diff mbox series

[v7,2/9] hwmon: pmbus: adm1266: Add Block process call

Message ID 20200727161928.14122-3-alexandru.tachici@analog.com (mailing list archive)
State Changes Requested
Headers show
Series hwmon: pmbus: adm1266: add support | expand

Commit Message

Alexandru Tachici July 27, 2020, 4:19 p.m. UTC 
From: Alexandru Tachici <alexandru.tachici@analog.com>

PmBus devices support Block Write-Block Read Process
Call described in SMBus specification v 2.0 with the
exception that Block writes and reads are permitted to
have up 255 data bytes instead of max 32 bytes (SMBus).

This patch adds Block WR process call support for ADM1266.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
---
 drivers/hwmon/pmbus/Kconfig   |  1 +
 drivers/hwmon/pmbus/adm1266.c | 73 +++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)

Comments

Dan Carpenter Aug. 5, 2020, 11:55 a.m. UTC | #1 
Hi,

url:    https://github.com/0day-ci/linux/commits/alexandru-tachici-analog-com/hwmon-pmbus-adm1266-add-support/20200728-002155
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
config: x86_64-randconfig-m001-20200731 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-14) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/hwmon/pmbus/adm1266.c:88 adm1266_pmbus_block_xfer() warn: inconsistent returns 'data->buf_mutex'.

# https://github.com/0day-ci/linux/commit/878684621a66ce0c9e2bdd10f9232b07e48ede96
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 878684621a66ce0c9e2bdd10f9232b07e48ede96
vim +88 drivers/hwmon/pmbus/adm1266.c

878684621a66ce0 Alexandru Tachici 2020-07-27  35  static int adm1266_pmbus_block_xfer(struct adm1266_data *data, u8 cmd, u8 w_len, u8 *data_w,
878684621a66ce0 Alexandru Tachici 2020-07-27  36  				    u8 *data_r)
878684621a66ce0 Alexandru Tachici 2020-07-27  37  {
878684621a66ce0 Alexandru Tachici 2020-07-27  38  	struct i2c_client *client = data->client;
878684621a66ce0 Alexandru Tachici 2020-07-27  39  	struct i2c_msg msgs[2] = {
878684621a66ce0 Alexandru Tachici 2020-07-27  40  		{
878684621a66ce0 Alexandru Tachici 2020-07-27  41  			.addr = client->addr,
878684621a66ce0 Alexandru Tachici 2020-07-27  42  			.flags = I2C_M_DMA_SAFE,
878684621a66ce0 Alexandru Tachici 2020-07-27  43  			.buf = data->write_buf,
878684621a66ce0 Alexandru Tachici 2020-07-27  44  			.len = w_len + 2,
878684621a66ce0 Alexandru Tachici 2020-07-27  45  		},
878684621a66ce0 Alexandru Tachici 2020-07-27  46  		{
878684621a66ce0 Alexandru Tachici 2020-07-27  47  			.addr = client->addr,
878684621a66ce0 Alexandru Tachici 2020-07-27  48  			.flags = I2C_M_RD | I2C_M_DMA_SAFE,
878684621a66ce0 Alexandru Tachici 2020-07-27  49  			.buf = data->read_buf,
878684621a66ce0 Alexandru Tachici 2020-07-27  50  			.len = ADM1266_PMBUS_BLOCK_MAX + 2,
878684621a66ce0 Alexandru Tachici 2020-07-27  51  		}
ac5fec412db3640 Alexandru Tachici 2020-07-27  52  	};
878684621a66ce0 Alexandru Tachici 2020-07-27  53  	u8 addr;
878684621a66ce0 Alexandru Tachici 2020-07-27  54  	u8 crc;
878684621a66ce0 Alexandru Tachici 2020-07-27  55  	int ret;
878684621a66ce0 Alexandru Tachici 2020-07-27  56  
878684621a66ce0 Alexandru Tachici 2020-07-27  57  	mutex_lock(&data->buf_mutex);
878684621a66ce0 Alexandru Tachici 2020-07-27  58  
878684621a66ce0 Alexandru Tachici 2020-07-27  59  	msgs[0].buf[0] = cmd;
878684621a66ce0 Alexandru Tachici 2020-07-27  60  	msgs[0].buf[1] = w_len;
878684621a66ce0 Alexandru Tachici 2020-07-27  61  	memcpy(&msgs[0].buf[2], data_w, w_len);
878684621a66ce0 Alexandru Tachici 2020-07-27  62  
878684621a66ce0 Alexandru Tachici 2020-07-27  63  	ret = i2c_transfer(client->adapter, msgs, 2);
878684621a66ce0 Alexandru Tachici 2020-07-27  64  	if (ret != 2) {
878684621a66ce0 Alexandru Tachici 2020-07-27  65  		if (ret >= 0)
878684621a66ce0 Alexandru Tachici 2020-07-27  66  			ret = -EPROTO;
878684621a66ce0 Alexandru Tachici 2020-07-27  67  		return ret;

