Re: [PATCH 4/4] pmbus (dps650ab): add power supply driver

From: Guenter Roeck
Date: Fri Jan 04 2019 - 09:41:38 EST


On 1/4/19 1:05 AM, Xiaoting Liu wrote:
The Delta dps650ab provides main power and standby power to server.
dps650ab can be detected by MFR_ID and MFR_MODEL referring to
manufacturer's feedback. This patch adds driver to moniter power
supply status.

Signed-off-by: Xiaoting Liu <xiaoting.liu@xxxxxxxxxxxxxxxx>
---
drivers/hwmon/pmbus/Kconfig | 10 +++++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/dps650ab.c | 100 +++++++++++++++++++++++++++++++++++++++++
drivers/hwmon/pmbus/pmbus.c | 3 ++
4 files changed, 114 insertions(+)

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 629cb45f8557..de4638396592 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -184,4 +184,14 @@ config SENSORS_ZL6100
This driver can also be built as a module. If so, the module will
be called zl6100.

+config SENSORS_DPS650AB
+ tristate "Delta DPS650AB"
+ default n
+ help
+ If you say yes here you get hardware monitoring support for the
+ Delta DPS650AB controller.
+
+ This driver can also be built as a module. If so, the module will
+ be called dps650ab.
+
endif # PMBUS
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index ea0e39518c21..414818230a26 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -21,3 +21,4 @@ obj-$(CONFIG_SENSORS_TPS53679) += tps53679.o
obj-$(CONFIG_SENSORS_UCD9000) += ucd9000.o
obj-$(CONFIG_SENSORS_UCD9200) += ucd9200.o
obj-$(CONFIG_SENSORS_ZL6100) += zl6100.o
+obj-$(CONFIG_SENSORS_DPS650AB) += dps650ab.o
diff --git a/drivers/hwmon/pmbus/dps650ab.c b/drivers/hwmon/pmbus/dps650ab.c
new file mode 100644
index 000000000000..3c300e621f5a
--- /dev/null
+++ b/drivers/hwmon/pmbus/dps650ab.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hardware monitoring driver for DELTA DPS650AB
+ *
+ * Copyright (c) 2018 Huaxintong Semiconductor Technology Co., Ltd.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+#define DPS650AB_MFR_ID "DELTA"
+#define DPS650AB_MFR_MODEL "DPS-650AB-16 A"
+
+static int dps650ab_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct pmbus_driver_info *info;
+ u8 buf[I2C_SMBUS_BLOCK_MAX];
+ int ret;
+
+ memset(buf, 0, I2C_SMBUS_BLOCK_MAX);
+

I don't think this is needed.

+ 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;
+
+ 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 (strncmp(buf, DPS650AB_MFR_ID, strlen(DPS650AB_MFR_ID))) {

It might make sense to verify the length of the returned string as well,
unless strings such as "DELTAX" are accepted on purpose. But even if
that is the case I would prefer an added check of "ret < strlen(DPS650AB_MFR_ID)"
over the memset() above....

+ dev_err(&client->dev, "DPS650AB_MFR_ID unrecognised\n");
+ return -ENODEV;
+ }
+
+ ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+ if (ret < 0) {
+ dev_err(&client->dev, "Failed to read PMBUS_MFR_MODEL\n");
+ return ret;
+ }
+
+ if (strncmp(buf, DPS650AB_MFR_MODEL, strlen(DPS650AB_MFR_MODEL))) {

... to ensure that nothing bad slips through here. As currently written, the code
accepts a MFR_ID of "DELTA50AB-16 A" combined with a MFR_MODEL "DPS-6" as valid.

+ dev_err(&client->dev, "DPS650AB_MFR_MODEL unrecognised\n");

It would be a nice touch to actually list the unrecognized model. Otherwise
the message is quite useless. Same for MFR_ID.

+ return -ENODEV;
+ }
+
+ info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->pages = 1;
+ info->format[PSC_VOLTAGE_IN] = linear;
+ info->format[PSC_VOLTAGE_OUT] = linear;
+ 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_IIN | PMBUS_HAVE_PIN
+ | PMBUS_HAVE_STATUS_INPUT
+ | PMBUS_HAVE_POUT | PMBUS_HAVE_FAN12
+ | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+ | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+ | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
+ | PMBUS_HAVE_STATUS_TEMP;
+ info->func[1] = info->func[0];
+
+ return pmbus_do_probe(client, id, info);
+}
+
+static const struct i2c_device_id dps650ab_id[] = {
+ {"dps650ab", 1},
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, dps650ab_id);
+
+static struct i2c_driver dps650ab_driver = {
+ .driver = {
+ .name = "dps650ab",
+ },
+ .probe = dps650ab_probe,
+ .remove = pmbus_do_remove,
+ .id_table = dps650ab_id,
+};
+
+module_i2c_driver(dps650ab_driver);
+
+MODULE_AUTHOR("Liuxiaoting <xiaoting.liu@xxxxxxxxxxxxxxxx");
+MODULE_DESCRIPTION("PMBus driver for DPS650AB");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/hwmon/pmbus/pmbus.c b/drivers/hwmon/pmbus/pmbus.c
index aa4cf9636e99..930e8a3e2366 100644
--- a/drivers/hwmon/pmbus/pmbus.c
+++ b/drivers/hwmon/pmbus/pmbus.c
@@ -204,6 +204,8 @@ static int pmbus_probe(struct i2c_client *client,
static const struct pmbus_device_info sgd009_pmbus_info = {
1, PMBUS_SKIP_STATUS_CHECK};
static const struct pmbus_device_info pmbus_info = {0, 0};
+static const struct pmbus_device_info dps650ab_pmbus_info = {
+ 1, PMBUS_SKIP_STATUS_CHECK};

Something is conceptually wrong here. Either this change or a new driver,
but not both.

/*
* Use driver_data to set the number of pages supported by the chip.
*/
@@ -227,6 +229,7 @@ static int pmbus_probe(struct i2c_client *client,
{"tps544c20", (kernel_ulong_t)&default_pmbus_info},
{"tps544c25", (kernel_ulong_t)&default_pmbus_info},
{"udt020", (kernel_ulong_t)&default_pmbus_info},
+ {"dps650ab", (kernel_ulong_t)&dps650ab_pmbus_info},

Also, FWIW, this should be kept in alphabetic order.

{}
};

--
1.8.3.1




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