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linux-next/drivers/pinctrl/pinctrl-mcp23s08.c
Thomas Preston b9b7fb2943 pinctrl: mcp23s08: Fix mcp23x17 precious range 
On page 23 of the datasheet [0] it says "The register remains unchanged
until the interrupt is cleared via a read of INTCAP or GPIO." Include
INTCAPA and INTCAPB registers in precious range, so that they aren't
accidentally cleared when we read via debugfs.

[0] https://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf

Fixes: 8f38910ba4 ("pinctrl: mcp23s08: switch to regmap caching")
Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200828213226.1734264-3-thomas.preston@codethink.co.uk
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2020-09-12 11:31:19 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/* MCP23S08 SPI/I2C GPIO driver */
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/export.h>
#include <linux/gpio/driver.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
#include <linux/interrupt.h>
#include <linux/regmap.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
#include <linux/pinctrl/pinconf-generic.h>
#include "pinctrl-mcp23s08.h"
/* Registers are all 8 bits wide.
*
* The mcp23s17 has twice as many bits, and can be configured to work
* with either 16 bit registers or with two adjacent 8 bit banks.
*/
#define MCP_IODIR 0x00 /* init/reset: all ones */
#define MCP_IPOL 0x01
#define MCP_GPINTEN 0x02
#define MCP_DEFVAL 0x03
#define MCP_INTCON 0x04
#define MCP_IOCON 0x05
# define IOCON_MIRROR (1 << 6)
# define IOCON_SEQOP (1 << 5)
# define IOCON_HAEN (1 << 3)
# define IOCON_ODR (1 << 2)
# define IOCON_INTPOL (1 << 1)
# define IOCON_INTCC (1)
#define MCP_GPPU 0x06
#define MCP_INTF 0x07
#define MCP_INTCAP 0x08
#define MCP_GPIO 0x09
#define MCP_OLAT 0x0a
static const struct reg_default mcp23x08_defaults[] = {
{.reg = MCP_IODIR, .def = 0xff},
{.reg = MCP_IPOL, .def = 0x00},
{.reg = MCP_GPINTEN, .def = 0x00},
{.reg = MCP_DEFVAL, .def = 0x00},
{.reg = MCP_INTCON, .def = 0x00},
{.reg = MCP_IOCON, .def = 0x00},
{.reg = MCP_GPPU, .def = 0x00},
{.reg = MCP_OLAT, .def = 0x00},
};
static const struct regmap_range mcp23x08_volatile_range = {
.range_min = MCP_INTF,
.range_max = MCP_GPIO,
};
static const struct regmap_access_table mcp23x08_volatile_table = {
.yes_ranges = &mcp23x08_volatile_range,
.n_yes_ranges = 1,
};
static const struct regmap_range mcp23x08_precious_range = {
.range_min = MCP_GPIO,
.range_max = MCP_GPIO,
};
static const struct regmap_access_table mcp23x08_precious_table = {
.yes_ranges = &mcp23x08_precious_range,
.n_yes_ranges = 1,
};
const struct regmap_config mcp23x08_regmap = {
.reg_bits = 8,
.val_bits = 8,
.reg_stride = 1,
.volatile_table = &mcp23x08_volatile_table,
.precious_table = &mcp23x08_precious_table,
.reg_defaults = mcp23x08_defaults,
.num_reg_defaults = ARRAY_SIZE(mcp23x08_defaults),
.cache_type = REGCACHE_FLAT,
.max_register = MCP_OLAT,
};
EXPORT_SYMBOL_GPL(mcp23x08_regmap);
static const struct reg_default mcp23x17_defaults[] = {
{.reg = MCP_IODIR << 1, .def = 0xffff},
{.reg = MCP_IPOL << 1, .def = 0x0000},
{.reg = MCP_GPINTEN << 1, .def = 0x0000},
{.reg = MCP_DEFVAL << 1, .def = 0x0000},
{.reg = MCP_INTCON << 1, .def = 0x0000},
{.reg = MCP_IOCON << 1, .def = 0x0000},
{.reg = MCP_GPPU << 1, .def = 0x0000},
{.reg = MCP_OLAT << 1, .def = 0x0000},
};
static const struct regmap_range mcp23x17_volatile_range = {
.range_min = MCP_INTF << 1,
.range_max = MCP_GPIO << 1,
};
static const struct regmap_access_table mcp23x17_volatile_table = {
