On 2016?12?15? 03:00, Andy Shevchenko wrote:

On Tue, 2016-12-13 at 21:34 +0100, Wolfram Sang wrote:

quoted

On Tue, Nov 22, 2016 at 12:41:40PM +0800, Zhangfei Gao wrote:

quoted

Some platforms like hi3660 need do reset first to allow accessing
registers

Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>

Adding designware maintainers to CC...

quoted

---
  drivers/i2c/busses/i2c-designware-core.h    | 1 +
  drivers/i2c/busses/i2c-designware-platdrv.c | 5 +++++
  2 files changed, 6 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-core.h

b/drivers/i2c/busses/i2c-designware-core.h
index 0d44d2a..94b14fa 100644

--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h

@@ -80,6 +80,7 @@ struct dw_i2c_dev {
  	void __iomem		*base;
  	struct completion	cmd_complete;
  	struct clk		*clk;
+	struct reset_control	*rst;
  	u32			(*get_clk_rate_khz) (struct

dw_i2c_dev *dev);
  	struct dw_pci_controller *controller;
  	int			cmd_err;

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c

b/drivers/i2c/busses/i2c-designware-platdrv.c
index 0b42a12..fd80e58 100644

--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c

@@ -38,6 +38,7 @@
  #include <linux/pm_runtime.h>
  #include <linux/property.h>
  #include <linux/io.h>
+#include <linux/reset.h>
  #include <linux/slab.h>
  #include <linux/acpi.h>
  #include <linux/platform_data/i2c-designware.h>

@@ -176,6 +177,10 @@ static int dw_i2c_plat_probe(struct

platform_device *pdev)
  	dev->irq = irq;
  	platform_set_drvdata(pdev, dev);
  
+	dev->rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (!IS_ERR(dev->rst))
+		reset_control_reset(dev->rst);

Do we care about EPROBE_DEFER?

Perhaps on error path we need to assert it.

And I guess it should be devm_reset_control_get_optional().

Thanks Andy
Good suggestion, will update accordingly.

Thanks