From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1415286177.7340.14.camel@spandruv-hsb-test> Subject: Re: [PATCH 2/3] iio: ak8975: add definition structure per compass type From: Srinivas Pandruvada To: Gwendal Grignou Cc: jic23@kernel.org, knaack.h@gmx.de, linux-iio@vger.kernel.org Date: Thu, 06 Nov 2014 07:02:57 -0800 In-Reply-To: <1415225452-21957-3-git-send-email-gwendal@chromium.org> References: <1415225452-21957-1-git-send-email-gwendal@chromium.org> <1415225452-21957-3-git-send-email-gwendal@chromium.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-ID: On Wed, 2014-11-05 at 14:10 -0800, Gwendal Grignou wrote: > For each type of compass supported (AK8975 and AK8963), > add a definition structure for register masks, important registers, > raw data interpretation. > This change will make integrating new type of devices easier. > > Remove i2c register cache. It is only used for one single register. > > Signed-off-by: Gwendal Grignou > --- > drivers/iio/magnetometer/ak8975.c | 279 +++++++++++++++++++++++++------------- > 1 file changed, 184 insertions(+), 95 deletions(-) > > diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c > index 12f0b00..b170654 100644 > --- a/drivers/iio/magnetometer/ak8975.c > +++ b/drivers/iio/magnetometer/ak8975.c > @@ -86,13 +86,153 @@ > #define AK8975_MAX_CONVERSION_TIMEOUT 500 > #define AK8975_CONVERSION_DONE_POLL_TIME 10 > #define AK8975_DATA_READY_TIMEOUT ((100*HZ)/1000) > -#define RAW_TO_GAUSS_8975(asa) ((((asa) + 128) * 3000) / 256) > -#define RAW_TO_GAUSS_8963(asa) ((((asa) + 128) * 6000) / 256) > + > +/* > + * Precalculate scale factor (in Gauss units) for each axis and > + * store in the device data. > + * > + * This scale factor is axis-dependent, and is derived from 3 calibration > + * factors ASA(x), ASA(y), and ASA(z). > + * > + * These ASA values are read from the sensor device at start of day, and > + * cached in the device context struct. > + * > + * Adjusting the flux value with the sensitivity adjustment value should be > + * done via the following formula: > + * > + * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 ) > + * where H is the raw value, ASA is the sensitivity adjustment, and Hadj > + * is the resultant adjusted value. > + * > + * We reduce the formula to: > + * > + * Hadj = H * (ASA + 128) / 256 > + * > + * H is in the range of -4096 to 4095. The magnetometer has a range of > + * +-1229uT. To go from the raw value to uT is: > + * > + * HuT = H * 1229/4096, or roughly, 3/10. > + * > + * Since 1uT = 0.01 gauss, our final scale factor becomes: > + * > + * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100 > + * Hadj = H * ((ASA + 128) * 0.003) / 256 > + * > + * Since ASA doesn't change, we cache the resultant scale factor into the > + * device context in ak8975_setup(). > + * > + * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we > + * multiply the stored scale value by 1e6. > + */ > +long ak8975_raw_to_gauss(u16 data) What about inline? > +{ > + return (((long)data + 128) * 3000) / 256; > +} > + > +/* > + * For AK8963, same calculation, but the device is less sensitive: > + * > + * H is in the range of +-8190. The magnetometer has a range of > + * +-4912uT. To go from the raw value to uT is: > + * > + * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10. > + */ > +long ak8963_raw_to_gauss(u16 data) What about inline? > +{ > + return (((long)data + 128) * 6000) / 256; > +} > > /* Compatible Asahi Kasei Compass parts */ > enum asahi_compass_chipset { > AK8975, > AK8963, > + AK_MAX_TYPE > +}; > + > +enum ak_ctrl_reg_addr { > + ST1, > + ST2, > + CNTL, > + ASA_BASE, > + MAX_REGS, > + REGS_END, > +}; > + > +enum ak_ctrl_reg_mask { > + ST1_DRDY, > + ST2_HOFL, > + ST2_DERR, > + CNTL_MODE, > + MASK_END, > +}; > + > +enum ak_ctrl_mode { > + POWER_DOWN, > + MODE_ONCE, > + SELF_TEST, > + FUSE_ROM, > + MODE_END, > +}; > + > +struct ak_def { > + enum asahi_compass_chipset type; > + long (*raw_to_gauss)(u16 data); > + u16 range; > + u8 ctrl_regs[REGS_END]; > + u8 ctrl_masks[MASK_END]; > + u8 ctrl_modes[MODE_END]; > + u8 data_regs[3]; > +} ak_def_array[AK_MAX_TYPE] = { > +{ > + .type = AK8975, > + .raw_to_gauss = ak8975_raw_to_gauss, > + .range = 4096, > + .ctrl_regs = { > + AK8975_REG_ST1, > + AK8975_REG_ST2, > + AK8975_REG_CNTL, > + AK8975_REG_ASAX, > + AK8975_MAX_REGS}, > + .ctrl_masks = { > + AK8975_REG_ST1_DRDY_MASK, > + AK8975_REG_ST2_HOFL_MASK, > + AK8975_REG_ST2_DERR_MASK, > + AK8975_REG_CNTL_MODE_MASK}, > + .ctrl_modes = { > + AK8975_REG_CNTL_MODE_POWER_DOWN, > + AK8975_REG_CNTL_MODE_ONCE, > + AK8975_REG_CNTL_MODE_SELF_TEST, > + AK8975_REG_CNTL_MODE_FUSE_ROM}, > + .data_regs = { > + AK8975_REG_HXL, > + AK8975_REG_HYL, > + AK8975_REG_HZL}, > +}, > +{ > + .type = AK8963, > + .raw_to_gauss = ak8963_raw_to_gauss, > + .range = 8190, > + .ctrl_regs = { > + AK8975_REG_ST1, > + AK8975_REG_ST2, > + AK8975_REG_CNTL, > + AK8975_REG_ASAX, > + AK8975_MAX_REGS}, > + .ctrl_masks = { > + AK8975_REG_ST1_DRDY_MASK, > + AK8975_REG_ST2_HOFL_MASK, > + 0, > + AK8975_REG_CNTL_MODE_MASK}, > + .ctrl_modes = { > + AK8975_REG_CNTL_MODE_POWER_DOWN, > + AK8975_REG_CNTL_MODE_ONCE, > + AK8975_REG_CNTL_MODE_SELF_TEST, > + AK8975_REG_CNTL_MODE_FUSE_ROM}, > + .data_regs = { > + AK8975_REG_HXL, > + AK8975_REG_HYL, > + AK8975_REG_HZL}, > +}, > }; > > /* > @@ -100,40 +240,36 @@ enum asahi_compass_chipset { > */ > struct ak8975_data { > struct i2c_client *client; > + struct ak_def *def; > struct attribute_group attrs; > struct mutex lock; > u8 asa[3]; > long raw_to_gauss[3]; > - u8 reg_cache[AK8975_MAX_REGS]; > int eoc_gpio; > int eoc_irq; > wait_queue_head_t data_ready_queue; > unsigned long flags; > - enum asahi_compass_chipset chipset; > -}; > - > -static const int ak8975_index_to_reg[] = { > - AK8975_REG_HXL, AK8975_REG_HYL, AK8975_REG_HZL, > + u8 cntl_cache; > }; > > /* > - * Helper function to write to the I2C device's registers. > + * Helper function to write to CNTL register. > */ > -static int ak8975_write_data(struct i2c_client *client, > - u8 reg, u8 val, u8 mask, u8 shift) > +static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode) > { > - struct iio_dev *indio_dev = i2c_get_clientdata(client); > - struct ak8975_data *data = iio_priv(indio_dev); > u8 regval; > int ret; > > - regval = (data->reg_cache[reg] & ~mask) | (val << shift); > - ret = i2c_smbus_write_byte_data(client, reg, regval); > + regval = (data->cntl_cache & ~data->def->ctrl_masks[CNTL_MODE]) | > + data->def->ctrl_modes[mode]; > + ret = i2c_smbus_write_byte_data( > + data->client, data->def->ctrl_regs[CNTL], regval); > if (ret < 0) { > - dev_err(&client->dev, "Write to device fails status %x\n", ret); > return ret; > } > - data->reg_cache[reg] = regval; > + data->cntl_cache = regval; > + /* After mode change wait atleast 100us */ > + usleep_range(100, 500); > > return 0; > } > @@ -207,18 +343,15 @@ static int ak8975_setup(struct i2c_client *client) > } > > /* Write the fused rom access mode. */ > - ret = ak8975_write_data(client, > - AK8975_REG_CNTL, > - AK8975_REG_CNTL_MODE_FUSE_ROM, > - AK8975_REG_CNTL_MODE_MASK, > - AK8975_REG_CNTL_MODE_SHIFT); > + ret = ak8975_set_mode(data, FUSE_ROM); > if (ret < 0) { > dev_err(&client->dev, "Error in setting fuse access mode\n"); > return ret; > } > > /* Get asa data and store in the device data. */ > - ret = i2c_smbus_read_i2c_block_data(client, AK8975_REG_ASAX, > + ret = i2c_smbus_read_i2c_block_data(client, > + data->def->ctrl_regs[ASA_BASE], > 3, data->asa); > if (ret < 0) { > dev_err(&client->dev, "Not able to read asa data\n"); > @@ -226,11 +359,7 @@ static int ak8975_setup(struct i2c_client *client) > } > > /* After reading fuse ROM data set power-down mode */ > - ret = ak8975_write_data(client, > - AK8975_REG_CNTL, > - AK8975_REG_CNTL_MODE_POWER_DOWN, > - AK8975_REG_CNTL_MODE_MASK, > - AK8975_REG_CNTL_MODE_SHIFT); > + ret = ak8975_set_mode(data, POWER_DOWN); > if (ret < 0) { > dev_err(&client->dev, "Error in setting power-down mode\n"); > return ret; > @@ -245,56 +374,9 @@ static int ak8975_setup(struct i2c_client *client) > } > } > > -/* > - * Precalculate scale factor (in Gauss units) for each axis and > - * store in the device data. > - * > - * This scale factor is axis-dependent, and is derived from 3 calibration > - * factors ASA(x), ASA(y), and ASA(z). > - * > - * These ASA values are read from the sensor device at start of day, and > - * cached in the device context struct. > - * > - * Adjusting the flux value with the sensitivity adjustment value should be > - * done via the following formula: > - * > - * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 ) > - * > - * where H is the raw value, ASA is the sensitivity adjustment, and Hadj > - * is the resultant adjusted value. > - * > - * We reduce the formula to: > - * > - * Hadj = H * (ASA + 128) / 256 > - * > - * H is in the range of -4096 to 4095. The magnetometer has a range of > - * +-1229uT. To go from the raw value to uT is: > - * > - * HuT = H * 1229/4096, or roughly, 3/10. > - * > - * Since 1uT = 0.01 gauss, our final scale factor becomes: > - * > - * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100 > - * Hadj = H * ((ASA + 128) * 0.003) / 256 > - * > - * Since ASA doesn't change, we cache the resultant scale factor into the > - * device context in ak8975_setup(). > - */ > - if (data->chipset == AK8963) { > - /* > - * H range is +-8190 and magnetometer range is +-4912. > - * So HuT using the above explanation for 8975, > - * 4912/8190 = ~ 6/10. > - * So the Hadj should use 6/10 instead of 3/10. > - */ > - data->raw_to_gauss[0] = RAW_TO_GAUSS_8963(data->asa[0]); > - data->raw_to_gauss[1] = RAW_TO_GAUSS_8963(data->asa[1]); > - data->raw_to_gauss[2] = RAW_TO_GAUSS_8963(data->asa[2]); > - } else { > - data->raw_to_gauss[0] = RAW_TO_GAUSS_8975(data->asa[0]); > - data->raw_to_gauss[1] = RAW_TO_GAUSS_8975(data->asa[1]); > - data->raw_to_gauss[2] = RAW_TO_GAUSS_8975(data->asa[2]); > - } > + data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]); > + data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]); > + data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]); > > return 0; > } > @@ -317,7 +399,7 @@ static int wait_conversion_complete_gpio(struct ak8975_data *data) > return -EINVAL; > } > > - ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1); > + ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]); > if (ret < 0) > dev_err(&client->dev, "Error in reading ST1\n"); > > @@ -334,7 +416,8 @@ static int wait_conversion_complete_polled(struct ak8975_data *data) > /* Wait for the conversion to complete. */ > while (timeout_ms) { > msleep(AK8975_CONVERSION_DONE_POLL_TIME); > - ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST1); > + ret = i2c_smbus_read_byte_data( > + client, data->def->ctrl_regs[ST1]); > if (ret < 0) { > dev_err(&client->dev, "Error in reading ST1\n"); > return ret; > @@ -377,11 +460,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) > mutex_lock(&data->lock); > > /* Set up the device for taking a sample. */ > - ret = ak8975_write_data(client, > - AK8975_REG_CNTL, > - AK8975_REG_CNTL_MODE_ONCE, > - AK8975_REG_CNTL_MODE_MASK, > - AK8975_REG_CNTL_MODE_SHIFT); > + ret = ak8975_set_mode(data, MODE_ONCE); > if (ret < 0) { > dev_err(&client->dev, "Error in setting operating mode\n"); > goto exit; > @@ -398,14 +477,15 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) > goto exit; > > /* This will be executed only for non-interrupt based waiting case */ > - if (ret & AK8975_REG_ST1_DRDY_MASK) { > - ret = i2c_smbus_read_byte_data(client, AK8975_REG_ST2); > + if (ret & data->def->ctrl_masks[ST1_DRDY]) { > + ret = i2c_smbus_read_byte_data( > + client, data->def->ctrl_regs[ST2]); > if (ret < 0) { > dev_err(&client->dev, "Error in reading ST2\n"); > goto exit; > } > - if (ret & (AK8975_REG_ST2_DERR_MASK | > - AK8975_REG_ST2_HOFL_MASK)) { > + if (ret & (data->def->ctrl_masks[ST2_DERR] | > + data->def->ctrl_masks[ST2_HOFL])) { > dev_err(&client->dev, "ST2 status error 0x%x\n", ret); > ret = -EINVAL; > goto exit; > @@ -414,7 +494,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) > > /* Read the flux value from the appropriate register > (the register is specified in the iio device attributes). */ > - ret = i2c_smbus_read_word_data(client, ak8975_index_to_reg[index]); > + ret = i2c_smbus_read_word_data(client, data->def->data_regs[index]); > if (ret < 0) { > dev_err(&client->dev, "Read axis data fails\n"); > goto exit; > @@ -423,7 +503,7 @@ static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val) > mutex_unlock(&data->lock); > > /* Clamp to valid range. */ > - *val = clamp_t(s16, ret, -4096, 4095); > + *val = clamp_t(s16, ret, -data->def->range, data->def->range); > return IIO_VAL_INT; > > exit: > @@ -497,6 +577,7 @@ static int ak8975_probe(struct i2c_client *client, > int eoc_gpio; > int err; > const char *name = NULL; > + enum asahi_compass_chipset chipset; > > /* Grab and set up the supplied GPIO. */ > if (client->dev.platform_data) > @@ -536,14 +617,20 @@ static int ak8975_probe(struct i2c_client *client, > > /* id will be NULL when enumerated via ACPI */ > if (id) { > - data->chipset = > - (enum asahi_compass_chipset)(id->driver_data); > + chipset = (enum asahi_compass_chipset)(id->driver_data); > name = id->name; > } else if (ACPI_HANDLE(&client->dev)) > - name = ak8975_match_acpi_device(&client->dev, &data->chipset); > + name = ak8975_match_acpi_device(&client->dev, &chipset); > else > return -ENOSYS; > > + if (chipset >= AK_MAX_TYPE) { > + dev_err(&client->dev, "AKM device type unsupported: %d\n", > + chipset); > + return -ENODEV; > + } > + > + data->def = &ak_def_array[chipset]; > dev_dbg(&client->dev, "Asahi compass chip %s\n", name); > > /* Perform some basic start-of-day setup of the device. */ > @@ -574,7 +661,9 @@ MODULE_DEVICE_TABLE(i2c, ak8975_id); > static const struct of_device_id ak8975_of_match[] = { > { .compatible = "asahi-kasei,ak8975", }, > { .compatible = "ak8975", }, > - { } > + { .compatible = "asahi-kasei,ak8963", }, > + { .compatible = "ak8963", }, > + {} > }; > MODULE_DEVICE_TABLE(of, ak8975_of_match); >