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linux-next/drivers/leds/leds-bcm6328.c
Álvaro Fernández Rojas 1b85a5a5ef leds: bcm6328: improve blink support 
BCM6328 controller has a margin of 20ms per blink step, which means that
we can only set it to 20, 40, 60 ... 1260 ms (0x3f * 20ms).
However, when checking if delay_on == delay_off, we were not considering
the case when the user had set delay_on=20 and delay_off=21, since this
will cause the driver to fallback to software blinking.
This update fixes this issue and improves blink steps by rounding them
in a more sensible way. Now 30-49ms is rounded to 40 ms, and previous
behaviour implied 40-59ms being rounded to 40 ms.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>
2016-01-04 09:57:40 +01:00

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/*
* Driver for BCM6328 memory-mapped LEDs, based on leds-syscon.c
*
* Copyright 2015 Álvaro Fernández Rojas <noltari@gmail.com>
* Copyright 2015 Jonas Gorski <jogo@openwrt.org>
*
* 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.
*/
#include <linux/io.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#define BCM6328_REG_INIT 0x00
#define BCM6328_REG_MODE_HI 0x04
#define BCM6328_REG_MODE_LO 0x08
#define BCM6328_REG_HWDIS 0x0c
#define BCM6328_REG_STROBE 0x10
#define BCM6328_REG_LNKACTSEL_HI 0x14
#define BCM6328_REG_LNKACTSEL_LO 0x18
#define BCM6328_REG_RBACK 0x1c
#define BCM6328_REG_SERMUX 0x20
#define BCM6328_LED_MAX_COUNT 24
#define BCM6328_LED_DEF_DELAY 500
#define BCM6328_LED_INTERVAL_MS 20
#define BCM6328_LED_INTV_MASK 0x3f
#define BCM6328_LED_FAST_INTV_SHIFT 6
#define BCM6328_LED_FAST_INTV_MASK (BCM6328_LED_INTV_MASK << \
BCM6328_LED_FAST_INTV_SHIFT)
#define BCM6328_SERIAL_LED_EN BIT(12)
#define BCM6328_SERIAL_LED_MUX BIT(13)
#define BCM6328_SERIAL_LED_CLK_NPOL BIT(14)
#define BCM6328_SERIAL_LED_DATA_PPOL BIT(15)
#define BCM6328_SERIAL_LED_SHIFT_DIR BIT(16)
#define BCM6328_LED_SHIFT_TEST BIT(30)
#define BCM6328_LED_TEST BIT(31)
#define BCM6328_INIT_MASK (BCM6328_SERIAL_LED_EN | \
BCM6328_SERIAL_LED_MUX | \
BCM6328_SERIAL_LED_CLK_NPOL | \
BCM6328_SERIAL_LED_DATA_PPOL | \
BCM6328_SERIAL_LED_SHIFT_DIR)
#define BCM6328_LED_MODE_MASK 3
#define BCM6328_LED_MODE_ON 0
#define BCM6328_LED_MODE_FAST 1
#define BCM6328_LED_MODE_BLINK 2
#define BCM6328_LED_MODE_OFF 3
#define BCM6328_LED_SHIFT(X) ((X) << 1)
/**
* struct bcm6328_led - state container for bcm6328 based LEDs
* @cdev: LED class device for this LED
* @mem: memory resource
* @lock: memory lock
* @pin: LED pin number
* @blink_leds: blinking LEDs
* @blink_delay: blinking delay
* @active_low: LED is active low
*/
struct bcm6328_led {
struct led_classdev cdev;
void __iomem *mem;
spinlock_t *lock;
unsigned long pin;
unsigned long *blink_leds;
unsigned long *blink_delay;
bool active_low;
};
static void bcm6328_led_write(void __iomem *reg, unsigned long data)
{
#ifdef CONFIG_CPU_BIG_ENDIAN
