On Fri, Jun 18, 2021 at 11:09:34AM +0800, ainux.wang@gmail.com wrote:

From: "Ainux.Wang" <redacted>

Add support for MP2949A device from Monolithic Power Systems, Inc. (MPS).
This is a triple-loop, digital, multi-phase controller.
This device:
- Supports up to three power rail.
- Provides 6 pulse-width modulations (PWMs), and can be configured up
  to 6-phase operation for Rail A , up to 2-phase operation for Rail B
  and up to 1-phase operation for Rail C.
- The PMBus registers are distributed into three pages: Page 0, Page 1,
  Page 2. Page 0 contains the registers for Rail A and most of the common
  settings for all of the rails. Page 1 contains register information for
  Rail B. Page 2 contains register information for Rail C.
- The MP2949A supports both 5mV VID step and 10mv VID step for IMVP8 and
  IMVP9 with only one DAC for each rail to generate REF.

Signed-off-by: Ainux.Wang <redacted>
---

Change log goes here. My normal response to patches with missing change log is:

<Formletter>  
Change log goes here. If it is missing, I won't know what changed.
That means I will have to dig out older patch versions to compare.
That costs time and would hold up both this patch as well as all other
patches which I still have to review.

For this reason, I will not review patches without change log.
</Formletter>

so you are lucky that your previous version is recent enough that I remember
at least some of it. However, please do provide change logs in the future.

rails

+- Provides 6 pulse-width modulations (PWMs), and can be configured up

can be configured for ...

+  to 6-phase operation for Rail A , up to 2-phase operation for Rail B

Rail B,

+  and up to 1-phase operation for Rail C.
+- The PMBus registers are distributed into three pages: Page 0, Page 1,
+  Page 2. Page 0 contains the registers for Rail A and most of the common
+  settings for all of the rails. Page 1 contains register information for
+  Rail B. Page 2 contains register information for Rail C.
+- The MP2949A supports both 5mV VID step and 10mv VID step for IMVP8 and
+  IMVP9 with only one DAC for each rail to generate REF.

Please explain REF.

+
+Device supports:
+
+- SVID interface.
+- PMBus rev 1.2 interface.
+
+Device supports direct format for reading output power.
+Device supports linear format for reading input voltage and output current

input voltage, output current, and temperature.

+and temperature.
+Device supports VID for reading output voltage.
+The below VID modes are supported: VR12, VR13, IMVP8, IMVP9.

The following

s/do/does/

This warrants a more detailed explanation: What happens if the command
is sent to the chip, and why is it not possible to rely on the standard
response to unsupported commands ? 

+		return -EINVAL;
+	default:
+		return -ENODATA;
+	}
+}
+
+static int mp2949a_identify(struct i2c_client *client,
+			    struct pmbus_driver_info *info)
+{
+	u8 vout_params;
+	int i, ret;
+
+	for (i = 0; i < MP2949A_PAGE_NUM; i++) {
+		/* Read the register with VOUT scaling value.*/
+		ret = pmbus_read_byte_data(client, i, PMBUS_VOUT_MODE);

                                                      ^^^^^^^^^^^^^^^
Should this be MFR_VR_CONFIG ?

+		if (ret < 0)
+			return ret;
+
+		/*
+		 * Rail A bit 5, Rail B bit 4, Rail C bit 3.
+		 * 1'b1: 5mV  (vr12/imvp8)
+		 * 1'b0: 10mv (imvp9)
+		 */
+		vout_params = ret & ~BIT(5-i);

space before and after '-'. vout_params is really unnecessary; just do
the check directly in the if() statement.

+		if (vout_params)
+			info->vrm_version[i] = vr12;
+		else
+			info->vrm_version[i] = imvp9;
+

Unnecessary empty line.

checkpatch --strict reports this and the above problem, plus another
alignment problem. Please fix everything it reports.

+	}
+
+	return 0;
+}
+
+static struct pmbus_driver_info mp2949a_info = {
+	.pages = MP2949A_PAGE_NUM,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = vid,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+	.format[PSC_POWER] = direct,
+	.m[PSC_POWER] = 1,
+	.b[PSC_POWER] = 0,
+	.R[PSC_POWER] = 0,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_TEMP | PMBUS_HAVE_POUT,
+	.func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_POUT,
+	.func[2] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_POUT,
+	.identify = mp2949a_identify,
+	.read_byte_data = mp2949a_read_byte_data,
+};
+
+static int mp2949a_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct pmbus_driver_info *info;
+
+	info = devm_kmemdup(&client->dev, &mp2949a_info, sizeof(*info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	return pmbus_do_probe(client, info);
+}
+
+static const struct i2c_device_id mp2949a_id[] = {
+	{"mp2949a", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, mp2949a_id);
+
+static const struct of_device_id mp2949a_of_match[] = {
+	{.compatible = "mps,mp2949a"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, mp2949a_of_match);
+
+static struct i2c_driver mp2949a_driver = {
+	.driver = {
+		.name = "mp2949a",
+		.of_match_table = of_match_ptr(mp2949a_of_match),
+	},
+	.probe = mp2949a_probe,
+	.id_table = mp2949a_id,
+};
+
+module_i2c_driver(mp2949a_driver);
+
+MODULE_AUTHOR("Ainux [off-list ref]");
+MODULE_DESCRIPTION("PMBus driver for Monolithic Power Systems MP2949A");
+MODULE_LICENSE("GPL");
-- 
2.18.1