Date:   Tue, 7 Aug 2018 18:59:21 +0200
From:   Boris Brezillon <boris.brezillon@...tlin.com>
To:     Janusz Krzysztofik <jmkrzyszt@...il.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Jonathan Corbet <corbet@....net>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Tony Lindgren <tony@...mide.com>,
        Aaro Koskinen <aaro.koskinen@....fi>,
        linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
        linux-mtd@...ts.infradead.org, linux-doc@...r.kernel.org,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v2 02/12] mtd: rawnand: ams-delta: Use private
 structure

On Tue,  7 Aug 2018 00:29:08 +0200
Janusz Krzysztofik <jmkrzyszt@...il.com> wrote:

> Introduce a driver private structure and allocate it on device probe.
> Use it for storing nand_chip structure, GPIO descriptors prevoiusly
> stored in static variables as well as io_base pointer previously passed
> as nand controller data or platform driver data.  Subsequent patches
> may populate the structure with more members as needed.
> 
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>

Reviewed-by: Boris Brezillon <boris.brezillon@...tlin.com>

> ---
>  drivers/mtd/nand/raw/ams-delta.c | 126 +++++++++++++++++++++------------------
>  1 file changed, 69 insertions(+), 57 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
> index af313c620264..48233d638d2a 100644
> --- a/drivers/mtd/nand/raw/ams-delta.c
> +++ b/drivers/mtd/nand/raw/ams-delta.c
> @@ -34,14 +34,18 @@
>  /*
>   * MTD structure for E3 (Delta)
>   */
> -static struct mtd_info *ams_delta_mtd = NULL;
> -static struct gpio_desc *gpiod_rdy;
> -static struct gpio_desc *gpiod_nce;
> -static struct gpio_desc *gpiod_nre;
> -static struct gpio_desc *gpiod_nwp;
> -static struct gpio_desc *gpiod_nwe;
> -static struct gpio_desc *gpiod_ale;
> -static struct gpio_desc *gpiod_cle;
> +
> +struct ams_delta_nand {
> +	struct nand_chip	nand_chip;
> +	struct gpio_desc	*gpiod_rdy;
> +	struct gpio_desc	*gpiod_nce;
> +	struct gpio_desc	*gpiod_nre;
> +	struct gpio_desc	*gpiod_nwp;
> +	struct gpio_desc	*gpiod_nwe;
> +	struct gpio_desc	*gpiod_ale;
> +	struct gpio_desc	*gpiod_cle;
> +	void __iomem		*io_base;
> +};
>  
>  /*
>   * Define partitions for flash devices
> @@ -71,26 +75,28 @@ static const struct mtd_partition partition_info[] = {
>  static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
>  {
>  	struct nand_chip *this = mtd_to_nand(mtd);
> -	void __iomem *io_base = (void __iomem *)nand_get_controller_data(this);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
> +	void __iomem *io_base = priv->io_base;
>  
>  	writew(0, io_base + OMAP_MPUIO_IO_CNTL);
>  	writew(byte, this->IO_ADDR_W);
> -	gpiod_set_value(gpiod_nwe, 0);
> +	gpiod_set_value(priv->gpiod_nwe, 0);
>  	ndelay(40);
> -	gpiod_set_value(gpiod_nwe, 1);
> +	gpiod_set_value(priv->gpiod_nwe, 1);
>  }
>  
>  static u_char ams_delta_read_byte(struct mtd_info *mtd)
>  {
>  	u_char res;
>  	struct nand_chip *this = mtd_to_nand(mtd);
> -	void __iomem *io_base = (void __iomem *)nand_get_controller_data(this);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
> +	void __iomem *io_base = priv->io_base;
>  
> -	gpiod_set_value(gpiod_nre, 0);
> +	gpiod_set_value(priv->gpiod_nre, 0);
>  	ndelay(40);
>  	writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
>  	res = readw(this->IO_ADDR_R);
> -	gpiod_set_value(gpiod_nre, 1);