iowrite32be(data, reg);
#else
writel(data, reg);
#endif
}
static unsigned long bcm6328_led_read(void __iomem *reg)
{
#ifdef CONFIG_CPU_BIG_ENDIAN
return ioread32be(reg);
#else
return readl(reg);
#endif
}
/**
* LEDMode 64 bits / 24 LEDs
* bits [31:0] -> LEDs 8-23
* bits [47:32] -> LEDs 0-7
* bits [63:48] -> unused
*/
static unsigned long bcm6328_pin2shift(unsigned long pin)
{
if (pin < 8)
return pin + 16; /* LEDs 0-7 (bits 47:32) */
else
return pin - 8; /* LEDs 8-23 (bits 31:0) */
}
static void bcm6328_led_mode(struct bcm6328_led *led, unsigned long value)
{
void __iomem *mode;
unsigned long val, shift;
shift = bcm6328_pin2shift(led->pin);
if (shift / 16)
mode = led->mem + BCM6328_REG_MODE_HI;
else
mode = led->mem + BCM6328_REG_MODE_LO;
val = bcm6328_led_read(mode);
val &= ~(BCM6328_LED_MODE_MASK << BCM6328_LED_SHIFT(shift % 16));
val |= (value << BCM6328_LED_SHIFT(shift % 16));
bcm6328_led_write(mode, val);
}
static void bcm6328_led_set(struct led_classdev *led_cdev,
enum led_brightness value)
{
struct bcm6328_led *led =
container_of(led_cdev, struct bcm6328_led, cdev);
unsigned long flags;
spin_lock_irqsave(led->lock, flags);
*(led->blink_leds) &= ~BIT(led->pin);
if ((led->active_low && value == LED_OFF) ||
(!led->active_low && value != LED_OFF))
bcm6328_led_mode(led, BCM6328_LED_MODE_ON);
else
bcm6328_led_mode(led, BCM6328_LED_MODE_OFF);
spin_unlock_irqrestore(led->lock, flags);
}
static unsigned long bcm6328_blink_delay(unsigned long delay)
{
unsigned long bcm6328_delay;
bcm6328_delay = delay + BCM6328_LED_INTERVAL_MS / 2;
bcm6328_delay = bcm6328_delay / BCM6328_LED_INTERVAL_MS;
if (bcm6328_delay == 0)
bcm6328_delay = 1;
return bcm6328_delay;
}
static int bcm6328_blink_set(struct led_classdev *led_cdev,
unsigned long *delay_on, unsigned long *delay_off)
{
struct bcm6328_led *led =
container_of(led_cdev, struct bcm6328_led, cdev);
unsigned long delay, flags;
int rc;
if (!*delay_on)
*delay_on = BCM6328_LED_DEF_DELAY;
if (!*delay_off)
*delay_off = BCM6328_LED_DEF_DELAY;
delay = bcm6328_blink_delay(*delay_on);
if (delay != bcm6328_blink_delay(*delay_off)) {
dev_dbg(led_cdev->dev,
"fallback to soft blinking (delay_on != delay_off)\n");
return -EINVAL;
}
if (delay > BCM6328_LED_INTV_MASK) {
dev_dbg(led_cdev->dev,
"fallback to soft blinking (delay > %ums)\n",
BCM6328_LED_INTV_MASK * BCM6328_LED_INTERVAL_MS);
return -EINVAL;
}
spin_lock_irqsave(led->lock, flags);
if (*(led->blink_leds) == 0 ||
*(led->blink_leds) == BIT(led->pin) ||
*(led->blink_delay) == delay) {
unsigned long val;
*(led->blink_leds) |= BIT(led->pin);
*(led->blink_delay) = delay;
val = bcm6328_led_read(led->mem + BCM6328_REG_INIT);
val &= ~BCM6328_LED_FAST_INTV_MASK;
val |= (delay << BCM6328_LED_FAST_INTV_SHIFT);
bcm6328_led_write(led->mem + BCM6328_REG_INIT, val);
bcm6328_led_mode(led, BCM6328_LED_MODE_BLINK);
rc = 0;
} else {
dev_dbg(led_cdev->dev,
"fallback to soft blinking (delay already set)\n");