.yes_ranges = &mcp23x17_volatile_range,
.n_yes_ranges = 1,
};
static const struct regmap_range mcp23x17_precious_range = {
.range_min = MCP_INTCAP << 1,
.range_max = MCP_GPIO << 1,
};
static const struct regmap_access_table mcp23x17_precious_table = {
.yes_ranges = &mcp23x17_precious_range,
.n_yes_ranges = 1,
};
const struct regmap_config mcp23x17_regmap = {
.reg_bits = 8,
.val_bits = 16,
.reg_stride = 2,
.max_register = MCP_OLAT << 1,
.volatile_table = &mcp23x17_volatile_table,
.precious_table = &mcp23x17_precious_table,
.reg_defaults = mcp23x17_defaults,
.num_reg_defaults = ARRAY_SIZE(mcp23x17_defaults),
.cache_type = REGCACHE_FLAT,
.val_format_endian = REGMAP_ENDIAN_LITTLE,
};
EXPORT_SYMBOL_GPL(mcp23x17_regmap);
static int mcp_read(struct mcp23s08 *mcp, unsigned int reg, unsigned int *val)
{
return regmap_read(mcp->regmap, reg << mcp->reg_shift, val);
}
static int mcp_write(struct mcp23s08 *mcp, unsigned int reg, unsigned int val)
{
return regmap_write(mcp->regmap, reg << mcp->reg_shift, val);
}
static int mcp_set_mask(struct mcp23s08 *mcp, unsigned int reg,
unsigned int mask, bool enabled)
{
u16 val = enabled ? 0xffff : 0x0000;
return regmap_update_bits(mcp->regmap, reg << mcp->reg_shift,
mask, val);
}
static int mcp_set_bit(struct mcp23s08 *mcp, unsigned int reg,
unsigned int pin, bool enabled)
{
u16 mask = BIT(pin);
return mcp_set_mask(mcp, reg, mask, enabled);
}
static const struct pinctrl_pin_desc mcp23x08_pins[] = {
PINCTRL_PIN(0, "gpio0"),
PINCTRL_PIN(1, "gpio1"),
PINCTRL_PIN(2, "gpio2"),
PINCTRL_PIN(3, "gpio3"),
PINCTRL_PIN(4, "gpio4"),
PINCTRL_PIN(5, "gpio5"),
PINCTRL_PIN(6, "gpio6"),
PINCTRL_PIN(7, "gpio7"),
};
static const struct pinctrl_pin_desc mcp23x17_pins[] = {
PINCTRL_PIN(0, "gpio0"),
PINCTRL_PIN(1, "gpio1"),
PINCTRL_PIN(2, "gpio2"),
PINCTRL_PIN(3, "gpio3"),
PINCTRL_PIN(4, "gpio4"),
PINCTRL_PIN(5, "gpio5"),
PINCTRL_PIN(6, "gpio6"),
PINCTRL_PIN(7, "gpio7"),
PINCTRL_PIN(8, "gpio8"),
PINCTRL_PIN(9, "gpio9"),
PINCTRL_PIN(10, "gpio10"),
PINCTRL_PIN(11, "gpio11"),
PINCTRL_PIN(12, "gpio12"),
PINCTRL_PIN(13, "gpio13"),
PINCTRL_PIN(14, "gpio14"),
PINCTRL_PIN(15, "gpio15"),
};
static int mcp_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
{
return 0;
}
static const char *mcp_pinctrl_get_group_name(struct pinctrl_dev *pctldev,
unsigned int group)
{
return NULL;
}
static int mcp_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
unsigned int group,
const unsigned int **pins,
unsigned int *num_pins)
{
return -ENOTSUPP;
}
static const struct pinctrl_ops mcp_pinctrl_ops = {
.get_groups_count = mcp_pinctrl_get_groups_count,
.get_group_name = mcp_pinctrl_get_group_name,
.get_group_pins = mcp_pinctrl_get_group_pins,
#ifdef CONFIG_OF
.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
.dt_free_map = pinconf_generic_dt_free_map,
#endif
};
static int mcp_pinconf_get(struct pinctrl_dev *pctldev, unsigned int pin,
unsigned long *config)
{
struct mcp23s08 *mcp = pinctrl_dev_get_drvdata(pctldev);
enum pin_config_param param = pinconf_to_config_param(*config);
unsigned int data, status;
int ret;
switch (param) {
case PIN_CONFIG_BIAS_PULL_UP:
ret = mcp_read(mcp, MCP_GPPU, &data);
if (ret < 0)
return ret;
status = (data & BIT(pin)) ? 1 : 0;
break;
default:
return -ENOTSUPP;
}
*config = 0;
return status ? 0 : -EINVAL;
}
static int mcp_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
unsigned long *configs, unsigned int num_configs)
{
struct mcp23s08 *mcp = pinctrl_dev_get_drvdata(pctldev);
enum pin_config_param param;
