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From: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
To: Ben Dooks <ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org>
Cc: Daniel Gl??ckner <dg-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>,
	Chris Zankel <chris-YvXeqwSYzG2sTnJN9+BGXg@public.gmane.org>,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Oskar Schirmer <os-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [patch 1/5] i2c: xtensa s6000 i2c driver
Date: Wed, 1 Apr 2009 00:01:34 +0100	[thread overview]
Message-ID: <20090331230134.GP19758@fluff.org.uk> (raw)
In-Reply-To: <20090331225258.GN19758-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>

On Tue, Mar 31, 2009 at 11:52:58PM +0100, Ben Dooks wrote:
> On Mon, Mar 23, 2009 at 04:05:14PM +0100, Daniel Gl??ckner wrote:
> > From: Oskar Schirmer <os-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> > 
> > Support for the s6000 on-chip i2c controller.
> > 
> > Signed-off-by: Oskar Schirmer <os-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> > Signed-off-by: Daniel Gl??ckner <dg-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> 
> Not going to merge this on my first pull request to linus, there's
> a few things that I'd like to get answered before.

and a few other things i've just noticed:
 
> > ---
> >  drivers/i2c/busses/Kconfig     |   10 +
> >  drivers/i2c/busses/Makefile    |    1 +
> >  drivers/i2c/busses/i2c-s6000.c |  380 ++++++++++++++++++++++++++++++++++++++++
> >  drivers/i2c/busses/i2c-s6000.h |   79 +++++++++
> >  include/linux/i2c/s6000.h      |   10 +
> >  5 files changed, 480 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/i2c/busses/i2c-s6000.c
> >  create mode 100644 drivers/i2c/busses/i2c-s6000.h
> >  create mode 100644 include/linux/i2c/s6000.h
> > 
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index 7f95905..904def4 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -461,6 +461,16 @@ config I2C_S3C2410
> >  	  Say Y here to include support for I2C controller in the
> >  	  Samsung S3C2410 based System-on-Chip devices.
> >  
> > +config I2C_S6000
> > +	tristate "S6000 I2C support"
> > +	depends on XTENSA_VARIANT_S6000
> > +	help
> > +	  This driver supports the on chip I2C device on the
> > +	  S6000 xtensa processor family.
> > +
> > +	  To compile this driver as a module, choose M here. The module
> > +	  will be called i2c-s6000.
> > +
> >  config I2C_SH7760
> >  	tristate "Renesas SH7760 I2C Controller"
> >  	depends on CPU_SUBTYPE_SH7760
> > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> > index 0c2c4b2..f7989d1 100644
> > --- a/drivers/i2c/busses/Makefile
> > +++ b/drivers/i2c/busses/Makefile
> > @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
> >  obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
> >  obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
> >  obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
> > +obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
> >  obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
> >  obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
> >  obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
> > diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
> > new file mode 100644
> > index 0000000..88e3fdc
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-s6000.c
> > @@ -0,0 +1,380 @@
> > +/*
> > + * drivers/i2c/busses/i2c-s6000.c
> > + *
> > + * Description: Driver for S6000 Family I2C Interface
> > + *	(c) 2008 emlix GmbH <info-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> 
> Note, I think you need Copyright here as well, (c) needs to be a
> proper c in circle i've been informed.
> 
> > + * Author:	Oskar Schirmer <os-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> > + *
> > + * Partially based on i2c-bfin-twi.c driver by <sonic.zhang-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org>
> > + * Copyright (c) 2005-2007 Analog Devices, Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/err.h>
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/init.h>
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/i2c/s6000.h>
> > +#include <linux/timer.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/completion.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <asm/io.h>
> > +#include "i2c-s6000.h"
> > +
> > +#define POLL_TIMEOUT	(2 * HZ)
> > +
> 
> would be nice to have some documentation for each of the members
> of this.
> 
> > +struct s6i2c_if {
> > +	u8 __iomem		*reg;
> > +	int			irq;
> > +	spinlock_t		lock;
> > +	struct i2c_msg		*msgs;
> > +	int			msgs_num, msgs_push, msgs_done;
> > +	unsigned		push, done;
> > +	int			timeout_count;
> > +	struct timer_list	timeout_timer;
> > +	struct i2c_adapter	adap;
> > +	struct completion	complete;
> > +	struct clk		*clk;
> > +	struct resource		*res;
> > +};
> > +
> > +#define I2C_RD16(iface, n) readw(iface->reg + (n))
> > +#define I2C_WR16(iface, n, v) writew(v, iface->reg + (n))
> > +#define I2C_RD32(iface, n) readl(iface->reg + (n))
> > +#define I2C_WR32(iface, n, v) writel(v, iface->reg + (n))
> 
> tried inline functions for these?
> 
> > +
> > +static struct s6i2c_if s6i2c_if;
> > +
> > +static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
> > +{
> > +	if (I2C_RD16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
> > +		I2C_RD16(iface, S6_I2C_CLRTXABRT);
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +		complete(&iface->complete);
> > +		return;
> > +	}
> > +	if (iface->msgs_done >= iface->msgs_num) {
> > +		printk(KERN_DEBUG "spurious I2C irq: %x\n",
> > +		       I2C_RD16(iface, S6_I2C_INTRSTAT));

storing the device and using dev_ functions would be much better.

> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +		return;
> > +	}
> > +	while ((iface->msgs_push < iface->msgs_num)
> > +	    && (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
> > +		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
> > +		if (!(m->flags & I2C_M_RD))
> > +			I2C_WR16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
> > +		else
> > +			I2C_WR16(iface, S6_I2C_DATACMD,
> > +				 1 << S6_I2C_DATACMD_READ);
> > +		if (++iface->push >= m->len) {
> > +			iface->push = 0;
> > +			iface->msgs_push += 1;
> > +		}
> > +	}
> > +	do {
> > +		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
> > +		if (!(m->flags & I2C_M_RD)) {
> > +			if (iface->msgs_done < iface->msgs_push)
> > +				iface->msgs_done += 1;
> > +			else
> > +				break;
> > +		} else if (I2C_RD16(iface, S6_I2C_STATUS)
> > +				& (1 << S6_I2C_STATUS_RFNE)) {
> > +			m->buf[iface->done] = I2C_RD16(iface, S6_I2C_DATACMD);
> > +			if (++iface->done >= m->len) {
> > +				iface->done = 0;
> > +				iface->msgs_done += 1;
> > +			}
> > +		} else{
> > +			break;
> > +		}
> > +	} while (iface->msgs_done < iface->msgs_num);
> > +	if (iface->msgs_done >= iface->msgs_num) {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
> > +		complete(&iface->complete);
> > +	} else if (iface->msgs_push >= iface->msgs_num) {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> > +						 (1 << S6_I2C_INTR_RXFULL));
> > +	} else {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> > +						 (1 << S6_I2C_INTR_TXEMPTY) |
> > +						 (1 << S6_I2C_INTR_RXFULL));
> > +	}
> > +}
> > +
> > +static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
> > +{
> > +	struct s6i2c_if *iface = dev_id;
> > +	if (!(I2C_RD16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
> > +					      | (1 << S6_I2C_INTR_RXOVER)
> > +					      | (1 << S6_I2C_INTR_RXFULL)
> > +					      | (1 << S6_I2C_INTR_TXOVER)
> > +					      | (1 << S6_I2C_INTR_TXEMPTY)
> > +					      | (1 << S6_I2C_INTR_RDREQ)
> > +					      | (1 << S6_I2C_INTR_TXABRT)
> > +					      | (1 << S6_I2C_INTR_RXDONE)
> > +					      | (1 << S6_I2C_INTR_ACTIVITY)
> > +					      | (1 << S6_I2C_INTR_STOPDET)
> > +					      | (1 << S6_I2C_INTR_STARTDET)
> > +					      | (1 << S6_I2C_INTR_GENCALL))))
> > +		return IRQ_NONE;
> > +
> > +	spin_lock(&iface->lock);
> > +	del_timer(&iface->timeout_timer);
> > +	s6i2c_handle_interrupt(iface);
> > +	spin_unlock(&iface->lock);
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static void s6i2c_timeout(unsigned long data)
> > +{
> > +	struct s6i2c_if *iface = (struct s6i2c_if *)data;
> > +	unsigned long flags;
> > +
> > +	spin_lock_irqsave(&iface->lock, flags);
> > +	s6i2c_handle_interrupt(iface);
> > +	if (--iface->timeout_count > 0) {
> > +		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> > +		add_timer(&iface->timeout_timer);
> > +	} else {
> > +		complete(&iface->complete);
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	}
> > +	spin_unlock_irqrestore(&iface->lock, flags);
> > +}
> > +
> > +static int s6i2c_master_xfer(struct i2c_adapter *adap,
> > +				struct i2c_msg *msgs, int num)
> > +{
> > +	struct s6i2c_if *iface = adap->algo_data;
> > +	int i;
> > +	if (num == 0)
> > +		return 0;
> > +	if (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> > +		yield();
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	I2C_RD16(iface, S6_I2C_CLRINTR);
> > +	for (i = 0; i < num; i++) {
> > +		if (msgs[i].flags & I2C_M_TEN) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: 10 bits addr not supported\n");
> > +			return -EINVAL;
> > +		}
> > +		if (msgs[i].len == 0) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: zero length message not supported\n");
> > +			return -EINVAL;
> > +		}
> > +		if (msgs[i].addr != msgs[0].addr) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: multiple xfer cannot change target\n");
> > +			return -EINVAL;
> > +		}
> > +	}
> > +	iface->msgs = msgs;
> > +	iface->msgs_num = num;
> > +	iface->msgs_push = 0;
> > +	iface->msgs_done = 0;
> > +	iface->push = 0;
> > +	iface->done = 0;
> > +	iface->timeout_count = 10;
> > +	I2C_WR16(iface, S6_I2C_TAR, msgs[0].addr);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 1);
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
> > +					 (1 << S6_I2C_INTR_TXABRT));
> > +	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> > +	add_timer(&iface->timeout_timer);
> > +	wait_for_completion(&iface->complete);
> > +	del_timer_sync(&iface->timeout_timer);
> > +	while (I2C_RD32(iface, S6_I2C_TXFLR) > 0)
> > +		schedule();
> > +	while (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> > +		schedule();
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	return iface->msgs_done;
> > +}
> > +
> > +static u32 s6i2c_functionality(struct i2c_adapter *adap)
> > +{
> > +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> > +}
> > +
> > +static struct i2c_algorithm s6i2c_algorithm = {
> > +	.master_xfer   = s6i2c_master_xfer,
> > +	.functionality = s6i2c_functionality,
> > +};
> > +
> > +static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
> > +{
> > +	u64 dividend = (u64)ns * clk_get_rate(iface->clk);
> > +	do_div(dividend, 1000000000);
> > +	if (dividend > 0xffff)
> > +		return 0xffff;
> > +	return dividend;
> > +}
> 
> do you desperately need to be _that_ accurate?
> 
> > +static int __devinit s6i2c_probe(struct platform_device *dev)
> > +{
> > +	struct s6i2c_if *iface = &s6i2c_if;
> > +	struct i2c_adapter *p_adap;
> > +	const char *clock;
> > +	int bus_num, rc;
> > +	spin_lock_init(&(iface->lock));
> > +	init_completion(&(iface->complete));
> 
> please don't do &(variable) it is fugly.
> 
> > +	iface->irq = platform_get_irq(dev, 0);
> > +	if (iface->irq < 0) {
> > +		rc = iface->irq;
> > +		goto err_out;
> > +	}
> > +	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> > +	if (!iface->res) {
> > +		rc = -ENXIO;
> > +		goto err_out;
> > +	}
> > +	iface->res = request_mem_region(iface->res->start,
> > +					iface->res->end - iface->res->start + 1,
> > +					dev->dev.bus_id);

resource_size() is your friend here too, and in various others bits
of the code.

