Hi Guenter,
On Mon, 10 Sep 2012 21:09:25 -0700, Guenter Roeck wrote:
> Replace per-device initialization and per-device calculation code with
> per-device configuration data, which is then used to configure the chip and
> perform calculations based on that data.
>
> Also use i2c_smbus_write_read_swapped i2c_smbus_write_word_swapped to read and
> write word swapped I2C data.
>
> This patch reduces code size by more than 400 bytes on x86_64.
>
> Cc: Lothar Felten <l-felten@xxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> drivers/hwmon/ina2xx.c | 168 ++++++++++++++++--------------------------------
> 1 file changed, 55 insertions(+), 113 deletions(-)
>
> diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
> index 7f3f4a3..eb42e8b 100644
> --- a/drivers/hwmon/ina2xx.c
> +++ b/drivers/hwmon/ina2xx.c
> @@ -57,8 +57,19 @@
>
> enum ina2xx_ids { ina219, ina226 };
>
> +struct ina2xx_config {
> + u16 config;
config_default would be a better name IMHO.
> + int calibration_factor;
> + int registers;
> + int shunt_div;
> + int bus_voltage_shift;
> + int bus_voltage_lsb; /* uV */
> + int power_lsb; /* uW */
> +};
> +
> struct ina2xx_data {
> struct device *hwmon_dev;
> + struct ina2xx_config *config;
This is data shared between clients, so it should be a const pointer.
>
> struct mutex update_lock;
> bool valid;
> @@ -69,21 +80,26 @@ struct ina2xx_data {
> u16 regs[INA2XX_MAX_REGISTERS];
> };
>
> -int ina2xx_read_word(struct i2c_client *client, int reg)
> -{
> - int val = i2c_smbus_read_word_data(client, reg);
> - if (unlikely(val < 0)) {
> - dev_dbg(&client->dev,
> - "Failed to read register: %d\n", reg);
> - return val;
> - }
> - return be16_to_cpu(val);
> -}
> -
> -void ina2xx_write_word(struct i2c_client *client, int reg, int data)
> -{
> - i2c_smbus_write_word_data(client, reg, cpu_to_be16(data));
> -}
This change doesn't belong to that patch.
Also note that these calls to be16_to_cpu() were suspicious.
i2c_smbus_read_word_swapped() uses swab16(), not *16_to_cpu(). The need
to swap depends on the slave I2C device, _not_ the host endianness. So
this was probably a bug in the driver originally, and calling
i2c_smbus_read_word_swapped() will fix it. This certainly deserves a
separate patch, as it may have to be backported.
> +static struct ina2xx_config ina2xx_config[] = {
> + [ina219] = {
> + .config = INA219_CONFIG_DEFAULT,
> + .calibration_factor = 40960000,
> + .registers = INA219_REGISTERS,
> + .shunt_div = 100,
> + .bus_voltage_shift = 3,
> + .bus_voltage_lsb = 4000,
> + .power_lsb = 20000,
> + },
> + [ina226] = {
> + .config = INA226_CONFIG_DEFAULT,
> + .calibration_factor = 5120000,
> + .registers = INA226_REGISTERS,
> + .shunt_div = 400,
> + .bus_voltage_shift = 0,
> + .bus_voltage_lsb = 1250,
> + .power_lsb = 25000,
> + },
> +};
Nobody should change these, so make them const.
>
> static struct ina2xx_data *ina2xx_update_device(struct device *dev)
> {
> @@ -102,7 +118,7 @@ static struct ina2xx_data *ina2xx_update_device(struct device *dev)
>
> /* Read all registers */
> for (i = 0; i < data->registers; i++) {
> - int rv = ina2xx_read_word(client, i);
> + int rv = i2c_smbus_read_word_swapped(client, i);
> if (rv < 0) {
> ret = ERR_PTR(rv);
> goto abort;
> @@ -117,73 +133,25 @@ abort:
> return ret;
> }
>
> -static int ina219_get_value(struct ina2xx_data *data, u8 reg)
> -{
> - /*
> - * calculate exact value for the given register
> - * we assume default power-on reset settings:
> - * bus voltage range 32V
> - * gain = /8
> - * adc 1 & 2 -> conversion time 532uS
> - * mode is continuous shunt and bus
> - * calibration value is INA219_CALIBRATION_VALUE
> - */
> - int val = data->regs[reg];
> -
> - switch (reg) {
> - case INA2XX_SHUNT_VOLTAGE:
> - /* LSB=10uV. Convert to mV. */
> - val = DIV_ROUND_CLOSEST(val, 100);
> - break;
> - case INA2XX_BUS_VOLTAGE:
> - /* LSB=4mV. Register is not right aligned, convert to mV. */
> - val = (val >> 3) * 4;
> - break;
> - case INA2XX_POWER:
> - /* LSB=20mW. Convert to uW */
> - val = val * 20 * 1000;
> - break;
> - case INA2XX_CURRENT:
> - /* LSB=1mA (selected). Is in mA */
> - break;
> - default:
> - /* programmer goofed */
> - WARN_ON_ONCE(1);
> - val = 0;
> - break;
> - }
> -
> - return val;
> -}
> -
> -static int ina226_get_value(struct ina2xx_data *data, u8 reg)
> +static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
> {
> - /*
> - * calculate exact value for the given register
> - * we assume default power-on reset settings:
> - * bus voltage range 32V
> - * gain = /8
> - * adc 1 & 2 -> conversion time 532uS
> - * mode is continuous shunt and bus
> - * calibration value is INA226_CALIBRATION_VALUE
> - */
> - int val = data->regs[reg];
> + int val;
>
> switch (reg) {
> case INA2XX_SHUNT_VOLTAGE:
> - /* LSB=2.5uV. Convert to mV. */
> - val = DIV_ROUND_CLOSEST(val, 400);
> + val = DIV_ROUND_CLOSEST(data->regs[reg],
> + data->config->shunt_div);
> break;
> case INA2XX_BUS_VOLTAGE:
> - /* LSB=1.25mV. Convert to mV. */
> - val = val + DIV_ROUND_CLOSEST(val, 4);
> + val = (data->regs[reg] >> data->config->bus_voltage_shift)
> + * data->config->bus_voltage_lsb / 1000;
You're dropping DIV_ROUND_CLOSEST(), don't you think this could result
in improper rounding for the INA226? For example for val = 3, old code
returned 4, new code returns 3.
