 u8 bpw, const void *buf, size_t len)

{

	size_t max_chunk = spi_max_transfer_size(spi);

	struct spi_transfer tr = {

		.bits_per_word = bpw,

		.speed_hz = speed_hz,

	};

	struct spi_message m;

	size_t chunk;

	int ret;



	spi_message_init_with_transfers(&m, &tr, 1);



	while (len) {

		chunk = min(len, max_chunk);



		tr.tx_buf = buf;

		tr.len = chunk;

		buf += chunk;

		len -= chunk;



		ret = spi_sync(spi, &m);

		if (ret)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL(tinydrm_spi_transfer);



#endif /* CONFIG_SPI */



MODULE_LICENSE("GPL");

drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c

+4 −0
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@@ -3,6 +3,8 @@ 
 * Copyright (C) 2016 Noralf Trønnes

 */



#include <linux/module.h>



#include <drm/drm_atomic_helper.h>

#include <drm/drm_drv.h>

#include <drm/drm_gem_framebuffer_helper.h>
@@ -177,3 +179,5 @@ int tinydrm_display_pipe_init(struct drm_device *drm, 
					    format_count, modifiers, connector);

}

EXPORT_SYMBOL(tinydrm_display_pipe_init);



MODULE_LICENSE("GPL");

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