Re: [PATCH v8 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver

From: Jonathan Cameron
Date: Thu Aug 15 2013 - 04:32:06 EST

On 08/15/13 06:45, Oleksandr Kozaruk wrote:
> Hello Jonathan,
>
> Thank you for the review and valuable comments.
>
> Multiple authors are done by having multiple MODULE_AUTHOR lines rather as
> one long string. See include/linux/module.h. I fixed that up and
> dealt with some trivial fuzz in the makefile/Kconfig.
>
>
> You might want to take advantage of devm_iio_allocate_device
> which has been introduced in the meantime and greatly simplifies error
> paths in IIO probe functions.
>
>
> Should I make new version of the patch, or just prepare a new patch that patches the patch?
I've applied the current one with the MODULE_AUTHOR line broken up. If you want to
do the devm_ patch then that will want to be as an additional patch on top of the togreg
branch of

git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git



>
> Regards,
> Sasha.
>
>
>
> Anyhow, applied to the togreg branch of iio.git
>
> Note I haven't taken the device tree patch. For that I would need and ack
> from the relevant maintainer(s). Personally I'd rather not touch device tree
> files unless i have to due to the high chance of merge conflicts occuring.
> I would expect the subarch maintainer to pick that one up (or to ask me
> to ;)
>
> Nice relatively clean driver for a somewhat 'interesting' bit of hardware.
>
> Thanks
>
> Jonathan
>
> > ---
> > drivers/iio/adc/Kconfig | 14 +
> > drivers/iio/adc/Makefile | 1 +
> > drivers/iio/adc/twl6030-gpadc.c | 1027 +++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 1042 insertions(+)
> > create mode 100644 drivers/iio/adc/twl6030-gpadc.c
> >
> > diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> > index 93129ec..f8f9f18 100644
> > --- a/drivers/iio/adc/Kconfig
> > +++ b/drivers/iio/adc/Kconfig
> > @@ -160,6 +160,20 @@ config TI_AM335X_ADC
> > Say yes here to build support for Texas Instruments ADC
> > driver which is also a MFD client.
> >
> > +config TWL6030_GPADC
> > + tristate "TWL6030 GPADC (General Purpose A/D Converter) Support"
> > + depends on TWL4030_CORE
> > + default n
> > + help
> > + Say yes here if you want support for the TWL6030/TWL6032 General
> > + Purpose A/D Converter. This will add support for battery type
> > + detection, battery voltage and temperature measurement, die
> > + temperature measurement, system supply voltage, audio accessory,
> > + USB ID detection.
> > +
> > + This driver can also be built as a module. If so, the module will be
> > + called twl6030-gpadc.
> > +
> > config VIPERBOARD_ADC
> > tristate "Viperboard ADC support"
> > depends on MFD_VIPERBOARD && USB
> > diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> > index 8f475d3..db430bd 100644
> > --- a/drivers/iio/adc/Makefile
> > +++ b/drivers/iio/adc/Makefile
> > @@ -17,4 +17,5 @@ obj-$(CONFIG_MAX1363) += max1363.o
> > obj-$(CONFIG_MCP320X) += mcp320x.o
> > obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
> > obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
> > +obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
> > obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
> > diff --git a/drivers/iio/adc/twl6030-gpadc.c b/drivers/iio/adc/twl6030-gpadc.c
> > new file mode 100644
> > index 0000000..2b63083
> > --- /dev/null
> > +++ b/drivers/iio/adc/twl6030-gpadc.c
> > @@ -0,0 +1,1027 @@
> > +/*
> > + * TWL6030 GPADC module driver
> > + *
> > + * Copyright (C) 2009-2013 Texas Instruments Inc.
> > + * Nishant Kamat <nskamat@xxxxxx <mailto:nskamat@xxxxxx>>
> > + * Balaji T K <balajitk@xxxxxx <mailto:balajitk@xxxxxx>>
> > + * Graeme Gregory <gg@xxxxxxxxxxxxxxx <mailto:gg@xxxxxxxxxxxxxxx>>
> > + * Girish S Ghongdemath <girishsg@xxxxxx <mailto:girishsg@xxxxxx>>
> > + * Ambresh K <ambresh@xxxxxx <mailto:ambresh@xxxxxx>>
> > + * Oleksandr Kozaruk <oleksandr.kozaruk@xxxxxx <mailto:oleksandr.kozaruk@xxxxxx>
> > + *
> > + * Based on twl4030-madc.c
> > + * Copyright (C) 2008 Nokia Corporation
> > + * Mikko Ylinen <mikko.k.ylinen@xxxxxxxxx <mailto:mikko.k.ylinen@xxxxxxxxx>>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * version 2 as published by the Free Software Foundation.
