Re: [PATCH v4 3/6] commands: add i2c commands

[Marc Kleine-Budde <mkl@pengutronix.de>]

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Eric Bénard wrote:
> theses commands allow low level access to i2c bus and can be useful
> to setup an i2c device without having to add code, compile and flash
> barebox.
> 
> Signed-off-by: Eric Bénard <eric@eukrea.com>
> ---
> v4 :
> 	updated as per Sascha and Marc's comments
> 	use bus 0 as a default for i2c_read & write
> 	replace malloc with xmalloc
> 	fix simple_strtol configuration for parameters
> v3 : 
> 	enable brain and fix v2
> 	tested on iMX27
> v2 :
> 	updated as per Sascha's comments
> 
>  commands/Kconfig  |    8 ++
>  commands/Makefile |    1 +
>  commands/i2c.c    |  212 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 221 insertions(+), 0 deletions(-)
>  create mode 100644 commands/i2c.c
> 
> diff --git a/commands/Kconfig b/commands/Kconfig
> index 0c09f91..0ea32d9 100644
> --- a/commands/Kconfig
> +++ b/commands/Kconfig
> @@ -314,4 +314,12 @@ config CMD_UNLZO
>  	  Say yes here to get the unlzo command. lzo is a fast compression
>  	  algorithm by Markus Franz Xaver Johannes Oberhumer.
>  
> +config CMD_I2C
> +	bool
> +	depends on I2C
> +	prompt "i2c commands"
> +	help
> +	  include i2c_probe, i2c_read and i2c_write commands to communicate
> +	  on i2c bus.
> +
>  endmenu
> diff --git a/commands/Makefile b/commands/Makefile
> index 74b0994..3eef5de 100644
> --- a/commands/Makefile
> +++ b/commands/Makefile
> @@ -48,3 +48,4 @@ obj-$(CONFIG_CMD_BMP)		+= bmp.o
>  obj-$(CONFIG_USB_GADGET_DFU)	+= dfu.o
>  obj-$(CONFIG_CMD_GPIO)		+= gpio.o
>  obj-$(CONFIG_CMD_UNLZO)		+= unlzo.o
> +obj-$(CONFIG_CMD_I2C)		+= i2c.o
> diff --git a/commands/i2c.c b/commands/i2c.c
> new file mode 100644
> index 0000000..1e617f6
> --- /dev/null
> +++ b/commands/i2c.c
> @@ -0,0 +1,212 @@
> +/*
> + * i2c.c - i2c commands
> + *
> + * Copyright (c) 2010 Eric Bénard <eric@eukrea.Com>, Eukréa Electromatique
> + *
> + * 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., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include <common.h>
> +#include <command.h>
> +#include <errno.h>
> +#include <malloc.h>
> +#include <getopt.h>
> +#include <i2c/i2c.h>
> +
> +static int do_i2c_probe(struct command *cmdtp, int argc, char *argv[])
> +{
> +	struct i2c_adapter *adapter;
> +	struct i2c_client client;
> +	int startaddr = -1, stopaddr = -1, addr, ret;
> +	u8 reg;
> +
> +	if (argc < 4)
> +		return COMMAND_ERROR_USAGE;
> +
> +	adapter = i2c_get_adapter(simple_strtoul(argv[1], NULL, 0));
> +	if (!adapter)
> +		return -ENODEV;
> +	client.adapter = adapter;
> +
> +	startaddr = simple_strtol(argv[2], NULL, 0);
> +	stopaddr = simple_strtol(argv[3], NULL, 0);
> +	if ((startaddr == -1) || (stopaddr == -1) || (startaddr > stopaddr))
> +		return COMMAND_ERROR_USAGE;
> +
> +	if (stopaddr > 0x7F)
> +		stopaddr = 0x7F;
> +
> +	printf("probing i2c range 0X%02x - 0x%02x :\n", startaddr, stopaddr);
> +	for (addr = startaddr; addr <= stopaddr; addr++) {
> +		client.addr = addr;
> +		ret = i2c_write_reg(&client, 0x00, &reg, 0);
> +		if (ret == 0)
> +			printf("0x%02x ", addr);
> +	}
> +	printf("\n");
> +	return 0;
> +}
> +
> +static const __maybe_unused char cmd_i2c_probe_help[] =
> +"Usage: i2c_probe bus 0xstartaddr 0xstopaddr\n"
> +"probe a range of i2c addresses.\n";
> +
> +BAREBOX_CMD_START(i2c_probe)
> +	.cmd		= do_i2c_probe,
> +	.usage		= "probe for an i2c device",
> +	BAREBOX_CMD_HELP(cmd_i2c_probe_help)
> +BAREBOX_CMD_END
> +
> +static int do_i2c_write(struct command *cmdtp, int argc, char *argv[])
> +{
> +	struct i2c_adapter *adapter = NULL;
> +	struct i2c_client client;
> +	int addr = -1, reg = -1, count = -1, verbose = 0, ret = 0, opt, i;
> +	u8 *buf;
> +	u8 tmp;
> +
> +	while ((opt = getopt(argc, argv, "a:b:r:v")) > 0) {
> +		switch (opt) {
> +		case 'a':
> +			addr = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'r':
> +			reg = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'b':
> +			adapter = i2c_get_adapter(simple_strtoul(optarg, NULL, 0));

I'd just save the optarg in a variable...

