[PATCH v4 7/7] iio: pressure: bmp280: Add nvmem operations for BMP580

From: Angel Iglesias
Date: Sun Feb 19 2023 - 12:04:28 EST

The pressure sensor BMP580 contains a non-volatile memory that stores
trimming and configuration params. That memory provides an programmable
user range of three 2-byte words.

Signed-off-by: Angel Iglesias <ang.iglesiasg@xxxxxxxxx>

diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index a7d26d81ec08..1e7534d7c4a6 100644
--- a/drivers/iio/pressure/bmp280-core.c
+++ b/drivers/iio/pressure/bmp280-core.c
@@ -28,6 +28,7 @@
#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/module.h>
+#include <linux/nvmem-provider.h>
#include <linux/regmap.h>
#include <linux/delay.h>
#include <linux/iio/iio.h>
@@ -1284,6 +1285,80 @@ static int bmp580_soft_reset(struct bmp280_data *data)
return 0;
}

+/**
+ * bmp580_nvm_operation() - Helper function to commit NVM memory operations
+ * @data: sensor data struct
+ * @is_write: flag to signal write operation
+ */
+static int bmp580_nvm_operation(struct bmp280_data *data, bool is_write)
+{
+ unsigned long timeout, poll;
+ unsigned int reg;
+ int ret;
+
+ /* Check NVM ready flag */
+ ret = regmap_read(data->regmap, BMP580_REG_STATUS, &reg);
+ if (ret) {
+ dev_err(data->dev, "failed to check nvm status\n");
+ return ret;
+ }
+ if (!(reg & BMP580_STATUS_NVM_RDY_MASK)) {
+ dev_err(data->dev, "sensor's nvm is not ready\n");
+ return -EIO;
+ }
+
+ /* Start NVM operation sequence */
+ ret = regmap_write(data->regmap, BMP580_REG_CMD, BMP580_CMD_NVM_OP_SEQ_0);
+ if (ret) {
+ dev_err(data->dev, "failed to send nvm operation's first sequence\n");
+ return ret;
+ }
+ if (is_write) {
+ /* Send NVM write sequence */
+ ret = regmap_write(data->regmap, BMP580_REG_CMD,
+ BMP580_CMD_NVM_WRITE_SEQ_1);
+ if (ret) {
+ dev_err(data->dev, "failed to send nvm write sequence\n");
+ return ret;
+ }
+ /* Datasheet says on 4.8.1.2 it takes approximately 10ms */
+ poll = 2000;
+ timeout = 12000;
+ } else {
+ /* Send NVM read sequence */
+ ret = regmap_write(data->regmap, BMP580_REG_CMD,
+ BMP580_CMD_NVM_READ_SEQ_1);
+ if (ret) {
+ dev_err(data->dev, "failed to send nvm read sequence\n");
+ return ret;
+ }
+ /* Datasheet says on 4.8.1.1 it takes approximately 200us */
+ poll = 50;
+ timeout = 400;
+ }
+ if (ret) {
+ dev_err(data->dev, "failed to write command sequence\n");
+ return -EIO;
+ }
+
+ /* Wait until NVM is ready again */
+ ret = regmap_read_poll_timeout(data->regmap, BMP580_REG_STATUS, reg,
+ (reg & BMP580_STATUS_NVM_RDY_MASK),
+ poll, timeout);
+ if (ret) {
+ dev_err(data->dev, "error checking nvm operation status\n");
+ return ret;
+ }
+
+ /* Check NVM error flags */
+ if ((reg & BMP580_STATUS_NVM_ERR_MASK) || (reg & BMP580_STATUS_NVM_CMD_ERR_MASK)) {
+ dev_err(data->dev, "error processing nvm operation\n");
+ return -EIO;
+ }
+
+ return 0;
+}
+
/*
* Contrary to previous sensors families, compensation algorithm is builtin.
* We are only required to read the register raw data and adapt the ranges
@@ -1379,8 +1454,140 @@ static const int bmp580_odr_table[][2] = {
[BMP580_ODR_0_125HZ] = {0, 125000},
};

