Re: [PATCH 1/3] drivers/mfd/menf21bmc: introduce MEN 14F021P00 BMC MFD Core driver
From: Guenter Roeck
Date: Mon May 19 2014 - 09:23:51 EST
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@xxxxxx>
---
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@xxxxxx>
+ * 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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