Revision a930d8790552658140d7d0d2e316af4f0d76a512 authored by Al Viro on 12 March 2013, 02:59:49 UTC, committed by Linus Torvalds on 12 March 2013, 15:29:17 UTC
If you open a pipe for neither read nor write, the pipe code will not
add any usage counters to the pipe, causing the 'struct pipe_inode_info"
to be potentially released early.
That doesn't normally matter, since you cannot actually use the pipe,
but the pipe release code - particularly fasync handling - still expects
the actual pipe infrastructure to all be there. And rather than adding
NULL pointer checks, let's just disallow this case, the same way we
already do for the named pipe ("fifo") case.
This is ancient going back to pre-2.4 days, and until trinity, nobody
naver noticed.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7c6baa3
pwm-twl-led.c
/*
* Driver for TWL4030/6030 Pulse Width Modulator used as LED driver
*
* Copyright (C) 2012 Texas Instruments
* Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
*
* This driver is a complete rewrite of the former pwm-twl6030.c authorded by:
* Hemanth V <hemanthv@ti.com>
*
* 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.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/i2c/twl.h>
#include <linux/slab.h>
/*
* This driver handles the PWM driven LED terminals of TWL4030 and TWL6030.
* To generate the signal on TWL4030:
* - LEDA uses PWMA
* - LEDB uses PWMB
* TWL6030 has one LED pin with dedicated LEDPWM
*/
#define TWL4030_LED_MAX 0x7f
#define TWL6030_LED_MAX 0xff
/* Registers, bits and macro for TWL4030 */
#define TWL4030_LEDEN_REG 0x00
#define TWL4030_PWMA_REG 0x01
#define TWL4030_LEDXON (1 << 0)
#define TWL4030_LEDXPWM (1 << 4)
#define TWL4030_LED_PINS (TWL4030_LEDXON | TWL4030_LEDXPWM)
#define TWL4030_LED_TOGGLE(led, x) ((x) << (led))
/* Register, bits and macro for TWL6030 */
#define TWL6030_LED_PWM_CTRL1 0xf4
#define TWL6030_LED_PWM_CTRL2 0xf5
#define TWL6040_LED_MODE_HW 0x00
#define TWL6040_LED_MODE_ON 0x01
#define TWL6040_LED_MODE_OFF 0x02
#define TWL6040_LED_MODE_MASK 0x03
struct twl_pwmled_chip {
struct pwm_chip chip;
struct mutex mutex;
};
static inline struct twl_pwmled_chip *to_twl(struct pwm_chip *chip)
{
return container_of(chip, struct twl_pwmled_chip, chip);
}
static int twl4030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
int duty_cycle = DIV_ROUND_UP(duty_ns * TWL4030_LED_MAX, period_ns) + 1;
u8 pwm_config[2] = { 1, 0 };
int base, ret;
/*
* To configure the duty period:
* On-cycle is set to 1 (the minimum allowed value)
* The off time of 0 is not configurable, so the mapping is:
* 0 -> off cycle = 2,
* 1 -> off cycle = 2,
* 2 -> off cycle = 3,
* 126 - > off cycle 127,
* 127 - > off cycle 1
* When on cycle == off cycle the PWM will be always on
*/
if (duty_cycle == 1)
duty_cycle = 2;
else if (duty_cycle > TWL4030_LED_MAX)
duty_cycle = 1;
base = pwm->hwpwm * 2 + TWL4030_PWMA_REG;
pwm_config[1] = duty_cycle;
ret = twl_i2c_write(TWL4030_MODULE_LED, pwm_config, base, 2);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
return ret;
}
static int twl4030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
if (ret < 0) {
dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
goto out;
}
val |= TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
out:
mutex_unlock(&twl->mutex);
return ret;
}
static void twl4030_pwmled_disable(struct pwm_chip *chip,
struct pwm_device *pwm)
{
struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL4030_MODULE_LED, &val, TWL4030_LEDEN_REG);
if (ret < 0) {
dev_err(chip->dev, "%s: Failed to read LEDEN\n", pwm->label);
goto out;
}
val &= ~TWL4030_LED_TOGGLE(pwm->hwpwm, TWL4030_LED_PINS);
ret = twl_i2c_write_u8(TWL4030_MODULE_LED, val, TWL4030_LEDEN_REG);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
