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Message-ID: <39df66cf-2580-5e49-17b5-2187469b5d44@roeck-us.net>
Date: Sat, 10 Mar 2018 08:44:46 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Eddie James <eajames@...ux.vnet.ibm.com>,
linux-hwmon@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, jdelvare@...e.com, joel@....id.au,
Christopher Bostic <cbostic@...ux.vnet.ibm.com>,
Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH 1/2] hwmon: (ucd9000) Add gpio chip interface
On 03/09/2018 11:19 AM, Eddie James wrote:
> From: Christopher Bostic <cbostic@...ux.vnet.ibm.com>
>
> Add a struct gpio_chip and define some methods so that this device's
> I/O can be accessed via /sys/class/gpio.
>
> Signed-off-by: Christopher Bostic <cbostic@...ux.vnet.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@...id.au>
> Signed-off-by: Eddie James <eajames@...ux.vnet.ibm.com>
> ---
> drivers/hwmon/pmbus/ucd9000.c | 220 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 220 insertions(+)
>
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index b74dbec..e3a507f 100644
> --- a/drivers/hwmon/pmbus/ucd9000.c
> +++ b/drivers/hwmon/pmbus/ucd9000.c
> @@ -27,6 +27,7 @@
> #include <linux/slab.h>
> #include <linux/i2c.h>
> #include <linux/pmbus.h>
> +#include <linux/gpio.h>
> #include "pmbus.h"
>
> enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
> @@ -35,8 +36,18 @@
> #define UCD9000_NUM_PAGES 0xd6
> #define UCD9000_FAN_CONFIG_INDEX 0xe7
> #define UCD9000_FAN_CONFIG 0xe8
> +#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_OUT_VALUE BIT(2)
> +#define UCD9000_GPIO_CONFIG_STATUS BIT(3)
> +#define UCD9000_GPIO_INPUT 0
> +#define UCD9000_GPIO_OUTPUT 1
> +
> #define UCD9000_MON_TYPE(x) (((x) >> 5) & 0x07)
> #define UCD9000_MON_PAGE(x) ((x) & 0x0f)
>
> @@ -47,9 +58,15 @@
>
> #define UCD9000_NUM_FAN 4
>
> +#define UCD9000_GPIO_NAME_LEN 16
> +#define UCD9090_NUM_GPIOS 23
> +#define UCD901XX_NUM_GPIOS 26
> +#define UCD90910_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)
>
> @@ -149,6 +166,168 @@ static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg)
> };
> MODULE_DEVICE_TABLE(of, ucd9000_of_match);
>
> +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);
> +
I am not a fan of kernel log error messages outside the probe function.
Please consider dropping those or making it dev_dbg.
Would it make sense to cache those values ?
> + 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 %d config: %d\n",
> + offset, ret);
> +
... even more so if a single error can result in multiple error messages.
> + return ret;
> + }
> +
> + return !!(ret & UCD9000_GPIO_CONFIG_STATUS);
> +}
> +
> +static void ucd9000_gpio_set(struct gpio_chip *gc, unsigned int offset,
> + int value)
> +{
> + 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 %d config: %d\n",
> + offset, ret);
> +
> + return;
> + }
> +
> + if (value) {
> + if (ret & UCD9000_GPIO_CONFIG_STATUS)
> + return;
> +
> + ret |= UCD9000_GPIO_CONFIG_STATUS;
> + } else {
> + if (!(ret & UCD9000_GPIO_CONFIG_STATUS))
> + return;
> +
> + ret &= ~UCD9000_GPIO_CONFIG_STATUS;
> + }
> +
> + ret |= UCD9000_GPIO_CONFIG_ENABLE;
> +
> + /* Page set not required */
> + ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
> + if (ret < 0) {
> + dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
> + offset, ret);
> +
> + return;
> + }
> +
> + ret &= ~UCD9000_GPIO_CONFIG_ENABLE;
> +
> + ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
> + if (ret < 0)
> + dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
> + offset, ret);
> +}
> +
> +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 %d config: %d\n",
> + offset, ret);
> +
