Re: [RFC V1 3/8] smi2021: Add smi2021_i2c.c

[Jon Arne JÃrgensen]

On Mon, Mar 18, 2013 at 09:04:56AM +0100, Hans Verkuil wrote:
> On Thu March 14 2013 15:06:59 Jon Arne JÃrgensen wrote:
> > This file is responsible for registering the device
> > with the kernel i2c subsystem.
> > v4l2 talks to the saa7113 chip of the device via i2c.
> > 
> > Signed-off-by: Jon Arne JÃrgensen <jonarne@xxxxxxxxxx>
> > ---
> >  drivers/media/usb/smi2021/smi2021_i2c.c | 160 ++++++++++++++++++++++++++++++++
> >  1 file changed, 160 insertions(+)
> >  create mode 100644 drivers/media/usb/smi2021/smi2021_i2c.c
> > 
> > diff --git a/drivers/media/usb/smi2021/smi2021_i2c.c b/drivers/media/usb/smi2021/smi2021_i2c.c
> > new file mode 100644
> > index 0000000..5b6f3f5
> > --- /dev/null
> > +++ b/drivers/media/usb/smi2021/smi2021_i2c.c
> > @@ -0,0 +1,160 @@
> > +/*******************************************************************************
> > + * smi2021_i2c.c                                                               *
> > + *                                                                             *
> > + * USB Driver for SMI2021 - EasyCAP                                            *
> > + * USB ID 1c88:003c                                                            *
> > + *                                                                             *
> > + * *****************************************************************************
> > + *
> > + * Copyright 2011-2013 Jon Arne JÃrgensen
> > + * <jonjon.arnearne--a.t--gmail.com>
> > + *
> > + * Copyright 2011, 2012 Tony Brown, Michal Demin, Jeffry Johnston
> > + *
> > + * This file is part of SMI2021
> > + * http://code.google.com/p/easycap-somagic-linux/
> > + *
> > + * 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, see <http://www.gnu.org/licenses/>.
> > + *
> > + * This driver is heavily influensed by the STK1160 driver.
> > + * Copyright (C) 2012 Ezequiel Garcia
> > + * <elezegarcia--a.t--gmail.com>
> > + *
> > + */
> > +
> > +#include "smi2021.h"
> > +
> > +/* The device will not return the chip_name on address 0x00.
> > + * But the saa7115 i2c driver needs the chip id to match "f7113"
> > + * if we want to use it,
> > + * so we have to fake the return of this value
> > + */
> > +
> > +static char chip_id[] = { 'x', 255, 55, 49, 49, 115, 0 };
> > +static int id_ptr;
> 
> Don't do this! Instead modify saa7115.c and add a new chip_id (the name of
> this saa7113 clone) and specify that in v4l2_i2c_new_subdev instead of "saa7113".
> The saa7115.c driver should skip the chip ID test if that name is specified.
> 
> Then you don't need this hack anymore and everything will look much cleaner.
> 

I'll do this.

> > +
> > +static unsigned int i2c_debug;
> > +module_param(i2c_debug, int, 0644);
> > +MODULE_PARM_DESC(i2c_debug, "enable debug messages [i2c]");
> > +
> > +#define dprint_i2c(fmt, args...)					\
> > +do {									\
> > +	if (i2c_debug)							\
> > +		pr_debug("smi2021[i2c]::%s: " fmt, __func__, ##args);	\
> > +} while (0)
> > +
> > +
> > +static int i2c_xfer(struct i2c_adapter *i2c_adap,
> > +				struct i2c_msg msgs[], int num)
> > +{
> > +	struct smi2021_dev *dev = i2c_adap->algo_data;
> > +
> > +	switch (num) {
> > +	case 2: { /* Read reg */
> > +		if (msgs[0].len != 1 || msgs[1].len != 1) {
> > +			dprint_i2c("both messages must be 1 byte\n");
> > +			goto err_out;
> > +
> > +		if ((msgs[1].flags & I2C_M_RD) != I2C_M_RD)
> > +			dprint_i2c("last message should have rd flag\n");
> > +			goto err_out;
> > +		}
> > +
> > +		if (msgs[0].buf[0] == 0) {
> > +			msgs[1].buf[0] = chip_id[id_ptr];
> > +			if (chip_id[id_ptr] != 0)
> > +				id_ptr += 1;
> > +		} else {
> > +			smi2021_read_reg(dev, msgs[0].addr, msgs[0].buf[0],
> > +						msgs[1].buf);
> > +		}
> > +		break;
> > +	}
> > +	case 1: { /* Write reg */
> > +		if (msgs[0].len == 0) {
> > +			break;
> > +		} else if (msgs[0].len != 2) {
> > +			dprint_i2c("unsupported len\n");
> > +			goto err_out;
> > +		}
> > +		if (msgs[0].buf[0] == 0) {
> > +			/* We don't handle writing to addr 0x00 */
> > +			break;
> > +		}
> > +
> > +		smi2021_write_reg(dev, msgs[0].addr, msgs[0].buf[0],
> > +						msgs[0].buf[1]);
> > +		break;
> > +	}
> > +	default: {
> > +		dprint_i2c("driver can only handle 1 or 2 messages\n");
> > +		goto err_out;
> > +	}
> > +	}
> > +	return num;
> > +
> > +err_out:
> > +	return -EOPNOTSUPP;
> > +}
> > +
> > +static u32 functionality(struct i2c_adapter *adap)
> > +{
> > +	return I2C_FUNC_SMBUS_EMUL;
> > +}
> > +
> > +static struct i2c_algorithm algo = {
> > +	.master_xfer = i2c_xfer,
> > +	.functionality = functionality,
> > +};
> > +
> > +static struct i2c_adapter adap_template = {
> > +	.owner = THIS_MODULE,
> > +	.name = "smi2021_easycap_dc60",
> > +	.algo = &algo,
> > +};
> > +
> > +static struct i2c_client client_template = {
> > +	.name = "smi2021 internal",
> > +};
> > +
> > +int smi2021_i2c_register(struct smi2021_dev *dev)
> > +{
> > +	int rc;
> > +
> > +	id_ptr = 0;
> > +
> > +	dev->i2c_adap = adap_template;
> > +	dev->i2c_adap.dev.parent = dev->dev;
> > +	strcpy(dev->i2c_adap.name, "smi2021");
> > +	dev->i2c_adap.algo_data = dev;
> > +
> > +	i2c_set_adapdata(&dev->i2c_adap, &dev->v4l2_dev);
> > +
> > +	rc = i2c_add_adapter(&dev->i2c_adap);
> > +	if (rc < 0) {
> > +		smi2021_err("can't add i2c adapter, errno: %d\n", rc);
> > +		return rc;
> > +	}
> > +
> > +	dev->i2c_client = client_template;
> > +	dev->i2c_client.adapter = &dev->i2c_adap;
> > +
> > +	return 0;
> > +}
> > +
> > +int smi2021_i2c_unregister(struct smi2021_dev *dev)
> > +{
> > +	i2c_del_adapter(&dev->i2c_adap);
> > +	return 0;
> > +}
> > 
> 
> Regards,
> 
> 	Hans
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