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From:   <alexandru.tachici@analog.com>
To:     <linux-hwmon@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>
CC:     <robh+dt@kernel.org>, <linux@roeck-us.net>,
        Alexandru Tachici <alexandru.tachici@analog.com>
Subject: [PATCH v4 5/7] hwmon: pmbus: adm1266: read blackbox
Date:   Tue, 23 Jun 2020 20:36:57 +0300
Message-ID: <20200623173659.41358-6-alexandru.tachici@analog.com>
In-Reply-To: <20200623173659.41358-1-alexandru.tachici@analog.com>
References: <20200623173659.41358-1-alexandru.tachici@analog.com>
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Sender: linux-kernel-owner@vger.kernel.org
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From: Alexandru Tachici <alexandru.tachici@analog.com>

Use the nvmem kernel api to expose the black box
chip functionality to userspace.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
---
 drivers/hwmon/pmbus/adm1266.c | 134 ++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
index 0960ead8d96a..b9e92ab1e39a 100644
--- a/drivers/hwmon/pmbus/adm1266.c
+++ b/drivers/hwmon/pmbus/adm1266.c
@@ -15,6 +15,8 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
 #include <linux/proc_fs.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
@@ -22,10 +24,13 @@
 #include <linux/adm1266.h>
 #include "pmbus.h"
 
+#define ADM1266_BLACKBOX_CONFIG	0xD3
 #define ADM1266_PDIO_CONFIG	0xD4
 #define ADM1266_GO_COMMAND	0xD8
 #define ADM1266_READ_STATE	0xD9
+#define ADM1266_READ_BLACKBOX	0xDE
 #define ADM1266_GPIO_CONFIG	0xE1
+#define ADM1266_BLACKBOX_INFO	0xE6
 #define ADM1266_PDIO_STATUS	0xE9
 #define ADM1266_GPIO_STATUS	0xEA
 
@@ -42,6 +47,9 @@
 #define ADM1266_PDIO_GLITCH_FILT(x)	FIELD_GET(GENMASK(12, 9), x)
 #define ADM1266_PDIO_OUT_CFG(x)		FIELD_GET(GENMASK(2, 0), x)
 
+#define ADM1266_BLACKBOX_OFFSET		0x7F700
+#define ADM1266_BLACKBOX_SIZE		64
+
 #define ADM1266_PMBUS_BLOCK_MAX		255
 
 DECLARE_CRC8_TABLE(pmbus_crc_table);
@@ -52,6 +60,17 @@ struct adm1266_data {
 	const char *gpio_names[ADM1266_GPIO_NR + ADM1266_PDIO_NR];
 	struct i2c_client *client;
 	struct mutex ioctl_mutex; /* lock ioctl access */
+	struct nvmem_config nvmem_config;
+	struct nvmem_device *nvmem;
+	u8 *dev_mem;
+};
+
+static const struct nvmem_cell_info adm1266_nvmem_cells[] = {
+	{
+		.name           = "blackbox",
+		.offset         = ADM1266_BLACKBOX_OFFSET,
+		.bytes          = 2048,
+	},
 };
 
 /* Different from Block Read as it sends data and waits for the slave to
@@ -404,6 +423,117 @@ static int adm1266_init_procfs(struct adm1266_data *data)
 	return 0;
 }
 
+static int adm1266_nvmem_read_blackbox(struct adm1266_data *data, u8 *buf)
+{
+	u8 read_buf[5];
+	char index;
+	int record_count;
+	int ret;
+
+	ret = i2c_smbus_read_block_data(data->client, ADM1266_BLACKBOX_INFO,
+					read_buf);
+	if (ret < 0)
+		return ret;
+
+	record_count = read_buf[3];
+
+	for (index = 0; index < record_count; index++) {
+		ret = pmbus_block_xfer(data->client, ADM1266_READ_BLACKBOX, 1,
+				       &index, buf);
+		if (ret < 0)
+			return ret;
+
+		buf += ADM1266_BLACKBOX_SIZE;
+	}
+
+	return 0;
+}
+
+static bool adm1266_cell_is_accessed(const struct nvmem_cell_info *mem_cell,
+				     unsigned int offset, size_t bytes)
+{
+	unsigned int start_addr = offset;
+	unsigned int end_addr = offset + bytes;
+	unsigned int cell_start = mem_cell->offset;
+	unsigned int cell_end = mem_cell->offset + mem_cell->bytes;
+
+	if (start_addr <= cell_end && cell_start <= end_addr)
+		return true;
+
+	return false;
+}
+
+static int adm1266_read_mem_cell(struct adm1266_data *data,
+				 const struct nvmem_cell_info *mem_cell)
+{
+	u8 *mem_offset;
+	int ret;
+
+	switch (mem_cell->offset) {
+	case ADM1266_BLACKBOX_OFFSET:
+		mem_offset = data->dev_mem + mem_cell->offset;
+		ret = adm1266_nvmem_read_blackbox(data, mem_offset);
+		if (ret)
+			dev_err(&data->client->dev, "Could not read blackbox!");
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int adm1266_nvmem_read(void *priv, unsigned int offset, void *val,
+			      size_t bytes)
+{
+	const struct nvmem_cell_info *mem_cell;
+	struct adm1266_data *data = priv;
+	int ret;
+	int i;
+
+	for (i = 0; i < data->nvmem_config.ncells; i++) {
+		mem_cell = &adm1266_nvmem_cells[i];
+		if (!adm1266_cell_is_accessed(mem_cell, offset, bytes))
+			continue;
+
+		ret = adm1266_read_mem_cell(data, mem_cell);
+		if (ret < 0)
+			return ret;
+	}
+
+	memcpy(val, data->dev_mem + offset, bytes);
+
+	return 0;
+}
+
+static int adm1266_config_nvmem(struct adm1266_data *data)
+{
+	data->nvmem_config.name = dev_name(&data->client->dev);
+	data->nvmem_config.dev = &data->client->dev;
+	data->nvmem_config.root_only = true;
+	data->nvmem_config.read_only = true;
+	data->nvmem_config.owner = THIS_MODULE;
+	data->nvmem_config.reg_read = adm1266_nvmem_read;
+	data->nvmem_config.cells = adm1266_nvmem_cells;
+	data->nvmem_config.ncells = ARRAY_SIZE(adm1266_nvmem_cells);
+	data->nvmem_config.priv = data;
+	data->nvmem_config.stride = 1;
+	data->nvmem_config.word_size = 1;
+	data->nvmem_config.size = 0x80000;
+
+	data->nvmem = nvmem_register(&data->nvmem_config);
+	if (IS_ERR(data->nvmem)) {
+		dev_err(&data->client->dev, "Could not register nvmem!");
+		return PTR_ERR(data->nvmem);
+	}
+
+	data->dev_mem = devm_kzalloc(&data->client->dev,
+				     data->nvmem_config.size,
+				     GFP_KERNEL);
+	if (!data->dev_mem)
+		return -ENOMEM;
+
+	return 0;
+}
+
 static int adm1266_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -430,6 +560,10 @@ static int adm1266_probe(struct i2c_client *client,
 	if (ret < 0)
 		return ret;
 
+	ret = adm1266_config_nvmem(data);
+	if (ret < 0)
+		return ret;
+
 	info = &data->info;
 	info->pages = 17;
 	info->format[PSC_VOLTAGE_OUT] = linear;
-- 
2.20.1