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Unverified Commit 7ff0b53c authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Mark Brown
Browse files

spi: sh-msiof: Avoid writing to registers from spi_master.setup() 



The spi_master.setup() callback must not change configuration registers,
as that could corrupt I/O that is in progress for other SPI slaves.

The only exception is the configuration of the native chip select
polarity in SPI master mode, as a wrong chip select polarity will cause
havoc during all future transfers to any other SPI slave.

Hence stop writing to registers in sh_msiof_spi_setup(), unless it is
the first call for a controller using a native chip select, or unless
native chip select polarity has changed (note that you'll loose anyway
if I/O is in progress).  Even then, only do what is strictly necessary,
instead of calling sh_msiof_spi_set_pin_regs().

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 5d8e614f

drivers/spi/spi-sh-msiof.c

+24 −11
Original line number Diff line number Diff line
@@ -55,6 +55,8 @@ struct sh_msiof_spi_priv { 
	void *rx_dma_page;

	dma_addr_t tx_dma_addr;

	dma_addr_t rx_dma_addr;

	bool native_cs_inited;

	bool native_cs_high;

	bool slave_aborted;

};
@@ -528,8 +530,7 @@ static int sh_msiof_spi_setup(struct spi_device *spi) 
{

	struct device_node	*np = spi->master->dev.of_node;

	struct sh_msiof_spi_priv *p = spi_master_get_devdata(spi->master);



	pm_runtime_get_sync(&p->pdev->dev);

	u32 clr, set, tmp;



	if (!np) {

		/*
@@ -539,19 +540,31 @@ static int sh_msiof_spi_setup(struct spi_device *spi) 
		spi->cs_gpio = (uintptr_t)spi->controller_data;

	}



	/* Configure pins before deasserting CS */

	sh_msiof_spi_set_pin_regs(p, !!(spi->mode & SPI_CPOL),

				  !!(spi->mode & SPI_CPHA),

				  !!(spi->mode & SPI_3WIRE),

				  !!(spi->mode & SPI_LSB_FIRST),

				  !!(spi->mode & SPI_CS_HIGH));



	if (spi->cs_gpio >= 0)

	if (spi->cs_gpio >= 0) {

		gpio_set_value(spi->cs_gpio, !(spi->mode & SPI_CS_HIGH));

		return 0;

	}



	if (spi_controller_is_slave(p->master))

		return 0;



	pm_runtime_put(&p->pdev->dev);

	if (p->native_cs_inited &&

	    (p->native_cs_high == !!(spi->mode & SPI_CS_HIGH)))

		return 0;



	/* Configure native chip select mode/polarity early */

	clr = MDR1_SYNCMD_MASK;

	set = MDR1_TRMD | TMDR1_PCON | MDR1_SYNCMD_SPI;

	if (spi->mode & SPI_CS_HIGH)

		clr |= BIT(MDR1_SYNCAC_SHIFT);

	else

		set |= BIT(MDR1_SYNCAC_SHIFT);

	pm_runtime_get_sync(&p->pdev->dev);

	tmp = sh_msiof_read(p, TMDR1) & ~clr;

	sh_msiof_write(p, TMDR1, tmp | set);

	pm_runtime_put(&p->pdev->dev);

	p->native_cs_high = spi->mode & SPI_CS_HIGH;

	p->native_cs_inited = true;

	return 0;

}