evie/android_kernel_oneplus_msm8998
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

spi: spi_qsd: Correct SPI slave hw init sequence

Browse source 
While configuring QUP in SPI slave mode, an internal
HW signal needs to propagate from AHB clock domain
to SPI core  clock domain. To make sure a safe and
correct propagation of this signal the software should
perform the SPI HW init sequence in proper order.

Change-Id: Ied621bb5d1ba793ce48c5a6a0f6be3b86b3a6773
Signed-off-by: Alok Chauhan <alokc@codeaurora.org>
This commit is contained in:
Alok Chauhan 2018-01-26 02:19:18 +05:30
parent 4938bb02a8
commit 363bbeba93
1 changed files with 23 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
drivers/spi/spi_qsd.c
View file

@ -1799,10 +1799,7 @@ static void msm_spi_slv_setup(struct msm_spi *dd)
u32 irq_en = GENMASK(6, 0);
qup_config &= ~QUP_CFG_MODE;
qup_config |= QUP_CONFIG_SPI_SLAVE;
qup_config |= (SPI_EN_EXT_OUT_FLAG | APP_CLK_ON_EN | CORE_CLK_ON_EN
| FIFO_CLK_ON_EN | CORE_EX_CLK_ON_EN);
spi_config |= SPI_CFG_SLAVE_OP;
qup_config |= SPI_EN_EXT_OUT_FLAG;
writel_relaxed(qup_config, dd->base + QUP_CONFIG);
writel_relaxed(spi_config, dd->base + SPI_CONFIG);
writel_relaxed(irq_en, (dd->base + SPI_SLAVE_IRQ_EN));
@ -1812,6 +1809,28 @@ static void msm_spi_slv_setup(struct msm_spi *dd)
slv_cfg |= (RX_UNBALANCED_MASK | SPI_S_CGC_EN);
writel_relaxed(slv_cfg, (dd->base + SPI_SLAVE_CONFIG));
}
/*
* Ensure the previous write completed before enabling slave mode.
*/
mb();
spi_config = readl_relaxed(dd->base + SPI_CONFIG);
qup_config = readl_relaxed(dd->base + QUP_CONFIG);
qup_config |= QUP_CONFIG_SPI_SLAVE;
spi_config |= SPI_CFG_SLAVE_OP;
writel_relaxed(qup_config, dd->base + QUP_CONFIG);
writel_relaxed(spi_config, dd->base + SPI_CONFIG);
/*
* Ensure the previous write completed before enabling clk_on bit.
*/
mb();
qup_config = readl_relaxed(dd->base + QUP_CONFIG);
qup_config |= (APP_CLK_ON_EN | CORE_CLK_ON_EN |
FIFO_CLK_ON_EN | CORE_EX_CLK_ON_EN);
writel_relaxed(qup_config, dd->base + QUP_CONFIG);
/*
* Ensure Slave setup completes before returning.
*/