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-rw-r--r--drivers/hwmon/ltc4245.c490
1 files changed, 490 insertions, 0 deletions
diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
new file mode 100644
index 000000000..5088d28b3
--- /dev/null
+++ b/drivers/hwmon/ltc4245.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
+ *
+ * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
+ *
+ * This driver is based on the ds1621 and ina209 drivers.
+ *
+ * Datasheet:
+ * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
+#include <linux/platform_data/ltc4245.h>
+
+/* Here are names of the chip's registers (a.k.a. commands) */
+enum ltc4245_cmd {
+ LTC4245_STATUS = 0x00, /* readonly */
+ LTC4245_ALERT = 0x01,
+ LTC4245_CONTROL = 0x02,
+ LTC4245_ON = 0x03,
+ LTC4245_FAULT1 = 0x04,
+ LTC4245_FAULT2 = 0x05,
+ LTC4245_GPIO = 0x06,
+ LTC4245_ADCADR = 0x07,
+
+ LTC4245_12VIN = 0x10,
+ LTC4245_12VSENSE = 0x11,
+ LTC4245_12VOUT = 0x12,
+ LTC4245_5VIN = 0x13,
+ LTC4245_5VSENSE = 0x14,
+ LTC4245_5VOUT = 0x15,
+ LTC4245_3VIN = 0x16,
+ LTC4245_3VSENSE = 0x17,
+ LTC4245_3VOUT = 0x18,
+ LTC4245_VEEIN = 0x19,
+ LTC4245_VEESENSE = 0x1a,
+ LTC4245_VEEOUT = 0x1b,
+ LTC4245_GPIOADC = 0x1c,
+};
+
+struct ltc4245_data {
+ struct i2c_client *client;
+
+ struct mutex update_lock;
+ bool valid;
+ unsigned long last_updated; /* in jiffies */
+
+ /* Control registers */
+ u8 cregs[0x08];
+
+ /* 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 ltc4245_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->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)) {
+ 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 ltc4245_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ s32 val;
+ int i;
+
+ mutex_lock(&data->update_lock);
+
+ if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+
+ /* Read control registers -- 0x00 to 0x07 */
+ for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
+ val = i2c_smbus_read_byte_data(client, i);
+ if (unlikely(val < 0))
+ data->cregs[i] = 0;
+ else
+ data->cregs[i] = val;
+ }
+
+ /* Read voltage registers -- 0x10 to 0x1c */
+ for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
+ val = i2c_smbus_read_byte_data(client, i+0x10);
+ if (unlikely(val < 0))
+ data->vregs[i] = 0;
+ else
+ data->vregs[i] = val;
+ }
+
+ /* Update GPIO readings */
+ ltc4245_update_gpios(dev);
+
+ data->last_updated = jiffies;
+ data->valid = true;
+ }
+
+ mutex_unlock(&data->update_lock);
+
+ return data;
+}
+
+/* Return the voltage from the given register in millivolts */
+static int ltc4245_get_voltage(struct device *dev, u8 reg)
+{
+ struct ltc4245_data *data = ltc4245_update_device(dev);
+ const u8 regval = data->vregs[reg - 0x10];
+ u32 voltage = 0;
+
+ switch (reg) {
+ case LTC4245_12VIN:
+ case LTC4245_12VOUT:
+ voltage = regval * 55;
+ break;
+ case LTC4245_5VIN:
+ case LTC4245_5VOUT:
+ voltage = regval * 22;
+ break;
+ case LTC4245_3VIN:
+ case LTC4245_3VOUT:
+ voltage = regval * 15;
+ break;
+ case LTC4245_VEEIN:
+ case LTC4245_VEEOUT:
+ voltage = regval * -55;
+ break;
+ case LTC4245_GPIOADC:
+ voltage = regval * 10;
+ break;
+ default:
+ /* If we get here, the developer messed up */
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ return voltage;
+}
+
+/* Return the current in the given sense register in milliAmperes */
+static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
+{
+ struct ltc4245_data *data = ltc4245_update_device(dev);
+ const u8 regval = data->vregs[reg - 0x10];
+ unsigned int voltage;
+ unsigned int curr;
+
+ /*
+ * The strange looking conversions that follow are fixed-point
+ * math, since we cannot do floating point in the kernel.
+ *
+ * Step 1: convert sense register to microVolts
+ * Step 2: convert voltage to milliAmperes
+ *
+ * If you play around with the V=IR equation, you come up with
+ * the following: X uV / Y mOhm == Z mA
+ *
+ * With the resistors that are fractions of a milliOhm, we multiply
+ * the voltage and resistance by 10, to shift the decimal point.
+ * Now we can use the normal division operator again.