Unlock

878684621a66ce0 Alexandru Tachici 2020-07-27  68  	}
878684621a66ce0 Alexandru Tachici 2020-07-27  69  
878684621a66ce0 Alexandru Tachici 2020-07-27  70  	if (client->flags & I2C_CLIENT_PEC) {
878684621a66ce0 Alexandru Tachici 2020-07-27  71  		addr = i2c_8bit_addr_from_msg(&msgs[0]);
878684621a66ce0 Alexandru Tachici 2020-07-27  72  		crc = crc8(pmbus_crc_table, &addr, 1, 0);
878684621a66ce0 Alexandru Tachici 2020-07-27  73  		crc = crc8(pmbus_crc_table, msgs[0].buf,  msgs[0].len, crc);
878684621a66ce0 Alexandru Tachici 2020-07-27  74  
878684621a66ce0 Alexandru Tachici 2020-07-27  75  		addr = i2c_8bit_addr_from_msg(&msgs[1]);
878684621a66ce0 Alexandru Tachici 2020-07-27  76  		crc = crc8(pmbus_crc_table, &addr, 1, crc);
878684621a66ce0 Alexandru Tachici 2020-07-27  77  		crc = crc8(pmbus_crc_table, msgs[1].buf,  msgs[1].buf[0] + 1, crc);
878684621a66ce0 Alexandru Tachici 2020-07-27  78  
878684621a66ce0 Alexandru Tachici 2020-07-27  79  		if (crc != msgs[1].buf[msgs[1].buf[0] + 1])
878684621a66ce0 Alexandru Tachici 2020-07-27  80  			return -EBADMSG;

And unlock here.

878684621a66ce0 Alexandru Tachici 2020-07-27  81  	}
878684621a66ce0 Alexandru Tachici 2020-07-27  82  
878684621a66ce0 Alexandru Tachici 2020-07-27  83  	memcpy(data_r, &msgs[1].buf[1], msgs[1].buf[0]);
878684621a66ce0 Alexandru Tachici 2020-07-27  84  
878684621a66ce0 Alexandru Tachici 2020-07-27  85  	ret = msgs[1].buf[0];
878684621a66ce0 Alexandru Tachici 2020-07-27  86  	mutex_unlock(&data->buf_mutex);
878684621a66ce0 Alexandru Tachici 2020-07-27  87  
878684621a66ce0 Alexandru Tachici 2020-07-27 @88  	return ret;
878684621a66ce0 Alexandru Tachici 2020-07-27  89  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index da34083e1ffd..c04068b665e6 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -28,6 +28,7 @@  config SENSORS_PMBUS
 
 config SENSORS_ADM1266
 	tristate "Analog Devices ADM1266 Sequencer"
+	select CRC8
 	help
 	  If you say yes here you get hardware monitoring support for Analog
 	  Devices ADM1266 Cascadable Super Sequencer.
diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
index 79e8d90886b8..63975eba34ad 100644
--- a/drivers/hwmon/pmbus/adm1266.c
+++ b/drivers/hwmon/pmbus/adm1266.c
@@ -6,6 +6,7 @@ 
  * Copyright 2020 Analog Devices Inc.
  */
 
