linux-stable/drivers/gpio/gpio-pcf857x.c

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/*
* Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
*
* Copyright (C) 2007 David Brownell
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/i2c/pcf857x.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
static const struct i2c_device_id pcf857x_id[] = {
{ "pcf8574", 8 },
{ "pcf8574a", 8 },
{ "pca8574", 8 },
{ "pca9670", 8 },
{ "pca9672", 8 },
{ "pca9674", 8 },
{ "pcf8575", 16 },
{ "pca8575", 16 },
{ "pca9671", 16 },
{ "pca9673", 16 },
{ "pca9675", 16 },
{ "max7328", 8 },
{ "max7329", 8 },
{ "tca9554", 8 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf857x_id);
#ifdef CONFIG_OF
static const struct of_device_id pcf857x_of_table[] = {
{ .compatible = "nxp,pcf8574" },
{ .compatible = "nxp,pcf8574a" },
{ .compatible = "nxp,pca8574" },
{ .compatible = "nxp,pca9670" },
{ .compatible = "nxp,pca9672" },
{ .compatible = "nxp,pca9674" },
{ .compatible = "nxp,pcf8575" },
{ .compatible = "nxp,pca8575" },
{ .compatible = "nxp,pca9671" },
{ .compatible = "nxp,pca9673" },
{ .compatible = "nxp,pca9675" },
{ .compatible = "maxim,max7328" },
{ .compatible = "maxim,max7329" },
{ .compatible = "ti,tca9554" },
{ }
};
MODULE_DEVICE_TABLE(of, pcf857x_of_table);
#endif
/*
* The pcf857x, pca857x, and pca967x chips only expose one read and one
* write register. Writing a "one" bit (to match the reset state) lets
* that pin be used as an input; it's not an open-drain model, but acts
* a bit like one. This is described as "quasi-bidirectional"; read the
* chip documentation for details.
*
* Many other I2C GPIO expander chips (like the pca953x models) have
* more complex register models and more conventional circuitry using
* push/pull drivers. They often use the same 0x20..0x27 addresses as
* pcf857x parts, making the "legacy" I2C driver model problematic.
*/
struct pcf857x {
struct gpio_chip chip;
struct i2c_client *client;
struct mutex lock; /* protect 'out' */
struct irq_domain *irq_domain; /* for irq demux */
spinlock_t slock; /* protect irq demux */
unsigned out; /* software latch */
unsigned status; /* current status */
unsigned irq_mapped; /* mapped gpio irqs */
int (*write)(struct i2c_client *client, unsigned data);
int (*read)(struct i2c_client *client);
};
/*-------------------------------------------------------------------------*/
/* Talk to 8-bit I/O expander */
static int i2c_write_le8(struct i2c_client *client, unsigned data)
{
return i2c_smbus_write_byte(client, data);
}
static int i2c_read_le8(struct i2c_client *client)
{
return (int)i2c_smbus_read_byte(client);
}
/* Talk to 16-bit I/O expander */
static int i2c_write_le16(struct i2c_client *client, unsigned word)
{
u8 buf[2] = { word & 0xff, word >> 8, };
int status;
status = i2c_master_send(client, buf, 2);
return (status < 0) ? status : 0;
}
static int i2c_read_le16(struct i2c_client *client)
{
u8 buf[2];
int status;
status = i2c_master_recv(client, buf, 2);
if (status < 0)
return status;
return (buf[1] << 8) | buf[0];
}
/*-------------------------------------------------------------------------*/
static int pcf857x_input(struct gpio_chip *chip, unsigned offset)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
int status;
mutex_lock(&gpio->lock);
gpio->out |= (1 << offset);
status = gpio->write(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static int pcf857x_get(struct gpio_chip *chip, unsigned offset)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
