[PATCH v5 2/2] mtd: nand: sunxi: add reset line support

Icenowy Zheng
2016-06-19T16:14:35Z

The NAND controller on some sun8i chips needs its reset line to be
deasserted before they can enter working state.

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".

Changes in v5:
- Added reassertion code in case of initialization error and device
remove.

drivers/mtd/nand/sunxi_nand.c | 27 ++++++++++++++++++++++++---
1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
index a83a690..3b40186 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;
@@ -1871,26 +1873,41 @@ 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;
+ goto out_ahb_reset_reassert;

writel(0, nfc->regs + NFC_REG_INT);
ret = devm_request_irq(dev, irq, sunxi_nfc_interrupt,
0, "sunxi-nand", nfc);
if (ret)
- goto out_mod_clk_unprepare;
+ goto out_ahb_reset_reassert;

platform_set_drvdata(pdev, nfc);

ret = sunxi_nand_chips_init(dev, nfc);
if (ret) {
dev_err(dev, "failed to init nand chips\n");
- goto out_mod_clk_unprepare;
+ goto out_ahb_reset_reassert;
}

return 0;

+out_ahb_reset_reassert:
+ if (!IS_ERR(nfc->reset))
+ reset_control_assert(nfc->reset);
out_mod_clk_unprepare:
clk_disable_unprepare(nfc->mod_clk);
out_ahb_clk_unprepare:
@@ -1904,6 +1921,10 @@ static int sunxi_nfc_remove(struct platform_device *pdev)
struct sunxi_nfc *nfc = platform_get_drvdata(pdev);

sunxi_nand_chips_cleanup(nfc);
+
+ if (!IS_ERR(nfc->reset))
+ reset_control_assert(nfc->reset);
+
clk_disable_unprepare(nfc->mod_clk);
clk_disable_unprepare(nfc->ahb_clk);

--
2.9.0