Re: [PATCH] MIPS/I2C: Move SEAD3 I2C driver to where it belongs.

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

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On Fri, Oct 24, 2014 at 02:26:57PM +0200, Ralf Baechle wrote:
> Fixes the following build problem if CONFIG_I2C is disabled:
> 
> arch/mips/mti-sead3/sead3-pic32-i2c-drv.c: In function 'i2c_platform_probe':
> arch/mips/mti-sead3/sead3-pic32-i2c-drv.c:345:2: error: implicit declaration of
> function 'i2c_add_numbered_adapter' [-Werror=implicit-function-declaration]
>   ret = i2c_add_numbered_adapter(&priv->adap);
>     ^
> arch/mips/mti-sead3/sead3-pic32-i2c-drv.c: In function
> 'i2c_platform_remove':
> arch/mips/mti-sead3/sead3-pic32-i2c-drv.c:361:2: error: implicit declaration
> of function 'i2c_del_adapter' [-Werror=implicit-function-declaration]
> i2c_del_adapter(&priv->adap);
> 

Uh, so this is already mainline? It has some issues.

> Signed-off-by: Ralf Baechle <ralf-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>
> Cc: Markos Chandras <markos.chandras-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>
> Cc: Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>
> Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Cc: linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org
> Cc: Chris Dearman <chris.dearman-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org>

No diffstat?

> diff --git a/drivers/i2c/busses/i2c-sead3.c b/drivers/i2c/busses/i2c-sead3.c
> new file mode 100644
> index 0000000..1f787a6
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-sead3.c
> @@ -0,0 +1,405 @@
> +/*
> + * This file is subject to the terms and conditions of the GNU General Public
> + * License.  See the file "COPYING" in the main directory of this archive
> + * for more details.
> + *
> + * Copyright (C) 2012 MIPS Technologies, Inc.  All rights reserved.
> + */
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/platform_device.h>

Please sort the includes.

> +
> +#define PIC32_I2CxCON		0x0000
> +#define	 PIC32_I2CCON_ON	(1<<15)
> +#define	 PIC32_I2CCON_ACKDT	(1<<5)
> +#define	 PIC32_I2CCON_ACKEN	(1<<4)
> +#define	 PIC32_I2CCON_RCEN	(1<<3)
> +#define	 PIC32_I2CCON_PEN	(1<<2)
> +#define	 PIC32_I2CCON_RSEN	(1<<1)
> +#define	 PIC32_I2CCON_SEN	(1<<0)
> +#define PIC32_I2CxCONCLR	0x0004
> +#define PIC32_I2CxCONSET	0x0008
> +#define PIC32_I2CxSTAT		0x0010
> +#define PIC32_I2CxSTATCLR	0x0014
> +#define	 PIC32_I2CSTAT_ACKSTAT	(1<<15)
> +#define	 PIC32_I2CSTAT_TRSTAT	(1<<14)
> +#define	 PIC32_I2CSTAT_BCL	(1<<10)
> +#define	 PIC32_I2CSTAT_IWCOL	(1<<7)
> +#define	 PIC32_I2CSTAT_I2COV	(1<<6)
> +#define PIC32_I2CxBRG		0x0040
> +#define PIC32_I2CxTRN		0x0050
> +#define PIC32_I2CxRCV		0x0060
> +
> +static DEFINE_SPINLOCK(pic32_bus_lock);
> +
> +static void __iomem *bus_xfer	= (void __iomem *)0xbf000600;
> +static void __iomem *bus_status = (void __iomem *)0xbf000060;
> +
> +#define DELAY() udelay(100)
> +
> +static inline unsigned int ioready(void)
> +{
> +	return readl(bus_status) & 1;
> +}
> +
> +static inline void wait_ioready(void)
> +{
> +	do { } while (!ioready());
> +}

No timeout?