> > + *
> > + * This program is distributed in the hope that it will be useful, but
> > + * WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU General Public License
> > + * along with this program; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
> > + * 02110-1301 USA
> > + *
> > + */
> > +#include <linux/init.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/i2c/twl.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +
> > +#define DRIVER_NAME "twl6030_gpadc"
> > +
> > +/*
> > + * twl6030 per TRM has 17 channels, and twl6032 has 19 channels
> > + * 2 test network channels are not used,
> > + * 2 die temperature channels are not used either, as it is not
> > + * defined how to convert ADC value to temperature
> > + */
> > +#define TWL6030_GPADC_USED_CHANNELS 13
> > +#define TWL6030_GPADC_MAX_CHANNELS 15
> > +#define TWL6032_GPADC_USED_CHANNELS 15
> > +#define TWL6032_GPADC_MAX_CHANNELS 19
> > +#define TWL6030_GPADC_NUM_TRIM_REGS 16
> > +
> > +#define TWL6030_GPADC_CTRL_P1 0x05
> > +
> > +#define TWL6032_GPADC_GPSELECT_ISB 0x07
> > +#define TWL6032_GPADC_CTRL_P1 0x08
> > +
> > +#define TWL6032_GPADC_GPCH0_LSB 0x0d
> > +#define TWL6032_GPADC_GPCH0_MSB 0x0e
> > +
> > +#define TWL6030_GPADC_CTRL_P1_SP1 BIT(3)
> > +
> > +#define TWL6030_GPADC_GPCH0_LSB (0x29)
> > +
> > +#define TWL6030_GPADC_RT_SW1_EOC_MASK BIT(5)
> > +
> > +#define TWL6030_GPADC_TRIM1 0xCD
> > +
> > +#define TWL6030_REG_TOGGLE1 0x90
> > +#define TWL6030_GPADCS BIT(1)
> > +#define TWL6030_GPADCR BIT(0)
> > +
> > +/**
> > + * struct twl6030_chnl_calib - channel calibration
> > + * @gain: slope coefficient for ideal curve
> > + * @gain_error: gain error
> > + * @offset_error: offset of the real curve
> > + */
> > +struct twl6030_chnl_calib {
> > + s32 gain;
> > + s32 gain_error;
> > + s32 offset_error;
> > +};
> > +
> > +/**
> > + * struct twl6030_ideal_code - GPADC calibration parameters
> > + * GPADC is calibrated in two points: close to the beginning and
> > + * to the and of the measurable input range
> > + *
> > + * @channel: channel number
> > + * @code1: ideal code for the input at the beginning
> > + * @code2: ideal code for at the end of the range
> > + * @volt1: voltage input at the beginning(low voltage)
> > + * @volt2: voltage input at the end(high voltage)
> > + */
> > +struct twl6030_ideal_code {
> > + int channel;
> > + u16 code1;
> > + u16 code2;
> > + u16 volt1;
> > + u16 volt2;
> > +};
> > +
> > +struct twl6030_gpadc_data;
> > +
> > +/**
> > + * struct twl6030_gpadc_platform_data - platform specific data
> > + * @nchannels: number of GPADC channels
> > + * @iio_channels: iio channels
> > + * @twl6030_ideal: pointer to calibration parameters
> > + * @start_conversion: pointer to ADC start conversion function
> > + * @channel_to_reg pointer to ADC function to convert channel to
> > + * register address for reading conversion result
> > + * @calibrate: pointer to calibration function
> > + */
> > +struct twl6030_gpadc_platform_data {
> > + const int nchannels;
> > + const struct iio_chan_spec *iio_channels;
> > + const struct twl6030_ideal_code *ideal;
> > + int (*start_conversion)(int channel);
> > + u8 (*channel_to_reg)(int channel);
> > + int (*calibrate)(struct twl6030_gpadc_data *gpadc);
> > +};
> > +
> > +/**
> > + * struct twl6030_gpadc_data - GPADC data
> > + * @dev: device pointer
> > + * @lock: mutual exclusion lock for the structure
> > + * @irq_complete: completion to signal end of conversion
> > + * @twl6030_cal_tbl: pointer to calibration data for each
> > + * channel with gain error and offset
> > + * @pdata: pointer to device specific data
> > + */
> > +struct twl6030_gpadc_data {
> > + struct device *dev;
> > + struct mutex lock;
> > + struct completion irq_complete;
> > + struct twl6030_chnl_calib *twl6030_cal_tbl;
> > + const struct twl6030_gpadc_platform_data *pdata;
> > +};
> > +
> > +/*
> > + * channels 11, 12, 13, 15 and 16 have no calibration data
> > + * calibration offset is same for channels 1, 3, 4, 5
> > + *
> > + * The data is taken from GPADC_TRIM registers description.