u32 arg;
int ret = 0;
int i;
for (i = 0; i < num_configs; i++) {
param = pinconf_to_config_param(configs[i]);
arg = pinconf_to_config_argument(configs[i]);
switch (param) {
case PIN_CONFIG_BIAS_PULL_UP:
ret = mcp_set_bit(mcp, MCP_GPPU, pin, arg);
break;
default:
dev_dbg(mcp->dev, "Invalid config param %04x\n", param);
return -ENOTSUPP;
}
}
return ret;
}
static const struct pinconf_ops mcp_pinconf_ops = {
.pin_config_get = mcp_pinconf_get,
.pin_config_set = mcp_pinconf_set,
.is_generic = true,
};
/*----------------------------------------------------------------------*/
static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct mcp23s08 *mcp = gpiochip_get_data(chip);
int status;
mutex_lock(&mcp->lock);
status = mcp_set_bit(mcp, MCP_IODIR, offset, true);
mutex_unlock(&mcp->lock);
return status;
}
static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
{
struct mcp23s08 *mcp = gpiochip_get_data(chip);
int status, ret;
mutex_lock(&mcp->lock);
/* REVISIT reading this clears any IRQ ... */
ret = mcp_read(mcp, MCP_GPIO, &status);
if (ret < 0)
status = 0;
else {
mcp->cached_gpio = status;
status = !!(status & (1 << offset));
}
mutex_unlock(&mcp->lock);
return status;
}
static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, bool value)
{
return mcp_set_mask(mcp, MCP_OLAT, mask, value);
}
static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct mcp23s08 *mcp = gpiochip_get_data(chip);
unsigned mask = BIT(offset);
mutex_lock(&mcp->lock);
__mcp23s08_set(mcp, mask, !!value);
mutex_unlock(&mcp->lock);
}
static int
mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
{
struct mcp23s08 *mcp = gpiochip_get_data(chip);
unsigned mask = BIT(offset);
int status;
mutex_lock(&mcp->lock);
status = __mcp23s08_set(mcp, mask, value);
if (status == 0) {
status = mcp_set_mask(mcp, MCP_IODIR, mask, false);
}
mutex_unlock(&mcp->lock);
return status;
}
/*----------------------------------------------------------------------*/
static irqreturn_t mcp23s08_irq(int irq, void *data)
{
struct mcp23s08 *mcp = data;
int intcap, intcon, intf, i, gpio, gpio_orig, intcap_mask, defval;
unsigned int child_irq;
bool intf_set, intcap_changed, gpio_bit_changed,
defval_changed, gpio_set;
mutex_lock(&mcp->lock);
if (mcp_read(mcp, MCP_INTF, &intf))
goto unlock;
if (mcp_read(mcp, MCP_INTCAP, &intcap))
goto unlock;
if (mcp_read(mcp, MCP_INTCON, &intcon))
goto unlock;
if (mcp_read(mcp, MCP_DEFVAL, &defval))
goto unlock;
/* This clears the interrupt(configurable on S18) */
if (mcp_read(mcp, MCP_GPIO, &gpio))
goto unlock;
gpio_orig = mcp->cached_gpio;
mcp->cached_gpio = gpio;
mutex_unlock(&mcp->lock);
if (intf == 0) {
/* There is no interrupt pending */
return IRQ_HANDLED;
}
dev_dbg(mcp->chip.parent,
"intcap 0x%04X intf 0x%04X gpio_orig 0x%04X gpio 0x%04X\n",
intcap, intf, gpio_orig, gpio);
for (i = 0; i < mcp->chip.ngpio; i++) {
/* We must check all of the inputs on the chip,
* otherwise we may not notice a change on >=2 pins.
*
* On at least the mcp23s17, INTCAP is only updated
* one byte at a time(INTCAPA and INTCAPB are
* not written to at the same time - only on a per-bank
* basis).
*
* INTF only contains the single bit that caused the
* interrupt per-bank. On the mcp23s17, there is
* INTFA and INTFB. If two pins are changed on the A
* side at the same time, INTF will only have one bit
* set. If one pin on the A side and one pin on the B
* side are changed at the same time, INTF will have
* two bits set. Thus, INTF can't be the only check
* to see if the input has changed.
