Re: [PATCH V4 2/2] staging: iio: light: isl29018: use regmap for register access

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On Fri, Apr 20, 2012 at 12:27 AM, Laxman Dewangan <ldewangan@xxxxxxxxxx> wrote:
> Using regmap for accessing register through i2c bus. This will
> remove the code for caching registers, read-modify-write logics.
> Also it will provide the debugfs feature to dump register
> through regmap debugfs.
>
> Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>

Reviewed-by: Grant Grundler <grundler@xxxxxxxxxxxx>

Thanks for explaining the COMMAND1 register usage and volatile bits. LGTM.

cheers,
grant

> ---
> Change from V1:
> - Spliting the changes in two patches.
> - Separate patch for indenting cleanups.
> - Rebased the code on top of -next which have Jonathan's recent changes.
>
> Changes from V2:
> - Taken care of Lars's review comment about wrong return.
>
> Changes from V3:
> Taken care of Lars's and Grant's comment about COMMAND1 register access.
> -Use regmap_write() for ADD_COMMAND1 and keeping this as volatile.
>
>  drivers/staging/iio/light/Kconfig    |    1 +
>  drivers/staging/iio/light/isl29018.c |  178 +++++++++++++++++-----------------
>  2 files changed, 91 insertions(+), 88 deletions(-)
>
> diff --git a/drivers/staging/iio/light/Kconfig b/drivers/staging/iio/light/Kconfig
> index bb633f6..fd39f72 100644
> --- a/drivers/staging/iio/light/Kconfig
> +++ b/drivers/staging/iio/light/Kconfig
> @@ -6,6 +6,7 @@ menu "Light sensors"
>  config SENSORS_ISL29018
>        tristate "ISL 29018 light and proximity sensor"
>        depends on I2C
> +       select REGMAP_I2C
>        default n
>        help
>         If you say yes here you get support for ambient light sensing and
> diff --git a/drivers/staging/iio/light/isl29018.c b/drivers/staging/iio/light/isl29018.c
> index 073e899..de079ae 100644
> --- a/drivers/staging/iio/light/isl29018.c
> +++ b/drivers/staging/iio/light/isl29018.c
> @@ -26,9 +26,11 @@
>  #include <linux/err.h>
>  #include <linux/mutex.h>
>  #include <linux/delay.h>
> +#include <linux/regmap.h>
>  #include <linux/slab.h>
>  #include "../iio.h"
>  #include "../sysfs.h"
> +
>  #define CONVERSION_TIME_MS             100
>
>  #define ISL29018_REG_ADD_COMMAND1      0x00
> @@ -51,49 +53,22 @@
>
>  #define ISL29018_REG_ADD_DATA_LSB      0x02
>  #define ISL29018_REG_ADD_DATA_MSB      0x03
> -#define ISL29018_MAX_REGS              (ISL29018_REG_ADD_DATA_MSB+1)
>
>  #define ISL29018_REG_TEST              0x08
>  #define ISL29018_TEST_SHIFT            0
>  #define ISL29018_TEST_MASK             (0xFF << ISL29018_TEST_SHIFT)
>
>  struct isl29018_chip {
> -       struct i2c_client       *client;
> +       struct device           *dev;
> +       struct regmap           *regmap;
>        struct mutex            lock;
>        unsigned int            lux_scale;
>        unsigned int            range;
>        unsigned int            adc_bit;
>        int                     prox_scheme;
> -       u8                      reg_cache[ISL29018_MAX_REGS];
>  };
>
> -static int isl29018_write_data(struct i2c_client *client, u8 reg,
> -                       u8 val, u8 mask, u8 shift)
> -{
> -       u8 regval = val;
> -       int ret;
> -       struct isl29018_chip *chip = iio_priv(i2c_get_clientdata(client));
> -
> -       /* don't cache or mask REG_TEST */
> -       if (reg < ISL29018_MAX_REGS) {
> -               regval = chip->reg_cache[reg];
> -               regval &= ~mask;
> -               regval |= val << shift;
> -       }
> -