int value;
value = gpio->read(gpio->client);
return (value < 0) ? 0 : (value & (1 << offset));
}
static int pcf857x_output(struct gpio_chip *chip, unsigned offset, int value)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
unsigned bit = 1 << offset;
int status;
mutex_lock(&gpio->lock);
if (value)
gpio->out |= bit;
else
gpio->out &= ~bit;
status = gpio->write(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static void pcf857x_set(struct gpio_chip *chip, unsigned offset, int value)
{
pcf857x_output(chip, offset, value);
}
/*-------------------------------------------------------------------------*/
static int pcf857x_to_irq(struct gpio_chip *chip, unsigned offset)
{
struct pcf857x *gpio = container_of(chip, struct pcf857x, chip);
int ret;
ret = irq_create_mapping(gpio->irq_domain, offset);
if (ret > 0)
gpio->irq_mapped |= (1 << offset);
return ret;
}
static irqreturn_t pcf857x_irq(int irq, void *data)
{
struct pcf857x *gpio = data;
unsigned long change, i, status, flags;
status = gpio->read(gpio->client);
spin_lock_irqsave(&gpio->slock, flags);
/*
* call the interrupt handler iff gpio is used as
* interrupt source, just to avoid bad irqs
*/
change = ((gpio->status ^ status) & gpio->irq_mapped);
for_each_set_bit(i, &change, gpio->chip.ngpio)
generic_handle_irq(irq_find_mapping(gpio->irq_domain, i));
gpio->status = status;
spin_unlock_irqrestore(&gpio->slock, flags);
return IRQ_HANDLED;
}
static int pcf857x_irq_domain_map(struct irq_domain *domain, unsigned int irq,
irq_hw_number_t hw)
{
struct pcf857x *gpio = domain->host_data;
irq_set_chip_and_handler(irq,
&dummy_irq_chip,
handle_level_irq);
#ifdef CONFIG_ARM
set_irq_flags(irq, IRQF_VALID);
#else
irq_set_noprobe(irq);
#endif
gpio->irq_mapped |= (1 << hw);
return 0;
}
static struct irq_domain_ops pcf857x_irq_domain_ops = {
.map = pcf857x_irq_domain_map,
};
static void pcf857x_irq_domain_cleanup(struct pcf857x *gpio)
{
if (gpio->irq_domain)
irq_domain_remove(gpio->irq_domain);
}
static int pcf857x_irq_domain_init(struct pcf857x *gpio,
struct i2c_client *client)
{
int status;
gpio->irq_domain = irq_domain_add_linear(client->dev.of_node,
gpio->chip.ngpio,
&pcf857x_irq_domain_ops,
gpio);
if (!gpio->irq_domain)
goto fail;
/* enable real irq */
status = devm_request_threaded_irq(&client->dev, client->irq,
NULL, pcf857x_irq, IRQF_ONESHOT |
IRQF_TRIGGER_FALLING | IRQF_SHARED,
dev_name(&client->dev), gpio);
if (status)
goto fail;
/* enable gpio_to_irq() */
gpio->chip.to_irq = pcf857x_to_irq;
return 0;
fail:
pcf857x_irq_domain_cleanup(gpio);
return -EINVAL;
}
/*-------------------------------------------------------------------------*/
static int pcf857x_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
struct device_node *np = client->dev.of_node;
struct pcf857x *gpio;
unsigned int n_latch = 0;
int status;
if (IS_ENABLED(CONFIG_OF) && np)
of_property_read_u32(np, "lines-initial-states", &n_latch);
else if (pdata)
n_latch = pdata->n_latch;
else
dev_dbg(&client->dev, "no platform data\n");
/* Allocate, initialize, and register this gpio_chip. */
gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
mutex_init(&gpio->lock);
spin_lock_init(&gpio->slock);
gpio->chip.base = pdata ? pdata->gpio_base : -1;
gpio->chip.can_sleep = true;
gpio->chip.dev = &client->dev;
gpio->chip.owner = THIS_MODULE;
gpio->chip.get = pcf857x_get;
gpio->chip.set = pcf857x_set;