> +
> +static inline void wait_ioclear(void)
> +{
> +	do { } while (ioready());
> +}

ditto

> +
> +static inline void check_ioclear(void)
> +{
> +	if (ioready()) {
> +		do {
> +			(void) readl(bus_xfer);
> +			DELAY();
> +		} while (ioready());
> +	}
> +}
> +
> +static u32 pic32_bus_readl(u32 reg)
> +{
> +	unsigned long flags;
> +	u32 status, val;
> +
> +	spin_lock_irqsave(&pic32_bus_lock, flags);
> +
> +	check_ioclear();
> +	writel((0x01 << 24) | (reg & 0x00ffffff), bus_xfer);

Can we have names for all these magic hex-values?

> +	DELAY();
> +	wait_ioready();
> +	status = readl(bus_xfer);
> +	DELAY();
> +	val = readl(bus_xfer);
> +	wait_ioclear();
> +
> +	spin_unlock_irqrestore(&pic32_bus_lock, flags);
> +
> +	return val;
> +}
> +
> +static void pic32_bus_writel(u32 val, u32 reg)
> +{
> +	unsigned long flags;
> +	u32 status;
> +
> +	spin_lock_irqsave(&pic32_bus_lock, flags);
> +
> +	check_ioclear();
> +	writel((0x10 << 24) | (reg & 0x00ffffff), bus_xfer);
> +	DELAY();
> +	writel(val, bus_xfer);
> +	DELAY();
> +	wait_ioready();
> +	status = readl(bus_xfer);
> +	wait_ioclear();
> +
> +	spin_unlock_irqrestore(&pic32_bus_lock, flags);
> +}
> +
> +struct pic32_i2c_platform_data {
> +	u32	base;
> +	struct i2c_adapter adap;
> +	u32	xfer_timeout;
> +	u32	ack_timeout;
> +	u32	ctl_timeout;
> +};

priv goes to the platform instead of the adapter? Unusual, why is that?

> +
> +static inline void pic32_i2c_start(struct pic32_i2c_platform_data *adap)
> +{
> +	pic32_bus_writel(PIC32_I2CCON_SEN, adap->base + PIC32_I2CxCONSET);
> +}
> +
> +static inline void pic32_i2c_stop(struct pic32_i2c_platform_data *adap)
> +{
> +	pic32_bus_writel(PIC32_I2CCON_PEN, adap->base + PIC32_I2CxCONSET);
> +}
> +
> +static inline void pic32_i2c_ack(struct pic32_i2c_platform_data *adap)
> +{
> +	pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR);
> +	pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
> +}
> +
> +static inline void pic32_i2c_nack(struct pic32_i2c_platform_data *adap)
> +{
> +	pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET);
> +	pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
> +}
> +
> +static inline int pic32_i2c_idle(struct pic32_i2c_platform_data *adap)
> +{
> +	int i;
> +
> +	for (i = 0; i < adap->ctl_timeout; i++) {
> +		if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) &
> +		      (PIC32_I2CCON_ACKEN | PIC32_I2CCON_RCEN |
> +		       PIC32_I2CCON_PEN | PIC32_I2CCON_RSEN |
> +		       PIC32_I2CCON_SEN)) == 0) &&
> +		    ((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
> +		      (PIC32_I2CSTAT_TRSTAT)) == 0))
> +			return 0;
> +		udelay(1);
> +	}
> +	return -ETIMEDOUT;
> +}
> +
> +static inline u32 pic32_i2c_master_write(struct pic32_i2c_platform_data *adap,
> +		u32 byte)
> +{
> +	pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN);
> +	return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
> +			PIC32_I2CSTAT_IWCOL;
> +}
> +
> +static inline u32 pic32_i2c_master_read(struct pic32_i2c_platform_data *adap)
> +{
> +	pic32_bus_writel(PIC32_I2CCON_RCEN, adap->base + PIC32_I2CxCONSET);
> +	while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & PIC32_I2CCON_RCEN)
> +		;
> +	pic32_bus_writel(PIC32_I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR);
> +	return pic32_bus_readl(adap->base + PIC32_I2CxRCV);
> +}
> +
> +static int pic32_i2c_address(struct pic32_i2c_platform_data *adap,
> +		unsigned int addr, int rd)
> +{
> +	pic32_i2c_idle(adap);
> +	pic32_i2c_start(adap);
> +	pic32_i2c_idle(adap);
> +
> +	addr <<= 1;
> +	if (rd)
> +		addr |= 1;
> +
> +	if (pic32_i2c_master_write(adap, addr))
> +		return -EIO;
> +	pic32_i2c_idle(adap);
> +	if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
> +			PIC32_I2CSTAT_ACKSTAT)
> +		return -EIO;

