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Date: Mon, 13 Feb 2012 23:22:05 +0000
From: Ben Dooks <ben-i2c@...ff.org>
To: Sascha Hauer <s.hauer@...gutronix.de>
Cc: linux-kernel@...r.kernel.org, Samuel Ortiz <sameo@...ux.intel.com>,
Jean Delvare <khali@...ux-fr.org>, linux-i2c@...r.kernel.org,
linux-watchdog@...r.kernel.org, Ben Dooks <ben-linux@...ff.org>,
kernel@...gutronix.de
Subject: Re: [PATCH 2/3] i2c: Add Congatec CGEB I2C driver
On Wed, Feb 01, 2012 at 02:26:32PM +0100, Sascha Hauer wrote:
> This driver provides a I2C bus driver for the CGEB interface
> found on some Congatec x86 modules. No devices are registered
> on the bus, the user has to do this via the i2c device /sys
> interface.
>
> Signed-off-by: Sascha Hauer <s.hauer@...gutronix.de>
> ---
> drivers/i2c/busses/Kconfig | 7 +
> drivers/i2c/busses/Makefile | 1 +
> drivers/i2c/busses/i2c-congatec-cgeb.c | 206 ++++++++++++++++++++++++++++++++
> 3 files changed, 214 insertions(+), 0 deletions(-)
> create mode 100644 drivers/i2c/busses/i2c-congatec-cgeb.c
>
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index a3afac4..cc8eb22 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -696,6 +696,13 @@ config I2C_EG20T
> ML7213/ML7223 is companion chip for Intel Atom E6xx series.
> ML7213/ML7223 is completely compatible for Intel EG20T PCH.
>
> +config I2C_CONGATEC_CGEB
> + tristate "Congatec CGEB I2C driver"
> + depends on MFD_CONGATEC_CGEB
> + help
> + This driver provides support for the I2C busses accssable via
> + the Congatec CGEB interface found on Congatec boards.
> +
> comment "External I2C/SMBus adapter drivers"
>
> config I2C_DIOLAN_U2C
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index fba6da6..4aab659 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -69,6 +69,7 @@ obj-$(CONFIG_I2C_VERSATILE) += i2c-versatile.o
> obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o
> obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o
> obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o
> +obj-$(CONFIG_I2C_CONGATEC_CGEB) += i2c-congatec-cgeb.o
>
> # External I2C/SMBus adapter drivers
> obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o
> diff --git a/drivers/i2c/busses/i2c-congatec-cgeb.c b/drivers/i2c/busses/i2c-congatec-cgeb.c
> new file mode 100644
> index 0000000..a387662
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-congatec-cgeb.c
> @@ -0,0 +1,206 @@
> +/*
> + * CGEB i2c driver
> + *
> + * (c) 2011 Sascha Hauer, Pengutronix
I'm going to note that (c) is not a universally legal representation of
Copyright © symbol. You probably want to add Copyright to the front
of that.
> +static int cgeb_i2c_xfer(struct i2c_adapter *adapter,
> + struct i2c_msg *msgs, int num)
> +{
> + struct cgeb_function_parameters fps;
> + int i, ret;
> + unsigned long flags = CG_I2C_FLAG_START;
> + struct cgeb_i2c_priv *priv = i2c_get_adapdata(adapter);
> + unsigned long rdlen, wrlen;
> + unsigned char *rdbuf, *wrbuf, *raw_wrbuf;
> + unsigned short lmax = 0;
Small note, it would have looked better to organise the longer items towards the top.
