--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for MAX20730, MAX20734, and MAX20743 Integrated, Step-Down
+ * Switching Regulators
+ *
+ * Copyright 2019 Google LLC.
+ */
+
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/pmbus.h>
+#include <linux/util_macros.h>
+#include "pmbus.h"
+
+enum chips {
+ max20730,
+ max20734,
+ max20743
+};
+
+struct max20730_data {
+ enum chips id;
+ struct pmbus_driver_info info;
+ struct mutex lock; /* Used to protect against parallel writes */
+ u16 mfr_devset1;
+};
+
+#define to_max20730_data(x) container_of(x, struct max20730_data, info)
+
+#define MAX20730_MFR_DEVSET1 0xd2
+
+/*
+ * Convert discreet value to direct data format. Strictly speaking, all passed
+ * values are constants, so we could do that calculation manually. On the
+ * downside, that would make the driver more difficult to maintain, so lets
+ * use this approach.
+ */
+static u16 val_to_direct(int v, enum pmbus_sensor_classes class,
+ const struct pmbus_driver_info *info)
+{
+ int R = info->R[class] - 3; /* take milli-units into account */
+ int b = info->b[class] * 1000;
+ long d;
+
+ d = v * info->m[class] + b;
+ /*
+ * R < 0 is true for all callers, so we don't need to bother
+ * about the R > 0 case.
+ */
+ while (R < 0) {
+ d = DIV_ROUND_CLOSEST(d, 10);
+ R++;
+ }
+ return (u16)d;
+}
+
+static long direct_to_val(u16 w, enum pmbus_sensor_classes class,
+ const struct pmbus_driver_info *info)
+{
+ int R = info->R[class] - 3;
+ int b = info->b[class] * 1000;
+ int m = info->m[class];
+ long d = (s16)w;
+
+ if (m == 0)
+ return 0;
+
+ while (R < 0) {
+ d *= 10;
+ R++;
+ }
+ d = (d - b) / m;
+ return d;
+}
+
+static u32 max_current[][5] = {
+ [max20730] = { 13000, 16600, 20100, 23600 },
+ [max20734] = { 21000, 27000, 32000, 38000 },
+ [max20743] = { 18900, 24100, 29200, 34100 },
+};
+
+static int max20730_read_word_data(struct i2c_client *client, int page, int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ const struct max20730_data *data = to_max20730_data(info);
+ int ret = 0;
+ u32 max_c;
+
+ switch (reg) {
+ case PMBUS_OT_FAULT_LIMIT:
+ switch ((data->mfr_devset1 >> 11) & 0x3) {
+ case 0x0:
+ ret = val_to_direct(150000, PSC_TEMPERATURE, info);
+ break;
+ case 0x1:
+ ret = val_to_direct(130000, PSC_TEMPERATURE, info);
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ break;
+ case PMBUS_IOUT_OC_FAULT_LIMIT:
+ max_c = max_current[data->id][(data->mfr_devset1 >> 5) & 0x3];
+ ret = val_to_direct(max_c, PSC_CURRENT_OUT, info);
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ return ret;
+}
+
+static int max20730_write_word_data(struct i2c_client *client, int page,
+ int reg, u16 word)
+{
+ struct pmbus_driver_info *info;
+ struct max20730_data *data;
+ u16 devset1;
+ int ret = 0;
+ int idx;
+
+ info = (struct pmbus_driver_info *)pmbus_get_driver_info(client);
+ data = to_max20730_data(info);
+
+ mutex_lock(&data->lock);
+ devset1 = data->mfr_devset1;
+
+ switch (reg) {
+ case PMBUS_OT_FAULT_LIMIT:
+ devset1 &= ~(BIT(11) | BIT(12));
+ if (direct_to_val(word, PSC_TEMPERATURE, info) < 140000)
+ devset1 |= BIT(11);
+ break;
+ case PMBUS_IOUT_OC_FAULT_LIMIT:
+ devset1 &= ~(BIT(5) | BIT(6));
+
+ idx = find_closest(direct_to_val(word, PSC_CURRENT_OUT, info),
+ max_current[data->id], 4);
+ devset1 |= (idx << 5);
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+
+ if (!ret && devset1 != data->mfr_devset1) {
+ ret = i2c_smbus_write_word_data(client, MAX20730_MFR_DEVSET1,
+ devset1);
+ if (!ret) {
+ data->mfr_devset1 = devset1;
+ pmbus_clear_cache(client);
+ }
+ }
+ mutex_unlock(&data->lock);
+ return ret;
+}
+
+static const struct pmbus_driver_info max20730_info[] = {
+ [max20730] = {
+ .pages = 1,
+ .read_word_data = max20730_read_word_data,
+ .write_word_data = max20730_write_word_data,
+
+ /* Source : Maxim AN6042 */
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_TEMPERATURE] = 21,
+ .b[PSC_TEMPERATURE] = 5887,
+ .R[PSC_TEMPERATURE] = -1,
+
+ .format[PSC_VOLTAGE_IN] = direct,
+ .m[PSC_VOLTAGE_IN] = 3609,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = -2,
+
+ /*
+ * Values in the datasheet are adjusted for temperature and
+ * for the relationship between Vin and Vout.
+ * Unfortunately, the data sheet suggests that Vout measurement
+ * may be scaled with a resistor array. This is indeed the case
+ * at least on the evaulation boards. As a result, any in-driver
+ * adjustments would either be wrong or require elaborate means
+ * to configure the scaling. Instead of doing that, just report
+ * raw values and let userspace handle adjustments.