> > +	if (!iface->res) {
> > +		rc = -EBUSY;
> > +		goto err_out;
> > +	}
> > +	iface->reg = ioremap_nocache(iface->res->start,
> > +				     iface->res->end - iface->res->start + 1);
> > +	if (!iface->reg) {
> > +		rc = -ENOMEM;
> > +		goto err_reg;
> > +	}
> > +	clock = 0;
> > +	bus_num = -1;
> > +	if (dev->dev.platform_data) {
> > +		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
> > +		bus_num = pdata->bus_num;
> > +		clock = pdata->clock;
> > +	}
> > +	iface->clk = clk_get(&dev->dev, clock);
> > +	if (IS_ERR(iface->clk)) {
> > +		rc = PTR_ERR(iface->clk);
> > +		goto err_map;
> > +	}
> 
> passing the name in the platform device is a bit nasty, if there's
> only one clock for the device then it should have been dealt with
> at the arch level and doing clk_get(&dev->dev, NULL) should be
> acceptable.
> 
> > +	rc = clk_enable(iface->clk);
> > +	if (rc < 0)
> > +		goto err_clk_put;
> > +	init_timer(&(iface->timeout_timer));
> > +	iface->timeout_timer.function = s6i2c_timeout;
> > +	iface->timeout_timer.data = (unsigned long)iface;
> > +	p_adap = &iface->adap;
> > +	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
> > +	p_adap->algo = &s6i2c_algorithm;
> > +	p_adap->algo_data = iface;
> > +	p_adap->nr = bus_num;
> > +	p_adap->class = 0;
> > +	p_adap->dev.parent = &dev->dev;
> 
> some spacing for readability would be nice.
> 
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
> > +			 IRQF_SHARED, dev->name, iface);
> > +	if (rc) {
> > +		dev_err(&(p_adap->dev), "s6i2c: cant get IRQ %d\n", iface->irq);
> > +		goto err_clk_dis;
> > +	}
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	udelay(1);
> > +	I2C_WR32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
> > +	I2C_WR16(iface, S6_I2C_CLRTXABRT, 1);
> > +	I2C_WR16(iface, S6_I2C_CON,
> > +			(1 << S6_I2C_CON_MASTER) |
> > +			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
> > +			(0 << S6_I2C_CON_10BITSLAVE) |
> > +			(0 << S6_I2C_CON_10BITMASTER) |
> > +			(1 << S6_I2C_CON_RESTARTENA) |
> > +			(1 << S6_I2C_CON_SLAVEDISABLE));
> > +	I2C_WR16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
> > +	I2C_WR16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
> > +	I2C_WR16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
> > +	I2C_WR16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
> > +	I2C_WR16(iface, S6_I2C_RXTL, 0);
> > +	I2C_WR16(iface, S6_I2C_TXTL, 0);
> > +	platform_set_drvdata(dev, iface);
> > +	if (bus_num < 0)
> > +		rc = i2c_add_adapter(p_adap);
> > +	else
> > +		rc = i2c_add_numbered_adapter(p_adap);
> > +	if (rc)
> > +		goto err_irq_free;
> > +	return 0;
> > +
> > +err_irq_free:
> > +	free_irq(iface->irq, iface);
> > +err_clk_dis:
> > +	clk_disable(iface->clk);
> > +err_clk_put:
> > +	clk_put(iface->clk);
> > +err_map:
> > +	iounmap(iface->reg);
> > +err_reg:
> > +	release_mem_region(iface->res->start,
> > +			   iface->res->end - iface->res->start + 1);
> > +err_out:
> > +	return rc;
> > +}
> > +
> > +static int __devexit s6i2c_remove(struct platform_device *pdev)
> > +{
> > +	struct s6i2c_if *iface = platform_get_drvdata(pdev);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	platform_set_drvdata(pdev, NULL);
> > +	i2c_del_adapter(&(iface->adap));
> > +	free_irq(iface->irq, iface);
> > +	clk_disable(iface->clk);
> > +	clk_put(iface->clk);
> > +	iounmap(iface->reg);
> > +	release_mem_region(iface->res->start,
> > +			   iface->res->end - iface->res->start + 1);
> 
> resource_size() would be good here, and elsewhere in the driver.
> 
> > +	return 0;
> > +}
> > +
> > +static struct platform_driver s6i2c_driver = {
> > +	.probe		= s6i2c_probe,
> > +	.remove		= __devexit_p(s6i2c_remove),
> > +	.driver		= {
> > +		.name	= "i2c-s6000",
> > +		.owner	= THIS_MODULE,
> > +	},
> > +};
> > +
> > +static int __init s6i2c_init(void)
> > +{
> > +	pr_info("I2C: S6000 I2C driver\n");
> > +	return platform_driver_register(&s6i2c_driver);
> > +}
> > +
> > +static void __exit s6i2c_exit(void)
> > +{
> > +	platform_driver_unregister(&s6i2c_driver);
> > +}
> > +
> > +MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
> > +MODULE_LICENSE("GPL");

alias for module loading would also be useful.

> > +
> > +subsys_initcall(s6i2c_init);
> > +module_exit(s6i2c_exit);


