On Sat, Sep 3, 2016 at 9:56 PM, Matt Ranostay <mranostay@xxxxxxxxx> wrote: > On Sat, Sep 3, 2016 at 7:59 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >> On 30/08/16 07:01, Matt Ranostay wrote: >>> On Mon, Aug 29, 2016 at 10:38 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >>>> On 26/08/16 04:09, Matt Ranostay wrote: >>>>> On Sun, Aug 21, 2016 at 3:46 AM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >>>>>> On 20/08/16 04:17, Matt Ranostay wrote: >>>>>>> Add support for the LMP91000 potentiostat which is used for chemical >>>>>>> sensing applications. >>>>>>> >>>>>>> Signed-off-by: Matt Ranostay <mranostay@xxxxxxxxx> >>>>>> As this is 'unusual' I'd appreciate more docs in general of what is >>>>>> going on. >>>>>> >>>>>> Mostly looking good but few bits and bobs that I think need tweaking inline. >>>>>> >>>>>> I'd be inclined to factor out the relevant code in industrialio-trigger.c >>>>>> (iio_trigger_write_current) to do validation etc as well on this. >>>>>> It's not strickly necessary but might be nice. Also you can then put >>>>>> a 'exclusive' mode check in there to prevent sysfs writes changing the >>>>>> trigger on you. >>>>>> >>>>>>> --- >>>>>>> .../bindings/iio/potentiostat/lmp91000.txt | 30 ++ >>>>>>> drivers/iio/Kconfig | 1 + >>>>>>> drivers/iio/Makefile | 1 + >>>>>>> drivers/iio/potentiostat/Kconfig | 22 ++ >>>>>>> drivers/iio/potentiostat/Makefile | 6 + >>>>>>> drivers/iio/potentiostat/lmp91000.c | 377 +++++++++++++++++++++ >>>>>>> 6 files changed, 437 insertions(+) >>>>>>> create mode 100644 Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt >>>>>>> create mode 100644 drivers/iio/potentiostat/Kconfig >>>>>>> create mode 100644 drivers/iio/potentiostat/Makefile >>>>>>> create mode 100644 drivers/iio/potentiostat/lmp91000.c >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt b/Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt >>>>>>> new file mode 100644 >>>>>>> index 000000000000..b9b621e94cd7 >>>>>>> --- /dev/null >>>>>>> +++ b/Documentation/devicetree/bindings/iio/potentiostat/lmp91000.txt >>>>>>> @@ -0,0 +1,30 @@ >>>>>>> +* Texas Instruments LMP91000 potentiostat >>>>>>> + >>>>>>> +http://www.ti.com/lit/ds/symlink/lmp91000.pdf >>>>>>> + >>>>>>> +Required properties: >>>>>>> + >>>>>>> + - compatible: should be "ti,lmp91000" >>>>>>> + - reg: the I2C address of the device >>>>>>> + - io-channels: the phandle of the iio provider >>>>>>> + >>>>>>> + - ti,external-tia-resistor: if the property ti,tia-gain-ohm is not defined this >>>>>>> + needs to be set to signal that an external resistor value is being used. >>>>>>> + >>>>>>> +Optional properties: >>>>>>> + >>>>>>> + - ti,tia-gain-ohm: ohm value of the internal resistor for the transimpedance >>>>>>> + amplifier. Must be 2750, 3500, 7000, 14000, 35000, 120000, or 350000 ohms. >>>>>>> + >>>>>>> + - ti,rload-ohm: ohm value of the internal resistor load applied to the gas >>>>>>> + sensor. Must be 10, 33, 50, or 100 (default) ohms. >>>>>>> + >>>>>>> +Example: >>>>>>> + >>>>>>> +lmp91000@48 { >>>>>>> + compatible = "ti,lmp91000"; >>>>>>> + reg = <0x48>; >>>>>>> + ti,tia-gain-ohm = <7500>; >>>>>>> + ti,rload = <100>; >>>>>>> + io-channels = <&adc>; >>>>>>> +}; >>>>>>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig >>>>>>> index 6743b18194fb..a31a8cf2c330 100644 >>>>>>> --- a/drivers/iio/Kconfig >>>>>>> +++ b/drivers/iio/Kconfig >>>>>>> @@ -87,6 +87,7 @@ if IIO_TRIGGER >>>>>>> source "drivers/iio/trigger/Kconfig" >>>>>>> endif #IIO_TRIGGER >>>>>>> source "drivers/iio/potentiometer/Kconfig" >>>>>>> +source "drivers/iio/potentiostat/Kconfig" >>>>>>> source "drivers/iio/pressure/Kconfig" >>>>>>> source "drivers/iio/proximity/Kconfig" >>>>>>> source "drivers/iio/temperature/Kconfig" >>>>>>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile >>>>>>> index 87e4c4369e2f..2b6e2762a886 100644 >>>>>>> --- a/drivers/iio/Makefile >>>>>>> +++ b/drivers/iio/Makefile >>>>>>> @@ -29,6 +29,7 @@ obj-y += light/ >>>>>>> obj-y += magnetometer/ >>>>>>> obj-y += orientation/ >>>>>>> obj-y += potentiometer/ >>>>>>> +obj-y += potentiostat/ >>>>>>> obj-y += pressure/ >>>>>>> obj-y += proximity/ >>>>>>> obj-y += temperature/ >>>>>>> diff --git a/drivers/iio/potentiostat/Kconfig b/drivers/iio/potentiostat/Kconfig >>>>>>> new file mode 100644 >>>>>>> index 000000000000..1e3baf2cc97d >>>>>>> --- /dev/null >>>>>>> +++ b/drivers/iio/potentiostat/Kconfig >>>>>>> @@ -0,0 +1,22 @@ >>>>>>> +# >>>>>>> +# Potentiostat drivers >>>>>>> +# >>>>>>> +# When adding new entries keep the list in alphabetical order >>>>>>> + >>>>>>> +menu "Digital potentiostats" >>>>>>> + >>>>>>> +config LMP91000 >>>>>>> + tristate "Texas Instruments LMP91000 potentiostat driver" >>>>>>> + depends on I2C >>>>>>> + select REGMAP_I2C >>>>>>> + select IIO_BUFFER >>>>>>> + select IIO_BUFFER_CB >>>>>>> + select IIO_TRIGGERED_BUFFER >>>>>>> + help >>>>>>> + Say yes here to build support for the Texas Instruments >>>>>>> + LMP91000 digital potentiostat chip. >>>>>>> + >>>>>>> + To compile this driver as a module, choose M here: the >>>>>>> + module will be called lmp91000 >>>>>>> + >>>>>>> +endmenu >>>>>>> diff --git a/drivers/iio/potentiostat/Makefile b/drivers/iio/potentiostat/Makefile >>>>>>> new file mode 100644 >>>>>>> index 000000000000..64d315ef4449 >>>>>>> --- /dev/null >>>>>>> +++ b/drivers/iio/potentiostat/Makefile >>>>>>> @@ -0,0 +1,6 @@ >>>>>>> +# >>>>>>> +# Makefile for industrial I/O potentiostat drivers >>>>>>> +# >>>>>>> + >>>>>>> +# When adding new entries keep the list in alphabetical order >>>>>>> +obj-$(CONFIG_LMP91000) += lmp91000.o >>>>>>> diff --git a/drivers/iio/potentiostat/lmp91000.c b/drivers/iio/potentiostat/lmp91000.c >>>>>>> new file mode 100644 >>>>>>> index 000000000000..5046d2d3da98 >>>>>>> --- /dev/null >>>>>>> +++ b/drivers/iio/potentiostat/lmp91000.c >>>>>>> @@ -0,0 +1,377 @@ >>>>>>> +/* >>>>>>> + * lmp91000.c - Support for Texas Instruments digital potentiostats >>>>>>> + * >>>>>>> + * Copyright (C) 2016 Matt Ranostay <mranostay@xxxxxxxxx> >>>>>>> + * >>>>>>> + * This program is free software; you can redistribute it and/or modify >>>>>>> + * it under the terms of the GNU General Public License as published by >>>>>>> + * the Free Software Foundation; either version 2 of the License, or >>>>>>> + * (at your option) any later version. >>>>>>> + * >>>>>>> + * 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. >>>>>>> + * >>>>>>> + * TODO: bias voltage + polarity control, and multiple chip support >>>>>>> + */ >>>>>>> + >>>>>>> +#include <linux/module.h> >>>>>>> +#include <linux/i2c.h> >>>>>>> +#include <linux/delay.h> >>>>>>> +#include <linux/of.h> >>>>>>> +#include <linux/regmap.h> >>>>>>> +#include <linux/iio/iio.h> >>>>>>> +#include <linux/iio/buffer.h> >>>>>>> +#include <linux/iio/consumer.h> >>>>>>> +#include <linux/iio/trigger.h> >>>>>>> +#include <linux/iio/trigger_consumer.h> >>>>>>> +#include <linux/iio/triggered_buffer.h> >>>>>>> + >>>>>>> +#define LMP91000_REG_LOCK 0x01 >>>>>>> +#define LMP91000_REG_TIACN 0x10 >>>>>>> +#define LMP91000_REG_TIACN_GAIN_SHIFT 2 >>>>>>> + >>>>>>> +#define LMP91000_REG_REFCN 0x11 >>>>>>> +#define LMP91000_REG_REFCN_EXT_REF 0x20 >>>>>>> +#define LMP91000_REG_REFCN_50_ZERO 0x80 >>>>>>> + >>>>>>> +#define LMP91000_REG_MODECN 0x12 >>>>>>> +#define LMP91000_REG_MODECN_3LEAD 0x03 >>>>>>> +#define LMP91000_REG_MODECN_TEMP 0x07 >>>>>>> + >>>>>>> +#define LMP91000_DRV_NAME "lmp91000" >>>>>>> + >>>>>>> +static const int lmp91000_tia_gain[] = { 0, 2750, 3500, 7000, 14000, 35000, >>>>>>> + 120000, 350000 }; >>>>>>> + >>>>>>> +static const int lmp91000_rload[] = { 10, 33, 50, 100 }; >>>>>>> + >>>>>>> +static const struct regmap_config lmp91000_regmap_config = { >>>>>>> + .reg_bits = 8, >>>>>>> + .val_bits = 8, >>>>>>> +}; >>>>>>> + >>>>>>> +struct lmp91000_data { >>>>>>> + struct regmap *regmap; >>>>>>> + struct device *dev; >>>>>>> + >>>>>>> + struct iio_trigger *trig; >>>>>>> + struct iio_cb_buffer *cb_buffer; >>>>>>> + >>>>>>> + struct completion completion; >>>>>>> + u8 chan_select; >>>>>>> + >>>>>>> + u32 buffer[4]; /* 64-bit data + 64-bit timestamp */ >>>>>>> +}; >>>>>>> + >>>>>>> +static const struct iio_chan_spec lmp91000_channels[] = { >>>>>>> + { /* chemical channel mV */ >>>>>>> + .type = IIO_VOLTAGE, >>>>>>> + .channel = 0, >>>>>>> + .indexed = 1, >>>>>>> + .address = LMP91000_REG_MODECN_3LEAD, >>>>>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), >>>>>>> + .scan_index = 0, >>>>>>> + .scan_type = { >>>>>>> + .sign = 's', >>>>>>> + .realbits = 32, >>>>>>> + .storagebits = 32, >>>>>>> + }, >>>>>>> + }, >>>>>>> + IIO_CHAN_SOFT_TIMESTAMP(1), >>>>>>> + { /* temperature channel mV */ >>>>>>> + .type = IIO_VOLTAGE, >>>>>>> + .channel = 1, >>>>>>> + .indexed = 1, >>>>>>> + .address = LMP91000_REG_MODECN_TEMP, >>>>>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), >>>>>>> + .scan_index = -1, >>>>>>> + }, >>>>>>> +}; >>>>>>> + >>>>>>> +static int lmp91000_read(struct lmp91000_data *data, int channel, int *val) >>>>>>> +{ >>>>>>> + int state, ret; >>>>>>> + >>>>>>> + ret = regmap_read(data->regmap, LMP91000_REG_MODECN, &state); >>>>>>> + if (ret) >>>>>>> + return -EINVAL; >>>>>>> + >>>>>>> + ret = regmap_write(data->regmap, LMP91000_REG_MODECN, channel); >>>>>>> + if (ret) >>>>>>> + return -EINVAL; >>>>>>> + >>>>>>> + /* delay till first temperature reading is complete */ >>>>>>> + if ((state != channel) && (channel == LMP91000_REG_MODECN_TEMP)) >>>>>>> + usleep_range(3000, 4000); >>>>>>> + >>>>>>> + data->chan_select = channel != LMP91000_REG_MODECN_3LEAD; >>>>>>> + >>>>>> I'd like a comment here to explain that