> > + * GPADC_TRIM registers keep difference between the code measured
> > + * at volt1 and volt2 input voltages and corresponding code1 and code2
> > + */
> > +static const struct twl6030_ideal_code
> > + twl6030_ideal[TWL6030_GPADC_USED_CHANNELS] = {
> > + [0] = { /* ch 0, external, battery type, resistor value */
> > + .channel = 0,
> > + .code1 = 116,
> > + .code2 = 745,
> > + .volt1 = 141,
> > + .volt2 = 910,
> > + },
> > + [1] = { /* ch 1, external, battery temperature, NTC resistor value */
> > + .channel = 1,
> > + .code1 = 82,
> > + .code2 = 900,
> > + .volt1 = 100,
> > + .volt2 = 1100,
> > + },
> > + [2] = { /* ch 2, external, audio accessory/general purpose */
> > + .channel = 2,
> > + .code1 = 55,
> > + .code2 = 818,
> > + .volt1 = 101,
> > + .volt2 = 1499,
> > + },
> > + [3] = { /* ch 3, external, general purpose */
> > + .channel = 3,
> > + .code1 = 82,
> > + .code2 = 900,
> > + .volt1 = 100,
> > + .volt2 = 1100,
> > + },
> > + [4] = { /* ch 4, external, temperature measurement/general purpose */
> > + .channel = 4,
> > + .code1 = 82,
> > + .code2 = 900,
> > + .volt1 = 100,
> > + .volt2 = 1100,
> > + },
> > + [5] = { /* ch 5, external, general purpose */
> > + .channel = 5,
> > + .code1 = 82,
> > + .code2 = 900,
> > + .volt1 = 100,
> > + .volt2 = 1100,
> > + },
> > + [6] = { /* ch 6, external, general purpose */
> > + .channel = 6,
> > + .code1 = 82,
> > + .code2 = 900,
> > + .volt1 = 100,
> > + .volt2 = 1100,
> > + },
> > + [7] = { /* ch 7, internal, main battery */
> > + .channel = 7,
> > + .code1 = 614,
> > + .code2 = 941,
> > + .volt1 = 3001,
> > + .volt2 = 4599,
> > + },
> > + [8] = { /* ch 8, internal, backup battery */
> > + .channel = 8,
> > + .code1 = 82,
> > + .code2 = 688,
> > + .volt1 = 501,
> > + .volt2 = 4203,
> > + },
> > + [9] = { /* ch 9, internal, external charger input */
> > + .channel = 9,
> > + .code1 = 182,
> > + .code2 = 818,
> > + .volt1 = 2001,
> > + .volt2 = 8996,
> > + },
> > + [10] = { /* ch 10, internal, VBUS */
> > + .channel = 10,
> > + .code1 = 149,
> > + .code2 = 818,
> > + .volt1 = 1001,
> > + .volt2 = 5497,
> > + },
> > + [11] = { /* ch 11, internal, VBUS charging current */
> > + .channel = 11,
> > + },
> > + /* ch 12, internal, Die temperature */
> > + /* ch 13, internal, Die temperature */
> > + [12] = { /* ch 14, internal, USB ID line */
> > + .channel = 14,
> > + .code1 = 48,
> > + .code2 = 714,
> > + .volt1 = 323,
> > + .volt2 = 4800,
> > + },
> > +};
> > +
> > +static const struct twl6030_ideal_code
> > + twl6032_ideal[TWL6032_GPADC_USED_CHANNELS] = {
> > + [0] = { /* ch 0, external, battery type, resistor value */
> > + .channel = 0,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 440,
> > + .volt2 = 1000,
> > + },
> > + [1] = { /* ch 1, external, battery temperature, NTC resistor value */
> > + .channel = 1,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 440,
> > + .volt2 = 1000,
> > + },
> > + [2] = { /* ch 2, external, audio accessory/general purpose */
> > + .channel = 2,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 660,
> > + .volt2 = 1500,
> > + },
> > + [3] = { /* ch 3, external, temperature with external diode/general
> > + purpose */
> > + .channel = 3,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 440,
> > + .volt2 = 1000,
> > + },
> > + [4] = { /* ch 4, external, temperature measurement/general purpose */
> > + .channel = 4,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 440,
> > + .volt2 = 1000,
> > + },
> > + [5] = { /* ch 5, external, general purpose */
> > + .channel = 5,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 440,
> > + .volt2 = 1000,
> > + },
> > + [6] = { /* ch 6, external, general purpose */
> > + .channel = 6,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 440,
> > + .volt2 = 1000,
> > + },
> > + [7] = { /* ch7, internal, system supply */
> > + .channel = 7,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 2200,
> > + .volt2 = 5000,
> > + },
> > + [8] = { /* ch8, internal, backup battery */
> > + .channel = 8,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 2200,
> > + .volt2 = 5000,
> > + },
> > + [9] = { /* ch 9, internal, external charger input */
> > + .channel = 9,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 3960,
> > + .volt2 = 9000,