gpio->chip.direction_input = pcf857x_input;
gpio->chip.direction_output = pcf857x_output;
gpio->chip.ngpio = id->driver_data;
/* enable gpio_to_irq() if platform has settings */
if (client->irq) {
status = pcf857x_irq_domain_init(gpio, client);
if (status < 0) {
dev_err(&client->dev, "irq_domain init failed\n");
gpio: pcf857x: Avoid calling irq_domain_cleanup twice Currently irq_domain_cleanup is called twice if irq_domain_init fails. This causes the following crash. Unable to handle kernel paging request at virtual address 00100104 pgd = c0004000 [00100104] *pgd=00000000 Internal error: Oops: 805 [#1] SMP ARM Modules linked in: CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 3.12.15-01889-gedd10a8-dirty #4 Workqueue: deferwq deferred_probe_work_func task: ed0ee800 ti: ed116000 task.ti: ed116000 PC is at irq_domain_remove+0x3c/0x8c LR is at 0x0 pc : [<c0089734>] lr : [<00000000>] psr: a0000013 sp : ed117b50 ip : 00100100 fp : ed117b64 r10: ed5d1a04 r9 : 00000008 r8 : 00000000 r7 : ffffffea r6 : ed5d1a20 r5 : ed5d1a00 r4 : ed5e7540 r3 : 00200200 r2 : 00100100 r1 : c08aa180 r0 : 00200200 Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c53c7d Table: 8000406a DAC: 00000017 Process kworker/u4:0 (pid: 6, stack limit = 0xed116248) Stack: (0xed117b50 to 0xed118000) 7b40: 0000016b ed5d5f10 ed117b74 ed117b68 7b60: c02c8910 c0089704 ed117bb4 ed117b78 c02c8e14 c02c8900 ed5d1a04 ed5d4e80 ... <snip> ... fe0: 00000000 00000000 00000000 00000000 00000013 00000000 384a13ea 1590210a Backtrace: [<c00896f8>] (irq_domain_remove+0x0/0x8c) from [<c02c8910>] (pcf857x_irq_domain_cleanup+0x1c/0x20) r4:ed5d5f10 r3:0000016b [<c02c88f4>] (pcf857x_irq_domain_cleanup+0x0/0x20) from [<c02c8e14>] (pcf857x_probe+0x2a8/0x364) [<c02c8b6c>] (pcf857x_probe+0x0/0x364) from [<c04787ac>] (i2c_device_probe+0x80/0xc0) [<c047872c>] (i2c_device_probe+0x0/0xc0) from [<c036c33c>] (driver_probe_device+0x104/0x240) r6:00000000 r5:ed5d1a20 r4:c08c709c r3:c047872c [<c036c238>] (driver_probe_device+0x0/0x240) from [<c036c558>] (__device_attach+0x48/0x4c) r7:ed4fc480 r6:c036c510 r5:ed5d1a20 r4:c0866bb8 [<c036c510>] (__device_attach+0x0/0x4c) from [<c036a6d8>] (bus_for_each_drv+0x4c/0x94) r5:ed5d1a20 r4:00000000 [<c036a68c>] (bus_for_each_drv+0x0/0x94) from [<c036c1f4>] (device_attach+0x78/0x90) r6:c087fe50 r5:ed5d1a54 r4:ed5d1a20 [<c036c17c>] (device_attach+0x0/0x90) from [<c036b76c>] (bus_probe_device+0x8c/0xb4) r6:c087fe50 r5:ed5d1a20 r4:ed5d1a20 r3:ed17e1c0 [<c036b6e0>] (bus_probe_device+0x0/0xb4) from [<c0369888>] (device_add+0x34c/0x624) r6:ed5d1a28 r5:00000000 r4:ed5d1a20 r3:fffffffe [<c036953c>] (device_add+0x0/0x624) from [<c0369b7c>] (device_register+0x1c/0x20) ... <snip> ... [<c0060844>] (process_one_work+0x0/0x37c) from [<c0061040>] (worker_thread+0x13c/0x3c4) [<c0060f04>] (worker_thread+0x0/0x3c4) from [<c00670ec>] (kthread+0xac/0xb8) [<c0067040>] (kthread+0x0/0xb8) from [<c00148b8>] (ret_from_fork+0x14/0x3c) r7:00000000 r6:00000000 r5:c0067040 r4:ed105d20 Code: e59fc04c e591e000 e59f0048 e154000e (e5823004) ---[ end trace 59dd1e90032c4217 ]--- Signed-off-by: George Cherian <george.cherian@ti.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-05-23 05:57:26 +00:00
goto fail_irq_domain;
}
}
/* NOTE: the OnSemi jlc1562b is also largely compatible with
* these parts, notably for output. It has a low-resolution
* DAC instead of pin change IRQs; and its inputs can be the
* result of comparators.