> as a note, the code is quite dense, a few blank lines would be
> nice.
> 
> > diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
> > new file mode 100644
> > index 0000000..ff23b81
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-s6000.h
> > @@ -0,0 +1,79 @@
> > +/*
> > + * drivers/i2c/busses/i2c-s6000.h
> > + *
> > + * 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) 2008 Emlix GmbH <info-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> > + * Author:	Oskar Schirmer <os-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
> > + */
> > +
> > +#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
> > +#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
> > +
> > +#define S6_I2C_CON		0x000
> > +#define S6_I2C_CON_MASTER		0
> > +#define S6_I2C_CON_SPEED		1
> > +#define S6_I2C_CON_SPEED_NORMAL			1
> > +#define S6_I2C_CON_SPEED_FAST			2
> > +#define S6_I2C_CON_SPEED_MASK			3
> > +#define S6_I2C_CON_10BITSLAVE		3
> > +#define S6_I2C_CON_10BITMASTER		4
> > +#define S6_I2C_CON_RESTARTENA		5
> > +#define S6_I2C_CON_SLAVEDISABLE		6
> > +#define S6_I2C_TAR		0x004
> > +#define S6_I2C_TAR_GCORSTART		10
> > +#define S6_I2C_TAR_SPECIAL		11
> > +#define S6_I2C_SAR		0x008
> > +#define S6_I2C_HSMADDR		0x00C
> > +#define S6_I2C_DATACMD		0x010
> > +#define S6_I2C_DATACMD_READ		8
> > +#define S6_I2C_SSHCNT		0x014
> > +#define S6_I2C_SSLCNT		0x018
> > +#define S6_I2C_FSHCNT		0x01C
> > +#define S6_I2C_FSLCNT		0x020
> > +#define S6_I2C_INTRSTAT		0x02C
> > +#define S6_I2C_INTRMASK		0x030
> > +#define S6_I2C_RAWINTR		0x034
> > +#define S6_I2C_INTR_RXUNDER		0
> > +#define S6_I2C_INTR_RXOVER		1
> > +#define S6_I2C_INTR_RXFULL		2
> > +#define S6_I2C_INTR_TXOVER		3
> > +#define S6_I2C_INTR_TXEMPTY		4
> > +#define S6_I2C_INTR_RDREQ		5
> > +#define S6_I2C_INTR_TXABRT		6
> > +#define S6_I2C_INTR_RXDONE		7
> > +#define S6_I2C_INTR_ACTIVITY		8
> > +#define S6_I2C_INTR_STOPDET		9
> > +#define S6_I2C_INTR_STARTDET		10
> > +#define S6_I2C_INTR_GENCALL		11
> > +#define S6_I2C_RXTL		0x038
> > +#define S6_I2C_TXTL		0x03C
> > +#define S6_I2C_CLRINTR		0x040
> > +#define S6_I2C_CLRRXUNDER	0x044
> > +#define S6_I2C_CLRRXOVER	0x048
> > +#define S6_I2C_CLRTXOVER	0x04C
> > +#define S6_I2C_CLRRDREQ		0x050
> > +#define S6_I2C_CLRTXABRT	0x054
> > +#define S6_I2C_CLRRXDONE	0x058
> > +#define S6_I2C_CLRACTIVITY	0x05C
> > +#define S6_I2C_CLRSTOPDET	0x060
> > +#define S6_I2C_CLRSTARTDET	0x064
> > +#define S6_I2C_CLRGENCALL	0x068
> > +#define S6_I2C_ENABLE		0x06C
> > +#define S6_I2C_STATUS		0x070
> > +#define S6_I2C_STATUS_ACTIVITY		0
> > +#define S6_I2C_STATUS_TFNF		1
> > +#define S6_I2C_STATUS_TFE		2
> > +#define S6_I2C_STATUS_RFNE		3
> > +#define S6_I2C_STATUS_RFF		4
> > +#define S6_I2C_TXFLR		0x074
> > +#define S6_I2C_RXFLR		0x078
> > +#define S6_I2C_SRESET		0x07C
> > +#define S6_I2C_SRESET_IC_SRST		0
> > +#define S6_I2C_SRESET_IC_MASTER_SRST	1
> > +#define S6_I2C_SRESET_IC_SLAVE_SRST	2
> > +#define S6_I2C_TXABRTSOURCE	0x080
> > +
> > +#endif
> > diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h
> 
> and again.
> 
> > new file mode 100644
> > index 0000000..0b6b0c6
> > --- /dev/null
> > +++ b/include/linux/i2c/s6000.h
> > @@ -0,0 +1,10 @@
> > +#ifndef __LINUX_I2C_S6000_H
> > +#define __LINUX_I2C_S6000_H
> > +
> 
> documentation comments would be nice here too.
> 
> > +struct s6_i2c_platform_data {
> > +	const char *clock;
> > +	int bus_num;
> > +};
> > +
> > +#endif
> > +
> > -- 
> > 1.6.2.107.ge47ee
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/)
> 
>   'a smiley only costs 4 bytes'
> --
> To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Ben (ben-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

WARNING: multiple messages have this Message-ID (diff)
From: Ben Dooks <ben-linux@fluff.org>
To: Ben Dooks <ben-linux@fluff.org>
Cc: Daniel Gl??ckner <dg@emlix.com>, Chris Zankel <chris@zankel.net>,
	linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
	Oskar Schirmer <os@emlix.com>
Subject: Re: [patch 1/5] i2c: xtensa s6000 i2c driver
Date: Wed, 1 Apr 2009 00:01:34 +0100	[thread overview]
Message-ID: <20090331230134.GP19758@fluff.org.uk> (raw)
In-Reply-To: <20090331225258.GN19758@fluff.org.uk>

On Tue, Mar 31, 2009 at 11:52:58PM +0100, Ben Dooks wrote:
> On Mon, Mar 23, 2009 at 04:05:14PM +0100, Daniel Gl??ckner wrote:
> > From: Oskar Schirmer <os@emlix.com>
> > 
> > Support for the s6000 on-chip i2c controller.
> > 
> > Signed-off-by: Oskar Schirmer <os@emlix.com>
> > Signed-off-by: Daniel Gl??ckner <dg@emlix.com>
> 
> Not going to merge this on my first pull request to linus, there's
> a few things that I'd like to get answered before.

and a few other things i've just noticed:
 