> > + },
> > + [10] = { /* ch10, internal, VBUS */
> > + .channel = 10,
> > + .code1 = 150,
> > + .code2 = 751,
> > + .volt1 = 1000,
> > + .volt2 = 5000,
> > + },
> > + [11] = { /* ch 11, internal, VBUS DC-DC output current */
> > + .channel = 11,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 660,
> > + .volt2 = 1500,
> > + },
> > + /* ch 12, internal, Die temperature */
> > + /* ch 13, internal, Die temperature */
> > + [12] = { /* ch 14, internal, USB ID line */
> > + .channel = 14,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 2420,
> > + .volt2 = 5500,
> > + },
> > + /* ch 15, internal, test network */
> > + /* ch 16, internal, test network */
> > + [13] = { /* ch 17, internal, battery charging current */
> > + .channel = 17,
> > + },
> > + [14] = { /* ch 18, internal, battery voltage */
> > + .channel = 18,
> > + .code1 = 1441,
> > + .code2 = 3276,
> > + .volt1 = 2200,
> > + .volt2 = 5000,
> > + },
> > +};
> > +
> > +static inline int twl6030_gpadc_write(u8 reg, u8 val)
> > +{
> > + return twl_i2c_write_u8(TWL6030_MODULE_GPADC, val, reg);
> > +}
> > +
> > +static inline int twl6030_gpadc_read(u8 reg, u8 *val)
> > +{
> > +
> > + return twl_i2c_read(TWL6030_MODULE_GPADC, val, reg, 2);
> > +}
> > +
> > +static int twl6030_gpadc_enable_irq(u8 mask)
> > +{
> > + int ret;
> > +
> > + ret = twl6030_interrupt_unmask(mask, REG_INT_MSK_LINE_B);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = twl6030_interrupt_unmask(mask, REG_INT_MSK_STS_B);
> > +
> > + return ret;
> > +}
> > +
> > +static void twl6030_gpadc_disable_irq(u8 mask)
> > +{
> > + twl6030_interrupt_mask(mask, REG_INT_MSK_LINE_B);
> > + twl6030_interrupt_mask(mask, REG_INT_MSK_STS_B);
> > +}
> > +
> > +static irqreturn_t twl6030_gpadc_irq_handler(int irq, void *indio_dev)
> > +{
> > + struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
> > +
> > + complete(&gpadc->irq_complete);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static int twl6030_start_conversion(int channel)
> > +{
> > + return twl6030_gpadc_write(TWL6030_GPADC_CTRL_P1,
> > + TWL6030_GPADC_CTRL_P1_SP1);
> > +}
> > +
> > +static int twl6032_start_conversion(int channel)
> > +{
> > + int ret;
> > +
> > + ret = twl6030_gpadc_write(TWL6032_GPADC_GPSELECT_ISB, channel);
> > + if (ret)
> > + return ret;
> > +
> > + return twl6030_gpadc_write(TWL6032_GPADC_CTRL_P1,
> > + TWL6030_GPADC_CTRL_P1_SP1);
> > +}
> > +
> > +static u8 twl6030_channel_to_reg(int channel)
> > +{
> > + return TWL6030_GPADC_GPCH0_LSB + 2 * channel;
> > +}
> > +
> > +static u8 twl6032_channel_to_reg(int channel)
> > +{
> > + /*
> > + * for any prior chosen channel, when the conversion is ready
> > + * the result is avalable in GPCH0_LSB, GPCH0_MSB.
> > + */
> > +
> > + return TWL6032_GPADC_GPCH0_LSB;
> > +}
> > +
> > +static int twl6030_gpadc_lookup(const struct twl6030_ideal_code *ideal,
> > + int channel, int size)
> > +{
> > + int i;
> > +
> > + for (i = 0; i < size; i++)
> > + if (ideal[i].channel == channel)
> > + break;
> > +
> > + return i;
> > +}
> > +
> > +static int twl6030_channel_calibrated(const struct twl6030_gpadc_platform_data
> > + *pdata, int channel)
> > +{
> > + const struct twl6030_ideal_code *ideal = pdata->ideal;
> > + int i;
> > +
> > + i = twl6030_gpadc_lookup(ideal, channel, pdata->nchannels);
> > + /* not calibrated channels have 0 in all structure members */
> > + return pdata->ideal[i].code2;
> > +}
> > +
> > +static int twl6030_gpadc_make_correction(struct twl6030_gpadc_data *gpadc,
> > + int channel, int raw_code)
> > +{
> > + const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
> > + int corrected_code;
> > + int i;
> > +
> > + i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
> > + corrected_code = ((raw_code * 1000) -
> > + gpadc->twl6030_cal_tbl[i].offset_error) /
> > + gpadc->twl6030_cal_tbl[i].gain_error;
> > +
> > + return corrected_code;
> > +}
> > +
> > +static int twl6030_gpadc_get_raw(struct twl6030_gpadc_data *gpadc,
> > + int channel, int *res)
> > +{
> > + u8 reg = gpadc->pdata->channel_to_reg(channel);
> > + __le16 val;
> > + int raw_code;
> > + int ret;
> > +
> > + ret = twl6030_gpadc_read(reg, (u8 *)&val);
> > + if (ret) {
> > + dev_dbg(gpadc->dev, "unable to read register 0x%X\n", reg);
> > + return ret;
