[PATCH v2 5/5] iio: pressure: bmp280: Add nvmem operations for BMP580

Angel Iglesias
2022-12-26T14:33:17Z

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@gmail.com>

diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
index 44901c6eb2f9..578d145be55d 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>
@@ -1628,8 +1629,140 @@ 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(u16)) {
+ addr = bmp580_nvmem_addrs[offset / sizeof(u16)];
+
+ 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_cmd(data, BMP580_NVM_READ_CMD);
+ 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(u16);
+ offset += sizeof(u16);
+ }
+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(u16)) {
+ addr = bmp580_nvmem_addrs[offset / sizeof(u16)];
+
+ 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_cmd(data, BMP580_NVM_WRITE_CMD);
+ 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(u16);
+ offset += sizeof(u16);
+ }
+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;

@@ -1653,8 +1786,8 @@ static int bmp580_preinit(struct bmp280_data *data)
dev_err(data->dev, "preinit: nvm error on powerup sequence\n");
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 27d2abc17d01..e2a093a4f767 100644
--- a/drivers/iio/pressure/bmp280.h
+++ b/drivers/iio/pressure/bmp280.h
@@ -101,6 +101,9 @@
#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

--
2.39.0