diff options
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/ltc4245.c | 177 |
1 files changed, 167 insertions, 10 deletions
diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c index 21d201befc2..65930832930 100644 --- a/drivers/hwmon/ltc4245.c +++ b/drivers/hwmon/ltc4245.c @@ -21,6 +21,7 @@ #include <linux/i2c.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> +#include <linux/i2c/ltc4245.h> /* Here are names of the chip's registers (a.k.a. commands) */ enum ltc4245_cmd { @@ -60,8 +61,72 @@ struct ltc4245_data { /* Voltage registers */ u8 vregs[0x0d]; + + /* GPIO ADC registers */ + bool use_extra_gpios; + int gpios[3]; }; +/* + * Update the readings from the GPIO pins. If the driver has been configured to + * sample all GPIO's as analog voltages, a round-robin sampling method is used. + * Otherwise, only the configured GPIO pin is sampled. + * + * LOCKING: must hold data->update_lock + */ +static void ltc4245_update_gpios(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct ltc4245_data *data = i2c_get_clientdata(client); + u8 gpio_curr, gpio_next, gpio_reg; + int i; + + /* no extra gpio support, we're basically done */ + if (!data->use_extra_gpios) { + data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10]; + return; + } + + /* + * If the last reading was too long ago, then we mark all old GPIO + * readings as stale by setting them to -EAGAIN + */ + if (time_after(jiffies, data->last_updated + 5 * HZ)) { + dev_dbg(&client->dev, "Marking GPIOs invalid\n"); + for (i = 0; i < ARRAY_SIZE(data->gpios); i++) + data->gpios[i] = -EAGAIN; + } + + /* + * Get the current GPIO pin + * + * The datasheet calls these GPIO[1-3], but we'll calculate the zero + * based array index instead, and call them GPIO[0-2]. This is much + * easier to think about. + */ + gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6; + if (gpio_curr > 0) + gpio_curr -= 1; + + /* Read the GPIO voltage from the GPIOADC register */ + data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10]; + + /* Find the next GPIO pin to read */ + gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios); + + /* + * Calculate the correct setting for the GPIO register so it will + * sample the next GPIO pin + */ + gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6); + + /* Update the GPIO register */ + i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg); + + /* Update saved data */ + data->cregs[LTC4245_GPIO] = gpio_reg; +} + static struct ltc4245_data *ltc4245_update_device(struct device *dev) { struct i2c_client *client = to_i2c_client(dev); @@ -93,6 +158,9 @@ static struct ltc4245_data *ltc4245_update_device(struct device *dev) data->vregs[i] = val; } + /* Update GPIO readings */ + ltc4245_update_gpios(dev); + data->last_updated = jiffies; data->valid = 1; } @@ -233,6 +301,22 @@ static ssize_t ltc4245_show_alarm(struct device *dev, return snprintf(buf, PAGE_SIZE, "%u\n", (reg & mask) ? 1 : 0); } +static ssize_t ltc4245_show_gpio(struct device *dev, + struct device_attribute *da, + char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); + struct ltc4245_data *data = ltc4245_update_device(dev); + int val = data->gpios[attr->index]; + + /* handle stale GPIO's */ + if (val < 0) + return val; + + /* Convert to millivolts and print */ + return snprintf(buf, PAGE_SIZE, "%u\n", val * 10); +} + /* These macros are used below in constructing device attribute objects * for use with sysfs_create_group() to make a sysfs device file * for each register. @@ -254,6 +338,10 @@ static ssize_t ltc4245_show_alarm(struct device *dev, static SENSOR_DEVICE_ATTR_2(name, S_IRUGO, \ ltc4245_show_alarm, NULL, (mask), reg) +#define LTC4245_GPIO_VOLTAGE(name, gpio_num) \ + static SENSOR_DEVICE_ATTR(name, S_IRUGO, \ + ltc4245_show_gpio, NULL, gpio_num) + /* Construct a sensor_device_attribute structure for each register */ /* Input voltages */ @@ -293,7 +381,9 @@ LTC4245_ALARM(in7_min_alarm, (1 << 2), LTC4245_FAULT2); LTC4245_ALARM(in8_min_alarm, (1 << 3), LTC4245_FAULT2); /* GPIO voltages */ -LTC4245_VOLTAGE(in9_input, LTC4245_GPIOADC); +LTC4245_GPIO_VOLTAGE(in9_input, 0); +LTC4245_GPIO_VOLTAGE(in10_input, 1); +LTC4245_GPIO_VOLTAGE(in11_input, 2); /* Power Consumption (virtual) */ LTC4245_POWER(power1_input, LTC4245_12VSENSE); @@ -304,7 +394,7 @@ LTC4245_POWER(power4_input, LTC4245_VEESENSE); /* Finally, construct an array of pointers to members of the above objects, * as required for sysfs_create_group() */ -static struct attribute *ltc4245_attributes[] = { +static struct attribute *ltc4245_std_attributes[] = { &sensor_dev_attr_in1_input.dev_attr.attr, &sensor_dev_attr_in2_input.dev_attr.attr, &sensor_dev_attr_in3_input.dev_attr.attr, @@ -345,10 +435,77 @@ static struct attribute *ltc4245_attributes[] = { NULL, }; -static const struct attribute_group ltc4245_group = { - .attrs = ltc4245_attributes, +static struct attribute *ltc4245_gpio_attributes[] = { + &sensor_dev_attr_in10_input.dev_attr.attr, + &sensor_dev_attr_in11_input.dev_attr.attr, + NULL, +}; + +static const struct attribute_group ltc4245_std_group = { + .attrs = ltc4245_std_attributes, +}; + +static const struct attribute_group ltc4245_gpio_group = { + .attrs = ltc4245_gpio_attributes, }; +static int ltc4245_sysfs_create_groups(struct i2c_client *client) +{ + struct ltc4245_data *data = i2c_get_clientdata(client); + struct device *dev = &client->dev; + int ret; + + /* register the standard sysfs attributes */ + ret = sysfs_create_group(&dev->kobj, <c4245_std_group); + if (ret) { + dev_err(dev, "unable to register standard attributes\n"); + return ret; + } + + /* if we're using the extra gpio support, register it's attributes */ + if (data->use_extra_gpios) { + ret = sysfs_create_group(&dev->kobj, <c4245_gpio_group); + if (ret) { + dev_err(dev, "unable to register gpio attributes\n"); + sysfs_remove_group(&dev->kobj, <c4245_std_group); + return ret; + } + } + + return 0; +} + +static void ltc4245_sysfs_remove_groups(struct i2c_client *client) +{ + struct ltc4245_data *data = i2c_get_clientdata(client); + struct device *dev = &client->dev; + + if (data->use_extra_gpios) + sysfs_remove_group(&dev->kobj, <c4245_gpio_group); + + sysfs_remove_group(&dev->kobj, <c4245_std_group); +} + +static bool ltc4245_use_extra_gpios(struct i2c_client *client) +{ + struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev); +#ifdef CONFIG_OF + struct device_node *np = client->dev.of_node; +#endif + + /* prefer platform data */ + if (pdata) + return pdata->use_extra_gpios; + +#ifdef CONFIG_OF + /* fallback on OF */ + if (of_find_property(np, "ltc4245,use-extra-gpios", NULL)) + return true; +#endif + + return false; +} + static int ltc4245_probe(struct i2c_client *client, const struct i2c_device_id *id) { @@ -367,15 +524,16 @@ static int ltc4245_probe(struct i2c_client *client, i2c_set_clientdata(client, data); mutex_init(&data->update_lock); + data->use_extra_gpios = ltc4245_use_extra_gpios(client); /* Initialize the LTC4245 chip */ i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00); i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00); /* Register sysfs hooks */ - ret = sysfs_create_group(&client->dev.kobj, <c4245_group); + ret = ltc4245_sysfs_create_groups(client); if (ret) - goto out_sysfs_create_group; + goto out_sysfs_create_groups; data->hwmon_dev = hwmon_device_register(&client->dev); if (IS_ERR(data->hwmon_dev)) { @@ -386,8 +544,8 @@ static int ltc4245_probe(struct i2c_client *client, return 0; out_hwmon_device_register: - sysfs_remove_group(&client->dev.kobj, <c4245_group); -out_sysfs_create_group: + ltc4245_sysfs_remove_groups(client); +out_sysfs_create_groups: kfree(data); out_kzalloc: return ret; @@ -398,8 +556,7 @@ static int ltc4245_remove(struct i2c_client *client) struct ltc4245_data *data = i2c_get_clientdata(client); hwmon_device_unregister(data->hwmon_dev); - sysfs_remove_group(&client->dev.kobj, <c4245_group); - + ltc4245_sysfs_remove_groups(client); kfree(data); return 0; |