[PATCH linux 5/7] hwmon: occ: Add hwmon implementation for the P8 OCC

Andrew Jeffery andrew at aj.id.au
Tue Dec 20 11:53:07 AEDT 2016


On Fri, 2016-12-16 at 14:35 -0600, eajames.ibm at gmail.com wrote:
> > From: "Edward A. James" <eajames at us.ibm.com>
> 
> Add code to tie the hwmon sysfs code and the POWER8 OCC code together, as
> well as probe the entire driver from the I2C bus. I2C is the communication
> method between the BMC and the P8 OCC.
> 
> > Signed-off-by: Edward A. James <eajames at us.ibm.com>
> > Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> ---
>  .../devicetree/bindings/i2c/i2c-ibm-occ.txt        |  13 ++
>  drivers/hwmon/occ/Kconfig                          |  14 ++
>  drivers/hwmon/occ/Makefile                         |   1 +
>  drivers/hwmon/occ/occ_p8_i2c.c                     | 141 +++++++++++++++++++++
>  4 files changed, 169 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/i2c/i2c-ibm-occ.txt
>  create mode 100644 drivers/hwmon/occ/occ_p8_i2c.c
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-ibm-occ.txt b/Documentation/devicetree/bindings/i2c/i2c-ibm-occ.txt
> new file mode 100644
> index 0000000..b0d2b36
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-ibm-occ.txt
> @@ -0,0 +1,13 @@
> +HWMON I2C driver for IBM POWER CPU OCC (On Chip Controller)
> +
> +Required properties:
> + - compatible: must be "ibm,p8-occ-i2c"
> + - reg: physical address
> +
> +Example:
> > +i2c3: i2c-bus at 100 {
> > +	occ at 50 {
> > +		compatible = "ibm,p8-occ-i2c";
> > +		reg = <0x50>;
> > +	};
> +};
> diff --git a/drivers/hwmon/occ/Kconfig b/drivers/hwmon/occ/Kconfig
> index cdb64a7..e690001 100644
> --- a/drivers/hwmon/occ/Kconfig
> +++ b/drivers/hwmon/occ/Kconfig
> @@ -13,3 +13,17 @@ menuconfig SENSORS_PPC_OCC
>  
> >  	  This driver can also be built as a module. If so, the module
> >  	  will be called occ.
> +
> +if SENSORS_PPC_OCC
> +
> +config SENSORS_PPC_OCC_P8_I2C
> > +	tristate "POWER8 OCC hwmon support"
> > +	depends on I2C
> > +	help
> > +	 Provide a hwmon sysfs interface for the POWER8 On-Chip Controller,
> > +	 exposing temperature, frequency and power measurements.
> +
> > +	 This driver can also be built as a module. If so, the module will be
> +	 called occ-p8-i2c.

I think this should be p8-occ-i2c by the #define below and your
compatible string. Though the C file is called 'occ_p8_i2c.c' as well;
maybe it should be renamed? Other than that, consider it tagged with
reviewed-by, these are minor issues.

