linux/drivers/iio/adc/stx104.c
Linus Torvalds 291b38a756 Annotation of module parameters that specify device settings
-----BEGIN PGP SIGNATURE-----
 
 iQIVAwUAWPiW6vSw1s6N8H32AQLOrw/+NTqGf7bjq+64YKS6NfR0XDgE+wNJltGO
 ck7zJW3NHIg76RNu8s0I9xg5aVmwizz3Z5DGROZquaolnezux4tQihZ3AFyxIzLc
 +Y3WHYagcML7yFfjl/WznCLRD5EW3yPln4lCvQO0nW/xICRYeRI057JaIbi2Dtek
 BhcXt3c4AjXDLdYJkgtHV3p2R2mt8hcdFdWqqx6s7JaIThZNRGNzxAgtbcB9k5IW
 HVG9ZEIL73VBYWHrYivzjHYF5rBnNCPt87eOwDQeTOSkhv8te+u9k+bH8vxZw1T0
 XUtDrLBndKiuVo2GUfLkkF8LItx3Q9eLCJYy0joaIliyPqTEsPx9KjQ+Af0cxS9s
 ZPCZ5SYf96stKmDeL5xaMfrAmeyVHJ4lc4JTOqdzbIT8blsOSfYO/03p0ALShSDv
 /RQLaKGlf8Bjoy8PwKFcXb4sIDufcd/U1Av/EMFXxOfgN/u2JUkGKq6EaIM5B68L
 fHPje+aR9VNELPmPjwNOWtmN4I79EH3EItQf7zv0KG+UeKhcHLx/EAcSJ3ZRKEkH
 Lathg7pPOEJGArPiVO79TZzBG01ADn1aiwv65XObMzNZ+54xI/mN/Y1DNF/kL5jU
 XzvNzEjFt8mwMIZGVNdAt4+pDyMfIZGZSyUkSRKFnaQZMIvQrfQIU9RLBYLX5eOx
 +/p0VkIwDpg=
 =lbS7
 -----END PGP SIGNATURE-----

Merge tag 'hwparam-20170420' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull hw lockdown support from David Howells:
 "Annotation of module parameters that configure hardware resources
  including ioports, iomem addresses, irq lines and dma channels.

  This allows a future patch to prohibit the use of such module
  parameters to prevent that hardware from being abused to gain access
  to the running kernel image as part of locking the kernel down under
  UEFI secure boot conditions.

  Annotations are made by changing:

        module_param(n, t, p)
        module_param_named(n, v, t, p)
        module_param_array(n, t, m, p)

  to:

        module_param_hw(n, t, hwtype, p)
        module_param_hw_named(n, v, t, hwtype, p)
        module_param_hw_array(n, t, hwtype, m, p)

  where the module parameter refers to a hardware setting

  hwtype specifies the type of the resource being configured. This can
  be one of:

        ioport          Module parameter configures an I/O port
        iomem           Module parameter configures an I/O mem address
        ioport_or_iomem Module parameter could be either (runtime set)
        irq             Module parameter configures an I/O port
        dma             Module parameter configures a DMA channel
        dma_addr        Module parameter configures a DMA buffer address
        other           Module parameter configures some other value

  Note that the hwtype is compile checked, but not currently stored (the
  lockdown code probably won't require it). It is, however, there for
  future use.

  A bonus is that the hwtype can also be used for grepping.

  The intention is for the kernel to ignore or reject attempts to set
  annotated module parameters if lockdown is enabled. This applies to
  options passed on the boot command line, passed to insmod/modprobe or
  direct twiddling in /sys/module/ parameter files.

  The module initialisation then needs to handle the parameter not being
  set, by (1) giving an error, (2) probing for a value or (3) using a
  reasonable default.

  What I can't do is just reject a module out of hand because it may
  take a hardware setting in the module parameters. Some important
  modules, some ipmi stuff for instance, both probe for hardware and
  allow hardware to be manually specified; if the driver is aborts with
  any error, you don't get any ipmi hardware.

  Further, trying to do this entirely in the module initialisation code
  doesn't protect against sysfs twiddling.

  [!] Note that in and of itself, this series of patches should have no
      effect on the the size of the kernel or code execution - that is
      left to a patch in the next series to effect. It does mark
      annotated kernel parameters with a KERNEL_PARAM_FL_HWPARAM flag in
      an already existing field"

* tag 'hwparam-20170420' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (38 commits)
  Annotate hardware config module parameters in sound/pci/
  Annotate hardware config module parameters in sound/oss/
  Annotate hardware config module parameters in sound/isa/
  Annotate hardware config module parameters in sound/drivers/
  Annotate hardware config module parameters in fs/pstore/
  Annotate hardware config module parameters in drivers/watchdog/
  Annotate hardware config module parameters in drivers/video/
  Annotate hardware config module parameters in drivers/tty/
  Annotate hardware config module parameters in drivers/staging/vme/
  Annotate hardware config module parameters in drivers/staging/speakup/
  Annotate hardware config module parameters in drivers/staging/media/
  Annotate hardware config module parameters in drivers/scsi/
  Annotate hardware config module parameters in drivers/pcmcia/
  Annotate hardware config module parameters in drivers/pci/hotplug/
  Annotate hardware config module parameters in drivers/parport/
  Annotate hardware config module parameters in drivers/net/wireless/
  Annotate hardware config module parameters in drivers/net/wan/
  Annotate hardware config module parameters in drivers/net/irda/
  Annotate hardware config module parameters in drivers/net/hamradio/
  Annotate hardware config module parameters in drivers/net/ethernet/
  ...
2017-05-10 19:13:03 -07:00

