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spi: ath79: add mem_ops for fast-read

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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: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Link: https://lore.kernel.org/r/20220129040453.8476-1-luizluca@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Luiz Angelo Daros de Luca 2022-01-29 01:04:53 -03:00 committed by Mark Brown
parent 47e8fe57a6
commit d08de0259d
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1 changed files with 34 additions and 0 deletions
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34
drivers/spi/spi-ath79.c
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@ -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;