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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");
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