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author | 2018-11-30 07:47:06 +0100 | |
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committer | 2018-12-11 11:59:33 +0000 | |
commit | 00b80ac9355397455adec24c9ee76f1b0225cd27 (patch) | |
tree | 0fbd92be173db751053573a99213bf97d5b00399 /drivers/spi/spi-imx.c | |
parent | spi: imx: add a device specific prepare_message callback (diff) | |
download | linux-00b80ac9355397455adec24c9ee76f1b0225cd27.tar.gz linux-00b80ac9355397455adec24c9ee76f1b0225cd27.tar.bz2 linux-00b80ac9355397455adec24c9ee76f1b0225cd27.zip |
spi: imx: mx51-ecspi: Move some initialisation to prepare_message hook.
The relevant difference between prepare_message and config is that the
former is run before the CS signal is asserted. So the polarity of the
CLK line must be configured in prepare_message as an edge generated by
config might already result in a latch of the MOSI line.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-imx.c')
-rw-r--r-- | drivers/spi/spi-imx.c | 67 |
1 files changed, 40 insertions, 27 deletions
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index c7db42d6b3bc..d3a1e7104556 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -490,14 +490,9 @@ static void mx51_ecspi_disable(struct spi_imx_data *spi_imx) static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx, struct spi_message *msg) { - return 0; -} - -static int mx51_ecspi_config(struct spi_device *spi) -{ - struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master); + struct spi_device *spi = msg->spi; u32 ctrl = MX51_ECSPI_CTRL_ENABLE; - u32 clk = spi_imx->speed_hz, delay, reg; + u32 testreg; u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG); /* set Master or Slave mode */ @@ -512,19 +507,21 @@ static int mx51_ecspi_config(struct spi_device *spi) if (spi->mode & SPI_READY) ctrl |= MX51_ECSPI_CTRL_DRCTL(spi_imx->spi_drctl); - /* set clock speed */ - ctrl |= mx51_ecspi_clkdiv(spi_imx, spi_imx->speed_hz, &clk); - spi_imx->spi_bus_clk = clk; - /* set chip select to use */ ctrl |= MX51_ECSPI_CTRL_CS(spi->chip_select); - if (spi_imx->slave_mode && is_imx53_ecspi(spi_imx)) - ctrl |= (spi_imx->slave_burst * 8 - 1) - << MX51_ECSPI_CTRL_BL_OFFSET; + /* + * The ctrl register must be written first, with the EN bit set other + * registers must not be written to. + */ + writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL); + + testreg = readl(spi_imx->base + MX51_ECSPI_TESTREG); + if (spi->mode & SPI_LOOP) + testreg |= MX51_ECSPI_TESTREG_LBC; else - ctrl |= (spi_imx->bits_per_word - 1) - << MX51_ECSPI_CTRL_BL_OFFSET; + testreg &= ~MX51_ECSPI_TESTREG_LBC; + writel(testreg, spi_imx->base + MX51_ECSPI_TESTREG); /* * eCSPI burst completion by Chip Select signal in Slave mode @@ -548,25 +545,42 @@ static int mx51_ecspi_config(struct spi_device *spi) cfg &= ~MX51_ECSPI_CONFIG_SCLKPOL(spi->chip_select); cfg &= ~MX51_ECSPI_CONFIG_SCLKCTL(spi->chip_select); } + if (spi->mode & SPI_CS_HIGH) cfg |= MX51_ECSPI_CONFIG_SSBPOL(spi->chip_select); else cfg &= ~MX51_ECSPI_CONFIG_SSBPOL(spi->chip_select); - if (spi_imx->usedma) - ctrl |= MX51_ECSPI_CTRL_SMC; + writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG); - /* CTRL register always go first to bring out controller from reset */ - writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL); + return 0; +} - reg = readl(spi_imx->base + MX51_ECSPI_TESTREG); - if (spi->mode & SPI_LOOP) - reg |= MX51_ECSPI_TESTREG_LBC; +static int mx51_ecspi_config(struct spi_device *spi) +{ + struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master); + u32 ctrl = readl(spi_imx->base + MX51_ECSPI_CTRL); + u32 clk = spi_imx->speed_hz, delay; + + /* Clear BL field and set the right value */ + ctrl &= ~MX51_ECSPI_CTRL_BL_MASK; + if (spi_imx->slave_mode && is_imx53_ecspi(spi_imx)) + ctrl |= (spi_imx->slave_burst * 8 - 1) + << MX51_ECSPI_CTRL_BL_OFFSET; else - reg &= ~MX51_ECSPI_TESTREG_LBC; - writel(reg, spi_imx->base + MX51_ECSPI_TESTREG); + ctrl |= (spi_imx->bits_per_word - 1) + << MX51_ECSPI_CTRL_BL_OFFSET; - writel(cfg, spi_imx->base + MX51_ECSPI_CONFIG); + /* set clock speed */ + ctrl &= ~(0xf << MX51_ECSPI_CTRL_POSTDIV_OFFSET | + 0xf << MX51_ECSPI_CTRL_PREDIV_OFFSET); + ctrl |= mx51_ecspi_clkdiv(spi_imx, spi_imx->speed_hz, &clk); + spi_imx->spi_bus_clk = clk; + + if (spi_imx->usedma) + ctrl |= MX51_ECSPI_CTRL_SMC; + + writel(ctrl, spi_imx->base + MX51_ECSPI_CTRL); /* * Wait until the changes in the configuration register CONFIGREG @@ -594,7 +608,6 @@ static void mx51_setup_wml(struct spi_imx_data *spi_imx) * Configure the DMA register: setup the watermark * and enable DMA request. */ - writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml - 1) | MX51_ECSPI_DMA_TX_WML(spi_imx->wml) | MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) | |