> break;
> case INA2XX_POWER:
> - /* LSB=25mW. Convert to uW */
> - val = val * 25 * 1000;
> + val = data->regs[reg] * data->config->power_lsb;
> break;
> case INA2XX_CURRENT:
> /* LSB=1mA (selected). Is in mA */
> + val = data->regs[reg];
> break;
> default:
> /* programmer goofed */
> @@ -200,23 +168,12 @@ static ssize_t ina2xx_show_value(struct device *dev,
> {
> struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
> struct ina2xx_data *data = ina2xx_update_device(dev);
> - int value = 0;
>
> if (IS_ERR(data))
> return PTR_ERR(data);
>
> - switch (data->kind) {
> - case ina219:
> - value = ina219_get_value(data, attr->index);
> - break;
> - case ina226:
> - value = ina226_get_value(data, attr->index);
> - break;
> - default:
> - WARN_ON_ONCE(1);
> - break;
> - }
> - return snprintf(buf, PAGE_SIZE, "%d\n", value);
> + return snprintf(buf, PAGE_SIZE, "%d\n",
> + ina2xx_get_value(data, attr->index));
> }
>
> /* shunt voltage */
> @@ -254,7 +211,7 @@ static int ina2xx_probe(struct i2c_client *client,
> struct i2c_adapter *adapter = client->adapter;
> struct ina2xx_data *data;
> struct ina2xx_platform_data *pdata;
> - int ret = 0;
> + int ret;
> long shunt = 10000; /* default shunt value 10mOhms */
>
> if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
> @@ -275,34 +232,16 @@ static int ina2xx_probe(struct i2c_client *client,
>
> /* set the device type */
> data->kind = id->driver_data;
> + data->config = &ina2xx_config[data->kind];
>
> - switch (data->kind) {
> - case ina219:
> - /* device configuration */
> - ina2xx_write_word(client, INA2XX_CONFIG, INA219_CONFIG_DEFAULT);
> -
> - /* set current LSB to 1mA, shunt is in uOhms */
> - /* (equation 13 in datasheet) */
> - ina2xx_write_word(client, INA2XX_CALIBRATION, 40960000 / shunt);
> - dev_info(&client->dev,
> - "power monitor INA219 (Rshunt = %li uOhm)\n", shunt);
> - data->registers = INA219_REGISTERS;
> - break;
> - case ina226:
> - /* device configuration */
> - ina2xx_write_word(client, INA2XX_CONFIG, INA226_CONFIG_DEFAULT);
> -
> - /* set current LSB to 1mA, shunt is in uOhms */
> - /* (equation 1 in datasheet)*/
> - ina2xx_write_word(client, INA2XX_CALIBRATION, 5120000 / shunt);
> - dev_info(&client->dev,
> - "power monitor INA226 (Rshunt = %li uOhm)\n", shunt);
> - data->registers = INA226_REGISTERS;
> - break;
> - default:
> - /* unknown device id */
> - return -ENODEV;
> - }
> + /* device configuration */
> + i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
> + data->config->config);
> + /* set current LSB to 1mA, shunt is in uOhms */
> + /* (equation 13 in datasheet) */
> + i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
> + data->config->calibration_factor / shunt);
> + data->registers = data->config->registers;
Maybe we can get rid of data->registers now?
>
> i2c_set_clientdata(client, data);
> mutex_init(&data->update_lock);
> @@ -317,6 +256,9 @@ static int ina2xx_probe(struct i2c_client *client,
> goto out_err_hwmon;
> }
>
> + dev_info(&client->dev, "power monitor %s (Rshunt = %li uOhm)\n",
> + id->name, shunt);
> +
> return 0;
>
> out_err_hwmon:
--
Jean Delvare
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