[PATCH AUTOSEL 4.19 03/20] spi: qup: call spi_qup_pm_resume_runtime before suspending

[PATCH AUTOSEL 4.19 03/20] spi: qup: call spi_qup_pm_resume_runtime before suspending

[Sasha Levin]

From: Yuji Sasaki <sasakiy@chromium.org>

[ Upstream commit 136b5cd2e2f97581ae560cff0db2a3b5369112da ]

spi_qup_suspend() will cause synchronous external abort when
runtime suspend is enabled and applied, as it tries to
access SPI controller register while clock is already disabled
in spi_qup_pm_suspend_runtime().

Signed-off-by: Yuji sasaki <sasakiy@chromium.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20200214074340.2286170-1-vkoul@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-qup.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
index 974a8ce58b68b..cb74fd1af2053 100644
--- a/drivers/spi/spi-qup.c
+++ b/drivers/spi/spi-qup.c
@@ -1190,6 +1190,11 @@ static int spi_qup_suspend(struct device *device)
 	struct spi_qup *controller = spi_master_get_devdata(master);
 	int ret;
 
+	if (pm_runtime_suspended(device)) {
+		ret = spi_qup_pm_resume_runtime(device);
+		if (ret)
+			return ret;
+	}
 	ret = spi_master_suspend(master);
 	if (ret)
 		return ret;
@@ -1198,10 +1203,8 @@ static int spi_qup_suspend(struct device *device)
 	if (ret)
 		return ret;
 
-	if (!pm_runtime_suspended(device)) {
-		clk_disable_unprepare(controller->cclk);
-		clk_disable_unprepare(controller->iclk);
-	}
+	clk_disable_unprepare(controller->cclk);
+	clk_disable_unprepare(controller->iclk);
 	return 0;
 }
 
-- 
2.20.1

[PATCH AUTOSEL 4.19 06/20] spi: pxa2xx: Add CS control clock quirk

[Sasha Levin]

From: Evan Green <evgreen@chromium.org>

[ Upstream commit 683f65ded66a9a7ff01ed7280804d2132ebfdf7e ]

In some circumstances on Intel LPSS controllers, toggling the LPSS
CS control register doesn't actually cause the CS line to toggle.
This seems to be failure of dynamic clock gating that occurs after
going through a suspend/resume transition, where the controller
is sent through a reset transition. This ruins SPI transactions
that either rely on delay_usecs, or toggle the CS line without
sending data.

Whenever CS is toggled, momentarily set the clock gating register
to "Force On" to poke the controller into acting on CS.

Signed-off-by: Rajat Jain <rajatja@google.com>
Signed-off-by: Evan Green <evgreen@chromium.org>
Link: https://lore.kernel.org/r/20200211223700.110252-1-rajatja@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-pxa2xx.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 525388126e260..e4482823d8d75 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -76,6 +76,10 @@ MODULE_ALIAS("platform:pxa2xx-spi");
 #define LPSS_CAPS_CS_EN_SHIFT			9
 #define LPSS_CAPS_CS_EN_MASK			(0xf << LPSS_CAPS_CS_EN_SHIFT)
 
+#define LPSS_PRIV_CLOCK_GATE 0x38
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3
+#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3
+
 struct lpss_config {
 	/* LPSS offset from drv_data->ioaddr */
 	unsigned offset;
@@ -92,6 +96,8 @@ struct lpss_config {
 	unsigned cs_sel_shift;
 	unsigned cs_sel_mask;
 	unsigned cs_num;
+	/* Quirks */
+	unsigned cs_clk_stays_gated : 1;
 };
 
 /* Keep these sorted with enum pxa_ssp_type */
@@ -162,6 +168,7 @@ static const struct lpss_config lpss_platforms[] = {
 		.tx_threshold_hi = 56,
 		.cs_sel_shift = 8,
 		.cs_sel_mask = 3 << 8,
+		.cs_clk_stays_gated = true,
 	},
 };
 
@@ -389,6 +396,22 @@ static void lpss_ssp_cs_control(struct spi_device *spi, bool enable)
 	else
 		value |= LPSS_CS_CONTROL_CS_HIGH;
 	__lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value);
+	if (config->cs_clk_stays_gated) {
+		u32 clkgate;
+
+		/*
+		 * Changing CS alone when dynamic clock gating is on won't
+		 * actually flip CS at that time. This ruins SPI transfers
+		 * that specify delays, or have no data. Toggle the clock mode
+		 * to force on briefly to poke the CS pin to move.
+		 */
+		clkgate = __lpss_ssp_read_priv(drv_data, LPSS_PRIV_CLOCK_GATE);
+		value = (clkgate & ~LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK) |
+			LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON;
+
+		__lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, value);
+		__lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, clkgate);
+	}
 }
 
 static void cs_assert(struct spi_device *spi)
-- 
2.20.1

[PATCH AUTOSEL 4.19 07/20] spi/zynqmp: remove entry that causes a cs glitch

[Sasha Levin]

From: Thommy Jakobsson <thommyj@gmail.com>

[ Upstream commit 5dd8304981ecffa77bb72b1c57c4be5dfe6cfae9 ]

In the public interface for chipselect, there is always an entry
commented as "Dummy generic FIFO entry" pushed down to the fifo right
after the activate/deactivate command. The dummy entry is 0x0,
irregardless if the intention was to activate or deactive the cs. This
causes the cs line to glitch rather than beeing activated in the case
when there was an activate command.

This has been observed on oscilloscope, and have caused problems for at
least one specific flash device type connected to the qspi port. After
the change the glitch is gone and cs goes active when intended.

The reason why this worked before (except for the glitch) was because
when sending the actual data, the CS bits are once again set. Since
most flashes uses mode 0, there is always a half clk period anyway for
cs to clk active setup time. If someone would rely on timing from a
chip_select call to a transfer_one, it would fail though.

It is unknown why the dummy entry was there in the first place, git log
seems to be of no help in this case. The reference manual gives no
indication of the necessity of this. In fact the lower 8 bits are a
setup (or hold in case of deactivate) time expressed in cycles. So this
should not be needed to fulfill any setup/hold timings.

Signed-off-by: Thommy Jakobsson <thommyj@gmail.com>
Reviewed-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Link: https://lore.kernel.org/r/20200224162643.29102-1-thommyj@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-zynqmp-gqspi.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/spi/spi-zynqmp-gqspi.c b/drivers/spi/spi-zynqmp-gqspi.c
index cc4d310334943..f2848c59b0b8e 100644
--- a/drivers/spi/spi-zynqmp-gqspi.c
+++ b/drivers/spi/spi-zynqmp-gqspi.c
@@ -403,9 +403,6 @@ static void zynqmp_qspi_chipselect(struct spi_device *qspi, bool is_high)
 
 	zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, genfifoentry);
 
-	/* Dummy generic FIFO entry */
-	zynqmp_gqspi_write(xqspi, GQSPI_GEN_FIFO_OFST, 0x0);
-
 	/* Manually start the generic FIFO command */
 	zynqmp_gqspi_write(xqspi, GQSPI_CONFIG_OFST,
 			zynqmp_gqspi_read(xqspi, GQSPI_CONFIG_OFST) |
-- 
2.20.1