From: Dinh Nguyen <dinguyen@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: dinguyen@kernel.org, devicetree@vger.kernel.org,
broonie@kernel.org, robh+dt@kernel.org,
linux-spi@vger.kernel.org, Sergey.Semin@baikalelectronics.ru,
fancer.lancer@gmail.com, andriy.shevchenko@linux.intel.com,
lars.povlsen@microchip.com,
Liang Jin J <liang.j.jin@ericsson.com>
Subject: [PATCHv2 1/2] spi: dw: add reset control
Date: Tue, 26 May 2020 10:12:17 -0500 [thread overview]
Message-ID: <20200526151218.6186-1-dinguyen@kernel.org> (raw)
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>
---
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..07e015b6d03d 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)) {
+ if (PTR_ERR(dwsmmio->rstc) == -EPROBE_DEFER)
+ return PTR_ERR(dwsmmio->rstc);
+ }
+ 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
next reply other threads:[~2020-05-26 15:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 15:12 Dinh Nguyen [this message]
2020-05-26 15:12 ` [PATCHv2 2/2] dt-bindings: snps,dw-apb-ssi: add optional reset property Dinh Nguyen
2020-05-26 15:21 ` [PATCHv2 1/2] spi: dw: add reset control Andy Shevchenko
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