this is causing the sample to >>>>>> be taken. >>>>>> >>>>>> To get it clear in my head: >>>>>> 1) Calls handle_nested_irq (should rename this function in general as my >>>>>> understanding of the meaning of chained interrupts was actually wrong when >>>>>> I came up with this name). >>>>> >>>>> Yeah the naming kinda doesn't make sense, and to be honest wasn't that >>>>> clear to me initially. >>>> Hmm. If you fancy fixing that feel free ;) >>>>> >>>>>> 2) poll func of the ADC is called (bottom half only, but that's fine). >>>>>> 3) This calls iio_push_to_buffer. >>>>>> 4) The demux plucks on the relevant channel (only one enabled so that's easy >>>>>> :) and passes it on to the callback buffer. >>>>>> 5) The completion below finishes, data is copied out and pushed into the >>>>>> buffer of this device with a timestamp added etc. Job done. >>>>> >>>>> Correct! >>>>> >>>>>> >>>>>>> + iio_trigger_poll_chained(data->trig); >>>>>>> + >>>>>>> + ret = wait_for_completion_timeout(&data->completion, HZ); >>>>>>> + reinit_completion(&data->completion); >>>>>>> + >>>>>>> + if (!ret) >>>>>>> + return -ETIMEDOUT; >>>>>>> + >>>>>>> + *val = data->buffer[data->chan_select]; >>>>>>> + >>>>>>> + return 0; >>>>>>> +} >>>>>>> + >>>>>>> +static irqreturn_t lmp91000_buffer_handler(int irq, void *private) >>>>>>> +{ >>>>>>> + struct iio_poll_func *pf = private; >>>>>>> + struct iio_dev *indio_dev = pf->indio_dev; >>>>>>> + struct lmp91000_data *data = iio_priv(indio_dev); >>>>>>> + int ret, val; >>>>>>> + >>>>>>> + memset(data->buffer, 0, sizeof(data->buffer)); >>>>>>> + >>>>>>> + ret = iio_channel_start_all_cb(data->cb_buffer); >>>>>>> + if (ret) >>>>>>> + goto error_out; >>>>>> Why the need for the explicit start each time? You have control of the >>>>>> trigger so it shouldn't capture otherwise. This is a fairly heavy weight >>>>>> operation so best avoided if we can keep it running across multiple scans. >>>>> >>>>> There is a few issues with locking in the code doing that... >>>>> indio_dev->mlock is already held before iio_channel_start_all_cb. So >>>>> we need to really rework a few things or have this hack for now. >>>> I'm not sure I follow. >>>> >>>> Talk me through the locking issue with doing the start in the preenable for >>>> the buffer and the stop in the post disable? >>>>> >>> >>> Yeah you get this doing that.... seems multiple attempts to get mlock >>> mutex with the update_buffers... >> >> Hmm. Let me try and get my head around this. I'm going to call the >> front end device the outer, and the adc the inner device.. >> >> We call enable on the outer buffer. (iio_buffer_store_enable). >> This takes the outer mlock and calls >> __iio_update_buffers which calls iio_enable_buffers. >> This calls indio_dev->setup_ops->preenable (for the outer device). >> >> This preenable will call the iio_channel_start_all_cb which looks >> dodgy as it'll call a nested iio_update_buffers which takes the >> lock. However, it should be calling it on the inner device whose >> mlock we haven't taken yet. >> >> So why is it going wrong? I can't immediately see... >> >> If I get a chance later I'll mock this up and see if I can track down >> why it's a problem. May well not