Unverified Commit d08de025 authored by Luiz Angelo Daros de Luca's avatar Luiz Angelo Daros de Luca Committed by Mark Brown
Browse files

spi: ath79: add mem_ops for fast-read 



Reading from memory is 3x faster than bit-bang read operation. Also,
for tl-wr2543nd, the bit-bang read was sporadically returning random
data, possibly a HW defect, while fast-read works as expected.

Signed-off-by: default avatarLuiz Angelo Daros de Luca <luizluca@gmail.com>
Link: https://lore.kernel.org/r/20220129040453.8476-1-luizluca@gmail.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 47e8fe57

drivers/spi/spi-ath79.c

+34 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/platform_device.h>

#include <linux/io.h>

#include <linux/spi/spi.h>

#include <linux/spi/spi-mem.h>

#include <linux/spi/spi_bitbang.h>

#include <linux/bitops.h>

#include <linux/clk.h>
@@ -133,6 +134,38 @@ static u32 ath79_spi_txrx_mode0(struct spi_device *spi, unsigned int nsecs, 
	return ath79_spi_rr(sp, AR71XX_SPI_REG_RDS);

}



static int ath79_exec_mem_op(struct spi_mem *mem,

			     const struct spi_mem_op *op)

{

	struct ath79_spi *sp = ath79_spidev_to_sp(mem->spi);



	/* Ensures that reading is performed on device connected to hardware cs0 */

	if (mem->spi->chip_select || mem->spi->cs_gpiod)

		return -ENOTSUPP;



	/* Only use for fast-read op. */

	if (op->cmd.opcode != 0x0b || op->data.dir != SPI_MEM_DATA_IN ||

	    op->addr.nbytes != 3 || op->dummy.nbytes != 1)

		return -ENOTSUPP;



	/* disable GPIO mode */

	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, 0);



	memcpy_fromio(op->data.buf.in, sp->base + op->addr.val, op->data.nbytes);



	/* enable GPIO mode */

	ath79_spi_wr(sp, AR71XX_SPI_REG_FS, AR71XX_SPI_FS_GPIO);



	/* restore IOC register */

	ath79_spi_wr(sp, AR71XX_SPI_REG_IOC, sp->ioc_base);



	return 0;

}



static const struct spi_controller_mem_ops ath79_mem_ops = {

	.exec_op = ath79_exec_mem_op,

};



static int ath79_spi_probe(struct platform_device *pdev)

{

	struct spi_master *master;
@@ -154,6 +187,7 @@ static int ath79_spi_probe(struct platform_device *pdev) 
	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);

	master->flags = SPI_MASTER_GPIO_SS;

	master->num_chipselect = 3;

	master->mem_ops = &ath79_mem_ops;



	sp->bitbang.master = master;

	sp->bitbang.chipselect = ath79_spi_chipselect;