> > + }
> > +
> > + raw_code = le16_to_cpu(val);
> > + dev_dbg(gpadc->dev, "GPADC raw code: %d", raw_code);
> > +
> > + if (twl6030_channel_calibrated(gpadc->pdata, channel))
> > + *res = twl6030_gpadc_make_correction(gpadc, channel, raw_code);
> > + else
> > + *res = raw_code;
> > +
> > + return ret;
> > +}
> > +
> > +static int twl6030_gpadc_get_processed(struct twl6030_gpadc_data *gpadc,
> > + int channel, int *val)
> > +{
> > + const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
> > + int corrected_code;
> > + int channel_value;
> > + int i;
> > + int ret;
> > +
> > + ret = twl6030_gpadc_get_raw(gpadc, channel, &corrected_code);
> > + if (ret)
> > + return ret;
> > +
> > + i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
> > + channel_value = corrected_code *
> > + gpadc->twl6030_cal_tbl[i].gain;
> > +
> > + /* Shift back into mV range */
> > + channel_value /= 1000;
> > +
> > + dev_dbg(gpadc->dev, "GPADC corrected code: %d", corrected_code);
> > + dev_dbg(gpadc->dev, "GPADC value: %d", channel_value);
> > +
> > + *val = channel_value;
> > +
> > + return ret;
> > +}
> > +
> > +static int twl6030_gpadc_read_raw(struct iio_dev *indio_dev,
> > + const struct iio_chan_spec *chan,
> > + int *val, int *val2, long mask)
> > +{
> > + struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
> > + int ret;
> > + long timeout;
> > +
> > + mutex_lock(&gpadc->lock);
> > +
> > + ret = gpadc->pdata->start_conversion(chan->channel);
> > + if (ret) {
> > + dev_err(gpadc->dev, "failed to start conversion\n");
> > + goto err;
> > + }
> > + /* wait for conversion to complete */
> > + timeout = wait_for_completion_interruptible_timeout(
> > + &gpadc->irq_complete, msecs_to_jiffies(5000));
> > + if (timeout == 0) {
> > + ret = -ETIMEDOUT;
> > + goto err;
> > + } else if (timeout < 0) {
> > + goto err;
> > + ret = -EINTR;
> > + }
> > +
> > + switch (mask) {
> > + case IIO_CHAN_INFO_RAW:
> > + ret = twl6030_gpadc_get_raw(gpadc, chan->channel, val);
> > + ret = ret ? -EIO : IIO_VAL_INT;
> > + break;
> > +
> > + case IIO_CHAN_INFO_PROCESSED:
> > + ret = twl6030_gpadc_get_processed(gpadc, chan->channel, val);
> > + ret = ret ? -EIO : IIO_VAL_INT;
> > + break;
> > +
> > + default:
> > + break;
> > + }
> > +err:
> > + mutex_unlock(&gpadc->lock);
> > +
> > + return ret;
> > +}
> > +
> > +/*
> > + * The GPADC channels are calibrated using a two point calibration method.
> > + * The channels measured with two known values: volt1 and volt2, and
> > + * ideal corresponding output codes are known: code1, code2.
> > + * The difference(d1, d2) between ideal and measured codes stored in trim
> > + * registers.
> > + * The goal is to find offset and gain of the real curve for each calibrated
> > + * channel.
> > + * gain: k = 1 + ((d2 - d1) / (x2 - x1))
> > + * offset: b = d1 + (k - 1) * x1
> > + */
> > +static void twl6030_calibrate_channel(struct twl6030_gpadc_data *gpadc,
> > + int channel, int d1, int d2)
> > +{
> > + int b, k, gain, x1, x2, i;
> > + const struct twl6030_ideal_code *ideal = gpadc->pdata->ideal;
> > +
> > + i = twl6030_gpadc_lookup(ideal, channel, gpadc->pdata->nchannels);
> > +
> > + /* Gain */
> > + gain = ((ideal[i].volt2 - ideal[i].volt1) * 1000) /
> > + (ideal[i].code2 - ideal[i].code1);
> > +
> > + x1 = ideal[i].code1;
> > + x2 = ideal[i].code2;
> > +
> > + /* k - real curve gain */
> > + k = 1000 + (((d2 - d1) * 1000) / (x2 - x1));
> > +
> > + /* b - offset of the real curve gain */
> > + b = (d1 * 1000) - (k - 1000) * x1;
> > +
> > + gpadc->twl6030_cal_tbl[i].gain = gain;
> > + gpadc->twl6030_cal_tbl[i].gain_error = k;
> > + gpadc->twl6030_cal_tbl[i].offset_error = b;
> > +
> > + dev_dbg(gpadc->dev, "GPADC d1 for Chn: %d = %d\n", channel, d1);
> > + dev_dbg(gpadc->dev, "GPADC d2 for Chn: %d = %d\n", channel, d2);
> > + dev_dbg(gpadc->dev, "GPADC x1 for Chn: %d = %d\n", channel, x1);
> > + dev_dbg(gpadc->dev, "GPADC x2 for Chn: %d = %d\n", channel, x2);
> > + dev_dbg(gpadc->dev, "GPADC Gain for Chn: %d = %d\n", channel, gain);
> > + dev_dbg(gpadc->dev, "GPADC k for Chn: %d = %d\n", channel, k);
> > + dev_dbg(gpadc->dev, "GPADC b for Chn: %d = %d\n", channel, b);
> > +}
> > +
> > +static inline int twl6030_gpadc_get_trim_offset(s8 d)
> > +{
> > + /*
> > + * XXX NOTE!
