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Message-ID: <520BFFFF.7040904@kernel.org>
Date: Wed, 14 Aug 2013 23:09:03 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Oleksandr Kozaruk <oleksandr.kozaruk@...com>
CC: tony@...mide.com, benoit.cousson@...aro.org, rnayak@...com,
peter.ujfalusi@...com, kishon@...com, jic23@....ac.uk,
grant.likely@...aro.org, rob.herring@...xeda.com, lars@...afoo.de,
sameo@...ux.intel.com, ch.naveen@...sung.com, poeschel@...onage.de,
milo.kim@...com, balajitk@...com, gg@...mlogic.co.uk,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-iio@...r.kernel.org, devicetree@...r.kernel.org,
linux-omap@...r.kernel.org
Subject: Re: [PATCH v8 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver
On 07/25/13 14:26, Oleksandr Kozaruk wrote:
> The GPADC is general purpose ADC found on TWL6030, and TWL6032 PMIC,
> known also as Phoenix and PhoenixLite.
>
> The TWL6030 and TWL6032 have GPADC with 17 and 19 channels
> respectively. Some channels have current source and are used for
> measuring voltage drop on resistive load for detecting battery ID
> resistance, or measuring voltage drop on NTC resistors for external
> temperature measurements. Some channels measure voltage, (i.e. battery
> voltage), and have voltage dividers, thus, capable to scale voltage.
> Some channels are dedicated for measuring die temperature.
>
> Some channels are calibrated in 2 points, having offsets from ideal
> values kept in trim registers. This is used to correct measurements.
>
> The differences between GPADC in TWL6030 and TWL6032:
> - 10 bit vs 12 bit ADC;
> - 17 vs 19 channels;
> - channels have different purpose(i.e. battery voltage
> channel 8 vs channel 18);
> - trim values are interpreted differently.
>
> Based on the driver patched from Balaji TK, Graeme Gregory, Ambresh K,
> Girish S Ghongdemath.
>
> Signed-off-by: Balaji T K <balajitk@...com>
> Signed-off-by: Graeme Gregory <gg@...mlogic.co.uk>
> Signed-off-by: Oleksandr Kozaruk <oleksandr.kozaruk@...com>
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.
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@...com>
> + * Balaji T K <balajitk@...com>
> + * Graeme Gregory <gg@...mlogic.co.uk>
> + * Girish S Ghongdemath <girishsg@...com>
> + * Ambresh K <ambresh@...com>
> + * Oleksandr Kozaruk <oleksandr.kozaruk@...com
> + *
> + * Based on twl4030-madc.c
> + * Copyright (C) 2008 Nokia Corporation
> + * Mikko Ylinen <mikko.k.ylinen@...ia.com>
> + *
> + * 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@...com>, Graeme Gregory <gg@...mlogic.co.uk>, Oleksandr Kozaruk <oleksandr.kozaruk@...com");
> +MODULE_DESCRIPTION("twl6030 ADC driver");
> +MODULE_LICENSE("GPL");
>
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