get back to it this weekend though. >> > > I am really perplexed as well since it should be different indio_dev->mlock's > >> If you get a chance to dig some more that would be great! Hmm is this a possible lockdep issue? Seen a few fixes go into in the stable branch.. >> >> Jonathan >> >>> >>> >>> 77.959336] ============================================= >>> [ 77.963451] [ INFO: possible recursive locking detected ] >>> [ 77.967575] 4.7.0-rc4-00044-g0e4912e9bd3b-dirty #15 Not tainted >>> [ 77.972212] --------------------------------------------- >>> [ 77.976335] sh/321 is trying to acquire lock: >>> [ 77.979406] (&dev->mlock){+.+.+.}, at: [<c0630ce0>] >>> iio_update_buffers+0x38/0xd4 >>> [ 77.985700] >>> but task is already holding lock: >>> [ 77.988940] (&dev->mlock){+.+.+.}, at: [<c0630db0>] >>> iio_buffer_store_enable+0x34/0x98 >>> [ 77.995632] >>> other info that might help us debug this: >>> [ 77.999572] Possible unsafe locking scenario: >>> [ 78.002899] CPU0 >>> [ 78.004045] ---- >>> [ 78.005190] lock(&dev->mlock); >>> [ 78.007142] lock(&dev->mlock); >>> [ 78.009095] >>> *** DEADLOCK *** >>> [ 78.011115] May be due to missing lock nesting notation >>> [ 78.015317] 5 locks held by sh/321: >>> [ 78.017511] #0: (sb_writers#4){.+.+.+}, at: [<c02967d0>] >>> __sb_start_write+0x8c/0xb0 >>> [ 78.024143] #1: (&of->mutex){+.+.+.}, at: [<c0314184>] >>> kernfs_fop_write+0x88/0x1f0 >>> [ 78.030677] #2: (s_active#80){.+.+.+}, at: [<c031418c>] >>> kernfs_fop_write+0x90/0x1f0 >>> [ 78.037300] #3: (&dev->mlock){+.+.+.}, at: [<c0630db0>] >>> iio_buffer_store_enable+0x34/0x98 >>> [ 78.044435] #4: (&dev->info_exist_lock){+.+...}, at: [<c0630cd4>] >>> iio_update_buffers+0x2c/0xd4 >>> [ 78.052006] >>> stack backtrace: >>> [ 78.053773] PU: 0 PID: 321 Comm: sh Not tainted >>> 4.7.0-rc4-00044-g0e4912e9bd3b-dirty #15 >>> [ 78.060591] Hardware name: Generic AM33XX (Flattened Device Tree) >>> [ 78.065428] [<c0110060>] (unwind_backtrace) from [<c010c1f8>] >>> (show_stack+0x10/0x14) >>> [ 78.071919] [<c010c1f8>] (show_stack) from [<c0485904>] >>> (dump_stack+0xac/0xe0) >>> [ 78.077884] [<c0485904>] (dump_stack) from [<c0190d38>] >>> (__lock_acquire+0xf0c/0x1880) >>> [ 78.084450] [<c0190d38>] (__lock_acquire) from [<c0191ad4>] >>> (lock_acquire+0xcc/0x238) >>> [ 78.091027] [<c0191ad4>] (lock_acquire) from [<c0751118>] >>> (mutex_lock_nested+0x3c/0x3d4) >>> [ 78.097856] [<c0751118>] (mutex_lock_nested) from [<c0630ce0>] >>> (iio_update_buffers+0x38/0xd4) >>> [ 78.105120] [<c0630ce0>] (iio_update_buffers) from [<c0630c50>] >>> (__iio_update_buffers+0x440/0x498) >>> [ 78.112820] [<c0630c50>] (__iio_update_buffers) from [<c0630de4>] >>> (iio_buffer_store_enable+0x68/0x98) >>> [ 78.120784] [<c0630de4>] (iio_buffer_store_enable) from >>> [<c03141c0>] (kernfs_fop_write+0xc4/0x1f0) >>> [ 78.128486] [<c03141c0>] (kernfs_fop_write) from [<c02927b8>] >>> (__vfs_write+0x1c/0x114) >>> [ 78.135136] [<c02927b8>] (__vfs_write) from [<c02936f8>] >>> (vfs_write+0xa0/0x180) >>> [ 78.141176] [<c02936f8>] (vfs_write) from [<c0294450>] (SyS_write+0x3c/0x90) >>> [ 78.146965] [<c0294450>] (SyS_write) from [<c0107840>] >>> (ret_fast_syscall+0x0/0x1c) >>> >>>>>> >>>>>> Would have thought you