> > ---
> >  drivers/i2c/busses/Kconfig     |   10 +
> >  drivers/i2c/busses/Makefile    |    1 +
> >  drivers/i2c/busses/i2c-s6000.c |  380 ++++++++++++++++++++++++++++++++++++++++
> >  drivers/i2c/busses/i2c-s6000.h |   79 +++++++++
> >  include/linux/i2c/s6000.h      |   10 +
> >  5 files changed, 480 insertions(+), 0 deletions(-)
> >  create mode 100644 drivers/i2c/busses/i2c-s6000.c
> >  create mode 100644 drivers/i2c/busses/i2c-s6000.h
> >  create mode 100644 include/linux/i2c/s6000.h
> > 
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index 7f95905..904def4 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -461,6 +461,16 @@ config I2C_S3C2410
> >  	  Say Y here to include support for I2C controller in the
> >  	  Samsung S3C2410 based System-on-Chip devices.
> >  
> > +config I2C_S6000
> > +	tristate "S6000 I2C support"
> > +	depends on XTENSA_VARIANT_S6000
> > +	help
> > +	  This driver supports the on chip I2C device on the
> > +	  S6000 xtensa processor family.
> > +
> > +	  To compile this driver as a module, choose M here. The module
> > +	  will be called i2c-s6000.
> > +
> >  config I2C_SH7760
> >  	tristate "Renesas SH7760 I2C Controller"
> >  	depends on CPU_SUBTYPE_SH7760
> > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> > index 0c2c4b2..f7989d1 100644
> > --- a/drivers/i2c/busses/Makefile
> > +++ b/drivers/i2c/busses/Makefile
> > @@ -43,6 +43,7 @@ obj-$(CONFIG_I2C_PASEMI)	+= i2c-pasemi.o
> >  obj-$(CONFIG_I2C_PNX)		+= i2c-pnx.o
> >  obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
> >  obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
> > +obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
> >  obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
> >  obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
> >  obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
> > diff --git a/drivers/i2c/busses/i2c-s6000.c b/drivers/i2c/busses/i2c-s6000.c
> > new file mode 100644
> > index 0000000..88e3fdc
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-s6000.c
> > @@ -0,0 +1,380 @@
> > +/*
> > + * drivers/i2c/busses/i2c-s6000.c
> > + *
> > + * Description: Driver for S6000 Family I2C Interface
> > + *	(c) 2008 emlix GmbH <info@emlix.com>
> 
> Note, I think you need Copyright here as well, (c) needs to be a
> proper c in circle i've been informed.
> 
> > + * Author:	Oskar Schirmer <os@emlix.com>
> > + *
> > + * Partially based on i2c-bfin-twi.c driver by <sonic.zhang@analog.com>
> > + * Copyright (c) 2005-2007 Analog Devices, Inc.
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
> > + */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/err.h>
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/init.h>
> > +#include <linux/delay.h>
> > +#include <linux/i2c.h>
> > +#include <linux/i2c/s6000.h>
> > +#include <linux/timer.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/completion.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <asm/io.h>
> > +#include "i2c-s6000.h"
> > +
> > +#define POLL_TIMEOUT	(2 * HZ)
> > +
> 
> would be nice to have some documentation for each of the members
> of this.
> 
> > +struct s6i2c_if {
> > +	u8 __iomem		*reg;
> > +	int			irq;
> > +	spinlock_t		lock;
> > +	struct i2c_msg		*msgs;
> > +	int			msgs_num, msgs_push, msgs_done;
> > +	unsigned		push, done;
> > +	int			timeout_count;
> > +	struct timer_list	timeout_timer;
> > +	struct i2c_adapter	adap;
> > +	struct completion	complete;
> > +	struct clk		*clk;
> > +	struct resource		*res;
> > +};
> > +
> > +#define I2C_RD16(iface, n) readw(iface->reg + (n))
> > +#define I2C_WR16(iface, n, v) writew(v, iface->reg + (n))
> > +#define I2C_RD32(iface, n) readl(iface->reg + (n))
> > +#define I2C_WR32(iface, n, v) writel(v, iface->reg + (n))
> 
> tried inline functions for these?
> 
> > +
> > +static struct s6i2c_if s6i2c_if;
> > +
> > +static void s6i2c_handle_interrupt(struct s6i2c_if *iface)
> > +{
> > +	if (I2C_RD16(iface, S6_I2C_INTRSTAT) & (1 << S6_I2C_INTR_TXABRT)) {
> > +		I2C_RD16(iface, S6_I2C_CLRTXABRT);
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +		complete(&iface->complete);
> > +		return;
> > +	}
> > +	if (iface->msgs_done >= iface->msgs_num) {
> > +		printk(KERN_DEBUG "spurious I2C irq: %x\n",
> > +		       I2C_RD16(iface, S6_I2C_INTRSTAT));

storing the device and using dev_ functions would be much better.

> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +		return;
> > +	}
> > +	while ((iface->msgs_push < iface->msgs_num)
> > +	    && (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_TFNF))) {
> > +		struct i2c_msg *m = &iface->msgs[iface->msgs_push];
> > +		if (!(m->flags & I2C_M_RD))
> > +			I2C_WR16(iface, S6_I2C_DATACMD, m->buf[iface->push]);
> > +		else
> > +			I2C_WR16(iface, S6_I2C_DATACMD,
> > +				 1 << S6_I2C_DATACMD_READ);
> > +		if (++iface->push >= m->len) {
> > +			iface->push = 0;
> > +			iface->msgs_push += 1;
> > +		}
> > +	}
> > +	do {
> > +		struct i2c_msg *m = &iface->msgs[iface->msgs_done];
> > +		if (!(m->flags & I2C_M_RD)) {
> > +			if (iface->msgs_done < iface->msgs_push)
> > +				iface->msgs_done += 1;
> > +			else
> > +				break;
> > +		} else if (I2C_RD16(iface, S6_I2C_STATUS)
> > +				& (1 << S6_I2C_STATUS_RFNE)) {
> > +			m->buf[iface->done] = I2C_RD16(iface, S6_I2C_DATACMD);
> > +			if (++iface->done >= m->len) {
> > +				iface->done = 0;
> > +				iface->msgs_done += 1;
> > +			}
> > +		} else{
> > +			break;
> > +		}
> > +	} while (iface->msgs_done < iface->msgs_num);
> > +	if (iface->msgs_done >= iface->msgs_num) {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 1 << S6_I2C_INTR_TXABRT);
> > +		complete(&iface->complete);
> > +	} else if (iface->msgs_push >= iface->msgs_num) {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> > +						 (1 << S6_I2C_INTR_RXFULL));
> > +	} else {
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXABRT) |
> > +						 (1 << S6_I2C_INTR_TXEMPTY) |
> > +						 (1 << S6_I2C_INTR_RXFULL));
> > +	}
> > +}
> > +
> > +static irqreturn_t s6i2c_interrupt_entry(int irq, void *dev_id)
> > +{
> > +	struct s6i2c_if *iface = dev_id;
> > +	if (!(I2C_RD16(iface, S6_I2C_STATUS) & ((1 << S6_I2C_INTR_RXUNDER)
> > +					      | (1 << S6_I2C_INTR_RXOVER)
> > +					      | (1 << S6_I2C_INTR_RXFULL)
> > +					      | (1 << S6_I2C_INTR_TXOVER)
> > +					      | (1 << S6_I2C_INTR_TXEMPTY)
> > +					      | (1 << S6_I2C_INTR_RDREQ)
> > +					      | (1 << S6_I2C_INTR_TXABRT)
> > +					      | (1 << S6_I2C_INTR_RXDONE)
> > +					      | (1 << S6_I2C_INTR_ACTIVITY)
> > +					      | (1 << S6_I2C_INTR_STOPDET)
> > +					      | (1 << S6_I2C_INTR_STARTDET)
> > +					      | (1 << S6_I2C_INTR_GENCALL))))
> > +		return IRQ_NONE;
> > +
> > +	spin_lock(&iface->lock);
> > +	del_timer(&iface->timeout_timer);
> > +	s6i2c_handle_interrupt(iface);
> > +	spin_unlock(&iface->lock);
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static void s6i2c_timeout(unsigned long data)
> > +{
> > +	struct s6i2c_if *iface = (struct s6i2c_if *)data;
> > +	unsigned long flags;
> > +
> > +	spin_lock_irqsave(&iface->lock, flags);
> > +	s6i2c_handle_interrupt(iface);
> > +	if (--iface->timeout_count > 0) {
> > +		iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> > +		add_timer(&iface->timeout_timer);
> > +	} else {
> > +		complete(&iface->complete);
> > +		I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	}
> > +	spin_unlock_irqrestore(&iface->lock, flags);
> > +}
> > +
> > +static int s6i2c_master_xfer(struct i2c_adapter *adap,
> > +				struct i2c_msg *msgs, int num)
> > +{
> > +	struct s6i2c_if *iface = adap->algo_data;
> > +	int i;
> > +	if (num == 0)
> > +		return 0;
> > +	if (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> > +		yield();
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	I2C_RD16(iface, S6_I2C_CLRINTR);
> > +	for (i = 0; i < num; i++) {
> > +		if (msgs[i].flags & I2C_M_TEN) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: 10 bits addr not supported\n");
> > +			return -EINVAL;
> > +		}
> > +		if (msgs[i].len == 0) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: zero length message not supported\n");
> > +			return -EINVAL;
> > +		}
> > +		if (msgs[i].addr != msgs[0].addr) {
> > +			dev_err(&(adap->dev),
> > +				"s6i2c: multiple xfer cannot change target\n");
> > +			return -EINVAL;
> > +		}
> > +	}
> > +	iface->msgs = msgs;
> > +	iface->msgs_num = num;
> > +	iface->msgs_push = 0;
> > +	iface->msgs_done = 0;
> > +	iface->push = 0;
> > +	iface->done = 0;
> > +	iface->timeout_count = 10;
> > +	I2C_WR16(iface, S6_I2C_TAR, msgs[0].addr);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 1);
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, (1 << S6_I2C_INTR_TXEMPTY) |
> > +					 (1 << S6_I2C_INTR_TXABRT));
> > +	iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
> > +	add_timer(&iface->timeout_timer);
> > +	wait_for_completion(&iface->complete);
> > +	del_timer_sync(&iface->timeout_timer);
> > +	while (I2C_RD32(iface, S6_I2C_TXFLR) > 0)
> > +		schedule();
> > +	while (I2C_RD16(iface, S6_I2C_STATUS) & (1 << S6_I2C_STATUS_ACTIVITY))
> > +		schedule();
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	return iface->msgs_done;
> > +}
> > +
> > +static u32 s6i2c_functionality(struct i2c_adapter *adap)
> > +{
> > +	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> > +}
> > +
> > +static struct i2c_algorithm s6i2c_algorithm = {
> > +	.master_xfer   = s6i2c_master_xfer,
> > +	.functionality = s6i2c_functionality,
> > +};
> > +
> > +static u16 __devinit nanoseconds_on_clk(struct s6i2c_if *iface, u32 ns)
> > +{
> > +	u64 dividend = (u64)ns * clk_get_rate(iface->clk);
> > +	do_div(dividend, 1000000000);
> > +	if (dividend > 0xffff)
> > +		return 0xffff;
> > +	return dividend;
> > +}
> 
> do you desperately need to be _that_ accurate?
> 
> > +static int __devinit s6i2c_probe(struct platform_device *dev)
> > +{
> > +	struct s6i2c_if *iface = &s6i2c_if;
> > +	struct i2c_adapter *p_adap;
> > +	const char *clock;
> > +	int bus_num, rc;
> > +	spin_lock_init(&(iface->lock));
> > +	init_completion(&(iface->complete));
> 
> please don't do &(variable) it is fugly.
> 
> > +	iface->irq = platform_get_irq(dev, 0);
> > +	if (iface->irq < 0) {
> > +		rc = iface->irq;
> > +		goto err_out;
> > +	}
> > +	iface->res = platform_get_resource(dev, IORESOURCE_MEM, 0);
> > +	if (!iface->res) {
> > +		rc = -ENXIO;
> > +		goto err_out;
> > +	}
> > +	iface->res = request_mem_region(iface->res->start,
> > +					iface->res->end - iface->res->start + 1,
> > +					dev->dev.bus_id);

resource_size() is your friend here too, and in various others bits
of the code.