+const int bmp580_nvmem_addrs[] = { 0x20, 0x21, 0x22 };
+
+static int bmp580_nvmem_read(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct bmp280_data *data = priv;
+ u16 *dst = val;
+ int ret, addr;
+
+ pm_runtime_get_sync(data->dev);
+ mutex_lock(&data->lock);
+
+ /* Set sensor in standby mode */
+ ret = regmap_update_bits(data->regmap, BMP580_REG_ODR_CONFIG,
+ BMP580_MODE_MASK | BMP580_ODR_DEEPSLEEP_DIS,
+ BMP580_ODR_DEEPSLEEP_DIS |
+ FIELD_PREP(BMP580_MODE_MASK, BMP580_MODE_SLEEP));
+ if (ret) {
+ dev_err(data->dev, "failed to change sensor to standby mode\n");
+ goto exit;
+ }
+ /* Wait standby transition time */
+ usleep_range(2500, 3000);
+
+ while (bytes >= sizeof(*dst)) {
+ addr = bmp580_nvmem_addrs[offset / sizeof(*dst)];
+
+ ret = regmap_write(data->regmap, BMP580_REG_NVM_ADDR,
+ FIELD_PREP(BMP580_NVM_ROW_ADDR_MASK, addr));
+ if (ret) {
+ dev_err(data->dev, "error writing nvm address\n");
+ goto exit;
+ }
+
+ ret = bmp580_nvm_operation(data, false);
+ if (ret)
+ goto exit;
+
+ ret = regmap_bulk_read(data->regmap, BMP580_REG_NVM_DATA_LSB, &data->le16,
+ sizeof(data->le16));
+ if (ret) {
+ dev_err(data->dev, "error reading nvm data regs\n");
+ goto exit;
+ }
+
+ *dst++ = le16_to_cpu(data->le16);
+ bytes -= sizeof(*dst);
+ offset += sizeof(*dst);
+ }
+exit:
+ /* Restore chip config */
+ data->chip_info->chip_config(data);
+ mutex_unlock(&data->lock);
+ pm_runtime_mark_last_busy(data->dev);
+ pm_runtime_put_autosuspend(data->dev);
+ return ret;
+}
+
+static int bmp580_nvmem_write(void *priv, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct bmp280_data *data = priv;
+ u16 *buf = val;
+ int ret, addr;
+
+ pm_runtime_get_sync(data->dev);
+ mutex_lock(&data->lock);
+
+ /* Set sensor in standby mode */
+ ret = regmap_update_bits(data->regmap, BMP580_REG_ODR_CONFIG,
+ BMP580_MODE_MASK | BMP580_ODR_DEEPSLEEP_DIS,
+ BMP580_ODR_DEEPSLEEP_DIS |
+ FIELD_PREP(BMP580_MODE_MASK, BMP580_MODE_SLEEP));
+ if (ret) {
+ dev_err(data->dev, "failed to change sensor to standby mode\n");
+ goto exit;
+ }
+ /* Wait standby transition time */
+ usleep_range(2500, 3000);
+
+ while (bytes >= sizeof(*buf)) {
+ addr = bmp580_nvmem_addrs[offset / sizeof(*buf)];
+
+ ret = regmap_write(data->regmap, BMP580_REG_NVM_ADDR, BMP580_NVM_PROG_EN |
+ FIELD_PREP(BMP580_NVM_ROW_ADDR_MASK, addr));
+ if (ret) {
+ dev_err(data->dev, "error writing nvm address\n");
+ goto exit;
+ }
+ data->le16 = cpu_to_le16(*buf++);
+
+ ret = regmap_bulk_write(data->regmap, BMP580_REG_NVM_DATA_LSB, &data->le16,
+ sizeof(data->le16));
+ if (ret) {
+ dev_err(data->dev, "error writing LSB NVM data regs\n");
+ goto exit;
+ }
+
+ ret = bmp580_nvm_operation(data, true);
+ if (ret)
+ goto exit;
+
+ /* Disable programming mode bit */
+ ret = regmap_update_bits(data->regmap, BMP580_REG_NVM_ADDR,
+ BMP580_NVM_PROG_EN, 0);
+ if (ret) {
+ dev_err(data->dev, "error resetting nvm write\n");
+ goto exit;
+ }
+
+ bytes -= sizeof(*buf);
+ offset += sizeof(*buf);
+ }
+exit:
+ /* Restore chip config */
+ data->chip_info->chip_config(data);
+ mutex_unlock(&data->lock);
+ pm_runtime_mark_last_busy(data->dev);
+ pm_runtime_put_autosuspend(data->dev);
+ return ret;
+}
+
static int bmp580_preinit(struct bmp280_data *data)
{
+ struct nvmem_config config = {
+ .dev = data->dev,
+ .priv = data,
+ .name = "bmp580_nvmem",
+ .word_size = sizeof(u16),
+ .stride = sizeof(u16),
+ .size = 3 * sizeof(u16),
+ .reg_read = bmp580_nvmem_read,
+ .reg_write = bmp580_nvmem_write,
+ };
unsigned int reg;
int ret;

@@ -1408,7 +1615,8 @@ static int bmp580_preinit(struct bmp280_data *data)
return -EIO;
}

- return 0;
+ /* Register nvmem device */
+ return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config));
}

static int bmp580_chip_config(struct bmp280_data *data)
diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
index cd4c5be36ed7..5c0563ce7572 100644
--- a/drivers/iio/pressure/bmp280.h
+++ b/drivers/iio/pressure/bmp280.h
@@ -104,6 +104,9 @@
#define BMP580_FILTER_63X 6
#define BMP580_FILTER_127X 7

+#define BMP580_NVM_ROW_ADDR_MASK GENMASK(5, 0)
+#define BMP580_NVM_PROG_EN BIT(6)
+
#define BMP580_TEMP_SKIPPED 0x7f7f7f
#define BMP580_PRESS_SKIPPED 0x7f7f7f

--
2.39.2