> + return ret;
> + }
> +
> + return !(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE);
> +}
> +
> +static int ucd9000_gpio_set_direction(struct gpio_chip *gc,
> + unsigned int offset, bool direction_out,
> + int requested_out)
> +{
> + struct i2c_client *client = gpiochip_get_data(gc);
> + int ret, config, out_val;
> +
> + ret = ucd9000_gpio_read_config(client, offset);
> + if (ret < 0) {
> + dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
> + offset, ret);
> +
> + return ret;
> + }
> +
> + if (direction_out) {
> + out_val = requested_out ? UCD9000_GPIO_CONFIG_OUT_VALUE : 0;
> +
> + if (ret & UCD9000_GPIO_CONFIG_OUT_ENABLE) {
> + if ((ret & UCD9000_GPIO_CONFIG_OUT_VALUE) == out_val)
> + return 0;
> + } else {
> + ret |= UCD9000_GPIO_CONFIG_OUT_ENABLE;
> + }
> +
> + if (out_val)
> + ret |= UCD9000_GPIO_CONFIG_OUT_VALUE;
> + else
> + ret &= ~UCD9000_GPIO_CONFIG_OUT_VALUE;
> +
> + } else {
> + if (!(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE))
> + return 0;
> +
> + ret &= ~UCD9000_GPIO_CONFIG_OUT_ENABLE;
> + }
> +
> + ret |= UCD9000_GPIO_CONFIG_ENABLE;
> + config = ret;
> +
> + /* Page set not required */
> + ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
> + if (ret < 0) {
> + dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
> + offset, ret);
> +
> + return ret;
> + }
> +
> + config &= ~UCD9000_GPIO_CONFIG_ENABLE;
> +
> + return i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
> +}
> +
> +static int ucd9000_gpio_direction_input(struct gpio_chip *gc,
> + unsigned int offset)
> +{
> + return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_INPUT, 0);
> +}
> +
> +static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
> + unsigned int offset, int val)
> +{
> + return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_OUTPUT,
> + val);
> +}
> +
> static int ucd9000_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -263,6 +442,47 @@ static int ucd9000_probe(struct i2c_client *client,
> | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
> }
>
> + /*
> + * Note:
> + *
> + * Pinmux support has not been added to the new gpio_chip.
> + * This support should be added when possible given the mux
> + * behavior of these IO devices.
> + */
> + data->gpio.label = (const char *)&client->name;
> + data->gpio.get_direction = ucd9000_gpio_get_direction;
> + data->gpio.direction_input = ucd9000_gpio_direction_input;
> + data->gpio.direction_output = ucd9000_gpio_direction_output;
> + data->gpio.get = ucd9000_gpio_get;
> + data->gpio.set = ucd9000_gpio_set;
> + data->gpio.can_sleep = 1;
> + data->gpio.base = -1;
> +
Also set of_node ?
> + /* No default case. No data available for ucd9000. */
> + switch (mid->driver_data) {
> + case ucd9090:
> + data->gpio.ngpio = UCD9090_NUM_GPIOS;
> + break;
> + case ucd90120:
> + case ucd90124:
> + case ucd90160:
> + data->gpio.ngpio = UCD901XX_NUM_GPIOS;
> + break;
> + case ucd90910:
> + data->gpio.ngpio = UCD90910_NUM_GPIOS;
> + break;
Why not:
default:
break;
instead of the comment above ?
> + }
> +
> + data->gpio.parent = &client->dev;
> + data->gpio.owner = THIS_MODULE;
> +
Since there are chips with no gpio support (ngpio=0), it would be better
to make the gpio registration conditional.
> + ret = devm_gpiochip_add_data(&client->dev, &data->gpio, client);
> + if (ret) {
> + data->gpio.parent = NULL;
> + dev_warn(&client->dev, "Could not add gpiochip: %d\n", ret);
Either dev_warn and ignore the error, or dev_err. Either case setting data->gpio.parent
to NULL should be unnecessary.
> + return ret;
> + }
> +
> return pmbus_do_probe(client, mid, info);
> }
>
>
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