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Commit 083a6c23 authored by Noralf Trønnes's avatar Noralf Trønnes
Browse files

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: default avatar: David Lechner <david@lechnology.com>
Signed-off-by: default avatarNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190719155916.62465-7-noralf@tronnes.org
parent e143364b

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

+4 −36
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/tinydrm/ili9225.c

+2 −2
Original line number Diff line number Diff line
@@ -323,7 +323,7 @@ static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 *cmd, u8 *par, 


	gpiod_set_value_cansleep(mipi->dc, 0);

	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);

	ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, cmd, 1);

	ret = tinydrm_spi_transfer(spi, speed_hz, 8, cmd, 1);

	if (ret || !num)

		return ret;
@@ -333,7 +333,7 @@ static int ili9225_dbi_command(struct mipi_dbi *mipi, u8 *cmd, u8 *par, 
	gpiod_set_value_cansleep(mipi->dc, 1);

	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);



	return tinydrm_spi_transfer(spi, speed_hz, NULL, bpw, par, num);

	return tinydrm_spi_transfer(spi, speed_hz, bpw, par, num);

}



static const struct drm_simple_display_pipe_funcs ili9225_pipe_funcs = {

drivers/gpu/drm/tinydrm/mipi-dbi.c

+2 −2
Original line number Diff line number Diff line
@@ -926,7 +926,7 @@ static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 *cmd, 


	gpiod_set_value_cansleep(mipi->dc, 0);

	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);

	ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, cmd, 1);

	ret = tinydrm_spi_transfer(spi, speed_hz, 8, cmd, 1);

	if (ret || !num)

		return ret;
@@ -936,7 +936,7 @@ static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 *cmd, 
	gpiod_set_value_cansleep(mipi->dc, 1);

	speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);



	return tinydrm_spi_transfer(spi, speed_hz, NULL, bpw, par, num);

	return tinydrm_spi_transfer(spi, speed_hz, bpw, par, num);

}



/**

include/drm/tinydrm/tinydrm-helpers.h

+1 −2
Original line number Diff line number Diff line
@@ -42,7 +42,6 @@ int tinydrm_display_pipe_init(struct drm_device *drm, 
			      unsigned int rotation);



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);



#endif /* __LINUX_TINYDRM_HELPERS_H */