> -       ret = i2c_smbus_write_byte_data(client, reg, regval);
> -       if (ret) {
> -               dev_err(&client->dev, "Write to device fails status %x\n", ret);
> -       } else {
> -               /* don't update cache on err */
> -               if (reg < ISL29018_MAX_REGS)
> -                       chip->reg_cache[reg] = regval;
> -       }
> -
> -       return ret;
> -}
> -
> -static int isl29018_set_range(struct i2c_client *client, unsigned long range,
> +static int isl29018_set_range(struct isl29018_chip *chip, unsigned long range,
>                unsigned int *new_range)
>  {
>        static const unsigned long supp_ranges[] = {1000, 4000, 16000, 64000};
> @@ -109,11 +84,11 @@ static int isl29018_set_range(struct i2c_client *client, unsigned long range,
>        if (i >= ARRAY_SIZE(supp_ranges))
>                return -EINVAL;
>
> -       return isl29018_write_data(client, ISL29018_REG_ADD_COMMANDII,
> -                       i, COMMANDII_RANGE_MASK, COMMANDII_RANGE_SHIFT);
> +       return regmap_update_bits(chip->regmap, ISL29018_REG_ADD_COMMANDII,
> +                       COMMANDII_RANGE_MASK, i << COMMANDII_RANGE_SHIFT);
>  }
>
> -static int isl29018_set_resolution(struct i2c_client *client,
> +static int isl29018_set_resolution(struct isl29018_chip *chip,
>                        unsigned long adcbit, unsigned int *conf_adc_bit)
>  {
>        static const unsigned long supp_adcbit[] = {16, 12, 8, 4};
> @@ -129,48 +104,49 @@ static int isl29018_set_resolution(struct i2c_client *client,
>        if (i >= ARRAY_SIZE(supp_adcbit))
>                return -EINVAL;
>
> -       return isl29018_write_data(client, ISL29018_REG_ADD_COMMANDII,
> -                       i, COMMANDII_RESOLUTION_MASK,
> -                       COMMANDII_RESOLUTION_SHIFT);
> +       return regmap_update_bits(chip->regmap, ISL29018_REG_ADD_COMMANDII,
> +                       COMMANDII_RESOLUTION_MASK,
> +                       i << COMMANDII_RESOLUTION_SHIFT);
>  }
>
> -static int isl29018_read_sensor_input(struct i2c_client *client, int mode)
> +static int isl29018_read_sensor_input(struct isl29018_chip *chip, int mode)
>  {
>        int status;
> -       int lsb;
> -       int msb;
> +       unsigned int lsb;
> +       unsigned int msb;
>
>        /* Set mode */
> -       status = isl29018_write_data(client, ISL29018_REG_ADD_COMMAND1,
> -                       mode, COMMMAND1_OPMODE_MASK, COMMMAND1_OPMODE_SHIFT);
> +       status = regmap_write(chip->regmap, ISL29018_REG_ADD_COMMAND1,
> +                       mode << COMMMAND1_OPMODE_SHIFT);
>        if (status) {
> -               dev_err(&client->dev, "Error in setting operating mode\n");
> +               dev_err(chip->dev,
> +                       "Error in setting operating mode err %d\n", status);
>                return status;
>        }
>        msleep(CONVERSION_TIME_MS);
> -       lsb = i2c_smbus_read_byte_data(client, ISL29018_REG_ADD_DATA_LSB);
> -       if (lsb < 0) {
> -               dev_err(&client->dev, "Error in reading LSB DATA\n");
> -               return lsb;
> +       status = regmap_read(chip->regmap, ISL29018_REG_ADD_DATA_LSB, &lsb);
> +       if (status < 0) {
> +               dev_err(chip->dev,
> +                       "Error in reading LSB DATA with err %d\n", status);
> +               return status;
>        }
>
> -       msb = i2c_smbus_read_byte_data(client, ISL29018_REG_ADD_DATA_MSB);
> -       if (msb < 0) {
> -               dev_err(&client->dev, "Error in reading MSB DATA\n");
> -               return msb;
