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Message-ID: <20130315122753.GD2989@localhost>
Date: Fri, 15 Mar 2013 09:27:54 -0300
From: Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>
To: Jon Arne Jørgensen <jonarne@...arne.no>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
hverkuil@...all.nl, elezegarcia@...il.com
Subject: Re: [RFC V1 3/8] smi2021: Add smi2021_i2c.c
On Thu, Mar 14, 2013 at 03:06:59PM +0100, Jon Arne Jørgensen 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 Jørgensen <jonarne@...arne.no>
> ---
> 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 Jørgensen
> + * <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
> + */
This comment style is wrong, check Documentation/CodingStyle.
BTW, Did you check the patches with checkpatch.pl?
(you can add checkpatch.pl as a git pre-commit hook, which I find very useful)
> +
> +static char chip_id[] = { 'x', 255, 55, 49, 49, 115, 0 };
> +static int id_ptr;
> +
> +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 */
Do you need a local scope in here?
> + if (msgs[0].len != 1 || msgs[1].len != 1) {
> + dprint_i2c("both messages must be 1 byte\n");
> + goto err_out;
> +
I think you missed a closing } here. And an opening { below...
> + 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;
You don't need to initialize id_ptr here.
> +
> + 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;
> +}
> --
> 1.8.1.1
>
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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