+#include <linux/crc8.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -13,11 +14,80 @@ 
 #include "pmbus.h"
 #include <linux/slab.h>
 
+#define ADM1266_PMBUS_BLOCK_MAX		255
+
 struct adm1266_data {
 	struct pmbus_driver_info info;
 	struct i2c_client *client;
+	struct mutex buf_mutex;
+	u8 write_buf[ADM1266_PMBUS_BLOCK_MAX + 1] ____cacheline_aligned;
+	u8 read_buf[ADM1266_PMBUS_BLOCK_MAX + 1] ____cacheline_aligned;
 };
 
+DECLARE_CRC8_TABLE(pmbus_crc_table);
+
+/*
+ * Different from Block Read as it sends data and waits for the slave to
+ * return a value dependent on that data. The protocol is simply a Write Block
+ * followed by a Read Block without the Read-Block command field and the
+ * Write-Block STOP bit.
+ */
+static int adm1266_pmbus_block_xfer(struct adm1266_data *data, u8 cmd, u8 w_len, u8 *data_w,
+				    u8 *data_r)
+{
+	struct i2c_client *client = data->client;
+	struct i2c_msg msgs[2] = {
+		{
+			.addr = client->addr,
+			.flags = I2C_M_DMA_SAFE,
+			.buf = data->write_buf,
+			.len = w_len + 2,
+		},
+		{
+			.addr = client->addr,
+			.flags = I2C_M_RD | I2C_M_DMA_SAFE,
+			.buf = data->read_buf,
+			.len = ADM1266_PMBUS_BLOCK_MAX + 2,
+		}
+	};
+	u8 addr;
+	u8 crc;
+	int ret;
+
+	mutex_lock(&data->buf_mutex);
+
+	msgs[0].buf[0] = cmd;
+	msgs[0].buf[1] = w_len;
+	memcpy(&msgs[0].buf[2], data_w, w_len);
+
+	ret = i2c_transfer(client->adapter, msgs, 2);
+	if (ret != 2) {
+		if (ret >= 0)
+			ret = -EPROTO;
+		return ret;
+	}
+
+	if (client->flags & I2C_CLIENT_PEC) {
+		addr = i2c_8bit_addr_from_msg(&msgs[0]);
+		crc = crc8(pmbus_crc_table, &addr, 1, 0);
+		crc = crc8(pmbus_crc_table, msgs[0].buf,  msgs[0].len, crc);
+
+		addr = i2c_8bit_addr_from_msg(&msgs[1]);
+		crc = crc8(pmbus_crc_table, &addr, 1, crc);
+		crc = crc8(pmbus_crc_table, msgs[1].buf,  msgs[1].buf[0] + 1, crc);
+
+		if (crc != msgs[1].buf[msgs[1].buf[0] + 1])
+			return -EBADMSG;
+	}
+
+	memcpy(data_r, &msgs[1].buf[1], msgs[1].buf[0]);
+
+	ret = msgs[1].buf[0];
+	mutex_unlock(&data->buf_mutex);
+
+	return ret;
+}
+
 static int adm1266_probe(struct i2c_client *client, const struct i2c_device_id *id)
 {
 	struct adm1266_data *data;
@@ -33,6 +103,9 @@  static int adm1266_probe(struct i2c_client *client, const struct i2c_device_id *
 	for (i = 0; i < data->info.pages; i++)
 		data->info.func[i] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT;
 
+	crc8_populate_msb(pmbus_crc_table, 0x7);
+	mutex_init(&data->buf_mutex);
+
 	return pmbus_do_probe(client, id, &data->info);
 }