+ */
+ .format[PSC_CURRENT_OUT] = direct,
+ .m[PSC_CURRENT_OUT] = 153,
+ .b[PSC_CURRENT_OUT] = 4976,
+ .R[PSC_CURRENT_OUT] = -1,
+
+ .format[PSC_VOLTAGE_OUT] = linear,
+
+ .func[0] = PMBUS_HAVE_VIN |
+ PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
+ },
+ [max20734] = {
+ .pages = 1,
+ .read_word_data = max20730_read_word_data,
+ .write_word_data = max20730_write_word_data,
+
+ /* Source : Maxim AN6209 */
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_TEMPERATURE] = 21,
+ .b[PSC_TEMPERATURE] = 5887,
+ .R[PSC_TEMPERATURE] = -1,
+
+ .format[PSC_VOLTAGE_IN] = direct,
+ .m[PSC_VOLTAGE_IN] = 3592,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = -2,
+
+ .format[PSC_CURRENT_OUT] = direct,
+ .m[PSC_CURRENT_OUT] = 111,
+ .b[PSC_CURRENT_OUT] = 3461,
+ .R[PSC_CURRENT_OUT] = -1,
+
+ .format[PSC_VOLTAGE_OUT] = linear,
+
+ .func[0] = PMBUS_HAVE_VIN |
+ PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
+ },
+ [max20743] = {
+ .pages = 1,
+ .read_word_data = max20730_read_word_data,
+ .write_word_data = max20730_write_word_data,
+
+ /* Source : Maxim AN6042 */
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_TEMPERATURE] = 21,
+ .b[PSC_TEMPERATURE] = 5887,
+ .R[PSC_TEMPERATURE] = -1,
+
+ .format[PSC_VOLTAGE_IN] = direct,
+ .m[PSC_VOLTAGE_IN] = 3597,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = -2,
+
+ .format[PSC_CURRENT_OUT] = direct,
+ .m[PSC_CURRENT_OUT] = 95,
+ .b[PSC_CURRENT_OUT] = 5014,
+ .R[PSC_CURRENT_OUT] = -1,
+
+ .format[PSC_VOLTAGE_OUT] = linear,
+
+ .func[0] = PMBUS_HAVE_VIN |
+ PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+ PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP,
+ },
+};
+
+static int max20730_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
+ struct max20730_data *data;
+ enum chips chip_id;
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_BYTE_DATA |
+ I2C_FUNC_SMBUS_READ_WORD_DATA |
+ I2C_FUNC_SMBUS_BLOCK_DATA))
+ return -ENODEV;
+
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failed to read Manufacturer ID\n");
+ return ret;
+ }
+ if (ret != 5 || strncmp(buf, "MAXIM", 5)) {
+ buf[ret] = '\0';
+ dev_err(dev, "Unsupported Manufacturer ID '%s'\n", buf);
+ return -ENODEV;
+ }
+
+ /*
+ * The chips support reading PMBUS_MFR_MODEL. On both MAX20730
+ * and MAX20734, reading it returns M20743. Presumably that is
+ * the reason why the command is not documented. Unfortunately,
+ * that means that there is no reliable means to detect the chip.
+ * However, we can at least detect the chip series. Compare
+ * the returned value against 'M20743' and bail out if there is
+ * a mismatch. If that doesn't work for all chips, we may have
+ * to remove this check.
+ */
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+ if (ret < 0) {
+ dev_err(dev, "Failed to read Manufacturer Model\n");
+ return ret;
+ }
+ if (ret != 6 || strncmp(buf, "M20743", 6)) {
+ buf[ret] = '\0';
+ dev_err(dev, "Unsupported Manufacturer Model '%s'\n", buf);
+ return -ENODEV;
+ }
+
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_REVISION, buf);
+ if (ret < 0) {
+ dev_err(dev, "Failed to read Manufacturer Revision\n");
+ return ret;
+ }
+ if (ret != 1 || buf[0] != 'F') {
+ buf[ret] = '\0';
+ dev_err(dev, "Unsupported Manufacturer Revision '%s'\n", buf);
+ return -ENODEV;
+ }
+
+ if (client->dev.of_node)
+ chip_id = (enum chips)of_device_get_match_data(dev);
+ else
+ chip_id = id->driver_data;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ data->id = chip_id;
+ mutex_init(&data->lock);
+ memcpy(&data->info, &max20730_info[chip_id], sizeof(data->info));
+
+ ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1);
+ if (ret < 0)
+ return ret;
+ data->mfr_devset1 = ret;
+
+ return pmbus_do_probe(client, id, &data->info);
+}
+
+static const struct i2c_device_id max20730_id[] = {
+ { "max20730", max20730 },
+ { "max20734", max20734 },
+ { "max20743", max20743 },
+ { },
+};
+
+MODULE_DEVICE_TABLE(i2c, max20730_id);
+
+static const struct of_device_id max20730_of_match[] = {
+ { .compatible = "maxim,max20730", .data = (void *)max20730 },
+ { .compatible = "maxim,max20734", .data = (void *)max20734 },
+ { .compatible = "maxim,max20743", .data = (void *)max20743 },
+ { },
+};
+
+MODULE_DEVICE_TABLE(of, max20730_of_match);
+
+static struct i2c_driver max20730_driver = {
+ .driver = {
+ .name = "max20730",
+ .of_match_table = max20730_of_match,
+ },
+ .probe = max20730_probe,
+ .remove = pmbus_do_remove,
+ .id_table = max20730_id,
+};
+
+module_i2c_driver(max20730_driver);
+
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("PMBus driver for Maxim MAX20730 / MAX20734 / MAX20743");
+MODULE_LICENSE("GPL");
projects / openwrt / staging / blogic.git / commitdiff