[PATCH linux dev-4.10 v4 1/2] hwmon: (ucd9000) Add gpio chip interface and clear logged faults
Andrew Jeffery
andrew at aj.id.au
Tue Aug 22 12:00:56 AEST 2017
Hi Chris,
On Mon, 2017-08-21 at 17:09 -0500, Christopher Bostic wrote:
> Add a struct gpio_chip and define some methods so that this device's
> I/O can be accessed via /sys/class/gpio.
>
> Present requirements only call for retrieving current state of pin
> values and their direction. No requirement at this time to switch
> modes between output and input within the device driver.
>
> Add capability to clear logged faults via sysfs.
>
> > Signed-off-by: Christopher Bostic <cbostic at linux.vnet.ibm.com>
> ---
> v4 - Change status check from branch to a !! non branching method
> - Remove usage comments on libgpiod for the struct gpio_chip
> methods.
> - Clean up some text formatting.
> v3 - Correct bug in gpio_chip get method. Wasn't retrieving
> gpio config information correctly.
> - Remove old debugfs flag from previous pmbus core changes.
> - Remove all sysfs files for mfr_status command.
> - Add comments on direct i2c_smbus calls to clarify that no page
> set is required.
> v2 - Remove clear_faults file - redundant since all other sysfs
> core accesses result in an automatic clear fault.
> - Removed local status_word and status_vout register dumps and
> use the new pmbus core status facilities instead.
> - Rename gpi<x>_fault to gpi<x>_alarm to better match core naming
> conventions.
> - Add full register dump for mfr_status.
> - Add gpio chip to device structure and use gpio interfaces.
> ---
> drivers/hwmon/pmbus/ucd9000.c | 128 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 126 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index 3e3aa95..5cea5f6 100644
> --- a/drivers/hwmon/pmbus/ucd9000.c
> +++ b/drivers/hwmon/pmbus/ucd9000.c
> @@ -26,6 +26,9 @@
> #include <linux/slab.h>
> #include <linux/i2c.h>
> #include <linux/i2c/pmbus.h>
> +#include <linux/sysfs.h>
> +#include <linux/hwmon-sysfs.h>
> +#include <linux/gpio.h>
> #include "pmbus.h"
>
> enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
> @@ -34,8 +37,16 @@
> > #define UCD9000_NUM_PAGES 0xd6
> > #define UCD9000_FAN_CONFIG_INDEX 0xe7
> > #define UCD9000_FAN_CONFIG 0xe8
> > +#define UCD9000_LOGGED_FAULTS 0xea
> > +#define UCD9000_GPIO_SELECT 0xfa
> > +#define UCD9000_GPIO_CONFIG 0xfb
> > #define UCD9000_DEVICE_ID 0xfd
>
> +/* GPIO CONFIG bits */
> > +#define UCD9000_GPIO_CONFIG_ENABLE BIT(0)
> > +#define UCD9000_GPIO_CONFIG_OUT_ENABLE BIT(1)
> > +#define UCD9000_GPIO_CONFIG_STATUS BIT(3)
> +
> > #define UCD9000_MON_TYPE(x) (((x) >> 5) & 0x07)
> > #define UCD9000_MON_PAGE(x) ((x) & 0x0f)
>
> @@ -46,9 +57,12 @@
>
> > #define UCD9000_NUM_FAN 4
>
> > +#define UCD90160_NUM_GPIOS 26
> +
> struct ucd9000_data {
> > u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
> > struct pmbus_driver_info info;
> > + struct gpio_chip gpio;
> };
> #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
>
> @@ -119,6 +133,87 @@ static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg)
> };
> MODULE_DEVICE_TABLE(i2c, ucd9000_id);
>
> +static int ucd9000_gpio_read_config(struct i2c_client *client,
> > + unsigned int offset)
> +{
> > + int ret;
> +
> > + /* No page set required */
> > + ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_SELECT, offset);
> > + if (ret < 0) {
> > + dev_err(&client->dev, "Failed to select GPIO %d: %d\n", offset,
> > + ret);
> > + return ret;
> > + }
> +
> > + return i2c_smbus_read_byte_data(client, UCD9000_GPIO_CONFIG);
> +}
> +
> +static int ucd9000_gpio_get(struct gpio_chip *gc, unsigned int offset)
> +{
> > + struct i2c_client *client = gpiochip_get_data(gc);
> > + int ret;
> +
> > + ret = ucd9000_gpio_read_config(client, offset);
> > + if (ret < 0) {
> > + dev_err(&client->dev, "failed to read GPIO config\n");
> > + return ret;
> > + }
> +
> > + return !!(ret & UCD9000_GPIO_CONFIG_STATUS);
I see you've fixed this case, but didn't audit the rest of the code to fix the
remainder. For example the return statement in ucd9000_gpio_get_direction()
still branches. Similarly there are error messages that don't report the error
return value*, and unnecessary line breaks in in dev_err() calls. In the future,
can you please audit your code for classes of problems that are identified in
review? I'd hate to have to comment on literally every instance to get them all
fixed, as that feels like a waste of my time and a bit patronising towards you.