> +	gpiod_set_value(priv->gpiod_nre, 1);
>  
>  	return res;
>  }
> @@ -123,11 +129,13 @@ static void ams_delta_read_buf(struct mtd_info *mtd, u_char *buf, int len)
>  static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
>  				unsigned int ctrl)
>  {
> +	struct nand_chip *this = mtd_to_nand(mtd);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
>  
>  	if (ctrl & NAND_CTRL_CHANGE) {
> -		gpiod_set_value(gpiod_nce, !(ctrl & NAND_NCE));
> -		gpiod_set_value(gpiod_cle, !!(ctrl & NAND_CLE));
> -		gpiod_set_value(gpiod_ale, !!(ctrl & NAND_ALE));
> +		gpiod_set_value(priv->gpiod_nce, !(ctrl & NAND_NCE));
> +		gpiod_set_value(priv->gpiod_cle, !!(ctrl & NAND_CLE));
> +		gpiod_set_value(priv->gpiod_ale, !!(ctrl & NAND_ALE));
>  	}
>  
>  	if (cmd != NAND_CMD_NONE)
> @@ -136,7 +144,10 @@ static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
>  
>  static int ams_delta_nand_ready(struct mtd_info *mtd)
>  {
> -	return gpiod_get_value(gpiod_rdy);
> +	struct nand_chip *this = mtd_to_nand(mtd);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
> +
> +	return gpiod_get_value(priv->gpiod_rdy);
>  }
>  
>  
> @@ -145,7 +156,9 @@ static int ams_delta_nand_ready(struct mtd_info *mtd)
>   */
>  static int ams_delta_init(struct platform_device *pdev)
>  {
> +	struct ams_delta_nand *priv;
>  	struct nand_chip *this;
> +	struct mtd_info *mtd;
>  	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	void __iomem *io_base;
>  	int err = 0;
> @@ -154,15 +167,16 @@ static int ams_delta_init(struct platform_device *pdev)
>  		return -ENXIO;
>  
>  	/* Allocate memory for MTD device structure and private data */
> -	this = kzalloc(sizeof(struct nand_chip), GFP_KERNEL);
> -	if (!this) {
> +	priv = devm_kzalloc(&pdev->dev, sizeof(struct ams_delta_nand),
> +			    GFP_KERNEL);
> +	if (!priv) {
>  		pr_warn("Unable to allocate E3 NAND MTD device structure.\n");
> -		err = -ENOMEM;
> -		goto out;
> +		return -ENOMEM;
>  	}
> +	this = &priv->nand_chip;
>  
> -	ams_delta_mtd = nand_to_mtd(this);
> -	ams_delta_mtd->dev.parent = &pdev->dev;
> +	mtd = nand_to_mtd(this);
> +	mtd->dev.parent = &pdev->dev;
>  
>  	/*
>  	 * Don't try to request the memory region from here,
> @@ -177,7 +191,8 @@ static int ams_delta_init(struct platform_device *pdev)
>  		goto out_free;
>  	}
>  
> -	nand_set_controller_data(this, (void *)io_base);
> +	priv->io_base = io_base;
> +	nand_set_controller_data(this, priv);
>  
>  	/* Set address of NAND IO lines */
>  	this->IO_ADDR_R = io_base + OMAP_MPUIO_INPUT_LATCH;
> @@ -187,14 +202,14 @@ static int ams_delta_init(struct platform_device *pdev)
>  	this->read_buf = ams_delta_read_buf;
>  	this->cmd_ctrl = ams_delta_hwcontrol;
>  
> -	gpiod_rdy = devm_gpiod_get_optional(&pdev->dev, "rdy", GPIOD_IN);
> -	if (IS_ERR(gpiod_rdy)) {
> -		err = PTR_ERR(gpiod_rdy);
> +	priv->gpiod_rdy = devm_gpiod_get_optional(&pdev->dev, "rdy", GPIOD_IN);
> +	if (IS_ERR(priv->gpiod_rdy)) {
> +		err = PTR_ERR(priv->gpiod_rdy);
>  		dev_warn(&pdev->dev, "RDY GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
> -	if (gpiod_rdy)
> +	if (priv->gpiod_rdy)
>  		this->dev_ready = ams_delta_nand_ready;
>  
>  	/* 25 us command delay time */
> @@ -202,66 +217,64 @@ static int ams_delta_init(struct platform_device *pdev)
>  	this->ecc.mode = NAND_ECC_SOFT;
>  	this->ecc.algo = NAND_ECC_HAMMING;
>  
> -	platform_set_drvdata(pdev, io_base);
> +	platform_set_drvdata(pdev, priv);