out:
mutex_unlock(&twl->mutex);
}
static int twl6030_pwmled_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
int duty_cycle = (duty_ns * TWL6030_LED_MAX) / period_ns;
u8 on_time;
int ret;
on_time = duty_cycle & 0xff;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, on_time,
TWL6030_LED_PWM_CTRL1);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to configure PWM\n", pwm->label);
return ret;
}
static int twl6030_pwmled_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
pwm->label);
goto out;
}
val &= ~TWL6040_LED_MODE_MASK;
val |= TWL6040_LED_MODE_ON;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to enable PWM\n", pwm->label);
out:
mutex_unlock(&twl->mutex);
return ret;
}
static void twl6030_pwmled_disable(struct pwm_chip *chip,
struct pwm_device *pwm)
{
struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
pwm->label);
goto out;
}
val &= ~TWL6040_LED_MODE_MASK;
val |= TWL6040_LED_MODE_OFF;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to disable PWM\n", pwm->label);
out:
mutex_unlock(&twl->mutex);
}
static int twl6030_pwmled_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
pwm->label);
goto out;
}
val &= ~TWL6040_LED_MODE_MASK;
val |= TWL6040_LED_MODE_OFF;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to request PWM\n", pwm->label);
out:
mutex_unlock(&twl->mutex);
return ret;
}
static void twl6030_pwmled_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct twl_pwmled_chip *twl = to_twl(chip);
int ret;
u8 val;
mutex_lock(&twl->mutex);
ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, TWL6030_LED_PWM_CTRL2);
if (ret < 0) {
dev_err(chip->dev, "%s: Failed to read PWM_CTRL2\n",
pwm->label);
goto out;
}
val &= ~TWL6040_LED_MODE_MASK;
val |= TWL6040_LED_MODE_HW;
ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, TWL6030_LED_PWM_CTRL2);
if (ret < 0)
dev_err(chip->dev, "%s: Failed to free PWM\n", pwm->label);
out:
mutex_unlock(&twl->mutex);
}
static const struct pwm_ops twl4030_pwmled_ops = {
.enable = twl4030_pwmled_enable,
.disable = twl4030_pwmled_disable,
.config = twl4030_pwmled_config,
};
static const struct pwm_ops twl6030_pwmled_ops = {
.enable = twl6030_pwmled_enable,
.disable = twl6030_pwmled_disable,
.config = twl6030_pwmled_config,
.request = twl6030_pwmled_request,
.free = twl6030_pwmled_free,
};
static int twl_pwmled_probe(struct platform_device *pdev)
{
struct twl_pwmled_chip *twl;
int ret;
twl = devm_kzalloc(&pdev->dev, sizeof(*twl), GFP_KERNEL);
if (!twl)
return -ENOMEM;
if (twl_class_is_4030()) {
twl->chip.ops = &twl4030_pwmled_ops;
twl->chip.npwm = 2;
} else {
twl->chip.ops = &twl6030_pwmled_ops;
twl->chip.npwm = 1;
}
twl->chip.dev = &pdev->dev;
twl->chip.base = -1;
twl->chip.can_sleep = true;
mutex_init(&twl->mutex);
ret = pwmchip_add(&twl->chip);
if (ret < 0)
return ret;
platform_set_drvdata(pdev, twl);
return 0;
}
static int twl_pwmled_remove(struct platform_device *pdev)
{
struct twl_pwmled_chip *twl = platform_get_drvdata(pdev);
return pwmchip_remove(&twl->chip);
}
#ifdef CONFIG_OF
static struct of_device_id twl_pwmled_of_match[] = {
{ .compatible = "ti,twl4030-pwmled" },
{ .compatible = "ti,twl6030-pwmled" },
{ },
};
MODULE_DEVICE_TABLE(of, twl_pwmled_of_match);
#endif
static struct platform_driver twl_pwmled_driver = {
.driver = {
.name = "twl-pwmled",
.of_match_table = of_match_ptr(twl_pwmled_of_match),
},
.probe = twl_pwmled_probe,
.remove = twl_pwmled_remove,
};
module_platform_driver(twl_pwmled_driver);
MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
MODULE_DESCRIPTION("PWM driver for TWL4030 and TWL6030 LED outputs");
MODULE_ALIAS("platform:twl-pwmled");
MODULE_LICENSE("GPL");
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