* Where and when we do this needs some judgement with respect to taste, but it
certainly frustrates me when I'm reading logs and I see vague messages like
"Failed". What failed? Why?
> +}
> +
> +static int ucd9000_gpio_get_direction(struct gpio_chip *gc,
> > + unsigned int offset)
> +{
> > + struct i2c_client *client = gpiochip_get_data(gc);
> > + int ret;
> +
> > + ret = ucd9000_gpio_read_config(client, offset);
> > + if (ret < 0) {
> > + dev_err(&client->dev,
> > + "failed to read GPIO config\n");
> > + return ret;
> > + }
> +
> > + return ret & UCD9000_GPIO_CONFIG_OUT_ENABLE ? 0 : 1;
> +}
> +
> +static int ucd9000_gpio_direction_input(struct gpio_chip *gc,
> > + unsigned int offset)
> +{
> > + return 0;
In your reply to my comments on v3 you said you'd implement the direction
switching, but this is still unimplemented. What happened? Also I spent some
time discussing documentation of assumptions in my reply to Matt, but that
seems to not be addressed either. Why is that?
Did you look at a bare-bones pinctrl implementation so we can describe the GPIO
ranges appropriately? If you did and it was too much effort then it would be
nice to know that, and why.
> +}
> +
> +static ssize_t ucd9000_clear_logged_faults(struct device *dev,
> > + struct device_attribute *attr, const char *buf,
> > + size_t count)
> +{
> > + struct i2c_client *client = to_i2c_client(dev);
> > + int ret;
> +
> > + /* No page set required */
> > + ret = i2c_smbus_write_byte_data(client, UCD9000_LOGGED_FAULTS, 0);
> > + if (ret) {
> > + dev_err(&client->dev, "Failed to clear logged faults\n");
> > + return ret;
> > + }
> +
> > + return count;
> +}
> +
> +static DEVICE_ATTR(clear_logged_faults, 0200, NULL,
> > + ucd9000_clear_logged_faults);
> +
> +static struct attribute *ucd9000_attributes[] = {
> > + &dev_attr_clear_logged_faults.attr,
> > + NULL
> +};
> +
> +static const struct attribute_group ucd9000_attr_group = {
> > + .attrs = ucd9000_attributes,
> +};
> +
Joel requested the patch be sent upstream to get a decision from the
maintainers on this new ABI, and I suggested to you yesterday that it should
probably be split out to address ABI changes separate to the GPIO problem, but
neither appear to have been done. Why was that?
Andrew
> static int ucd9000_probe(struct i2c_client *client,
> > const struct i2c_device_id *id)
> {
> @@ -227,7 +322,36 @@ static int ucd9000_probe(struct i2c_client *client,
> > | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
> > }
>
> > - return pmbus_do_probe(client, mid, info);
> > + data->gpio.label = "gpio-ucd9000";
> > + data->gpio.get_direction = ucd9000_gpio_get_direction;
> > + data->gpio.direction_input = ucd9000_gpio_direction_input;
> > + data->gpio.get = ucd9000_gpio_get;
> > + data->gpio.can_sleep = 1;
> > + data->gpio.base = -1;
> > + if (mid->driver_data == ucd90160)
> > + data->gpio.ngpio = UCD90160_NUM_GPIOS;
> > + data->gpio.parent = &client->dev;
> > + data->gpio.owner = THIS_MODULE;
> +
> > + ret = devm_gpiochip_add_data(&client->dev, &data->gpio, client);
> > + if (ret) {
> > + data->gpio.parent = NULL;
> > + dev_warn(&client->dev, "Count not add gpiochip\n");
> > + return ret;
> > + }
> +
> > + ret = sysfs_create_group(&client->dev.kobj,
> > + &ucd9000_attr_group);
> > + if (ret < 0)
> > + return ret;
> +
> > + return pmbus_do_probe(client, mid, info);
> +}
> +
> +static int ucd9000_remove(struct i2c_client *client)
> +{
> > + sysfs_remove_group(&client->dev.kobj, &ucd9000_attr_group);
> > + return pmbus_do_remove(client);
> }
>
> /* This is the driver that will be inserted */
> @@ -236,7 +360,7 @@ static int ucd9000_probe(struct i2c_client *client,
> > .name = "ucd9000",
> > },
> > .probe = ucd9000_probe,
> > - .remove = pmbus_do_remove,
> > + .remove = ucd9000_remove,
> > .id_table = ucd9000_id,
> };
>
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