*/
intf_set = intf & BIT(i);
if (i < 8 && intf_set)
intcap_mask = 0x00FF;
else if (i >= 8 && intf_set)
intcap_mask = 0xFF00;
else
intcap_mask = 0x00;
intcap_changed = (intcap_mask &
(intcap & BIT(i))) !=
(intcap_mask & (BIT(i) & gpio_orig));
gpio_set = BIT(i) & gpio;
gpio_bit_changed = (BIT(i) & gpio_orig) !=
(BIT(i) & gpio);
defval_changed = (BIT(i) & intcon) &&
((BIT(i) & gpio) !=
(BIT(i) & defval));
if (((gpio_bit_changed || intcap_changed) &&
(BIT(i) & mcp->irq_rise) && gpio_set) ||
((gpio_bit_changed || intcap_changed) &&
(BIT(i) & mcp->irq_fall) && !gpio_set) ||
defval_changed) {
child_irq = irq_find_mapping(mcp->chip.irq.domain, i);
handle_nested_irq(child_irq);
}
}
return IRQ_HANDLED;
unlock:
mutex_unlock(&mcp->lock);
return IRQ_HANDLED;
}
static void mcp23s08_irq_mask(struct irq_data *data)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
struct mcp23s08 *mcp = gpiochip_get_data(gc);
unsigned int pos = data->hwirq;
mcp_set_bit(mcp, MCP_GPINTEN, pos, false);
}
static void mcp23s08_irq_unmask(struct irq_data *data)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
struct mcp23s08 *mcp = gpiochip_get_data(gc);
unsigned int pos = data->hwirq;
mcp_set_bit(mcp, MCP_GPINTEN, pos, true);
}
static int mcp23s08_irq_set_type(struct irq_data *data, unsigned int type)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
struct mcp23s08 *mcp = gpiochip_get_data(gc);
unsigned int pos = data->hwirq;
if ((type & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH) {
mcp_set_bit(mcp, MCP_INTCON, pos, false);
mcp->irq_rise |= BIT(pos);
mcp->irq_fall |= BIT(pos);
} else if (type & IRQ_TYPE_EDGE_RISING) {
mcp_set_bit(mcp, MCP_INTCON, pos, false);
mcp->irq_rise |= BIT(pos);
mcp->irq_fall &= ~BIT(pos);
} else if (type & IRQ_TYPE_EDGE_FALLING) {
mcp_set_bit(mcp, MCP_INTCON, pos, false);
mcp->irq_rise &= ~BIT(pos);
mcp->irq_fall |= BIT(pos);
} else if (type & IRQ_TYPE_LEVEL_HIGH) {
mcp_set_bit(mcp, MCP_INTCON, pos, true);
mcp_set_bit(mcp, MCP_DEFVAL, pos, false);
} else if (type & IRQ_TYPE_LEVEL_LOW) {
mcp_set_bit(mcp, MCP_INTCON, pos, true);
mcp_set_bit(mcp, MCP_DEFVAL, pos, true);
} else
return -EINVAL;
return 0;
}
static void mcp23s08_irq_bus_lock(struct irq_data *data)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
struct mcp23s08 *mcp = gpiochip_get_data(gc);
mutex_lock(&mcp->lock);
regcache_cache_only(mcp->regmap, true);
}
static void mcp23s08_irq_bus_unlock(struct irq_data *data)
{
struct gpio_chip *gc = irq_data_get_irq_chip_data(data);
struct mcp23s08 *mcp = gpiochip_get_data(gc);
regcache_cache_only(mcp->regmap, false);
regcache_sync(mcp->regmap);
mutex_unlock(&mcp->lock);
}
static int mcp23s08_irq_setup(struct mcp23s08 *mcp)
{
struct gpio_chip *chip = &mcp->chip;
int err;
unsigned long irqflags = IRQF_ONESHOT | IRQF_SHARED;
if (mcp->irq_active_high)
irqflags |= IRQF_TRIGGER_HIGH;
else
irqflags |= IRQF_TRIGGER_LOW;
err = devm_request_threaded_irq(chip->parent, mcp->irq, NULL,
mcp23s08_irq,
irqflags, dev_name(chip->parent), mcp);
if (err != 0) {
dev_err(chip->parent, "unable to request IRQ#%d: %d\n",
mcp->irq, err);
return err;
}
return 0;
}
/*----------------------------------------------------------------------*/
int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev,
unsigned int addr, unsigned int type, unsigned int base)
{
