From edf7550a1f93a88be2bf743b5d352b278d1b789c Mon Sep 17 00:00:00 2001
From: Joel Stanley <joel@jms.id.au>
Date: Tue, 31 Oct 2017 12:42:03 +1030
Subject: [PATCH] iio: adc: aspeed: Deassert reset in probe
The ASPEED SoC must deassert a reset in order to use the ADC peripheral.
The device tree bindings are updated to document the resets phandle, and
the example is updated to match what is expected for both the reset and
clock phandle. Note that the bindings should have always had the reset
controller, as the hardware is unusable without it.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
.../bindings/iio/adc/aspeed_adc.txt | 4 ++-
drivers/iio/adc/aspeed_adc.c | 25 ++++++++++++++-----
2 files changed, 22 insertions(+), 7 deletions(-)
diff --git a/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt b/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt
index 674e133b7cd7d..034fc2ba100e7 100644
--- a/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/aspeed_adc.txt
@@ -8,6 +8,7 @@ Required properties:
- reg: memory window mapping address and length
- clocks: Input clock used to derive the sample clock. Expected to be the
SoC's APB clock.
+- resets: Reset controller phandle
- #io-channel-cells: Must be set to <1> to indicate channels are selected
by index.
@@ -15,6 +16,7 @@ Example:
adc@1e6e9000 {
compatible = "aspeed,ast2400-adc";
reg = <0x1e6e9000 0xb0>;
- clocks = <&clk_apb>;
+ clocks = <&syscon ASPEED_CLK_APB>;
+ resets = <&syscon ASPEED_RESET_ADC>;
#io-channel-cells = <1>;
};
diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index 8a958d5f1905c..327a49ba19916 100644
--- a/drivers/iio/adc/aspeed_adc.c
+++ b/drivers/iio/adc/aspeed_adc.c
@@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
+#include <linux/reset.h>
#include <linux/spinlock.h>
#include <linux/types.h>
@@ -53,11 +54,12 @@ struct aspeed_adc_model_data {
};
struct aspeed_adc_data {
- struct device *dev;
- void __iomem *base;
- spinlock_t clk_lock;
- struct clk_hw *clk_prescaler;
- struct clk_hw *clk_scaler;
+ struct device *dev;
+ void __iomem *base;
+ spinlock_t clk_lock;
+ struct clk_hw *clk_prescaler;
+ struct clk_hw *clk_scaler;
+ struct reset_control *rst;
};
#define ASPEED_CHAN(_idx, _data_reg_addr) { \
@@ -217,6 +219,15 @@ static int aspeed_adc_probe(struct platform_device *pdev)
goto scaler_error;
}
+ data->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(data->rst)) {
+ dev_err(&pdev->dev,
+ "invalid or missing reset controller device tree entry");
+ ret = PTR_ERR(data->rst);
+ goto reset_error;
+ }
+ reset_control_deassert(data->rst);
+
model_data = of_device_get_match_data(&pdev->dev);
if (model_data->wait_init_sequence) {
@@ -263,9 +274,10 @@ static int aspeed_adc_probe(struct platform_device *pdev)
writel(ASPEED_OPERATION_MODE_POWER_DOWN,
data->base + ASPEED_REG_ENGINE_CONTROL);
clk_disable_unprepare(data->clk_scaler->clk);
+reset_error:
+ reset_control_assert(data->rst);
clk_enable_error:
clk_hw_unregister_divider(data->clk_scaler);
-
scaler_error:
clk_hw_unregister_divider(data->clk_prescaler);
return ret;
@@ -280,6 +292,7 @@ static int aspeed_adc_remove(struct platform_device *pdev)
writel(ASPEED_OPERATION_MODE_POWER_DOWN,
data->base + ASPEED_REG_ENGINE_CONTROL);
clk_disable_unprepare(data->clk_scaler->clk);
+ reset_control_assert(data->rst);
clk_hw_unregister_divider(data->clk_scaler);
clk_hw_unregister_divider(data->clk_prescaler);
--
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