I'd think this is -ENXIO. Please have a look at
Documentation/i2c/fault-codes for the error codes we use.

> +	return 0;
> +}
> +
> +static int sead3_i2c_read(struct pic32_i2c_platform_data *adap,
> +		unsigned char *buf, unsigned int len)
> +{
> +	u32 data;
> +	int i;
> +
> +	i = 0;
> +	while (i < len) {
> +		data = pic32_i2c_master_read(adap);
> +		buf[i++] = data;
> +		if (i < len)
> +			pic32_i2c_ack(adap);
> +		else
> +			pic32_i2c_nack(adap);
> +	}
> +
> +	pic32_i2c_stop(adap);
> +	pic32_i2c_idle(adap);
> +	return 0;
> +}
> +
> +static int sead3_i2c_write(struct pic32_i2c_platform_data *adap,
> +		unsigned char *buf, unsigned int len)
> +{
> +	int i;
> +	u32 data;
> +
> +	i = 0;
> +	while (i < len) {
> +		data = buf[i];
> +		if (pic32_i2c_master_write(adap, data))
> +			return -EIO;
> +		pic32_i2c_idle(adap);
> +		if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
> +					PIC32_I2CSTAT_ACKSTAT)
> +			return -EIO;

ditto

> +		i++;
> +	}
> +
> +	pic32_i2c_stop(adap);
> +	pic32_i2c_idle(adap);
> +	return 0;
> +}
> +
> +static int sead3_pic32_platform_xfer(struct i2c_adapter *i2c_adap,
> +		struct i2c_msg *msgs, int num)
> +{
> +	struct pic32_i2c_platform_data *adap = i2c_adap->algo_data;
> +	struct i2c_msg *p;
> +	int i, err = 0;
> +
> +	for (i = 0; i < num; i++) {
> +#define __BUFSIZE 80
> +		int ii;
> +		static char buf[__BUFSIZE];
> +		char *b = buf;
> +
> +		p = &msgs[i];
> +		b += sprintf(buf, " [%d bytes]", p->len);
> +		if ((p->flags & I2C_M_RD) == 0) {
> +			for (ii = 0; ii < p->len; ii++) {
> +				if (b < &buf[__BUFSIZE-4]) {
> +					b += sprintf(b, " %02x", p->buf[ii]);
> +				} else {
> +					strcat(b, "...");
> +					break;
> +				}
> +			}
> +		}

??? Where is buf used? And we have other debugging options and support
even tracing. Not needed.

> +	}
> +
> +	for (i = 0; !err && i < num; i++) {
> +		p = &msgs[i];
> +		err = pic32_i2c_address(adap, p->addr, p->flags & I2C_M_RD);
> +		if (err || !p->len)
> +			continue;

So, you don't support SMBUS_QUICK? You should remove it from the
functionality then. Or add support for it.

