From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH 2/2] mtd: nand: sunxi: add reset line support Date: Sun, 19 Jun 2016 14:06:52 +0200 Message-ID: <20160619140652.07ab03c9@bbrezillon> References: <20160619113739.30362-1-icenowy@aosc.xyz> <20160619113739.30362-2-icenowy@aosc.xyz> Reply-To: boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org In-Reply-To: <20160619113739.30362-2-icenowy-ymACFijhrKM@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Icenowy Zheng Cc: maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, wens-jdAy2FN1RRM@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, richard-/L3Ra7n9ekc@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Philipp Zabel List-Id: devicetree@vger.kernel.org +Philipp On Sun, 19 Jun 2016 19:37:39 +0800 Icenowy Zheng 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 > --- > drivers/mtd/nand/sunxi_nand.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c > index a83a690..1502748 100644 > --- a/drivers/mtd/nand/sunxi_nand.c > +++ b/drivers/mtd/nand/sunxi_nand.c > @@ -39,6 +39,7 @@ > #include > #include > #include > +#include > > #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 +1873,18 @@ 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 (PTR_ERR(nfc->reset) == -EPROBE_DEFER) > + return PTR_ERR(nfc->reset); Actually you should test for != -ENOENT, because all error codes except this one should stop the ->probe(). BTW, this devm_reset_control_get_optional() is really weird. While most _optional() methods return NULL when the element is not defined in the DT, this one returns -ENOTENT, which makes it impossible to differentiate a real error from a undefined reset line (which is a valid case for _optional()). Philipp, is there a good reason for doing that? > + > + 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; > + } > + } > +