374 lines
9.5 KiB
C

/*
* IIO driver for the Apex Embedded Systems STX104
* Copyright (C) 2016 William Breathitt Gray
*
* 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.
*/
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/iio/iio.h>
#include <linux/iio/types.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#define STX104_OUT_CHAN(chan) { \
.type = IIO_VOLTAGE, \
.channel = chan, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.indexed = 1, \
.output = 1 \
}
#define STX104_IN_CHAN(chan, diff) { \
.type = IIO_VOLTAGE, \
.channel = chan, \
.channel2 = chan, \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) | \
BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.indexed = 1, \
.differential = diff \
}
#define STX104_NUM_OUT_CHAN 2
#define STX104_EXTENT 16
static unsigned int base[max_num_isa_dev(STX104_EXTENT)];
static unsigned int num_stx104;
module_param_hw_array(base, uint, ioport, &num_stx104, 0);
MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
/**
* struct stx104_iio - IIO device private data structure
* @chan_out_states: channels' output states
* @base: base port address of the IIO device
*/
struct stx104_iio {
unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
unsigned int base;
};
/**
* struct stx104_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @lock: synchronization lock to prevent I/O race conditions
* @base: base port address of the GPIO device
* @out_state: output bits state
*/
struct stx104_gpio {
struct gpio_chip chip;
spinlock_t lock;
unsigned int base;
unsigned int out_state;
};
static int stx104_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int *val, int *val2, long mask)
{
struct stx104_iio *const priv = iio_priv(indio_dev);
unsigned int adc_config;
int adbu;
int gain;
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
/* get gain configuration */
adc_config = inb(priv->base + 11);
gain = adc_config & 0x3;
*val = 1 << gain;
return IIO_VAL_INT;
case IIO_CHAN_INFO_RAW:
if (chan->output) {
*val = priv->chan_out_states[chan->channel];
return IIO_VAL_INT;
}
/* select ADC channel */
outb(chan->channel | (chan->channel << 4), priv->base + 2);
/* trigger ADC sample capture and wait for completion */
outb(0, priv->base);
while (inb(priv->base + 8) & BIT(7));
*val = inw(priv->base);
return IIO_VAL_INT;
case IIO_CHAN_INFO_OFFSET:
/* get ADC bipolar/unipolar configuration */
adc_config = inb(priv->base + 11);
adbu = !(adc_config & BIT(2));
*val = -32768 * adbu;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
/* get ADC bipolar/unipolar and gain configuration */
adc_config = inb(priv->base + 11);
adbu = !(adc_config & BIT(2));
gain = adc_config & 0x3;
*val = 5;
*val2 = 15 - adbu + gain;
return IIO_VAL_FRACTIONAL_LOG2;
}
return -EINVAL;
}
static int stx104_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan, int val, int val2, long mask)
{
struct stx104_iio *const priv = iio_priv(indio_dev);
switch (mask) {
case IIO_CHAN_INFO_HARDWAREGAIN:
/* Only four gain states (x1, x2, x4, x8) */
switch (val) {
case 1:
outb(0, priv->base + 11);
break;
case 2:
outb(1, priv->base + 11);
break;
case 4:
outb(2, priv->base + 11);
break;
case 8:
outb(3, priv->base + 11);
break;
default:
return -EINVAL;
}
return 0;
case IIO_CHAN_INFO_RAW:
if (chan->output) {
/* DAC can only accept up to a 16-bit value */
if ((unsigned int)val > 65535)
return -EINVAL;
priv->chan_out_states[chan->channel] = val;
outw(val, priv->base + 4 + 2 * chan->channel);
return 0;
}
return -EINVAL;
}
return -EINVAL;
}
static const struct iio_info stx104_info = {
.driver_module = THIS_MODULE,
.read_raw = stx104_read_raw,
.write_raw = stx104_write_raw
};
/* single-ended input channels configuration */
static const struct iio_chan_spec stx104_channels_sing[] = {
STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
STX104_IN_CHAN(0, 0), STX104_IN_CHAN(1, 0), STX104_IN_CHAN(2, 0),
STX104_IN_CHAN(3, 0), STX104_IN_CHAN(4, 0), STX104_IN_CHAN(5, 0),
STX104_IN_CHAN(6, 0), STX104_IN_CHAN(7, 0), STX104_IN_CHAN(8, 0),
STX104_IN_CHAN(9, 0), STX104_IN_CHAN(10, 0), STX104_IN_CHAN(11, 0),
STX104_IN_CHAN(12, 0), STX104_IN_CHAN(13, 0), STX104_IN_CHAN(14, 0),
STX104_IN_CHAN(15, 0)