> +		if (p->flags & I2C_M_RD)
> +			err = sead3_i2c_read(adap, p->buf, p->len);
> +		else
> +			err = sead3_i2c_write(adap, p->buf, p->len);
> +	}
> +
> +	/* Return the number of messages processed, or the error code. */
> +	if (err == 0)
> +		err = num;
> +
> +	return err;
> +}
> +
> +static u32 sead3_pic32_platform_func(struct i2c_adapter *adap)
> +{
> +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static const struct i2c_algorithm sead3_platform_algo = {
> +	.master_xfer	= sead3_pic32_platform_xfer,
> +	.functionality	= sead3_pic32_platform_func,
> +};
> +
> +static void sead3_i2c_platform_setup(struct pic32_i2c_platform_data *priv)
> +{
> +	pic32_bus_writel(500, priv->base + PIC32_I2CxBRG);
> +	pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONCLR);
> +	pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONSET);
> +	pic32_bus_writel(PIC32_I2CSTAT_BCL | PIC32_I2CSTAT_IWCOL,
> +		priv->base + PIC32_I2CxSTATCLR);
> +}
> +
> +static int sead3_i2c_platform_probe(struct platform_device *pdev)
> +{
> +	struct pic32_i2c_platform_data *priv;
> +	struct resource *r;
> +	int ret;
> +
> +	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!r) {
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	priv = kzalloc(sizeof(struct pic32_i2c_platform_data), GFP_KERNEL);
> +	if (!priv) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	priv->base = r->start;

OK. MIPS doesn't need ioremap?

> +	if (!priv->base) {
> +		ret = -EBUSY;
> +		goto out_mem;
> +	}
> +
> +	priv->xfer_timeout = 200;
> +	priv->ack_timeout = 200;
> +	priv->ctl_timeout = 200;

Why have three if they are all the same?

> +
> +	priv->adap.nr = pdev->id;
> +	priv->adap.algo = &sead3_platform_algo;
> +	priv->adap.algo_data = priv;
> +	priv->adap.dev.parent = &pdev->dev;
> +	strlcpy(priv->adap.name, "SEAD3 PIC32", sizeof(priv->adap.name));
> +
> +	sead3_i2c_platform_setup(priv);
> +
> +	ret = i2c_add_numbered_adapter(&priv->adap);
> +	if (ret == 0) {
> +		platform_set_drvdata(pdev, priv);

No, it must be set before! If I2C gets called after add_adapter and
before the if, we have an OOPS.

> +		return 0;
> +	}
> +
> +out_mem:
> +	kfree(priv);
> +out:
> +	return ret;
> +}
> +
> +static int sead3_i2c_platform_remove(struct platform_device *pdev)
> +{
> +	struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	i2c_del_adapter(&priv->adap);
> +	kfree(priv);
> +	return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int sead3_i2c_platform_suspend(struct platform_device *pdev,
> +		pm_message_t state)
> +{
> +	dev_dbg(&pdev->dev, "i2c_platform_disable\n");
> +	return 0;
> +}
> +
> +static int sead3_i2c_platform_resume(struct platform_device *pdev)
> +{
> +	struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev);
> +
> +	dev_dbg(&pdev->dev, "sead3_i2c_platform_setup\n");
> +	sead3_i2c_platform_setup(priv);
> +
> +	return 0;
> +}
> +#else
> +#define sead3_i2c_platform_suspend	NULL
> +#define sead3_i2c_platform_resume	NULL
> +#endif
> +
> +static struct platform_driver sead3_i2c_platform_driver = {
> +	.driver = {
> +		.name	= "sead3-i2c",
> +		.owner	= THIS_MODULE,

Not needed.

> +	},
> +	.probe		= sead3_i2c_platform_probe,
> +	.remove		= sead3_i2c_platform_remove,
> +	.suspend	= sead3_i2c_platform_suspend,
> +	.resume		= sead3_i2c_platform_resume,
> +};
> +
> +static int __init sead3_i2c_platform_init(void)
> +{
> +	return platform_driver_register(&sead3_i2c_platform_driver);
> +}
> +module_init(sead3_i2c_platform_init);
> +
> +static void __exit sead3_i2c_platform_exit(void)
> +{
> +	platform_driver_unregister(&sead3_i2c_platform_driver);
> +}
> +module_exit(sead3_i2c_platform_exit);

module_platform_driver()

> +
> +MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC.");
> +MODULE_DESCRIPTION("SEAD3 PIC32 I2C driver");
> +MODULE_LICENSE("GPL");

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