Messages in this thread | | | Date | Mon, 19 May 2014 06:23:32 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH 1/3] drivers/mfd/menf21bmc: introduce MEN 14F021P00 BMC MFD Core driver |
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On 05/19/2014 05:43 AM, Andreas Werner wrote: > aOn Sat, May 17, 2014 at 08:47:42AM -0700, Guenter Roeck wrote: >> On 05/16/2014 09:37 AM, Andreas Werner wrote: >>> The MEN 14F021P00 Board Management Controller provides an >>> I2C interface to the host to access the feature implemented in the BMC. >>> The BMC is a PIC Microntroller assembled on CPCI Card from MEN Mikroelektronik >>> and on a few Box/Display Computer. >>> >>> Added MFD Core driver, supporting the I2C communication to the device. >>> >>> The MFD driver currently supports the following features: >>> - Watchdog >>> - LEDs >>> >>> Signed-off-by: Andreas Werner <andreas.werner@men.de> >>> --- >>> drivers/mfd/Kconfig | 12 +++ >>> drivers/mfd/Makefile | 1 + >>> drivers/mfd/menf21bmc.c | 193 ++++++++++++++++++++++++++++++++++++++++++ >>> include/linux/mfd/menf21bmc.h | 32 +++++++ >>> 4 files changed, 238 insertions(+) >>> create mode 100644 drivers/mfd/menf21bmc.c >>> create mode 100644 include/linux/mfd/menf21bmc.h >>> >>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig >>> index ab5a43c..7c2e8d2 100644 >>> --- a/drivers/mfd/Kconfig >>> +++ b/drivers/mfd/Kconfig >>> @@ -427,6 +427,18 @@ config MFD_MAX8998 >>> additional drivers must be enabled in order to use the functionality >>> of the device. >>> >>> +config MFD_MENF21BMC >>> + tristate "MEN 14F021P00 Board Management Controller Support" >>> + depends on I2C=y >>> + select MFD_CORE >>> + help >>> + Say yes here to add support for the MEN 14F021P00 BMC >>> + which is a Board Management Controller connected to the I2C bus. >>> + This driver provides common support for accessing the devices; >>> + additional drivers must be enabled in order to use the >>> + functionality of the BMC device. >>> + >>> + >>> config EZX_PCAP >>> bool "Motorola EZXPCAP Support" >>> depends on SPI_MASTER >>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile >>> index 5913208..8f2be38 100644 >>> --- a/drivers/mfd/Makefile >>> +++ b/drivers/mfd/Makefile >>> @@ -167,3 +167,4 @@ obj-$(CONFIG_MFD_AS3711) += as3711.o >>> obj-$(CONFIG_MFD_AS3722) += as3722.o >>> obj-$(CONFIG_MFD_STW481X) += stw481x.o >>> obj-$(CONFIG_MFD_IPAQ_MICRO) += ipaq-micro.o >>> +obj-$(CONFIG_MFD_MENF21BMC) += menf21bmc.o >>> diff --git a/drivers/mfd/menf21bmc.c b/drivers/mfd/menf21bmc.c >>> new file mode 100644 >>> index 0000000..77de1a8 >>> --- /dev/null >>> +++ b/drivers/mfd/menf21bmc.c >>> @@ -0,0 +1,193 @@ >>> +/* >>> + * MEN 14F021P00 Board Management Controller (BMC) MFD Core Driver. >>> + * >>> + * Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH >>> + * Author: Andreas Werner <andreas.werner@men.de> >>> + * All rights reserved. >>> + * >>> + * 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. >>> + * >>> + */ >>> + >>> +#include <linux/kernel.h> >>> +#include <linux/device.h> >>> +#include <linux/module.h> >>> +#include <linux/i2c.h> >>> +#include <linux/mfd/core.h> >>> +#include <linux/mfd/menf21bmc.h> >>> + >>> +#define BMC_CMD_REV_MAJOR 0x80 >>> +#define BMC_CMD_REV_MINOR 0x81 >>> +#define BMC_CMD_REV_MAIN 0x82 >>> +#define BMC_CMD_REV_BUILD 0x83 >>> +#define BMC_CMD_REV_VERI 0x84 >>> + >>> +static struct mfd_cell menf21bmc_cell[] = { >>> + { >>> + .name = "menf21bmc_wd", >>> + }, >>> + { >>> + .name = "menf21bmc_led", >>> + }, >>> +}; >>> + >>> +static int >>> +menf21bmc_read_byte_data(struct i2c_client *client, u8 reg, uint8_t *val) >>> +{ >>> + int ret; >>> + struct menf21bmc *data = i2c_get_clientdata(client); >>> + >>> + mutex_lock(&data->lock); >>> + ret = i2c_smbus_read_byte_data(client, reg); >>> + mutex_unlock(&data->lock); >>> + >>> + if (ret < 0) { >>> + dev_err(&client->dev, "failed to read byte at 0x%02x\n", reg); >>> + return ret; >>> + } >>> + >>> + *val = (uint8_t)ret; >>> + >>> + return 0; >>> +} >>> + >> I personally would prefer if you would retain the original API, which returns both value >> and error code as return value. I don't see the benefit of changing the API as you did - >> it just complicates the code. >> >> Thanks, >> Guenter >> > I think it is ok for a wrapper like this because it does not really change an API because > it is menf21bmc related. > > I did the same in rtc-rx8581, and it was already done in rtc_ds1307.c. > > I personally prefer this way because the return of the function and the return > value of the i2c_smbus_read - which is the value read from the device - are seperated. > > If it is a no go for the mfd/wdt core i can change it back to the original i2c_smbus API. > If it is ok on your side for a wrapper like this, we can let it as it is. >
Not my call to make; depends on the mfd maintainer. I would not accept it, as I see it as unnecessary, adding complexity, and pointless. Sure, you can always find examples for everything somewhere in the kernel, but that doesn't make it better.
Guenter
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