Re: [PATCH 2/2] hwmon: pmbus: Add ltc4286 driver

From: Guenter Roeck
Date: Mon Jul 24 2023 - 09:56:53 EST

On 7/24/23 03:05, Delphine CC Chiu wrote:
Add a driver to support ltc4286 chip


No change log, no versioning, did not address all feedback,
sent as reply to previous version instead of independently.

I am not going to re-review this patch. Address all feedback
comments, provide change log and patch versions, and do not
send as reply to previous patch series.

Guenter

Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@xxxxxxxxxx>
---
drivers/hwmon/pmbus/Kconfig | 9 +++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/ltc4286.c | 147 ++++++++++++++++++++++++++++++++++
3 files changed, 157 insertions(+)
create mode 100644 drivers/hwmon/pmbus/ltc4286.c

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 270b6336b76d..7cb9cbff587d 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -226,6 +226,15 @@ config SENSORS_LTC3815
This driver can also be built as a module. If so, the module will
be called ltc3815.
+config SENSORS_LTC4286
+ bool "Analog Devices LTC4286"
+ help
+ LTC4286 is an integrated solution for hot swap applications that
+ allows a board to be safely inserted and removed from a
+ live backplane.
+ This chip could be used to monitor voltage, current, ...etc.
+ If you say yes here you get hardware monitoring support for Analog
+ Devices LTC4286.
config SENSORS_MAX15301
tristate "Maxim MAX15301"
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 84ee960a6c2d..94e28f6d6a61 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_SENSORS_LM25066) += lm25066.o
obj-$(CONFIG_SENSORS_LT7182S) += lt7182s.o
obj-$(CONFIG_SENSORS_LTC2978) += ltc2978.o
obj-$(CONFIG_SENSORS_LTC3815) += ltc3815.o
+obj-$(CONFIG_SENSORS_LTC4286) += ltc4286.o
obj-$(CONFIG_SENSORS_MAX15301) += max15301.o
obj-$(CONFIG_SENSORS_MAX16064) += max16064.o
obj-$(CONFIG_SENSORS_MAX16601) += max16601.o
diff --git a/drivers/hwmon/pmbus/ltc4286.c b/drivers/hwmon/pmbus/ltc4286.c
new file mode 100644
index 000000000000..b86bf31cfbae
--- /dev/null
+++ b/drivers/hwmon/pmbus/ltc4286.c
@@ -0,0 +1,147 @@
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+/* LTC4286 register */
+#define LTC4286_MFR_CONFIG1 0xF2
+
+/* LTC4286 configuration */
+#define VRANGE_SELECT_BIT BIT(1)
+
+#define LTC4286_MFR_ID_SIZE 3
+
+enum chips { ltc4286, ltc4287 };
+
+/*
+ * Initialize the MBR as default settings which is referred to LTC4286 datasheet
+ * (March 22, 2022 version) table 3 page 16
+ */
+static struct pmbus_driver_info ltc4286_info = {
+ .pages = 1,
+ .format[PSC_VOLTAGE_IN] = direct,
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .format[PSC_CURRENT_OUT] = direct,
+ .format[PSC_POWER] = direct,
+ .format[PSC_TEMPERATURE] = direct,
+ .m[PSC_VOLTAGE_IN] = 32,
+ .b[PSC_VOLTAGE_IN] = 0,
+ .R[PSC_VOLTAGE_IN] = 1,
+ .m[PSC_VOLTAGE_OUT] = 32,
+ .b[PSC_VOLTAGE_OUT] = 0,
+ .R[PSC_VOLTAGE_OUT] = 1,
+ .m[PSC_CURRENT_OUT] = 1024,
+ .b[PSC_CURRENT_OUT] = 0,
+ .R[PSC_CURRENT_OUT] = 3 - 6, /* To support small shunt resistor value */
+ .m[PSC_POWER] = 1,
+ .b[PSC_POWER] = 0,
+ .R[PSC_POWER] = 4 - 6, /* To support small shunt resistor value */
+ .m[PSC_TEMPERATURE] = 1,
+ .b[PSC_TEMPERATURE] = 273,
+ .R[PSC_TEMPERATURE] = 0,
+ .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT |
+ PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT |
+ PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP,
+};
+
+static const struct i2c_device_id ltc4286_id[] = { { "ltc4286", ltc4286 },
+ { "ltc4287", ltc4287 },
+ {} };
+MODULE_DEVICE_TABLE(i2c, ltc4286_id);
+
+static int ltc4286_probe(struct i2c_client *client)
+{
+ int ret;
+ u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1];
+ struct pmbus_driver_info *info;
+ u32 rsense;
+
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to read manufacturer id\n");
+ return ret;
+ }
+
+ /*
+ * Refer to ltc4286 datasheet page 20
+ * the manufacturer id is LTC
+ */
+ if (ret != LTC4286_MFR_ID_SIZE ||
+ strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) {
+ return dev_err_probe(&client->dev, err,
+ "failed to read manufacturer id\n");
+ }
+
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to read manufacturer model\n");
+ return ret;
+ }
+
+ for (mid = ltc4286_id; mid->name[0]; mid++) {
+ if (!strncasecmp(mid->name, block_buffer, strlen(mid->name)))
+ break;
+ }
+
+ ret = of_property_read_u32(client->dev.of_node,
+ "shunt-resistor-micro-ohms", &rsense);
+ if (ret < 0)
+ return ret;
+
+ if (rsense == 0)
+ return -EINVAL;
+
+ info = &ltc4286_info;
+
+ /* Default of VRANGE_SELECT = 1, 102.4V */
+ if (device_property_read_bool(client->dev, "vrange_select_25p6")) {
+ /* Setup MFR1 CONFIG register bit 1 VRANGE_SELECT */
+ ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "failed to read manufacturer configuration one\n");
+ return ret;
+ }
+
+ ret &= ~VRANGE_SELECT; /* VRANGE_SELECT = 0, 25.6V */
+ ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1,
+ ret);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed to set vrange\n");
+ return ret;
+ }
+
+ info->m[PSC_VOLTAGE_IN] = 128;
+ info->m[PSC_VOLTAGE_OUT] = 128;
+ info->m[PSC_POWER] = 4 * rsense;
+ } else
+ info->m[PSC_POWER] = rsense;
+
+ info->m[PSC_CURRENT_OUT] = 1024 * rsense;
+
+ return pmbus_do_probe(client, info);
+}
+
+static const struct of_device_id ltc4286_of_match[] = {
+ { .compatible = "lltc,ltc4286" },
+ { .compatible = "lltc,ltc4287" },
+ {}
+};
+
+static struct i2c_driver ltc4286_driver = {
+ .driver = {
+ .name = "ltc4286",
+ .of_match_table = ltc4286_of_match,
+ },
+ .probe = ltc4286_probe,
+ .id_table = ltc4286_id,
+};
+
+module_i2c_driver(ltc4286_driver);
+
+MODULE_AUTHOR("Delphine CC Chiu <Delphine_CC_Chiu@xxxxxxxxxx>");
+MODULE_DESCRIPTION("PMBUS driver for LTC4286 and compatibles");
+MODULE_LICENSE("GPL");