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author | Noralf Trønnes <noralf@tronnes.org> | 2019-07-19 17:59:11 +0200 |
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committer | Noralf Trønnes <noralf@tronnes.org> | 2019-07-23 15:46:56 +0200 |
commit | 083a6c23b9ecf478265bb27ccacb8d587732058e (patch) | |
tree | 8eb5c8f95bc4b54f2180375b98d4eb153e87d5f1 /drivers/gpu/drm/tinydrm/core | |
parent | e143364b4c1774f68e923a5a0bb0fca28ac25888 (diff) | |
download | linux-083a6c23b9ecf478265bb27ccacb8d587732058e.tar.bz2 |
drm/tinydrm: Clean up tinydrm_spi_transfer()
Prep work before moving the function to mipi-dbi.
tinydrm_spi_transfer() was made to support one class of drivers in
drivers/staging/fbtft that has not been converted to DRM yet, so strip
away the unused functionality:
- Start byte (header) is not used.
- No driver relies on the automatic 16-bit byte swapping on little endian
machines with SPI controllers only supporting 8 bits per word.
Other changes:
- No need to initialize ret
- No need for the WARN since mipi-dbi only uses 8 and 16 bpw.
- Use spi_message_init_with_transfers()
Cc: David Lechner <david@lechnology.com>
Acked-by: : David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-7-noralf@tronnes.org
Diffstat (limited to 'drivers/gpu/drm/tinydrm/core')
-rw-r--r-- | drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c | 40 |
1 files changed, 4 insertions, 36 deletions
diff --git a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c index af5bec8861de..d95eb50fa9d4 100644 --- a/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c +++ b/drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c @@ -24,23 +24,18 @@ * tinydrm_spi_transfer - SPI transfer helper * @spi: SPI device * @speed_hz: Override speed (optional) - * @header: Optional header transfer * @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 master driver can handle. If the machine is Little Endian and the - * SPI master driver doesn't support 16 bits per word, it swaps the bytes and - * does a 8-bit transfer. - * If @header is set, it is prepended to each SPI message. + * 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, - struct spi_transfer *header, u8 bpw, const void *buf, - size_t len) + u8 bpw, const void *buf, size_t len) { size_t max_chunk = spi_max_transfer_size(spi); struct spi_transfer tr = { @@ -48,43 +43,16 @@ int tinydrm_spi_transfer(struct spi_device *spi, u32 speed_hz, .speed_hz = speed_hz, }; struct spi_message m; - u16 *swap_buf = NULL; size_t chunk; - int ret = 0; + int ret; - if (WARN_ON_ONCE(bpw != 8 && bpw != 16)) - return -EINVAL; - - if (bpw == 16 && !spi_is_bpw_supported(spi, 16)) { - tr.bits_per_word = 8; - if (tinydrm_machine_little_endian()) { - swap_buf = kmalloc(min(len, max_chunk), GFP_KERNEL); - if (!swap_buf) - return -ENOMEM; - } - } - - spi_message_init(&m); - if (header) - spi_message_add_tail(header, &m); - spi_message_add_tail(&tr, &m); + spi_message_init_with_transfers(&m, &tr, 1); while (len) { chunk = min(len, max_chunk); tr.tx_buf = buf; tr.len = chunk; - - if (swap_buf) { - const u16 *buf16 = buf; - unsigned int i; - - for (i = 0; i < chunk / 2; i++) - swap_buf[i] = swab16(buf16[i]); - - tr.tx_buf = swap_buf; - } - buf += chunk; len -= chunk; |