can just do this in the postenable callback. Then >>>>>> disable in the predisable. >>>>>>> + >>>>>>> + ret = lmp91000_read(data, LMP91000_REG_MODECN_3LEAD, &val); >>>>>>> + iio_channel_stop_all_cb(data->cb_buffer); >>>>>>> + >>>>>>> + if (!ret) { >>>>>>> + data->buffer[0] = val; >>>>>>> + iio_push_to_buffers_with_timestamp(indio_dev, data->buffer, >>>>>>> + iio_get_time_ns(indio_dev)); >>>>>>> + } >>>>>>> + >>>>>>> +error_out: >>>>>>> + iio_trigger_notify_done(indio_dev->trig); >>>>>>> + >>>>>>> + return IRQ_HANDLED; >>>>>>> +} >>>>>>> + >>>>>>> +static int lmp91000_read_raw(struct iio_dev *indio_dev, >>>>>>> + struct iio_chan_spec const *chan, >>>>>>> + int *val, int *val2, long mask) >>>>>>> +{ >>>>>>> + struct lmp91000_data *data = iio_priv(indio_dev); >>>>>>> + int ret; >>>>>>> + >>>>>>> + if (mask != IIO_CHAN_INFO_RAW) >>>>>>> + return -EINVAL; >>>>>>> + >>>>>> I'd protect this with claim_direct. We don't want this occuring >>>>>> mid way through a buffered read - or two of these happening at >>>>>> once. >>>>>> >>>>>>> + ret = iio_channel_start_all_cb(data->cb_buffer); >>>>>>> + if (ret) >>>>>>> + return ret; >>>>>>> + >>>>>>> + ret = lmp91000_read(data, chan->address, val); >>>>>>> + >>>>>>> + iio_channel_stop_all_cb(data->cb_buffer); >>>>>>> + >>>>>>> + if (!ret) >>>>>>> + return IIO_VAL_INT; >>>>>>> + >>>>>>> + return ret; >>>>>>> +} >>>>>>> + >>>>>>> +static const struct iio_info lmp91000_info = { >>>>>>> + .driver_module = THIS_MODULE, >>>>>>> + .read_raw = lmp91000_read_raw, >>>>>>> +}; >>>>>>> + >>>>>>> +static int lmp91000_read_config(struct lmp91000_data *data) >>>>>>> +{ >>>>>>> + struct device *dev = data->dev; >>>>>>> + struct device_node *np = dev->of_node; >>>>>>> + unsigned int reg, val; >>>>>>> + int i, ret; >>>>>>> + >>>>>>> + ret = of_property_read_u32(np, "ti,tia-gain-ohm", &val); >>>>>>> + if (ret) { >>>>>>> + if (of_property_read_bool(np, "ti,external-tia-resistor")) >>>>>>> + val = 0; >>>>>>> + else { >>>>>>> + dev_err(dev, "no ti,tia-gain-ohm defined"); >>>>>>> + return ret; >>>>>>> + } >>>>>>> + } >>>>>>> + >>>>>>> + ret = -EINVAL; >>>>>>> + for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) { >>>>>>> + if (lmp91000_tia_gain[i] == val) { >>>>>>> + reg = i << LMP91000_REG_TIACN_GAIN_SHIFT; >>>>>>> + ret = 0; >>>>>>> + break; >>>>>>> + } >>>>>>> + } >>>>>>> + >>>>>>> + if (ret) { >>>>>>> + dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val); >>>>>>> + return ret; >>>>>>> + } >>>>>>> + >>>>>>> + ret = of_property_read_u32(np, "ti,rload-ohm", &val); >>>>>>> + if (ret) { >>>>>>> + val = 100; >>>>>>> + dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val); >>>>>>> + } >>>>>>> + >>>>>>> + ret = -EINVAL; >>>>>>> + for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) { >>>>>>> + if (lmp91000_rload[i] == val) { >>>>>>> + reg |= i; >>>>>>> + ret = 0; >>>>>>> + break; >>>>>>> + } >>>>>>> + } >>>>>>> + >>>>>>> + if (ret) { >>>>>>> + dev_err(dev, "invalid ti,rload-ohm %d\n", val); >>>>>>> + return ret; >>>>>>> + } >>>>>>> + >>>>>>> + regmap_write(data->regmap, LMP91000_REG_LOCK, 0); >>>>>>> + regmap_write(data->regmap, LMP91000_REG_TIACN, reg); >>>>>>> + regmap_write(data->regmap, LMP91000_REG_REFCN, LMP91000_REG_REFCN_EXT_REF >>>>>>> + | LMP91000_REG_REFCN_50_ZERO); >>>>>>> + regmap_write(data->regmap, LMP91000_REG_LOCK, 1); >>>>>>> + >>>>>>> + return 0; >>>>>>> +} >>>>>>> + >>>>>>> +static int lmp91000_buffer_cb(const void *val, void *private) >>>>>>> +{ >>>>>>> + struct iio_dev *indio_dev = private; >>>>>>> + struct lmp91000_data *data = iio_priv(indio_dev); >>>>>>> + >>>>>>> + data->buffer[data->chan_select] = *((int *)val); >>>>>>> + complete_all(&data->completion); >>>>>>> + >>>>>>> + return 0; >>>>>>> +} >>>>>>> + >>>>>>> +static const struct iio_trigger_ops lmp91000_trigger_ops = { >>>>>>> + .owner = THIS_MODULE, >>>>>>> +}; >>>>>>> + >>>>>>> +static int lmp91000_probe(struct i2c_client *client, >>>>>>> + const struct i2c_device_id *id) >>>>>>> +{ >>>>>>> + struct device *dev = &client->dev; >>>>>>> + struct lmp91000_data *data; >>>>>>> + struct iio_dev *indio_dev; >>>>>>> + int ret; >>>>>>> + >>>>>>> + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); >>>>>>> + if (!indio_dev) >>>>>>> + return -ENOMEM; >>>>>>> + >>>>>>> + indio_dev->info = &lmp91000_info; >>>>>>> + indio_dev->channels = lmp91000_channels; >>>>>>> + indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels); >>>>>>> + indio_dev->name = LMP91000_DRV_NAME; >>>>>>> + indio_dev->modes = INDIO_DIRECT_MODE; >>>>>>> + i2c_set_clientdata(client, indio_dev); >>>>>>> + >>>>>>> + data = iio_priv(indio_dev); >>>>>>> + data->dev = dev; >>>>>>> + data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config); >>>>>>> + if (IS_ERR(data->regmap)) { >>>>>>> + dev_err(dev, "regmap initialization failed.\n"); >>>>>>> + return PTR_ERR(data->regmap); >>>>>>> + } >>>>>>> + >>>>>>> + data->trig = devm_iio_trigger_alloc(data->dev, "%s-mux%d", >>>>>>> + indio_dev->name, indio_dev->id); >>>>>>> + if (!data->trig) { >>>>>>> + dev_err(dev, "cannot allocate iio trigger.\n"); >>>>>>> + return -ENOMEM; >>>>>>> + } >>>>>>> + >>>>>>> + data->trig->ops = &lmp91000_trigger_ops; >>>>>>> + data->trig->dev.parent = dev; >>>>>>> + init_completion(&data->completion); >>>>>>> + >>>>>>> + ret = lmp91000_read_config(data); >>>>>>> + if (ret) >>>>>>> + return ret; >>>>>>> + >>>>>>> + data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb, >>>>>>> + indio_dev); >>>>>>> + if (IS_ERR(data->cb_buffer)) { >>>>>>> + if (PTR_ERR(data->cb_buffer) == -ENODEV) >>>>>>> + return -EPROBE_DEFER; >>>>>>> + return PTR_ERR(data->cb_buffer); >>>>>>> + } >>>>>>> + >>>>>>> + ret = iio_triggered_buffer_setup(indio_dev, NULL, >>>>>>> + &lmp91000_buffer_handler, NULL); >>>>>>> + if (ret) >>>>>>> + goto error_unreg_cb_buffer; >>>>>>> + >>>>>>> + ret = iio_trigger_register(data->trig); >>>>>>> + if (ret) { >>>>>>> + dev_err(dev, "cannot register iio trigger.