> > +	if (!iface->res) {
> > +		rc = -EBUSY;
> > +		goto err_out;
> > +	}
> > +	iface->reg = ioremap_nocache(iface->res->start,
> > +				     iface->res->end - iface->res->start + 1);
> > +	if (!iface->reg) {
> > +		rc = -ENOMEM;
> > +		goto err_reg;
> > +	}
> > +	clock = 0;
> > +	bus_num = -1;
> > +	if (dev->dev.platform_data) {
> > +		struct s6_i2c_platform_data *pdata = dev->dev.platform_data;
> > +		bus_num = pdata->bus_num;
> > +		clock = pdata->clock;
> > +	}
> > +	iface->clk = clk_get(&dev->dev, clock);
> > +	if (IS_ERR(iface->clk)) {
> > +		rc = PTR_ERR(iface->clk);
> > +		goto err_map;
> > +	}
> 
> passing the name in the platform device is a bit nasty, if there's
> only one clock for the device then it should have been dealt with
> at the arch level and doing clk_get(&dev->dev, NULL) should be
> acceptable.
> 
> > +	rc = clk_enable(iface->clk);
> > +	if (rc < 0)
> > +		goto err_clk_put;
> > +	init_timer(&(iface->timeout_timer));
> > +	iface->timeout_timer.function = s6i2c_timeout;
> > +	iface->timeout_timer.data = (unsigned long)iface;
> > +	p_adap = &iface->adap;
> > +	strlcpy(p_adap->name, dev->name, sizeof(p_adap->name));
> > +	p_adap->algo = &s6i2c_algorithm;
> > +	p_adap->algo_data = iface;
> > +	p_adap->nr = bus_num;
> > +	p_adap->class = 0;
> > +	p_adap->dev.parent = &dev->dev;
> 
> some spacing for readability would be nice.
> 
> > +	I2C_WR16(iface, S6_I2C_INTRMASK, 0);
> > +	rc = request_irq(iface->irq, s6i2c_interrupt_entry,
> > +			 IRQF_SHARED, dev->name, iface);
> > +	if (rc) {
> > +		dev_err(&(p_adap->dev), "s6i2c: cant get IRQ %d\n", iface->irq);
> > +		goto err_clk_dis;
> > +	}
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	udelay(1);
> > +	I2C_WR32(iface, S6_I2C_SRESET, 1 << S6_I2C_SRESET_IC_SRST);
> > +	I2C_WR16(iface, S6_I2C_CLRTXABRT, 1);
> > +	I2C_WR16(iface, S6_I2C_CON,
> > +			(1 << S6_I2C_CON_MASTER) |
> > +			(S6_I2C_CON_SPEED_NORMAL << S6_I2C_CON_SPEED) |
> > +			(0 << S6_I2C_CON_10BITSLAVE) |
> > +			(0 << S6_I2C_CON_10BITMASTER) |
> > +			(1 << S6_I2C_CON_RESTARTENA) |
> > +			(1 << S6_I2C_CON_SLAVEDISABLE));
> > +	I2C_WR16(iface, S6_I2C_SSHCNT, nanoseconds_on_clk(iface, 4000));
> > +	I2C_WR16(iface, S6_I2C_SSLCNT, nanoseconds_on_clk(iface, 4700));
> > +	I2C_WR16(iface, S6_I2C_FSHCNT, nanoseconds_on_clk(iface, 600));
> > +	I2C_WR16(iface, S6_I2C_FSLCNT, nanoseconds_on_clk(iface, 1300));
> > +	I2C_WR16(iface, S6_I2C_RXTL, 0);
> > +	I2C_WR16(iface, S6_I2C_TXTL, 0);
> > +	platform_set_drvdata(dev, iface);
> > +	if (bus_num < 0)
> > +		rc = i2c_add_adapter(p_adap);
> > +	else
> > +		rc = i2c_add_numbered_adapter(p_adap);
> > +	if (rc)
> > +		goto err_irq_free;
> > +	return 0;
> > +
> > +err_irq_free:
> > +	free_irq(iface->irq, iface);
> > +err_clk_dis:
> > +	clk_disable(iface->clk);
> > +err_clk_put:
> > +	clk_put(iface->clk);
> > +err_map:
> > +	iounmap(iface->reg);
> > +err_reg:
> > +	release_mem_region(iface->res->start,
> > +			   iface->res->end - iface->res->start + 1);
> > +err_out:
> > +	return rc;
> > +}
> > +
> > +static int __devexit s6i2c_remove(struct platform_device *pdev)
> > +{
> > +	struct s6i2c_if *iface = platform_get_drvdata(pdev);
> > +	I2C_WR16(iface, S6_I2C_ENABLE, 0);
> > +	platform_set_drvdata(pdev, NULL);
> > +	i2c_del_adapter(&(iface->adap));
> > +	free_irq(iface->irq, iface);
> > +	clk_disable(iface->clk);
> > +	clk_put(iface->clk);
> > +	iounmap(iface->reg);
> > +	release_mem_region(iface->res->start,
> > +			   iface->res->end - iface->res->start + 1);
> 
> resource_size() would be good here, and elsewhere in the driver.
> 
> > +	return 0;
> > +}
> > +
> > +static struct platform_driver s6i2c_driver = {
> > +	.probe		= s6i2c_probe,
> > +	.remove		= __devexit_p(s6i2c_remove),
> > +	.driver		= {
> > +		.name	= "i2c-s6000",
> > +		.owner	= THIS_MODULE,
> > +	},
> > +};
> > +
> > +static int __init s6i2c_init(void)
> > +{
> > +	pr_info("I2C: S6000 I2C driver\n");
> > +	return platform_driver_register(&s6i2c_driver);
> > +}
> > +
> > +static void __exit s6i2c_exit(void)
> > +{
> > +	platform_driver_unregister(&s6i2c_driver);
> > +}
> > +
> > +MODULE_DESCRIPTION("I2C-Bus adapter routines for S6000 I2C");
> > +MODULE_LICENSE("GPL");

alias for module loading would also be useful.

> > +
> > +subsys_initcall(s6i2c_init);
> > +module_exit(s6i2c_exit);