> +       status = regmap_read(chip->regmap, ISL29018_REG_ADD_DATA_MSB, &msb);
> +       if (status < 0) {
> +               dev_err(chip->dev,
> +                       "Error in reading MSB DATA with error %d\n", status);
> +               return status;
>        }
> -       dev_vdbg(&client->dev, "MSB 0x%x and LSB 0x%x\n", msb, lsb);
> +       dev_vdbg(chip->dev, "MSB 0x%x and LSB 0x%x\n", msb, lsb);
>
>        return (msb << 8) | lsb;
>  }
>
> -static int isl29018_read_lux(struct i2c_client *client, int *lux)
> +static int isl29018_read_lux(struct isl29018_chip *chip, int *lux)
>  {
>        int lux_data;
> -       struct isl29018_chip *chip = iio_priv(i2c_get_clientdata(client));
>
> -       lux_data = isl29018_read_sensor_input(client,
> -                               COMMMAND1_OPMODE_ALS_ONCE);
> +       lux_data = isl29018_read_sensor_input(chip, COMMMAND1_OPMODE_ALS_ONCE);
>
>        if (lux_data < 0)
>                return lux_data;
> @@ -180,11 +156,11 @@ static int isl29018_read_lux(struct i2c_client *client, int *lux)
>        return 0;
>  }
>
> -static int isl29018_read_ir(struct i2c_client *client, int *ir)
> +static int isl29018_read_ir(struct isl29018_chip *chip, int *ir)
>  {
>        int ir_data;
>
> -       ir_data = isl29018_read_sensor_input(client, COMMMAND1_OPMODE_IR_ONCE);
> +       ir_data = isl29018_read_sensor_input(chip, COMMMAND1_OPMODE_IR_ONCE);
>
>        if (ir_data < 0)
>                return ir_data;
> @@ -194,7 +170,7 @@ static int isl29018_read_ir(struct i2c_client *client, int *ir)
>        return 0;
>  }
>
> -static int isl29018_read_proximity_ir(struct i2c_client *client, int scheme,
> +static int isl29018_read_proximity_ir(struct isl29018_chip *chip, int scheme,
>                int *near_ir)
>  {
>        int status;
> @@ -202,14 +178,15 @@ static int isl29018_read_proximity_ir(struct i2c_client *client, int scheme,
>        int ir_data = -1;
>
>        /* Do proximity sensing with required scheme */
> -       status = isl29018_write_data(client, ISL29018_REG_ADD_COMMANDII,
> -                       scheme, COMMANDII_SCHEME_MASK, COMMANDII_SCHEME_SHIFT);
> +       status = regmap_update_bits(chip->regmap, ISL29018_REG_ADD_COMMANDII,
> +                       COMMANDII_SCHEME_MASK,
> +                       scheme << COMMANDII_SCHEME_SHIFT);
>        if (status) {
> -               dev_err(&client->dev, "Error in setting operating mode\n");
> +               dev_err(chip->dev, "Error in setting operating mode\n");
>                return status;
>        }
>
> -       prox_data = isl29018_read_sensor_input(client,
> +       prox_data = isl29018_read_sensor_input(chip,
>                                        COMMMAND1_OPMODE_PROX_ONCE);
>        if (prox_data < 0)
>                return prox_data;
> @@ -219,8 +196,7 @@ static int isl29018_read_proximity_ir(struct i2c_client *client, int scheme,
>                return 0;
>        }
>
> -       ir_data = isl29018_read_sensor_input(client,
> -                               COMMMAND1_OPMODE_IR_ONCE);
> +       ir_data = isl29018_read_sensor_input(chip, COMMMAND1_OPMODE_IR_ONCE);
>
>        if (ir_data < 0)
>                return ir_data;
> @@ -249,7 +225,6 @@ static ssize_t store_range(struct device *dev,
>  {
>        struct iio_dev *indio_dev = dev_get_drvdata(dev);
>        struct isl29018_chip *chip = iio_priv(indio_dev);
> -       struct i2c_client *client = chip->client;
>        int status;
>        unsigned long lval;
>        unsigned int new_range;
> @@ -264,10 +239,11 @@ static ssize_t store_range(struct device *dev,