rc = -EINVAL;
}
spin_unlock_irqrestore(led->lock, flags);
return rc;
}
static int bcm6328_hwled(struct device *dev, struct device_node *nc, u32 reg,
void __iomem *mem, spinlock_t *lock)
{
int i, cnt;
unsigned long flags, val;
spin_lock_irqsave(lock, flags);
val = bcm6328_led_read(mem + BCM6328_REG_HWDIS);
val &= ~BIT(reg);
bcm6328_led_write(mem + BCM6328_REG_HWDIS, val);
spin_unlock_irqrestore(lock, flags);
/* Only LEDs 0-7 can be activity/link controlled */
if (reg >= 8)
return 0;
cnt = of_property_count_elems_of_size(nc, "brcm,link-signal-sources",
sizeof(u32));
for (i = 0; i < cnt; i++) {
u32 sel;
void __iomem *addr;
if (reg < 4)
addr = mem + BCM6328_REG_LNKACTSEL_LO;
else
addr = mem + BCM6328_REG_LNKACTSEL_HI;
of_property_read_u32_index(nc, "brcm,link-signal-sources", i,
&sel);
if (reg / 4 != sel / 4) {
dev_warn(dev, "invalid link signal source\n");
continue;
}
spin_lock_irqsave(lock, flags);
val = bcm6328_led_read(addr);
val |= (BIT(reg) << (((sel % 4) * 4) + 16));
bcm6328_led_write(addr, val);
spin_unlock_irqrestore(lock, flags);
}
cnt = of_property_count_elems_of_size(nc,
"brcm,activity-signal-sources",
sizeof(u32));
for (i = 0; i < cnt; i++) {
u32 sel;
void __iomem *addr;
if (reg < 4)
addr = mem + BCM6328_REG_LNKACTSEL_LO;
else
addr = mem + BCM6328_REG_LNKACTSEL_HI;
of_property_read_u32_index(nc, "brcm,activity-signal-sources",
i, &sel);
if (reg / 4 != sel / 4) {
dev_warn(dev, "invalid activity signal source\n");
continue;
}
spin_lock_irqsave(lock, flags);
val = bcm6328_led_read(addr);
val |= (BIT(reg) << ((sel % 4) * 4));
bcm6328_led_write(addr, val);
spin_unlock_irqrestore(lock, flags);
}
return 0;
}
static int bcm6328_led(struct device *dev, struct device_node *nc, u32 reg,
void __iomem *mem, spinlock_t *lock,
unsigned long *blink_leds, unsigned long *blink_delay)
{
struct bcm6328_led *led;
const char *state;
int rc;
led = devm_kzalloc(dev, sizeof(*led), GFP_KERNEL);
if (!led)
return -ENOMEM;
led->pin = reg;
led->mem = mem;
led->lock = lock;
led->blink_leds = blink_leds;
led->blink_delay = blink_delay;
if (of_property_read_bool(nc, "active-low"))
led->active_low = true;
led->cdev.name = of_get_property(nc, "label", NULL) ? : nc->name;
led->cdev.default_trigger = of_get_property(nc,
"linux,default-trigger",
NULL);
if (!of_property_read_string(nc, "default-state", &state)) {
if (!strcmp(state, "on")) {
led->cdev.brightness = LED_FULL;
} else if (!strcmp(state, "keep")) {
void __iomem *mode;
unsigned long val, shift;
shift = bcm6328_pin2shift(led->pin);
if (shift / 16)
mode = mem + BCM6328_REG_MODE_HI;
else
mode = mem + BCM6328_REG_MODE_LO;
val = bcm6328_led_read(mode) >>
BCM6328_LED_SHIFT(shift % 16);
val &= BCM6328_LED_MODE_MASK;
if ((led->active_low && val == BCM6328_LED_MODE_OFF) ||
(!led->active_low && val == BCM6328_LED_MODE_ON))
led->cdev.brightness = LED_FULL;
else
led->cdev.brightness = LED_OFF;
} else {