> > + * bit 0 - sign, bit 7 - reserved, 6..1 - trim value
> > + * though, the documentation states that trim value
> > + * is absolute value, the correct conversion results are
> > + * obtained if the value is interpreted as 2's complement.
> > + */
> > + __u32 temp = ((d & 0x7f) >> 1) | ((d & 1) << 6);
> > +
> > + return sign_extend32(temp, 6);
> > +}
> > +
> > +static int twl6030_calibration(struct twl6030_gpadc_data *gpadc)
> > +{
> > + int ret;
> > + int chn;
> > + u8 trim_regs[TWL6030_GPADC_NUM_TRIM_REGS];
> > + s8 d1, d2;
> > +
> > + /*
> > + * for calibration two measurements have been performed at
> > + * factory, for some channels, during the production test and
> > + * have been stored in registers. This two stored values are
> > + * used to correct the measurements. The values represent
> > + * offsets for the given input from the output on ideal curve.
> > + */
> > + ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs,
> > + TWL6030_GPADC_TRIM1, TWL6030_GPADC_NUM_TRIM_REGS);
> > + if (ret < 0) {
> > + dev_err(gpadc->dev, "calibration failed\n");
> > + return ret;
> > + }
> > +
> > + for (chn = 0; chn < TWL6030_GPADC_MAX_CHANNELS; chn++) {
> > +
> > + switch (chn) {
> > + case 0:
> > + d1 = trim_regs[0];
> > + d2 = trim_regs[1];
> > + break;
> > + case 1:
> > + case 3:
> > + case 4:
> > + case 5:
> > + case 6:
> > + d1 = trim_regs[4];
> > + d2 = trim_regs[5];
> > + break;
> > + case 2:
> > + d1 = trim_regs[12];
> > + d2 = trim_regs[13];
> > + break;
> > + case 7:
> > + d1 = trim_regs[6];
> > + d2 = trim_regs[7];
> > + break;
> > + case 8:
> > + d1 = trim_regs[2];
> > + d2 = trim_regs[3];
> > + break;
> > + case 9:
> > + d1 = trim_regs[8];
> > + d2 = trim_regs[9];
> > + break;
> > + case 10:
> > + d1 = trim_regs[10];
> > + d2 = trim_regs[11];
> > + break;
> > + case 14:
> > + d1 = trim_regs[14];
> > + d2 = trim_regs[15];
> > + break;
> > + default:
> > + continue;
> > + }
> > +
> > + d1 = twl6030_gpadc_get_trim_offset(d1);
> > + d2 = twl6030_gpadc_get_trim_offset(d2);
> > +
> > + twl6030_calibrate_channel(gpadc, chn, d1, d2);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int twl6032_get_trim_value(u8 *trim_regs, unsigned int reg0,
> > + unsigned int reg1, unsigned int mask0, unsigned int mask1,
> > + unsigned int shift0)
> > +{
> > + int val;
> > +
> > + val = (trim_regs[reg0] & mask0) << shift0;
> > + val |= (trim_regs[reg1] & mask1) >> 1;
> > + if (trim_regs[reg1] & 0x01)
> > + val = -val;
> > +
> > + return val;
> > +}
> > +
> > +static int twl6032_calibration(struct twl6030_gpadc_data *gpadc)
> > +{
> > + int chn, d1 = 0, d2 = 0, temp;
> > + u8 trim_regs[TWL6030_GPADC_NUM_TRIM_REGS];
> > + int ret;
> > +
> > + ret = twl_i2c_read(TWL6030_MODULE_ID2, trim_regs,
> > + TWL6030_GPADC_TRIM1, TWL6030_GPADC_NUM_TRIM_REGS);
> > + if (ret < 0) {
> > + dev_err(gpadc->dev, "calibration failed\n");
> > + return ret;
> > + }
> > +
> > + /*
> > + * Loop to calculate the value needed for returning voltages from
> > + * GPADC not values.
> > + *
> > + * gain is calculated to 3 decimal places fixed point.
