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! > > 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
