Re: [PATCH 1/2] hwmon: pmbus: Add Infineon PXE1610 VR driver

From: Guenter Roeck
Date: Wed May 29 2019 - 21:04:05 EST


On 5/29/19 3:35 PM, Vijay Khemka wrote:
Added pmbus driver for the new device Infineon pxe1610
voltage regulator. It also supports similar family device
PXE1110 and PXM1310.

Signed-off-by: Vijay Khemka <vijaykhemka@xxxxxx>
---
drivers/hwmon/pmbus/Kconfig | 9 +++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/pxe1610.c | 119 ++++++++++++++++++++++++++++++++++
3 files changed, 129 insertions(+)
create mode 100644 drivers/hwmon/pmbus/pxe1610.c

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 30751eb9550a..338ef9b5a395 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -154,6 +154,15 @@ config SENSORS_MAX8688
This driver can also be built as a module. If so, the module will
be called max8688.
+config SENSORS_PXE1610
+ tristate "Infineon PXE1610"
+ help
+ If you say yes here you get hardware monitoring support for Infineon
+ PXE1610.
+
+ This driver can also be built as a module. If so, the module will
+ be called pxe1610.
+
config SENSORS_TPS40422
tristate "TI TPS40422"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 2219b9300316..b0fbd017a91a 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_SENSORS_MAX20751) += max20751.o
obj-$(CONFIG_SENSORS_MAX31785) += max31785.o
obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
+obj-$(CONFIG_SENSORS_PXE1610) += pxe1610.o
obj-$(CONFIG_SENSORS_TPS40422) += tps40422.o
obj-$(CONFIG_SENSORS_TPS53679) += tps53679.o
obj-$(CONFIG_SENSORS_UCD9000) += ucd9000.o
diff --git a/drivers/hwmon/pmbus/pxe1610.c b/drivers/hwmon/pmbus/pxe1610.c
new file mode 100644
index 000000000000..01e267944df5
--- /dev/null
+++ b/drivers/hwmon/pmbus/pxe1610.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Hardware monitoring driver for Infineon PXE1610
+ *
+ * Copyright (c) 2019 Facebook Inc
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+/*
+ * Identify chip parameters.
+ */
+static int pxe1610_identify(struct i2c_client *client,
+ struct pmbus_driver_info *info)

Please align continuation lines with '('.

+{
+ if (pmbus_check_byte_register(client, 0, PMBUS_VOUT_MODE)) {
+ int vout_mode;
+
+ vout_mode = pmbus_read_byte_data(client, 0, PMBUS_VOUT_MODE);

pmbus_read_byte_data() can return an error. Calling pmbus_check_byte_register()
doesn't really add any value here, since the second call can still fail,
which needs to be checked.

+ switch (vout_mode & 0x1f) {
+ case 1:
+ info->vrm_version = vr12;
+ break;

Alignment is off.

+ case 2:
+ info->vrm_version = vr13;
+ break;

Same here.

+ default:
+ return -ENODEV;
+ }
+ }
+ return 0;
+}
+
+static int pxe1610_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct pmbus_driver_info *info;
+ u8 buf[I2C_SMBUS_BLOCK_MAX];
+ int ret;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_BYTE_DATA
+ | I2C_FUNC_SMBUS_READ_WORD_DATA
+ | I2C_FUNC_SMBUS_READ_BLOCK_DATA))
+ return -ENODEV;
+
+ /* By default this device doesn't boot to page 0, so set page 0
+ * to access all pmbus registers.
+ */

Please use standard multi-line comments.

+ i2c_smbus_write_byte_data(client, 0, 0);
+

Please use the PMBUS_PAGE command definition.

I wonder if it would make sense to initialize currpage in the core to an unreasonable
number for multi-page chips, but I guess that is a different question.

+ /* Read Manufacturer id */
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failed to read PMBUS_MFR_ID\n");
+ return ret;
+ }
+ if (ret != 2 || strncmp(buf, "XP", strlen("XP"))) {

The strlen() is really unnecessary here. Just use 2 (and a define
for it if you like).

+ dev_err(&client->dev, "MFR_ID unrecognised\n");

unrecognized. Oh well, turns out unrecognised is the British spelling and
just as valid, so feel free to keep it if you like.

+ return -ENODEV;
+ }
+
+ info = devm_kzalloc(&client->dev, sizeof(struct pmbus_driver_info),
+ GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->format[PSC_VOLTAGE_IN] = linear;
+ info->format[PSC_VOLTAGE_OUT] = vid;
+ info->format[PSC_CURRENT_IN] = linear;
+ info->format[PSC_CURRENT_OUT] = linear;
+ info->format[PSC_POWER] = linear;
+ info->format[PSC_TEMPERATURE] = linear;
+
+ info->func[0] = PMBUS_HAVE_VIN
+ | PMBUS_HAVE_VOUT | PMBUS_HAVE_IIN
+ | PMBUS_HAVE_IOUT | PMBUS_HAVE_PIN
+ | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
+ | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_IOUT
+ | PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_STATUS_TEMP;
+ info->func[1] = info->func[0];
+ info->func[2] = info->func[0];
+
+ info->pages = id->driver_data;
+ info->identify = pxe1610_identify;
+

It doesn't really add value to initialize all these parameters manually.
I would suggest to use the approach from tps53679.c, ie have a static
structure and use devm_kmemdup() to pass a copy to pmbus_do_probe().

+ return pmbus_do_probe(client, id, info);
+}
+
+static const struct i2c_device_id pxe1610_id[] = {
+ {"pxe1610", 3},
+ {"pxe1110", 3},
+ {"pxm1310", 3},

Unless there are chips with different page counts in the queue, using
driver_data to pass the number of pages does not add any value. Just
set num_pages to 3.

If you like, feel free to use a define instead of a constant.

+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, pxe1610_id);
+
+/* This is the driver that will be inserted */

This comment does not add any value.

+static struct i2c_driver pxe1610_driver = {
+ .driver = {
+ .name = "pxe1610",
+ },
+ .probe = pxe1610_probe,
+ .remove = pmbus_do_remove,
+ .id_table = pxe1610_id,
+};
+
+module_i2c_driver(pxe1610_driver);
+
+MODULE_AUTHOR("Vijay Khemka <vijaykhemka@xxxxxx>");
+MODULE_DESCRIPTION("PMBus driver for Infineon PXE1610, PXE1110 and PXM1310");
+MODULE_LICENSE("GPL");