> > + */
> > + for (chn = 0; chn < TWL6032_GPADC_MAX_CHANNELS; chn++) {
> > +
> > + switch (chn) {
> > + case 0:
> > + case 1:
> > + case 2:
> > + case 3:
> > + case 4:
> > + case 5:
> > + case 6:
> > + case 11:
> > + case 14:
> > + d1 = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
> > + 0x06, 2);
> > + d2 = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
> > + 0x06, 2);
> > + break;
> > + case 8:
> > + temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
> > + 0x06, 2);
> > + d1 = temp + twl6032_get_trim_value(trim_regs, 7, 6,
> > + 0x18, 0x1E, 1);
> > +
> > + temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3F,
> > + 0x06, 2);
> > + d2 = temp + twl6032_get_trim_value(trim_regs, 9, 7,
> > + 0x1F, 0x06, 2);
> > + break;
> > + case 9:
> > + temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
> > + 0x06, 2);
> > + d1 = temp + twl6032_get_trim_value(trim_regs, 13, 11,
> > + 0x18, 0x1E, 1);
> > +
> > + temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
> > + 0x06, 2);
> > + d2 = temp + twl6032_get_trim_value(trim_regs, 15, 13,
> > + 0x1F, 0x06, 1);
> > + break;
> > + case 10:
> > + d1 = twl6032_get_trim_value(trim_regs, 10, 8, 0x0f,
> > + 0x0E, 3);
> > + d2 = twl6032_get_trim_value(trim_regs, 14, 12, 0x0f,
> > + 0x0E, 3);
> > + break;
> > + case 7:
> > + case 18:
> > + temp = twl6032_get_trim_value(trim_regs, 2, 0, 0x1f,
> > + 0x06, 2);
> > +
> > + d1 = (trim_regs[4] & 0x7E) >> 1;
> > + if (trim_regs[4] & 0x01)
> > + d1 = -d1;
> > + d1 += temp;
> > +
> > + temp = twl6032_get_trim_value(trim_regs, 3, 1, 0x3f,
> > + 0x06, 2);
> > +
> > + d2 = (trim_regs[5] & 0xFE) >> 1;
> > + if (trim_regs[5] & 0x01)
> > + d2 = -d2;
> > +
> > + d2 += temp;
> > + break;
> > + default:
> > + /* No data for other channels */
> > + continue;
> > + }
> > +
> > + twl6030_calibrate_channel(gpadc, chn, d1, d2);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +#define TWL6030_GPADC_CHAN(chn, _type, chan_info) { \
> > + .type = _type, \
> > + .channel = chn, \
> > + .info_mask_separate = BIT(chan_info), \
> > + .indexed = 1, \
> > +}
> > +
> > +static const struct iio_chan_spec twl6030_gpadc_iio_channels[] = {
> > + TWL6030_GPADC_CHAN(0, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(1, IIO_TEMP, IIO_CHAN_INFO_RAW),
> > + TWL6030_GPADC_CHAN(2, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(3, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(4, IIO_TEMP, IIO_CHAN_INFO_RAW),
> > + TWL6030_GPADC_CHAN(5, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(6, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(7, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(8, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(9, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(10, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(11, IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> > + TWL6030_GPADC_CHAN(14, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > +};
> > +
> > +static const struct iio_chan_spec twl6032_gpadc_iio_channels[] = {
> > + TWL6030_GPADC_CHAN(0, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(1, IIO_TEMP, IIO_CHAN_INFO_RAW),
> > + TWL6030_GPADC_CHAN(2, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(3, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(4, IIO_TEMP, IIO_CHAN_INFO_RAW),
> > + TWL6030_GPADC_CHAN(5, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(6, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(7, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(8, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(9, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(10, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(11, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(14, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > + TWL6030_GPADC_CHAN(17, IIO_VOLTAGE, IIO_CHAN_INFO_RAW),
> > + TWL6030_GPADC_CHAN(18, IIO_VOLTAGE, IIO_CHAN_INFO_PROCESSED),
> > +};
> > +
> > +static const struct iio_info twl6030_gpadc_iio_info = {
> > + .read_raw = &twl6030_gpadc_read_raw,
> > + .driver_module = THIS_MODULE,
> > +};
> > +
> > +static const struct twl6030_gpadc_platform_data twl6030_pdata = {
> > + .iio_channels = twl6030_gpadc_iio_channels,
> > + .nchannels = TWL6030_GPADC_USED_CHANNELS,
> > + .ideal = twl6030_ideal,
> > + .start_conversion = twl6030_start_conversion,
> > + .channel_to_reg = twl6030_channel_to_reg,
> > + .calibrate = twl6030_calibration,
> > +};
> > +
> > +static const struct twl6030_gpadc_platform_data twl6032_pdata = {
> > + .iio_channels = twl6032_gpadc_iio_channels,
> > + .nchannels = TWL6032_GPADC_USED_CHANNELS,
> > + .ideal = twl6032_ideal,
> > + .start_conversion = twl6032_start_conversion,
> > + .channel_to_reg = twl6032_channel_to_reg,
> > + .calibrate = twl6032_calibration,
> > +};
> > +
> > +static const struct of_device_id of_twl6030_match_tbl[] = {