>        }
>
>        mutex_lock(&chip->lock);
> -       status = isl29018_set_range(client, lval, &new_range);
> +       status = isl29018_set_range(chip, lval, &new_range);
>        if (status < 0) {
>                mutex_unlock(&chip->lock);
> -               dev_err(dev, "Error in setting max range\n");
> +               dev_err(dev,
> +                       "Error in setting max range with err %d\n", status);
>                return status;
>        }
>        chip->range = new_range;
> @@ -291,7 +267,6 @@ static ssize_t store_resolution(struct device *dev,
>  {
>        struct iio_dev *indio_dev = dev_get_drvdata(dev);
>        struct isl29018_chip *chip = iio_priv(indio_dev);
> -       struct i2c_client *client = chip->client;
>        int status;
>        unsigned long lval;
>        unsigned int new_adc_bit;
> @@ -304,7 +279,7 @@ static ssize_t store_resolution(struct device *dev,
>        }
>
>        mutex_lock(&chip->lock);
> -       status = isl29018_set_resolution(client, lval, &new_adc_bit);
> +       status = isl29018_set_resolution(chip, lval, &new_adc_bit);
>        if (status < 0) {
>                mutex_unlock(&chip->lock);
>                dev_err(dev, "Error in setting resolution\n");
> @@ -379,7 +354,6 @@ static int isl29018_read_raw(struct iio_dev *indio_dev,
>  {
>        int ret = -EINVAL;
>        struct isl29018_chip *chip = iio_priv(indio_dev);
> -       struct i2c_client *client = chip->client;
>
>        mutex_lock(&chip->lock);
>        switch (mask) {
> @@ -387,13 +361,13 @@ static int isl29018_read_raw(struct iio_dev *indio_dev,
>        case IIO_CHAN_INFO_PROCESSED:
>                switch (chan->type) {
>                case IIO_LIGHT:
> -                       ret = isl29018_read_lux(client, val);
> +                       ret = isl29018_read_lux(chip, val);
>                        break;
>                case IIO_INTENSITY:
> -                       ret = isl29018_read_ir(client, val);
> +                       ret = isl29018_read_ir(chip, val);
>                        break;
>                case IIO_PROXIMITY:
> -                       ret = isl29018_read_proximity_ir(client,
> +                       ret = isl29018_read_proximity_ir(chip,
>                                        chip->prox_scheme, val);
>                        break;
>                default:
> @@ -459,15 +433,12 @@ static const struct attribute_group isl29108_group = {
>        .attrs = isl29018_attributes,
>  };
>
> -static int isl29018_chip_init(struct i2c_client *client)
> +static int isl29018_chip_init(struct isl29018_chip *chip)
>  {
> -       struct isl29018_chip *chip = iio_priv(i2c_get_clientdata(client));
>        int status;
>        int new_adc_bit;
>        unsigned int new_range;
>
> -       memset(chip->reg_cache, 0, sizeof(chip->reg_cache));
> -
>        /* Code added per Intersil Application Note 1534:
>         *     When VDD sinks to approximately 1.8V or below, some of
>         * the part's registers may change their state. When VDD
> @@ -488,10 +459,9 @@ static int isl29018_chip_init(struct i2c_client *client)
>         * the same thing EXCEPT the data sheet asks for a 1ms delay after
>         * writing the CMD1 register.
>         */
> -       status = isl29018_write_data(client, ISL29018_REG_TEST, 0,
> -                               ISL29018_TEST_MASK, ISL29018_TEST_SHIFT);
> +       status = regmap_write(chip->regmap, ISL29018_REG_TEST, 0x0);
>        if (status < 0) {
> -               dev_err(&client->dev, "Failed to clear isl29018 TEST reg."