> + /*
> + * With cgeb the I2C address is part of the write data
> + * buffer, so allocate a buffer with the length of the
> + * longest write buffer + 1
> + */
> + for (i = 0; i < num; i++)
> + if (!(msgs[i].flags & I2C_M_RD))
> + lmax = max(lmax, msgs[i].len);
> +
> + raw_wrbuf = kmalloc(lmax + 1, GFP_KERNEL);
> + if (!raw_wrbuf)
> + return -ENOMEM;
> +
> + for (i = 0; i < num; i++) {
> +
> + if (msgs[i].flags & I2C_M_RD) {
> + rdbuf = msgs[i].buf;
> + rdlen = msgs[i].len;
> + wrbuf = NULL;
> + wrlen = 0;
> + } else {
> + rdbuf = NULL;
> + rdlen = 0;
> + wrbuf = msgs[i].buf;
> + wrlen = msgs[i].len;
> + }
> +
> + raw_wrbuf[0] = msgs[i].addr << 1;
> + if (wrlen)
> + memcpy(&raw_wrbuf[1], wrbuf, wrlen);
> +
> + if (msgs[i].flags & I2C_M_RD)
> + raw_wrbuf[0] |= 1;
Hmm, surely buts of that can go in the above if () statement?
> + if (i == num - 1)
> + flags |= CG_I2C_FLAG_STOP;
> +
> + dev_dbg(&adapter->dev,
> + "%s: rd: %p/%ld wr: %p/%ld flags: 0x%08lx %s\n",
> + __func__, rdbuf, rdlen, raw_wrbuf, wrlen + 1,
> + flags,
> + msgs[i].flags & I2C_M_RD ? "READ" : "WRITE");
> +
> + memset(&fps, 0, sizeof(fps));
> +
> + fps.unit = priv->unit;
> + fps.pars[0] = wrlen + 1;
> + fps.pars[1] = rdlen;
> + fps.pars[2] = flags;
> + fps.iptr = raw_wrbuf;
> + fps.optr = rdbuf;
> +
> + ret = cgeb_call(priv->board, &fps, CgebI2CTransfer);
> + if (ret) {
> + ret = -EREMOTEIO;
> + goto out;
> + }
> + }
> +
> + ret = num;
> +
> +out:
> + kfree(raw_wrbuf);
> +
> + return ret;
> +
> +}
> +static int __devinit cgeb_i2c_probe(struct platform_device *pdev)
> +{
> + struct cgeb_i2c_priv *priv;
> + struct cgeb_pdata *pdata = pdev->dev.platform_data;
> + int ret;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
it might be nice to print an error, but not necessary.
> + strcpy(priv->adapter.name, pdev->name);
> + priv->adapter.owner = THIS_MODULE;
> + priv->adapter.algo = &cgeb_i2c_algo;
> + priv->adapter.dev.parent = &pdev->dev;
> + priv->unit = pdata->unit;
> + priv->board = pdata->board;
> + i2c_set_adapdata(&priv->adapter, priv);
> +
> + platform_set_drvdata(pdev, priv);
> +
> + ret = cgeb_i2c_set_speed(priv, 400000);
> + if (ret)
> + /*
> + * not a critical error, we can continue with the default speed.
> + */
> + dev_warn(&pdev->dev, "Could not set speed to 400KHz\n");
> +
> + ret = i2c_add_adapter(&priv->adapter);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "registration failed\n");
> + return ret;
> + }
> +
> + dev_info(&pdev->dev, "registered\n");
> +
> + return 0;
> +};
> +
> +static int __devexit cgeb_i2c_remove(struct platform_device *pdev)
> +{
> + struct cgeb_i2c_priv *priv = platform_get_drvdata(pdev);
> +
> + i2c_del_adapter(&priv->adapter);
> +
> + platform_set_drvdata(pdev, NULL);
> +
> + return 0;
> +}
> +
> +static struct platform_driver cgeb_i2c_driver = {
> + .probe = cgeb_i2c_probe,
> + .remove = __exit_p(cgeb_i2c_remove),
__devexit_p here.
> + .driver = {
> + .name = "cgeb-i2c",
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +static int __init cgeb_i2c_driver_init(void)
> +{
> + return platform_driver_register(&cgeb_i2c_driver);
> +}
> +
> +static void __exit cgeb_i2c_driver_exit(void)
> +{
> + platform_driver_unregister(&cgeb_i2c_driver);
> +}
> +
> +module_init(cgeb_i2c_driver_init);
> +module_exit(cgeb_i2c_driver_exit);
> +
> +MODULE_AUTHOR("Sascha Hauer <s.hauer@...gutronix.de>");
> +MODULE_DESCRIPTION("cgeb i2c driver");
> +MODULE_LICENSE("GPL");
--
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