};
/* differential input channels configuration */
static const struct iio_chan_spec stx104_channels_diff[] = {
STX104_OUT_CHAN(0), STX104_OUT_CHAN(1),
STX104_IN_CHAN(0, 1), STX104_IN_CHAN(1, 1), STX104_IN_CHAN(2, 1),
STX104_IN_CHAN(3, 1), STX104_IN_CHAN(4, 1), STX104_IN_CHAN(5, 1),
STX104_IN_CHAN(6, 1), STX104_IN_CHAN(7, 1)
};
static int stx104_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
/* GPIO 0-3 are input only, while the rest are output only */
if (offset < 4)
return 1;
return 0;
}
static int stx104_gpio_direction_input(struct gpio_chip *chip,
unsigned int offset)
{
if (offset >= 4)
return -EINVAL;
return 0;
}
static int stx104_gpio_direction_output(struct gpio_chip *chip,
unsigned int offset, int value)
{
if (offset < 4)
return -EINVAL;
chip->set(chip, offset, value);
return 0;
}
static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
if (offset >= 4)
return -EINVAL;
return !!(inb(stx104gpio->base) & BIT(offset));
}
static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
const unsigned int mask = BIT(offset) >> 4;
unsigned long flags;
if (offset < 4)
return;
spin_lock_irqsave(&stx104gpio->lock, flags);
if (value)
stx104gpio->out_state |= mask;
else
stx104gpio->out_state &= ~mask;
outb(stx104gpio->out_state, stx104gpio->base);
spin_unlock_irqrestore(&stx104gpio->lock, flags);
}
#define STX104_NGPIO 8
static const char *stx104_names[STX104_NGPIO] = {
"DIN0", "DIN1", "DIN2", "DIN3", "DOUT0", "DOUT1", "DOUT2", "DOUT3"
};
static void stx104_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
unsigned long flags;
/* verify masked GPIO are output */
if (!(*mask & 0xF0))
return;
*mask >>= 4;
*bits >>= 4;
spin_lock_irqsave(&stx104gpio->lock, flags);
stx104gpio->out_state &= ~*mask;
stx104gpio->out_state |= *mask & *bits;
outb(stx104gpio->out_state, stx104gpio->base);
spin_unlock_irqrestore(&stx104gpio->lock, flags);
}
static int stx104_probe(struct device *dev, unsigned int id)
{
struct iio_dev *indio_dev;
struct stx104_iio *priv;
struct stx104_gpio *stx104gpio;
int err;
indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
if (!indio_dev)
return -ENOMEM;
stx104gpio = devm_kzalloc(dev, sizeof(*stx104gpio), GFP_KERNEL);
if (!stx104gpio)
return -ENOMEM;
if (!devm_request_region(dev, base[id], STX104_EXTENT,
dev_name(dev))) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + STX104_EXTENT);
return -EBUSY;
}
indio_dev->info = &stx104_info;
indio_dev->modes = INDIO_DIRECT_MODE;
/* determine if differential inputs */
if (inb(base[id] + 8) & BIT(5)) {
indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
indio_dev->channels = stx104_channels_diff;
} else {
indio_dev->num_channels = ARRAY_SIZE(stx104_channels_sing);
indio_dev->channels = stx104_channels_sing;
}
indio_dev->name = dev_name(dev);
indio_dev->dev.parent = dev;
priv = iio_priv(indio_dev);
priv->base = base[id];
/* configure device for software trigger operation */
outb(0, base[id] + 9);
/* initialize gain setting to x1 */
outb(0, base[id] + 11);
/* initialize DAC output to 0V */
outw(0, base[id] + 4);
outw(0, base[id] + 6);
stx104gpio->chip.label = dev_name(dev);
stx104gpio->chip.parent = dev;
stx104gpio->chip.owner = THIS_MODULE;
stx104gpio->chip.base = -1;
stx104gpio->chip.ngpio = STX104_NGPIO;
stx104gpio->chip.names = stx104_names;
stx104gpio->chip.get_direction = stx104_gpio_get_direction;
stx104gpio->chip.direction_input = stx104_gpio_direction_input;
stx104gpio->chip.direction_output = stx104_gpio_direction_output;
stx104gpio->chip.get = stx104_gpio_get;
stx104gpio->chip.set = stx104_gpio_set;
stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
stx104gpio->base = base[id] + 3;
stx104gpio->out_state = 0x0;
spin_lock_init(&stx104gpio->lock);
err = devm_gpiochip_add_data(dev, &stx104gpio->chip, stx104gpio);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
return err;
}
return devm_iio_device_register(dev, indio_dev);
}
static struct isa_driver stx104_driver = {
.probe = stx104_probe,
.driver = {
.name = "stx104"
},
};
module_isa_driver(stx104_driver, num_stx104);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("Apex Embedded Systems STX104 IIO driver");
MODULE_LICENSE("GPL v2");