*/
/* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
* 9670, 9672, 9764, and 9764a use quite a variety.
*
* NOTE: we don't distinguish here between *4 and *4a parts.
*/
if (gpio->chip.ngpio == 8) {
gpio->write = i2c_write_le8;
gpio->read = i2c_read_le8;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE))
status = -EIO;
/* fail if there's no chip present */
else
status = i2c_smbus_read_byte(client);
/* '75/'75c addresses are 0x20..0x27, just like the '74;
* the '75c doesn't have a current source pulling high.
* 9671, 9673, and 9765 use quite a variety of addresses.
*
* NOTE: we don't distinguish here between '75 and '75c parts.
*/
} else if (gpio->chip.ngpio == 16) {
gpio->write = i2c_write_le16;
gpio->read = i2c_read_le16;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
status = -EIO;
/* fail if there's no chip present */
else
status = i2c_read_le16(client);
} else {
dev_dbg(&client->dev, "unsupported number of gpios\n");
status = -EINVAL;
}
if (status < 0)
goto fail;
gpio->chip.label = client->name;
gpio->client = client;
i2c_set_clientdata(client, gpio);
/* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
* We can't actually know whether a pin is configured (a) as output
* and driving the signal low, or (b) as input and reporting a low
* value ... without knowing the last value written since the chip
* came out of reset (if any). We can't read the latched output.
*
* In short, the only reliable solution for setting up pin direction
* is to do it explicitly. The setup() method can do that, but it
* may cause transient glitching since it can't know the last value
* written (some pins may need to be driven low).
*
* Using n_latch avoids that trouble. When left initialized to zero,
* our software copy of the "latch" then matches the chip's all-ones
* reset state. Otherwise it flags pins to be driven low.
*/
gpio->out = ~n_latch;
gpio->status = gpio->out;
status = gpiochip_add(&gpio->chip);
if (status < 0)
goto fail;
/* Let platform code set up the GPIOs and their users.
* Now is the first time anyone could use them.
*/
if (pdata && pdata->setup) {
status = pdata->setup(client,
gpio->chip.base, gpio->chip.ngpio,
pdata->context);
if (status < 0)
dev_warn(&client->dev, "setup --> %d\n", status);
}
dev_info(&client->dev, "probed\n");
return 0;
fail:
if (client->irq)
pcf857x_irq_domain_cleanup(gpio);
gpio: pcf857x: Avoid calling irq_domain_cleanup twice Currently irq_domain_cleanup is called twice if irq_domain_init fails. This causes the following crash. Unable to handle kernel paging request at virtual address 00100104 pgd = c0004000 [00100104] *pgd=00000000 Internal error: Oops: 805 [#1] SMP ARM Modules linked in: CPU: 0 PID: 6 Comm: kworker/u4:0 Not tainted 3.12.15-01889-gedd10a8-dirty #4 Workqueue: deferwq deferred_probe_work_func task: ed0ee800 ti: ed116000 task.ti: ed116000 PC is at irq_domain_remove+0x3c/0x8c LR is at 0x0 pc : [<c0089734>] lr : [<00000000>] psr: a0000013 sp : ed117b50 ip : 00100100 fp : ed117b64 r10: ed5d1a04 r9 : 00000008 r8 : 00000000 r7 : ffffffea r6 : ed5d1a20 r5 : ed5d1a00 r4 : ed5e7540 r3 : 00200200 r2 : 00100100 r1 : c08aa180 r0 : 00200200 Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c53c7d Table: 8000406a DAC: 