> +			break;
> +		case 'v':
> +			verbose = 1;
> +			break;
> +		}
> +	}
> +
> +	count = argc - optind;
> +
> +	if ((addr < 0) || (reg < 0) || (count == 0) || (addr > 0x7F))
> +		return COMMAND_ERROR_USAGE;
> +
> +	if (!adapter)
> +		adapter = i2c_get_adapter(0);

and use it here. Because if you specify an invalid adapter number,
adapter 0 will be used silently (if it exists).

> +	if (!adapter)
> +		return -ENODEV;
> +
> +	client.adapter = adapter;
> +	client.addr = addr;
> +
> +	buf = xmalloc(count);
> +	for (i = 0; i < count; i++)
> +		*(buf + i) = (char) simple_strtol(argv[optind+i], NULL, 16);
> +
> +	ret = i2c_write_reg(&client, reg, buf, count);
> +	if (ret != count)
> +		goto out;

better set a return value indicating an error here...

> +
> +	if (verbose) {
> +		printf("wrote %i bytes starting at reg 0x%02x to i2cdev 0x%02x on bus %i\n",
> +			count, reg, addr, adapter->nr);
> +		for (i = 0; i < count; i++)
> +			printf("0x%02x ", *(buf + i));
> +		printf("\n");
> +	}
> +
> +out:
> +	free(buf);
> +	return 0;

... and return it here.
> +}
> +
> +static const __maybe_unused char cmd_i2c_write_help[] =
> +"Usage: i2c_write [OPTION] ... hexdatas\n"
> +"write to i2c device.\n"
> +"  -a 0x<addr>   i2c device address\n"
> +"  -b <bus_num>  i2c bus number (default = 0)\n"
> +"  -r 0x<reg>    start register\n";
> +
> +BAREBOX_CMD_START(i2c_write)
> +	.cmd		= do_i2c_write,
> +	.usage		= "write to an i2c device",
> +	BAREBOX_CMD_HELP(cmd_i2c_write_help)
> +BAREBOX_CMD_END
> +
> +static int do_i2c_read(struct command *cmdtp, int argc, char *argv[])
> +{
> +	struct i2c_adapter *adapter = NULL;
> +	struct i2c_client client;
> +	u8 *buf;
> +	int count = -1, addr = -1, reg = -1, verbose = 0, ret = 0, opt;
> +
> +	while ((opt = getopt(argc, argv, "a:b:c:r:v")) > 0) {
> +		switch (opt) {
> +		case 'a':
> +			addr = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'c':
> +			count = simple_strtoul(optarg, NULL, 0);
> +			break;
> +		case 'b':
> +			adapter = i2c_get_adapter(simple_strtoul(optarg, NULL, 0));
> +			break;
> +		case 'r':
> +			reg = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'v':
> +			verbose = 1;
> +			break;
> +		}
> +	}
> +
> +	if ((addr < 0) || (reg < 0) || (count == 0) || (addr > 0x7F))
> +		return COMMAND_ERROR_USAGE;
> +
> +	if (!adapter)
> +		adapter = i2c_get_adapter(0);
> +	if (!adapter)
> +		return -ENODEV;
> +
> +	client.adapter = adapter;
> +	client.addr = addr;
> +
> +	buf = xmalloc(count);
> +	ret = i2c_read_reg(&client, reg, buf, count);
> +	if (ret == count) {
> +		int i;
> +		if (verbose)
> +			printf("read %i bytes starting at reg 0x%02x from i2cdev 0x%02x on bus %i\n",
> +				count, reg, addr, adapter->nr);
> +		for (i = 0; i < count; i++)
> +			printf("0x%02x ", *(buf + i));
> +		printf("\n");
> +		ret = 0;
> +	}
> +
> +	free(buf);
> +	return ret;
> +}
> +
> +static const __maybe_unused char cmd_i2c_read_help[] =
> +"Usage: i2c_read [OPTION]\n"
> +"read i2c device.\n"
> +"  -a 0x<addr>   i2c device address\n"
> +"  -b <bus_num>  i2c bus number (default = 0)\n"
> +"  -r 0x<reg>    start register\n"
> +"  -c <count>    byte count\n";
> +
> +BAREBOX_CMD_START(i2c_read)
> +	.cmd		= do_i2c_read,
> +	.usage		= "read from an i2c device",
> +	BAREBOX_CMD_HELP(cmd_i2c_read_help)
> +BAREBOX_CMD_END

cheers, Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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