>  
>  	/* Set chip enabled, but  */
> -	gpiod_nwp = devm_gpiod_get(&pdev->dev, "nwp", GPIOD_OUT_HIGH);
> -	if (IS_ERR(gpiod_nwp)) {
> -		err = PTR_ERR(gpiod_nwp);
> +	priv->gpiod_nwp = devm_gpiod_get(&pdev->dev, "nwp", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->gpiod_nwp)) {
> +		err = PTR_ERR(priv->gpiod_nwp);
>  		dev_err(&pdev->dev, "NWP GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
> -	gpiod_nce = devm_gpiod_get(&pdev->dev, "nce", GPIOD_OUT_HIGH);
> -	if (IS_ERR(gpiod_nce)) {
> -		err = PTR_ERR(gpiod_nce);
> +	priv->gpiod_nce = devm_gpiod_get(&pdev->dev, "nce", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->gpiod_nce)) {
> +		err = PTR_ERR(priv->gpiod_nce);
>  		dev_err(&pdev->dev, "NCE GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
> -	gpiod_nre = devm_gpiod_get(&pdev->dev, "nre", GPIOD_OUT_HIGH);
> -	if (IS_ERR(gpiod_nre)) {
> -		err = PTR_ERR(gpiod_nre);
> +	priv->gpiod_nre = devm_gpiod_get(&pdev->dev, "nre", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->gpiod_nre)) {
> +		err = PTR_ERR(priv->gpiod_nre);
>  		dev_err(&pdev->dev, "NRE GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
> -	gpiod_nwe = devm_gpiod_get(&pdev->dev, "nwe", GPIOD_OUT_HIGH);
> -	if (IS_ERR(gpiod_nwe)) {
> -		err = PTR_ERR(gpiod_nwe);
> +	priv->gpiod_nwe = devm_gpiod_get(&pdev->dev, "nwe", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->gpiod_nwe)) {
> +		err = PTR_ERR(priv->gpiod_nwe);
>  		dev_err(&pdev->dev, "NWE GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
> -	gpiod_ale = devm_gpiod_get(&pdev->dev, "ale", GPIOD_OUT_LOW);
> -	if (IS_ERR(gpiod_ale)) {
> -		err = PTR_ERR(gpiod_ale);
> +	priv->gpiod_ale = devm_gpiod_get(&pdev->dev, "ale", GPIOD_OUT_LOW);
> +	if (IS_ERR(priv->gpiod_ale)) {
> +		err = PTR_ERR(priv->gpiod_ale);
>  		dev_err(&pdev->dev, "ALE GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
> -	gpiod_cle = devm_gpiod_get(&pdev->dev, "cle", GPIOD_OUT_LOW);
> -	if (IS_ERR(gpiod_cle)) {
> -		err = PTR_ERR(gpiod_cle);
> +	priv->gpiod_cle = devm_gpiod_get(&pdev->dev, "cle", GPIOD_OUT_LOW);
> +	if (IS_ERR(priv->gpiod_cle)) {
> +		err = PTR_ERR(priv->gpiod_cle);
>  		dev_err(&pdev->dev, "CLE GPIO request failed (%d)\n", err);
>  		goto out_mtd;
>  	}
>  
>  	/* Scan to find existence of the device */
> -	err = nand_scan(ams_delta_mtd, 1);
> +	err = nand_scan(mtd, 1);
>  	if (err)
>  		goto out_mtd;
>  
>  	/* Register the partitions */
> -	mtd_device_register(ams_delta_mtd, partition_info,
> -			    ARRAY_SIZE(partition_info));
> +	mtd_device_register(mtd, partition_info, ARRAY_SIZE(partition_info));
>  
>  	goto out;
>  
>   out_mtd:
>  	iounmap(io_base);
>  out_free:
> -	kfree(this);
>   out:
>  	return err;
>  }
> @@ -271,16 +284,15 @@ static int ams_delta_init(struct platform_device *pdev)
>   */
>  static int ams_delta_cleanup(struct platform_device *pdev)
>  {
> -	void __iomem *io_base = platform_get_drvdata(pdev);
> +	struct ams_delta_nand *priv = platform_get_drvdata(pdev);
> +	struct mtd_info *mtd = nand_to_mtd(&priv->nand_chip);
> +	void __iomem *io_base = priv->io_base;
>  
>  	/* Release resources, unregister device */
> -	nand_release(ams_delta_mtd);
> +	nand_release(mtd);
>  
>  	iounmap(io_base);
>  
> -	/* Free the MTD device structure */
> -	kfree(mtd_to_nand(ams_delta_mtd));
> -
>  	return 0;
>  }
>  

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