00000017 Process kworker/u4:0 (pid: 6, stack limit = 0xed116248) Stack: (0xed117b50 to 0xed118000) 7b40: 0000016b ed5d5f10 ed117b74 ed117b68 7b60: c02c8910 c0089704 ed117bb4 ed117b78 c02c8e14 c02c8900 ed5d1a04 ed5d4e80 ... <snip> ... fe0: 00000000 00000000 00000000 00000000 00000013 00000000 384a13ea 1590210a Backtrace: [<c00896f8>] (irq_domain_remove+0x0/0x8c) from [<c02c8910>] (pcf857x_irq_domain_cleanup+0x1c/0x20) r4:ed5d5f10 r3:0000016b [<c02c88f4>] (pcf857x_irq_domain_cleanup+0x0/0x20) from [<c02c8e14>] (pcf857x_probe+0x2a8/0x364) [<c02c8b6c>] (pcf857x_probe+0x0/0x364) from [<c04787ac>] (i2c_device_probe+0x80/0xc0) [<c047872c>] (i2c_device_probe+0x0/0xc0) from [<c036c33c>] (driver_probe_device+0x104/0x240) r6:00000000 r5:ed5d1a20 r4:c08c709c r3:c047872c [<c036c238>] (driver_probe_device+0x0/0x240) from [<c036c558>] (__device_attach+0x48/0x4c) r7:ed4fc480 r6:c036c510 r5:ed5d1a20 r4:c0866bb8 [<c036c510>] (__device_attach+0x0/0x4c) from [<c036a6d8>] (bus_for_each_drv+0x4c/0x94) r5:ed5d1a20 r4:00000000 [<c036a68c>] (bus_for_each_drv+0x0/0x94) from [<c036c1f4>] (device_attach+0x78/0x90) r6:c087fe50 r5:ed5d1a54 r4:ed5d1a20 [<c036c17c>] (device_attach+0x0/0x90) from [<c036b76c>] (bus_probe_device+0x8c/0xb4) r6:c087fe50 r5:ed5d1a20 r4:ed5d1a20 r3:ed17e1c0 [<c036b6e0>] (bus_probe_device+0x0/0xb4) from [<c0369888>] (device_add+0x34c/0x624) r6:ed5d1a28 r5:00000000 r4:ed5d1a20 r3:fffffffe [<c036953c>] (device_add+0x0/0x624) from [<c0369b7c>] (device_register+0x1c/0x20) ... <snip> ... [<c0060844>] (process_one_work+0x0/0x37c) from [<c0061040>] (worker_thread+0x13c/0x3c4) [<c0060f04>] (worker_thread+0x0/0x3c4) from [<c00670ec>] (kthread+0xac/0xb8) [<c0067040>] (kthread+0x0/0xb8) from [<c00148b8>] (ret_from_fork+0x14/0x3c) r7:00000000 r6:00000000 r5:c0067040 r4:ed105d20 Code: e59fc04c e591e000 e59f0048 e154000e (e5823004) ---[ end trace 59dd1e90032c4217 ]--- Signed-off-by: George Cherian <george.cherian@ti.com> Reviewed-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2014-05-23 05:57:26 +00:00
fail_irq_domain:
dev_dbg(&client->dev, "probe error %d for '%s'\n",
status, client->name);
return status;
}
static int pcf857x_remove(struct i2c_client *client)
{
struct pcf857x_platform_data *pdata = dev_get_platdata(&client->dev);
struct pcf857x *gpio = i2c_get_clientdata(client);
int status = 0;
if (pdata && pdata->teardown) {
status = pdata->teardown(client,
gpio->chip.base, gpio->chip.ngpio,
pdata->context);
if (status < 0) {
dev_err(&client->dev, "%s --> %d\n",
"teardown", status);
return status;
}
}
if (client->irq)
pcf857x_irq_domain_cleanup(gpio);
gpiochip_remove(&gpio->chip);
return status;
}
static struct i2c_driver pcf857x_driver = {
.driver = {
.name = "pcf857x",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(pcf857x_of_table),
},
.probe = pcf857x_probe,
.remove = pcf857x_remove,
.id_table = pcf857x_id,
};
static int __init pcf857x_init(void)
{
return i2c_add_driver(&pcf857x_driver);
}
/* register after i2c postcore initcall and before
* subsys initcalls that may rely on these GPIOs
*/
subsys_initcall(pcf857x_init);
static void __exit pcf857x_exit(void)
{
i2c_del_driver(&pcf857x_driver);
}
module_exit(pcf857x_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");