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... 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