> > + {
> > + .compatible = "ti,twl6030-gpadc",
> > + .data = &twl6030_pdata,
> > + },
> > + {
> > + .compatible = "ti,twl6032-gpadc",
> > + .data = &twl6032_pdata,
> > + },
> > + { /* end */ }
> > +};
> > +
> > +static int twl6030_gpadc_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct twl6030_gpadc_data *gpadc;
> > + const struct twl6030_gpadc_platform_data *pdata;
> > + const struct of_device_id *match;
> > + struct iio_dev *indio_dev;
> > + int irq;
> > + int ret;
> > +
> > + match = of_match_device(of_match_ptr(of_twl6030_match_tbl), dev);
> > + if (!match)
> > + return -EINVAL;
> > +
> > + pdata = match->data;
> > +
> > + indio_dev = iio_device_alloc(sizeof(*gpadc));
> > + if (!indio_dev) {
> > + dev_err(dev, "failed allocating iio device\n");
> > + ret = -ENOMEM;
> > + }
> > +
> > + gpadc = iio_priv(indio_dev);
> > +
> > + gpadc->twl6030_cal_tbl = devm_kzalloc(dev,
> > + sizeof(*gpadc->twl6030_cal_tbl) *
> > + pdata->nchannels, GFP_KERNEL);
> > + if (!gpadc->twl6030_cal_tbl)
> > + goto err_free_device;
> > +
> > + gpadc->dev = dev;
> > + gpadc->pdata = pdata;
> > +
> > + platform_set_drvdata(pdev, indio_dev);
> > + mutex_init(&gpadc->lock);
> > + init_completion(&gpadc->irq_complete);
> > +
> > + ret = pdata->calibrate(gpadc);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "failed to read calibration registers\n");
> > + goto err_free_device;
> > + }
> > +
> > + irq = platform_get_irq(pdev, 0);
> > + if (irq < 0) {
> > + dev_err(&pdev->dev, "failed to get irq\n");
> > + goto err_free_device;
> > + }
> > +
> > + ret = request_threaded_irq(irq, NULL, twl6030_gpadc_irq_handler,
> > + IRQF_ONESHOT, "twl6030_gpadc", indio_dev);
> > + if (ret) {
> > + dev_dbg(&pdev->dev, "could not request irq\n");
> > + goto err_free_device;
> > + }
> > +
> > + ret = twl6030_gpadc_enable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "failed to enable GPADC interrupt\n");
> > + goto err_free_irq;
> > + }
> > +
> > + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
> > + TWL6030_REG_TOGGLE1);
> > + if (ret < 0) {
> > + dev_err(&pdev->dev, "failed to enable GPADC module\n");
> > + goto err_free_irq;
> > + }
> > +
> > + indio_dev->name = DRIVER_NAME;
> > + indio_dev->dev.parent = dev;
> > + indio_dev->info = &twl6030_gpadc_iio_info;
> > + indio_dev->modes = INDIO_DIRECT_MODE;
> > + indio_dev->channels = pdata->iio_channels;
> > + indio_dev->num_channels = pdata->nchannels;
> > +
> > + ret = iio_device_register(indio_dev);
> > + if (ret)
> > + goto err_free_irq;
> > +
> > + return ret;
> > +
> > +err_free_irq:
> > + free_irq(irq, indio_dev);
> > +err_free_device:
> > + iio_device_free(indio_dev);
> > +
> > + return ret;
> > +}
> > +
> > +static int twl6030_gpadc_remove(struct platform_device *pdev)
> > +{
> > + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> > +
> > + twl6030_gpadc_disable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
> > + free_irq(platform_get_irq(pdev, 0), indio_dev);
> > + iio_device_unregister(indio_dev);
> > + iio_device_free(indio_dev);
> > +
> > + return 0;
> > +}
> > +
> > +#ifdef CONFIG_PM_SLEEP
> > +static int twl6030_gpadc_suspend(struct device *pdev)
> > +{
> > + int ret;
> > +
> > + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCR,
> > + TWL6030_REG_TOGGLE1);
> > + if (ret)
> > + dev_err(pdev, "error reseting GPADC (%d)!\n", ret);
> > +
> > + return 0;
> > +};
> > +
> > +static int twl6030_gpadc_resume(struct device *pdev)
> > +{
> > + int ret;
> > +
> > + ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
> > + TWL6030_REG_TOGGLE1);
> > + if (ret)
> > + dev_err(pdev, "error setting GPADC (%d)!\n", ret);
> > +
> > + return 0;
> > +};
> > +#endif
> > +
> > +static SIMPLE_DEV_PM_OPS(twl6030_gpadc_pm_ops, twl6030_gpadc_suspend,
> > + twl6030_gpadc_resume);
> > +
> > +static struct platform_driver twl6030_gpadc_driver = {
> > + .probe = twl6030_gpadc_probe,
> > + .remove = twl6030_gpadc_remove,
> > + .driver = {
> > + .name = DRIVER_NAME,
> > + .owner = THIS_MODULE,
> > + .pm = &twl6030_gpadc_pm_ops,
> > + .of_match_table = of_twl6030_match_tbl,
> > + },
> > +};
> > +
> > +module_platform_driver(twl6030_gpadc_driver);
> > +
> > +MODULE_ALIAS("platform: " DRIVER_NAME);
> > +MODULE_AUTHOR("Balaji T K <balajitk@xxxxxx <mailto:balajitk@xxxxxx>>, Graeme Gregory <gg@xxxxxxxxxxxxxxx <mailto:gg@xxxxxxxxxxxxxxx>>,
> Oleksandr Kozaruk <oleksandr.kozaruk@xxxxxx <mailto:oleksandr.kozaruk@xxxxxx>");
> > +MODULE_DESCRIPTION("twl6030 ADC driver");
> > +MODULE_LICENSE("GPL");
> >
> --
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>
>
> --
> Regards,
> Oleksandr Kozaruk | embedded developer
> GlobalLogic
> M +38.067.944.7905
> www.globallogic.com <http://www.globallogic.com/>
> <http://www.globallogic.com/>
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