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Subject[PATCHv3 1/2] spi: dw: add reset control
Date
Add mechanism to get the reset control and deassert it in order to bring
the IP out of reset.

Signed-off-by: Liang Jin J <liang.j.jin@ericsson.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
---
v3: allow for other failures
remove tab for rstc reset_control
v2: use _get_optional_exclusive
put IP back into reset if there was an error in probe function
---
drivers/spi/spi-dw-mmio.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 384a3ab6dc2d..1e921c40d79b 100644
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -20,6 +20,7 @@
#include <linux/acpi.h>
#include <linux/property.h>
#include <linux/regmap.h>
+#include <linux/reset.h>

#include "spi-dw.h"

@@ -30,6 +31,7 @@ struct dw_spi_mmio {
struct clk *clk;
struct clk *pclk;
void *priv;
+ struct reset_control *rstc;
};

#define MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL 0x24
@@ -175,6 +177,14 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
if (ret)
goto out_clk;

+ /* find an optional reset controller */
+ dwsmmio->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, "spi");
+ if (IS_ERR(dwsmmio->rstc)) {
+ ret = PTR_ERR(dwsmmio->rstc);
+ goto out_clk;
+ }
+ reset_control_deassert(dwsmmio->rstc);
+
dws->bus_num = pdev->id;

dws->max_freq = clk_get_rate(dwsmmio->clk);
@@ -208,6 +218,8 @@ static int dw_spi_mmio_probe(struct platform_device *pdev)
clk_disable_unprepare(dwsmmio->pclk);
out_clk:
clk_disable_unprepare(dwsmmio->clk);
+ reset_control_assert(dwsmmio->rstc);
+
return ret;
}

@@ -219,6 +231,7 @@ static int dw_spi_mmio_remove(struct platform_device *pdev)
pm_runtime_disable(&pdev->dev);
clk_disable_unprepare(dwsmmio->pclk);
clk_disable_unprepare(dwsmmio->clk);
+ reset_control_assert(dwsmmio->rstc);

return 0;
}
--
2.17.1
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