From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752012AbbJZUtG (ORCPT ); Mon, 26 Oct 2015 16:49:06 -0400 Received: from mail-pa0-f51.google.com ([209.85.220.51]:36093 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbbJZUtD (ORCPT ); Mon, 26 Oct 2015 16:49:03 -0400 Date: Mon, 26 Oct 2015 13:49:00 -0700 From: Brian Norris To: Roger Quadros Cc: tony@atomide.com, dwmw2@infradead.org, ezequiel@vanguardiasur.com.ar, javier@dowhile0.org, fcooper@ti.com, nsekhar@ti.com, linux-mtd@lists.infradead.org, linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Boris Brezillon , Alex Smith , Harvey Hunt Subject: Re: [PATCH v3 18/27] mtd: nand: omap2: Implement NAND ready using gpiolib Message-ID: <20151026204900.GI13239@google.com> References: <1442588029-13769-1-git-send-email-rogerq@ti.com> <1442588029-13769-19-git-send-email-rogerq@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1442588029-13769-19-git-send-email-rogerq@ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org + others A few comments below. On Fri, Sep 18, 2015 at 05:53:40PM +0300, Roger Quadros wrote: > The GPMC WAIT pin status are now available over gpiolib. > Update the omap_dev_ready() function to use gpio instead of > directly accessing GPMC register space. > > Signed-off-by: Roger Quadros > --- > drivers/mtd/nand/omap2.c | 29 +++++++++++++++++----------- > include/linux/platform_data/mtd-nand-omap2.h | 2 +- > 2 files changed, 19 insertions(+), 12 deletions(-) > > diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c > index 228f498..d0f2620 100644 > --- a/drivers/mtd/nand/omap2.c > +++ b/drivers/mtd/nand/omap2.c > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -184,6 +185,8 @@ struct omap_nand_info { > /* fields specific for BCHx_HW ECC scheme */ > struct device *elm_dev; > struct device_node *of_node; > + /* NAND ready gpio */ > + struct gpio_desc *ready_gpiod; > }; > > /** > @@ -1047,22 +1050,17 @@ static int omap_wait(struct mtd_info *mtd, struct nand_chip *chip) > } > > /** > - * omap_dev_ready - calls the platform specific dev_ready function > + * omap_dev_ready - checks the NAND Ready GPIO line > * @mtd: MTD device structure > + * > + * Returns true if ready and false if busy. > */ > static int omap_dev_ready(struct mtd_info *mtd) > { > - unsigned int val = 0; > struct omap_nand_info *info = container_of(mtd, struct omap_nand_info, > mtd); > > - val = readl(info->reg.gpmc_status); > - > - if ((val & 0x100) == 0x100) { > - return 1; > - } else { > - return 0; > - } > + return gpiod_get_value(info->ready_gpiod); > } > > /** > @@ -1782,7 +1780,9 @@ static int omap_nand_probe(struct platform_device *pdev) > info->reg = pdata->reg; > info->of_node = pdata->of_node; > info->ecc_opt = pdata->ecc_opt; > - info->dev_ready = pdata->dev_ready; > + if (pdata->dev_ready) > + dev_info(&pdev->dev, "pdata->dev_ready is deprecated\n"); > + > info->xfer_type = pdata->xfer_type; > info->devsize = pdata->devsize; > info->elm_of_node = pdata->elm_of_node; > @@ -1815,6 +1815,13 @@ static int omap_nand_probe(struct platform_device *pdev) > nand_chip->IO_ADDR_W = nand_chip->IO_ADDR_R; > nand_chip->cmd_ctrl = omap_hwcontrol; > > + info->ready_gpiod = devm_gpiod_get_optional(&pdev->dev, "ready", > + GPIOD_IN); Others have been looking at using GPIOs for the ready/busy pin too. At a minimum, we need an updated DT binding doc for this, since I see you're adding this via device tree in a later patch (I don't see any DT binding patch for this; but I could just be overlooking it). It'd also be great if this support was moved to nand_dt_init() so other platforms can benefit, but I won't require that. Also, previous [0] proposers had suggested 'rb-gpios', not 'ready-gpio' (the hardware docs typically call it 'rb' for ready/busy, FWIW). I don't really care, but the name should be going into a doc, so we can choose the same one everywhere. EDIT: looks like the discussion was partly here [1] and it seems we're landing on "rb-gpios" in the latest version [2]. Can we stick with that? Regards, Brian [0] "Previous" may be subject to debate, as both series have been going for several revisions. [1] http://patchwork.ozlabs.org/patch/515327/ [2] http://patchwork.ozlabs.org/patch/526819/ > + if (IS_ERR(info->ready_gpiod)) { > + dev_err(dev, "failed to get ready gpio\n"); > + return PTR_ERR(info->ready_gpiod); > + } > + > /* > * If RDY/BSY line is connected to OMAP then use the omap ready > * function and the generic nand_wait function which reads the status > @@ -1822,7 +1829,7 @@ static int omap_nand_probe(struct platform_device *pdev) > * chip delay which is slightly more than tR (AC Timing) of the NAND > * device and read status register until you get a failure or success > */ > - if (info->dev_ready) { > + if (info->ready_gpiod) { > nand_chip->dev_ready = omap_dev_ready; > nand_chip->chip_delay = 0; > } else { > diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h > index ff27e5a..19e509d 100644 > --- a/include/linux/platform_data/mtd-nand-omap2.h > +++ b/include/linux/platform_data/mtd-nand-omap2.h > @@ -70,7 +70,6 @@ struct omap_nand_platform_data { > int cs; > struct mtd_partition *parts; > int nr_parts; > - bool dev_ready; > bool flash_bbt; > enum nand_io xfer_type; > int devsize; > @@ -81,5 +80,6 @@ struct omap_nand_platform_data { > /* deprecated */ > struct gpmc_nand_regs reg; > struct device_node *of_node; > + bool dev_ready; > }; > #endif > -- > 2.1.4 >