+ */
+
+ switch (reg) {
+ case LTC4245_12VSENSE:
+ voltage = regval * 250; /* voltage in uV */
+ curr = voltage / 50; /* sense resistor 50 mOhm */
+ break;
+ case LTC4245_5VSENSE:
+ voltage = regval * 125; /* voltage in uV */
+ curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
+ break;
+ case LTC4245_3VSENSE:
+ voltage = regval * 125; /* voltage in uV */
+ curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
+ break;
+ case LTC4245_VEESENSE:
+ voltage = regval * 250; /* voltage in uV */
+ curr = voltage / 100; /* sense resistor 100 mOhm */
+ break;
+ default:
+ /* If we get here, the developer messed up */
+ WARN_ON_ONCE(1);
+ curr = 0;
+ break;
+ }
+
+ return curr;
+}
+
+/* Map from voltage channel index to voltage register */
+
+static const s8 ltc4245_in_regs[] = {
+ LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN,
+ LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT,
+};
+
+/* Map from current channel index to current register */
+
+static const s8 ltc4245_curr_regs[] = {
+ LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE,
+};
+
+static int ltc4245_read_curr(struct device *dev, u32 attr, int channel,
+ long *val)
+{
+ struct ltc4245_data *data = ltc4245_update_device(dev);
+
+ switch (attr) {
+ case hwmon_curr_input:
+ *val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
+ return 0;
+ case hwmon_curr_max_alarm:
+ *val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4));
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val)
+{
+ struct ltc4245_data *data = ltc4245_update_device(dev);
+
+ switch (attr) {
+ case hwmon_in_input:
+ if (channel < 8) {
+ *val = ltc4245_get_voltage(dev,
+ ltc4245_in_regs[channel]);
+ } else {
+ int regval = data->gpios[channel - 8];
+
+ if (regval < 0)
+ return regval;
+ *val = regval * 10;
+ }
+ return 0;
+ case hwmon_in_min_alarm:
+ if (channel < 4)
+ *val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel));
+ else
+ *val = !!(data->cregs[LTC4245_FAULT2] &
+ BIT(channel - 4));
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4245_read_power(struct device *dev, u32 attr, int channel,
+ long *val)
+{
+ unsigned long curr;
+ long voltage;
+
+ switch (attr) {
+ case hwmon_power_input:
+ (void)ltc4245_update_device(dev);
+ curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
+ voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]);
+ *val = abs(curr * voltage);
+ return 0;
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+
+ switch (type) {
+ case hwmon_curr:
+ return ltc4245_read_curr(dev, attr, channel, val);
+ case hwmon_power:
+ return ltc4245_read_power(dev, attr, channel, val);
+ case hwmon_in:
+ return ltc4245_read_in(dev, attr, channel - 1, val);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+static umode_t ltc4245_is_visible(const void *_data,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct ltc4245_data *data = _data;
+
+ switch (type) {
+ case hwmon_in:
+ if (channel == 0)
+ return 0;
+ switch (attr) {
+ case hwmon_in_input:
+ if (channel > 9 && !data->use_extra_gpios)
+ return 0;
+ return 0444;
+ case hwmon_in_min_alarm:
+ if (channel > 8)
+ return 0;
+ return 0444;
+ default:
+ return 0;
+ }
+ case hwmon_curr:
+ switch (attr) {
+ case hwmon_curr_input:
+ case hwmon_curr_max_alarm:
+ return 0444;
+ default:
+ return 0;
+ }
+ case hwmon_power:
+ switch (attr) {
+ case hwmon_power_input:
+ return 0444;
+ default:
+ return 0;
+ }
+ default:
+ return 0;
+ }
+}
+
+static const struct hwmon_channel_info *ltc4245_info[] = {
+ HWMON_CHANNEL_INFO(in,
+ HWMON_I_INPUT,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+ HWMON_I_INPUT,
+ HWMON_I_INPUT,
+ HWMON_I_INPUT),
+ HWMON_CHANNEL_INFO(curr,
+ HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+ HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+ HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+ HWMON_C_INPUT | HWMON_C_MAX_ALARM),
+ HWMON_CHANNEL_INFO(power,
+ HWMON_P_INPUT,
+ HWMON_P_INPUT,
+ HWMON_P_INPUT,
+ HWMON_P_INPUT),
+ NULL
+};
+
+static const struct hwmon_ops ltc4245_hwmon_ops = {
+ .is_visible = ltc4245_is_visible,
+ .read = ltc4245_read,
+};
+
+static const struct hwmon_chip_info ltc4245_chip_info = {
+ .ops = &ltc4245_hwmon_ops,
+ .info = ltc4245_info,
+};
+
+static bool ltc4245_use_extra_gpios(struct i2c_client *client)
+{
+ struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
+ struct device_node *np = client->dev.of_node;
+
+ /* prefer platform data */
+ if (pdata)
+ return pdata->use_extra_gpios;
+
+ /* fallback on OF */
+ if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
+ return true;
+
+ return false;
+}
+
+static int ltc4245_probe(struct i2c_client *client)
+{
+ struct i2c_adapter *adapter = client->adapter;
+ struct ltc4245_data *data;
+ struct device *hwmon_dev;
+
+ if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+ return -ENODEV;
+
+ data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = client;
+ 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);
+
+ hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
+ client->name, data,
+ &ltc4245_chip_info,
+ NULL);
+ return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ltc4245_id[] = {
+ { "ltc4245", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4245_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ltc4245_driver = {
+ .driver = {
+ .name = "ltc4245",
+ },
+ .probe_new = ltc4245_probe,
+ .id_table = ltc4245_id,
+};
+
+module_i2c_driver(ltc4245_driver);
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("LTC4245 driver");
+MODULE_LICENSE("GPL");
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