> +               dev_err(chip->dev, "Failed to clear isl29018 TEST reg."
>                                        "(%d)\n", status);
>                return status;
>        }
> @@ -500,10 +470,9 @@ static int isl29018_chip_init(struct i2c_client *client)
>         * "Operating Mode" (COMMAND1) register is reprogrammed when
>         * data is read from the device.
>         */
> -       status = isl29018_write_data(client, ISL29018_REG_ADD_COMMAND1, 0,
> -                               0xff, 0);
> +       status = regmap_write(chip->regmap, ISL29018_REG_ADD_COMMAND1, 0);
>        if (status < 0) {
> -               dev_err(&client->dev, "Failed to clear isl29018 CMD1 reg."
> +               dev_err(chip->dev, "Failed to clear isl29018 CMD1 reg."
>                                        "(%d)\n", status);
>                return status;
>        }
> @@ -511,13 +480,13 @@ static int isl29018_chip_init(struct i2c_client *client)
>        msleep(1);      /* per data sheet, page 10 */
>
>        /* set defaults */
> -       status = isl29018_set_range(client, chip->range, &new_range);
> +       status = isl29018_set_range(chip, chip->range, &new_range);
>        if (status < 0) {
> -               dev_err(&client->dev, "Init of isl29018 fails\n");
> +               dev_err(chip->dev, "Init of isl29018 fails\n");
>                return status;
>        }
>
> -       status = isl29018_set_resolution(client, chip->adc_bit,
> +       status = isl29018_set_resolution(chip, chip->adc_bit,
>                                                &new_adc_bit);
>
>        return 0;
> @@ -530,6 +499,32 @@ static const struct iio_info isl29108_info = {
>        .write_raw = &isl29018_write_raw,
>  };
>
> +static bool is_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +       switch (reg) {
> +       case ISL29018_REG_ADD_DATA_LSB:
> +       case ISL29018_REG_ADD_DATA_MSB:
> +       case ISL29018_REG_ADD_COMMAND1:
> +       case ISL29018_REG_TEST:
> +               return true;
> +       default:
> +               return false;
> +       }
> +}
> +
> +/*
> + * isl29018_regmap_config: regmap configuration.
> + * Use RBTREE mechanism for caching.
> + */
> +static const struct regmap_config isl29018_regmap_config = {
> +       .reg_bits = 8,
> +       .val_bits = 8,
> +       .volatile_reg = is_volatile_reg,
> +       .max_register = ISL29018_REG_TEST,
> +       .num_reg_defaults_raw = ISL29018_REG_TEST + 1,
> +       .cache_type = REGCACHE_RBTREE,
> +};
> +
>  static int __devinit isl29018_probe(struct i2c_client *client,
>                         const struct i2c_device_id *id)
>  {
> @@ -546,7 +541,7 @@ static int __devinit isl29018_probe(struct i2c_client *client,
>        chip = iio_priv(indio_dev);
>
>        i2c_set_clientdata(client, indio_dev);
> -       chip->client = client;
> +       chip->dev = &client->dev;
>
>        mutex_init(&chip->lock);
>
> @@ -554,7 +549,14 @@ static int __devinit isl29018_probe(struct i2c_client *client,
>        chip->range = 1000;
>        chip->adc_bit = 16;
>
> -       err = isl29018_chip_init(client);
> +       chip->regmap = devm_regmap_init_i2c(client, &isl29018_regmap_config);
> +       if (IS_ERR(chip->regmap)) {
> +               err = PTR_ERR(chip->regmap);
> +               dev_err(chip->dev, "regmap initialization failed: %d\n", err);
> +               goto exit;
> +       }
> +
> +       err = isl29018_chip_init(chip);
>        if (err)
>                goto exit_iio_free;
>
> --
> 1.7.1.1
>
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