> +
> +endif
> diff --git a/drivers/hwmon/occ/Makefile b/drivers/hwmon/occ/Makefile
> index a6881f9..05a84e9 100644
> --- a/drivers/hwmon/occ/Makefile
> +++ b/drivers/hwmon/occ/Makefile
> @@ -1 +1,2 @@
>  obj-$(CONFIG_SENSORS_PPC_OCC) += occ.o occ_sysfs.o
> +obj-$(CONFIG_SENSORS_PPC_OCC_P8_I2C) += occ_scom_i2c.o occ_p8.o occ_p8_i2c.o
> diff --git a/drivers/hwmon/occ/occ_p8_i2c.c b/drivers/hwmon/occ/occ_p8_i2c.c
> new file mode 100644
> index 0000000..a151b3a
> --- /dev/null
> +++ b/drivers/hwmon/occ/occ_p8_i2c.c
> @@ -0,0 +1,141 @@
> +/*
> + * occ_p8_i2c.c - hwmon OCC driver
> + *
> + * This file contains the i2c layer for accessing the P8 OCC over i2c bus.
> + *
> + * Copyright 2016 IBM Corp.
> + *
> + * 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.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/slab.h>
> +#include <linux/i2c.h>
> +#include <linux/err.h>
> +#include <linux/of.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +
> +#include "scom.h"
> +#include "occ_scom_i2c.h"
> +#include "occ_p8.h"
> +#include "occ_sysfs.h"
> +
> > +#define P8_OCC_I2C_NAME	"p8-occ-i2c"
> +
> +static char *caps_sensor_names[] = {
> > +	"curr_powercap",
> > +	"curr_powerreading",
> > +	"norm_powercap",
> > +	"max_powercap",
> > +	"min_powercap",
> > +	"user_powerlimit"
> +};
> +
> +int p8_i2c_getscom(void *bus, u32 address, u8 *data)
> +{
> > +	/* P8 i2c slave requires address to be shifted by 1 */
> > +	address = address << 1;
> +
> > +	return occ_i2c_getscom(bus, address, data);
> +}
> +
> +int p8_i2c_putscom(void *bus, u32 address, u32 data0, u32 data1)
> +{
> > +	/* P8 i2c slave requires address to be shifted by 1 */
> > +	address = address << 1;
> +
> > +	return occ_i2c_putscom(bus, address, data0, data1);
> +}
> +
> +static struct occ_bus_ops p8_bus_ops = {
> > +	.getscom = p8_i2c_getscom,
> > +	.putscom = p8_i2c_putscom,
> +};
> +
> +static struct occ_sysfs_config p8_sysfs_config = {
> > +	.num_caps_fields = ARRAY_SIZE(caps_sensor_names),
> > +	.caps_names = caps_sensor_names,
> +};
> +
> +static int p8_occ_probe(struct i2c_client *client,
> > +			const struct i2c_device_id *id)
> +{
> > +	struct occ *occ;
> > +	struct occ_sysfs *hwmon;
> +
> > +	occ = p8_occ_start(&client->dev, client, &p8_bus_ops);
> > +	if (IS_ERR(occ))
> > +		return PTR_ERR(occ);
> +
> > +	hwmon = occ_sysfs_start(&client->dev, occ, &p8_sysfs_config);
> > +	if (IS_ERR(hwmon))
> > +		return PTR_ERR(hwmon);
> +
> > +	i2c_set_clientdata(client, hwmon);
> +
> > +	return 0;
> +}
> +
> +static int p8_occ_remove(struct i2c_client *client)
> +{
> > +	int rc;
> > +	struct occ_sysfs *hwmon = i2c_get_clientdata(client);
> > +	struct occ *occ = hwmon->occ;
> +
> > +	rc = occ_sysfs_stop(&client->dev, hwmon);
> +
> > +	rc = rc || p8_occ_stop(occ);
> +
> > +	return rc;
> +}
> +
> +/* used by old-style board info. */
> +static const struct i2c_device_id occ_ids[] = {
> > +	{ P8_OCC_I2C_NAME, 0 },
> > +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, occ_ids);
> +
> +/* used by device table */
> +static const struct of_device_id occ_of_match[] = {
> > +	{ .compatible = "ibm,p8-occ-i2c" },
> > +	{}
> +};
> +MODULE_DEVICE_TABLE(of, occ_of_match);
> +
> +/*
> + * i2c-core uses i2c-detect() to detect device in below address list.
> + * If exists, address will be assigned to client.
> + * It is also possible to read address from device table.
> + */
> +static const unsigned short normal_i2c[] = {0x50, 0x51, I2C_CLIENT_END };
> +
> +static struct i2c_driver p8_occ_driver = {
> > +	.class = I2C_CLASS_HWMON,
> > +	.driver = {
> > +		.name = P8_OCC_I2C_NAME,
> > +		.pm = NULL,
> > +		.of_match_table = occ_of_match,
> > +	},
> > +	.probe = p8_occ_probe,
> > +	.remove = p8_occ_remove,
> > +	.id_table = occ_ids,
> > +	.address_list = normal_i2c,
> +};
> +
> +module_i2c_driver(p8_occ_driver);
> +
> > +MODULE_AUTHOR("Eddie James <eajames at us.ibm.com>");
> +MODULE_DESCRIPTION("BMC P8 OCC hwmon driver");
> +MODULE_LICENSE("GPL");
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