\n"); >>>>>>> + goto error_unreg_cb_buffer; >>>>>>> + } >>>>>>> + >>>>>>> + ret = iio_device_register(indio_dev); >>>>>>> + if (ret) >>>>>>> + goto error_unreg_buffer; >>>>>>> + >>>>>> >>>>>>> + iio_channel_cb_get_iio_dev(data->cb_buffer)->trig = >>>>>>> + iio_trigger_get(data->trig); >>>>>> >>>>>> Hmm. Is this really all there is to it? >>>>>> >>>>>> * What prevents the trigger from being changed? The buffer is only enabled >>>>>> currently during each reading so there is plenty of time to 'steal' it. >>>>>> We need some for of 'exclusive' lock on this. As we are explicitly clocking >>>>>> the ADC capture from here I can't see where a non exclusive mode would work >>>>>> without some very very fiddly handling. >>>>>> >>>>> >>>>> Ok yeah this is a bit ugly... and you are correct the trigger could be changed. >>>>> So do we need to have a flag in the iio_dev struct that signals the >>>>> trigger isn't changeable? >>>> Yes, something along those lines I think. >>>>> >>>>>> * I'd prefer this happening through a utility function as it's more >>>>>> that possible it'll be used in drivers that don't know about struct iio_dev. >>>>>> So keep that opaque. >>>>>> >>>>>> It's racey with the iio_device_register... So probably needs to be >>>>>> prior to that. I'd even be inclined to work out how to do the cb_buffer >>>>>> start in the probe and stop in the remove. I'm not 100% sure all the >>>>>> infrastructure is in place before the iio_device_register though. If it's >>>>>> not we may need ot think about adding another stage for this usecase. >>>>>> Might just push races into iio_device_register itself. >>>>>> >>>>> >>>>> See locking issues noted above :). >>>> We need to fix those... Should not be the case. >>>>> >>>>>>> + >>>>>>> + return 0; >>>>>>> + >>>>>>> +error_unreg_buffer: >>>>>>> + iio_triggered_buffer_cleanup(indio_dev); >>>>>>> + iio_trigger_unregister(data->trig); >>>>>>> + >>>>>>> +error_unreg_cb_buffer: >>>>>>> + iio_channel_release_all_cb(data->cb_buffer); >>>>>>> + >>>>>>> + return ret; >>>>>>> +} >>>>>>> + >>>>>>> +static int lmp91000_remove(struct i2c_client *client) >>>>>>> +{ >>>>>>> + struct iio_dev *indio_dev = i2c_get_clientdata(client); >>>>>>> + struct lmp91000_data *data = iio_priv(indio_dev); >>>>>>> + >>>>>>> + iio_device_unregister(indio_dev); >>>>>>> + >>>>>>> + iio_channel_stop_all_cb(data->cb_buffer); >>>>>>> + iio_channel_release_all_cb(data->cb_buffer); >>>>>>> + >>>>>>> + iio_triggered_buffer_cleanup(indio_dev); >>>>>>> + iio_trigger_unregister(data->trig); >>>>>>> + >>>>>>> + return 0; >>>>>>> +} >>>>>>> + >>>>>>> +static const struct of_device_id lmp91000_of_match[] = { >>>>>>> + { .compatible = "ti,lmp91000", }, >>>>>>> + { }, >>>>>>> +}; >>>>>>> +MODULE_DEVICE_TABLE(of, lmp91000_of_match); >>>>>>> + >>>>>>> +static const struct i2c_device_id lmp91000_id[] = { >>>>>>> + { "lmp91000", 0 }, >>>>>>> + {} >>>>>>> +}; >>>>>>> +MODULE_DEVICE_TABLE(i2c, lmp91000_id); >>>>>>> + >>>>>>> +static struct i2c_driver lmp91000_driver = { >>>>>>> + .driver = { >>>>>>> + .name = LMP91000_DRV_NAME, >>>>>>> + .of_match_table = of_match_ptr(lmp91000_of_match), >>>>>>> + }, >>>>>>> + .probe = lmp91000_probe, >>>>>>> + .remove = lmp91000_remove, >>>>>>> + .id_table = lmp91000_id, >>>>>>> +}; >>>>>>> +module_i2c_driver(lmp91000_driver); >>>>>>> + >>>>>>> +MODULE_AUTHOR("Matt Ranostay <mranostay@xxxxxxxxx>"); >>>>>>> +MODULE_DESCRIPTION("LMP91000 digital potentiostat"); >>>>>>> +MODULE_LICENSE("GPL"); >>>>>>> >>>>>> >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe linux-iio" in >>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>>> >>>> >> -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
