[PATCH v4 1/2] mtd: nand: sunxi: update DT bindings

[PATCH v4 1/2] mtd: nand: sunxi: update DT bindings

[Icenowy Zheng]

Document the reset lines

Signed-off-by: Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org>
---
Changes since v2:
  - Nothing.

 Documentation/devicetree/bindings/mtd/sunxi-nand.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/mtd/sunxi-nand.txt b/Documentation/devicetree/bindings/mtd/sunxi-nand.txt
index 086d6f4..a328fbb 100644
--- a/Documentation/devicetree/bindings/mtd/sunxi-nand.txt
+++ b/Documentation/devicetree/bindings/mtd/sunxi-nand.txt
@@ -15,6 +15,8 @@ Optional children nodes:
 Children nodes represent the available nand chips.
 
 Optional properties:
+- reset : phandle + reset specifier pair
+- reset-names : must contain "ahb"
 - allwinner,rb : shall contain the native Ready/Busy ids.
  or
 - rb-gpios : shall contain the gpios used as R/B pins.
-- 
2.9.0

[PATCH v4 2/2] mtd: nand: sunxi: add reset line support

[Icenowy Zheng]

The NAND controller on some sun8i chips needs its reset line to be deasserted
before they can enter working state. This commit added the reset line process
to the driver.

Signed-off-by: Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org>
---
Changes in v2:
  - Corrected the error checking code of reset line.

Changes in v3:
  - Corrected a more serious error brought in the "fix" of v2.

Changes in v4:
  - Removed unneeded code block after "else".

 drivers/mtd/nand/sunxi_nand.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
index a83a690..b37075b 100644
--- a/drivers/mtd/nand/sunxi_nand.c
+++ b/drivers/mtd/nand/sunxi_nand.c
@@ -39,6 +39,7 @@
 #include <linux/gpio.h>
 #include <linux/interrupt.h>
 #include <linux/iopoll.h>
+#include <linux/reset.h>
 
 #define NFC_REG_CTL		0x0000
 #define NFC_REG_ST		0x0004
@@ -269,6 +270,7 @@ struct sunxi_nfc {
 	void __iomem *regs;
 	struct clk *ahb_clk;
 	struct clk *mod_clk;
+	struct reset_control *reset;
 	unsigned long assigned_cs;
 	unsigned long clk_rate;
 	struct list_head chips;
@@ -1871,6 +1873,19 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
 	if (ret)
 		goto out_ahb_clk_unprepare;
 
+	nfc->reset = devm_reset_control_get_optional(dev, "ahb");
+
+	if (!IS_ERR(nfc->reset)) {
+		ret = reset_control_deassert(nfc->reset);
+		if (ret) {
+			dev_err(dev, "reset err %d\n", ret);
+			goto out_mod_clk_unprepare;
+		}
+	}
+	else if (PTR_ERR(nfc->reset) != -ENOENT) {
+		return PTR_ERR(nfc->reset);
+	}
+
 	ret = sunxi_nfc_rst(nfc);
 	if (ret)
 		goto out_mod_clk_unprepare;
-- 
2.9.0

Re: [PATCH v4 2/2] mtd: nand: sunxi: add reset line support

[Boris Brezillon]

On Sun, 19 Jun 2016 23:40:35 +0800
Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org> wrote:

> The NAND controller on some sun8i chips needs its reset line to be deasserted
> before they can enter working state. This commit added the reset line process
> to the driver.
> 
> Signed-off-by: Icenowy Zheng <icenowy-ymACFijhrKM@public.gmane.org>
> ---
> Changes in v2:
>   - Corrected the error checking code of reset line.
> 
> Changes in v3:
>   - Corrected a more serious error brought in the "fix" of v2.
> 
> Changes in v4:
>   - Removed unneeded code block after "else".
> 
>  drivers/mtd/nand/sunxi_nand.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
> index a83a690..b37075b 100644
> --- a/drivers/mtd/nand/sunxi_nand.c
> +++ b/drivers/mtd/nand/sunxi_nand.c
> @@ -39,6 +39,7 @@
>  #include <linux/gpio.h>
>  #include <linux/interrupt.h>
>  #include <linux/iopoll.h>
> +#include <linux/reset.h>
>  
>  #define NFC_REG_CTL		0x0000
>  #define NFC_REG_ST		0x0004
> @@ -269,6 +270,7 @@ struct sunxi_nfc {
>  	void __iomem *regs;
>  	struct clk *ahb_clk;
>  	struct clk *mod_clk;
> +	struct reset_control *reset;
>  	unsigned long assigned_cs;
>  	unsigned long clk_rate;
>  	struct list_head chips;
> @@ -1871,6 +1873,19 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto out_ahb_clk_unprepare;
>  
> +	nfc->reset = devm_reset_control_get_optional(dev, "ahb");
> +
> +	if (!IS_ERR(nfc->reset)) {
> +		ret = reset_control_deassert(nfc->reset);
> +		if (ret) {
> +			dev_err(dev, "reset err %d\n", ret);
> +			goto out_mod_clk_unprepare;
> +		}
> +	}
> +	else if (PTR_ERR(nfc->reset) != -ENOENT) {

	} else if (...) {

> +		return PTR_ERR(nfc->reset);
> +	}
> +
>  	ret = sunxi_nfc_rst(nfc);
>  	if (ret)
>  		goto out_mod_clk_unprepare;


And you should probably reassert the reset line in case of errors and
in the ->remove() hook.