led->cdev.brightness = LED_OFF;
}
} else {
led->cdev.brightness = LED_OFF;
}
bcm6328_led_set(&led->cdev, led->cdev.brightness);
led->cdev.brightness_set = bcm6328_led_set;
led->cdev.blink_set = bcm6328_blink_set;
rc = led_classdev_register(dev, &led->cdev);
if (rc < 0)
return rc;
dev_dbg(dev, "registered LED %s\n", led->cdev.name);
return 0;
}
static int bcm6328_leds_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = pdev->dev.of_node;
struct device_node *child;
struct resource *mem_r;
void __iomem *mem;
spinlock_t *lock; /* memory lock */
unsigned long val, *blink_leds, *blink_delay;
mem_r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem_r)
return -EINVAL;
mem = devm_ioremap_resource(dev, mem_r);
if (IS_ERR(mem))
return PTR_ERR(mem);
lock = devm_kzalloc(dev, sizeof(*lock), GFP_KERNEL);
if (!lock)
return -ENOMEM;
blink_leds = devm_kzalloc(dev, sizeof(*blink_leds), GFP_KERNEL);
if (!blink_leds)
return -ENOMEM;
blink_delay = devm_kzalloc(dev, sizeof(*blink_delay), GFP_KERNEL);
if (!blink_delay)
return -ENOMEM;
spin_lock_init(lock);
bcm6328_led_write(mem + BCM6328_REG_HWDIS, ~0);
bcm6328_led_write(mem + BCM6328_REG_LNKACTSEL_HI, 0);
bcm6328_led_write(mem + BCM6328_REG_LNKACTSEL_LO, 0);
val = bcm6328_led_read(mem + BCM6328_REG_INIT);
val &= ~(BCM6328_INIT_MASK);
if (of_property_read_bool(np, "brcm,serial-leds"))
val |= BCM6328_SERIAL_LED_EN;
if (of_property_read_bool(np, "brcm,serial-mux"))
val |= BCM6328_SERIAL_LED_MUX;
if (of_property_read_bool(np, "brcm,serial-clk-low"))
val |= BCM6328_SERIAL_LED_CLK_NPOL;
if (!of_property_read_bool(np, "brcm,serial-dat-low"))
val |= BCM6328_SERIAL_LED_DATA_PPOL;
if (!of_property_read_bool(np, "brcm,serial-shift-inv"))
val |= BCM6328_SERIAL_LED_SHIFT_DIR;
bcm6328_led_write(mem + BCM6328_REG_INIT, val);
for_each_available_child_of_node(np, child) {
int rc;
u32 reg;
if (of_property_read_u32(child, "reg", &reg))
continue;
if (reg >= BCM6328_LED_MAX_COUNT) {
dev_err(dev, "invalid LED (%u >= %d)\n", reg,
BCM6328_LED_MAX_COUNT);
continue;
}
if (of_property_read_bool(child, "brcm,hardware-controlled"))
rc = bcm6328_hwled(dev, child, reg, mem, lock);
else
rc = bcm6328_led(dev, child, reg, mem, lock,
blink_leds, blink_delay);
if (rc < 0) {
of_node_put(child);
return rc;
}
}
return 0;
}
static const struct of_device_id bcm6328_leds_of_match[] = {
{ .compatible = "brcm,bcm6328-leds", },
{ },
};
MODULE_DEVICE_TABLE(of, bcm6328_leds_of_match);
static struct platform_driver bcm6328_leds_driver = {
.probe = bcm6328_leds_probe,
.driver = {
.name = "leds-bcm6328",
.of_match_table = bcm6328_leds_of_match,
},
};
module_platform_driver(bcm6328_leds_driver);
MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
MODULE_AUTHOR("Jonas Gorski <jogo@openwrt.org>");
MODULE_DESCRIPTION("LED driver for BCM6328 controllers");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:leds-bcm6328");
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