> as a note, the code is quite dense, a few blank lines would be
> nice.
> 
> > diff --git a/drivers/i2c/busses/i2c-s6000.h b/drivers/i2c/busses/i2c-s6000.h
> > new file mode 100644
> > index 0000000..ff23b81
> > --- /dev/null
> > +++ b/drivers/i2c/busses/i2c-s6000.h
> > @@ -0,0 +1,79 @@
> > +/*
> > + * drivers/i2c/busses/i2c-s6000.h
> > + *
> > + * 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) 2008 Emlix GmbH <info@emlix.com>
> > + * Author:	Oskar Schirmer <os@emlix.com>
> > + */
> > +
> > +#ifndef __DRIVERS_I2C_BUSSES_I2C_S6000_H
> > +#define __DRIVERS_I2C_BUSSES_I2C_S6000_H
> > +
> > +#define S6_I2C_CON		0x000
> > +#define S6_I2C_CON_MASTER		0
> > +#define S6_I2C_CON_SPEED		1
> > +#define S6_I2C_CON_SPEED_NORMAL			1
> > +#define S6_I2C_CON_SPEED_FAST			2
> > +#define S6_I2C_CON_SPEED_MASK			3
> > +#define S6_I2C_CON_10BITSLAVE		3
> > +#define S6_I2C_CON_10BITMASTER		4
> > +#define S6_I2C_CON_RESTARTENA		5
> > +#define S6_I2C_CON_SLAVEDISABLE		6
> > +#define S6_I2C_TAR		0x004
> > +#define S6_I2C_TAR_GCORSTART		10
> > +#define S6_I2C_TAR_SPECIAL		11
> > +#define S6_I2C_SAR		0x008
> > +#define S6_I2C_HSMADDR		0x00C
> > +#define S6_I2C_DATACMD		0x010
> > +#define S6_I2C_DATACMD_READ		8
> > +#define S6_I2C_SSHCNT		0x014
> > +#define S6_I2C_SSLCNT		0x018
> > +#define S6_I2C_FSHCNT		0x01C
> > +#define S6_I2C_FSLCNT		0x020
> > +#define S6_I2C_INTRSTAT		0x02C
> > +#define S6_I2C_INTRMASK		0x030
> > +#define S6_I2C_RAWINTR		0x034
> > +#define S6_I2C_INTR_RXUNDER		0
> > +#define S6_I2C_INTR_RXOVER		1
> > +#define S6_I2C_INTR_RXFULL		2
> > +#define S6_I2C_INTR_TXOVER		3
> > +#define S6_I2C_INTR_TXEMPTY		4
> > +#define S6_I2C_INTR_RDREQ		5
> > +#define S6_I2C_INTR_TXABRT		6
> > +#define S6_I2C_INTR_RXDONE		7
> > +#define S6_I2C_INTR_ACTIVITY		8
> > +#define S6_I2C_INTR_STOPDET		9
> > +#define S6_I2C_INTR_STARTDET		10
> > +#define S6_I2C_INTR_GENCALL		11
> > +#define S6_I2C_RXTL		0x038
> > +#define S6_I2C_TXTL		0x03C
> > +#define S6_I2C_CLRINTR		0x040
> > +#define S6_I2C_CLRRXUNDER	0x044
> > +#define S6_I2C_CLRRXOVER	0x048
> > +#define S6_I2C_CLRTXOVER	0x04C
> > +#define S6_I2C_CLRRDREQ		0x050
> > +#define S6_I2C_CLRTXABRT	0x054
> > +#define S6_I2C_CLRRXDONE	0x058
> > +#define S6_I2C_CLRACTIVITY	0x05C
> > +#define S6_I2C_CLRSTOPDET	0x060
> > +#define S6_I2C_CLRSTARTDET	0x064
> > +#define S6_I2C_CLRGENCALL	0x068
> > +#define S6_I2C_ENABLE		0x06C
> > +#define S6_I2C_STATUS		0x070
> > +#define S6_I2C_STATUS_ACTIVITY		0
> > +#define S6_I2C_STATUS_TFNF		1
> > +#define S6_I2C_STATUS_TFE		2
> > +#define S6_I2C_STATUS_RFNE		3
> > +#define S6_I2C_STATUS_RFF		4
> > +#define S6_I2C_TXFLR		0x074
> > +#define S6_I2C_RXFLR		0x078
> > +#define S6_I2C_SRESET		0x07C
> > +#define S6_I2C_SRESET_IC_SRST		0
> > +#define S6_I2C_SRESET_IC_MASTER_SRST	1
> > +#define S6_I2C_SRESET_IC_SLAVE_SRST	2
> > +#define S6_I2C_TXABRTSOURCE	0x080
> > +
> > +#endif
> > diff --git a/include/linux/i2c/s6000.h b/include/linux/i2c/s6000.h
> 
> and again.
> 
> > new file mode 100644
> > index 0000000..0b6b0c6
> > --- /dev/null
> > +++ b/include/linux/i2c/s6000.h
> > @@ -0,0 +1,10 @@
> > +#ifndef __LINUX_I2C_S6000_H
> > +#define __LINUX_I2C_S6000_H
> > +
> 
> documentation comments would be nice here too.
> 
> > +struct s6_i2c_platform_data {
> > +	const char *clock;
> > +	int bus_num;
> > +};
> > +
> > +#endif
> > +
> > -- 
> > 1.6.2.107.ge47ee
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> Ben (ben@fluff.org, http://www.fluff.org/)
> 
>   'a smiley only costs 4 bytes'
> --
> To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

  parent reply	other threads:[~2009-03-31 23:01 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-23 15:05 [patch 1/5] i2c: xtensa s6000 i2c driver Daniel Glöckner
2009-03-23 15:05 ` Daniel Glöckner
     [not found] ` <1237820718-30607-1-git-send-email-dg-QdrG9jWwCLEAvxtiuMwx3w@public.gmane.org>
2009-03-23 15:05   ` [patch 2/5] xtensa: s6105 specific configuration for the s6000 i2c host Daniel Glöckner
2009-03-23 15:05     ` Daniel Glöckner
2009-03-23 15:05   ` [patch 4/5] xtensa: enable s6000 i2c host driver in s6105_defconfig Daniel Glöckner
2009-03-23 15:05     ` Daniel Glöckner
2009-03-23 15:05   ` [patch 5/5] xtensa: enable at24 " Daniel Glöckner
2009-03-23 15:05     ` Daniel Glöckner
2009-03-31 22:52   ` [patch 1/5] i2c: xtensa s6000 i2c driver Ben Dooks
2009-03-31 22:52     ` Ben Dooks
     [not found]     ` <20090331225258.GN19758-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2009-03-31 23:01       ` Ben Dooks [this message]
2009-03-31 23:01         ` Ben Dooks
     [not found]         ` <20090331230134.GP19758-elnMNo+KYs3pIgCt6eIbzw@public.gmane.org>
2009-04-02 11:19           ` [patch v2] " Oskar Schirmer
2009-04-02 11:19             ` Oskar Schirmer
2009-03-23 15:05 ` [patch 3/5] xtensa: add at24hc02b to s6105 platform Daniel Glöckner

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