int status, ret;
bool mirror = false;
bool open_drain = false;
mutex_init(&mcp->lock);
mcp->dev = dev;
mcp->addr = addr;
mcp->irq_active_high = false;
mcp->irq_chip.name = dev_name(dev);
mcp->irq_chip.irq_mask = mcp23s08_irq_mask;
mcp->irq_chip.irq_unmask = mcp23s08_irq_unmask;
mcp->irq_chip.irq_set_type = mcp23s08_irq_set_type;
mcp->irq_chip.irq_bus_lock = mcp23s08_irq_bus_lock;
mcp->irq_chip.irq_bus_sync_unlock = mcp23s08_irq_bus_unlock;
mcp->chip.direction_input = mcp23s08_direction_input;
mcp->chip.get = mcp23s08_get;
mcp->chip.direction_output = mcp23s08_direction_output;
mcp->chip.set = mcp23s08_set;
#ifdef CONFIG_OF_GPIO
mcp->chip.of_gpio_n_cells = 2;
mcp->chip.of_node = dev->of_node;
#endif
mcp->chip.base = base;
mcp->chip.can_sleep = true;
mcp->chip.parent = dev;
mcp->chip.owner = THIS_MODULE;
/* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
* and MCP_IOCON.HAEN = 1, so we work with all chips.
*/
ret = mcp_read(mcp, MCP_IOCON, &status);
if (ret < 0)
return dev_err_probe(dev, ret, "can't identify chip %d\n", addr);
mcp->irq_controller =
device_property_read_bool(dev, "interrupt-controller");
if (mcp->irq && mcp->irq_controller) {
mcp->irq_active_high =
device_property_read_bool(dev,
"microchip,irq-active-high");
mirror = device_property_read_bool(dev, "microchip,irq-mirror");
open_drain = device_property_read_bool(dev, "drive-open-drain");
}
if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN) || mirror ||
mcp->irq_active_high || open_drain) {
/* mcp23s17 has IOCON twice, make sure they are in sync */
status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8));
status |= IOCON_HAEN | (IOCON_HAEN << 8);
if (mcp->irq_active_high)
status |= IOCON_INTPOL | (IOCON_INTPOL << 8);
else
status &= ~(IOCON_INTPOL | (IOCON_INTPOL << 8));
if (mirror)
status |= IOCON_MIRROR | (IOCON_MIRROR << 8);
if (open_drain)
status |= IOCON_ODR | (IOCON_ODR << 8);
if (type == MCP_TYPE_S18 || type == MCP_TYPE_018)
status |= IOCON_INTCC | (IOCON_INTCC << 8);
ret = mcp_write(mcp, MCP_IOCON, status);
if (ret < 0)
return dev_err_probe(dev, ret, "can't write IOCON %d\n", addr);
}
if (mcp->irq && mcp->irq_controller) {
struct gpio_irq_chip *girq = &mcp->chip.irq;
girq->chip = &mcp->irq_chip;
/* This will let us handle the parent IRQ in the driver */
girq->parent_handler = NULL;
girq->num_parents = 0;
girq->parents = NULL;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_simple_irq;
girq->threaded = true;
}
ret = devm_gpiochip_add_data(dev, &mcp->chip, mcp);
if (ret < 0)
return dev_err_probe(dev, ret, "can't add GPIO chip\n");
mcp->pinctrl_desc.pctlops = &mcp_pinctrl_ops;
mcp->pinctrl_desc.confops = &mcp_pinconf_ops;
mcp->pinctrl_desc.npins = mcp->chip.ngpio;
if (mcp->pinctrl_desc.npins == 8)
mcp->pinctrl_desc.pins = mcp23x08_pins;
else if (mcp->pinctrl_desc.npins == 16)
mcp->pinctrl_desc.pins = mcp23x17_pins;
mcp->pinctrl_desc.owner = THIS_MODULE;
mcp->pctldev = devm_pinctrl_register(dev, &mcp->pinctrl_desc, mcp);
if (IS_ERR(mcp->pctldev))
return dev_err_probe(dev, PTR_ERR(mcp->pctldev), "can't register controller\n");
if (mcp->irq) {
ret = mcp23s08_irq_setup(mcp);
if (ret)
return dev_err_probe(dev, ret, "can't setup IRQ\n");
}
return 0;
}
EXPORT_SYMBOL_GPL(mcp23s08_probe_one);
MODULE_LICENSE("GPL");
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