spi: dw: add reset control

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>
Link: https://lore.kernel.org/r/20200529155806.16758-1-dinguyen@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-dw-mmio.c b/drivers/spi/spi-dw-mmio.c
index 0894b4c..a1b87d4 100644 (file)
--- a/drivers/spi/spi-dw-mmio.c
+++ b/drivers/spi/spi-dw-mmio.c
@@ -19,6 +19,7 @@
 #include <linux/acpi.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
+#include <linux/reset.h>
 
 #include "spi-dw.h"
 
@@ -29,6 +30,7 @@ struct dw_spi_mmio {
        struct clk     *clk;
        struct clk     *pclk;
        void           *priv;
+       struct reset_control *rstc;
 };
 
 #define MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL      0x24
@@ -224,6 +226,14 @@ 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);
@@ -257,6 +267,8 @@ out:
        clk_disable_unprepare(dwsmmio->pclk);
 out_clk:
        clk_disable_unprepare(dwsmmio->clk);
+       reset_control_assert(dwsmmio->rstc);
+
        return ret;
 }
 
@@ -268,6 +280,7 @@ 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;
 }