diff options
Diffstat (limited to 'drivers/leds/leds-tca6507.c')
| -rw-r--r-- | drivers/leds/leds-tca6507.c | 779 |
1 files changed, 779 insertions, 0 deletions
diff --git a/drivers/leds/leds-tca6507.c b/drivers/leds/leds-tca6507.c new file mode 100644 index 0000000..133f89f --- /dev/null +++ b/drivers/leds/leds-tca6507.c @@ -0,0 +1,779 @@ +/* + * leds-tca6507 + * + * The TCA6507 is a programmable LED controller that can drive 7 + * separate lines either by holding them low, or by pulsing them + * with modulated width. + * The modulation can be varied in a simple pattern to produce a blink or + * double-blink. + * + * This driver can configure each line either as a 'GPIO' which is out-only + * (no pull-up) or as an LED with variable brightness and hardware-assisted + * blinking. + * + * Apart from OFF and ON there are three programmable brightness levels which + * can be programmed from 0 to 15 and indicate how many 500usec intervals in + * each 8msec that the led is 'on'. The levels are named MASTER, BANK0 and + * BANK1. + * + * There are two different blink rates that can be programmed, each with + * separate time for rise, on, fall, off and second-off. Thus if 3 or more + * different non-trivial rates are required, software must be used for the extra + * rates. The two different blink rates must align with the two levels BANK0 and + * BANK1. + * This driver does not support double-blink so 'second-off' always matches + * 'off'. + * + * Only 16 different times can be programmed in a roughly logarithmic scale from + * 64ms to 16320ms. To be precise the possible times are: + * 0, 64, 128, 192, 256, 384, 512, 768, + * 1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320 + * + * Times that cannot be closely matched with these must be + * handled in software. This driver allows 12.5% error in matching. + * + * This driver does not allow rise/fall rates to be set explicitly. When trying + * to match a given 'on' or 'off' period, an appropriate pair of 'change' and + * 'hold' times are chosen to get a close match. If the target delay is even, + * the 'change' number will be the smaller; if odd, the 'hold' number will be + * the smaller. + + * Choosing pairs of delays with 12.5% errors allows us to match delays in the + * ranges: 56-72, 112-144, 168-216, 224-27504, 28560-36720. + * 26% of the achievable sums can be matched by multiple pairings. For example + * 1536 == 1536+0, 1024+512, or 768+768. This driver will always choose the + * pairing with the least maximum - 768+768 in this case. Other pairings are + * not available. + * + * Access to the 3 levels and 2 blinks are on a first-come, first-served basis. + * Access can be shared by multiple leds if they have the same level and + * either same blink rates, or some don't blink. + * When a led changes, it relinquishes access and tries again, so it might + * lose access to hardware blink. + * If a blink engine cannot be allocated, software blink is used. + * If the desired brightness cannot be allocated, the closest available non-zero + * brightness is used. As 'full' is always available, the worst case would be + * to have two different blink rates at '1', with Max at '2', then other leds + * will have to choose between '2' and '16'. Hopefully this is not likely. + * + * Each bank (BANK0 and BANK1) has two usage counts - LEDs using the brightness + * and LEDs using the blink. It can only be reprogrammed when the appropriate + * counter is zero. The MASTER level has a single usage count. + * + * Each Led has programmable 'on' and 'off' time as milliseconds. With each + * there is a flag saying if it was explicitly requested or defaulted. + * Similarly the banks know if each time was explicit or a default. Defaults + * are permitted to be changed freely - they are not recognised when matching. + * + * + * An led-tca6507 device must be provided with platform data. This data + * lists for each output: the name, default trigger, and whether the signal + * is being used as a GPiO rather than an led. 'struct led_plaform_data' + * is used for this. If 'name' is NULL, the output isn't used. If 'flags' + * is TCA6507_MAKE_CPIO, the output is a GPO. + * The "struct led_platform_data" can be embedded in a + * "struct tca6507_platform_data" which adds a 'gpio_base' for the GPiOs, + * and a 'setup' callback which is called once the GPiOs are available. + * + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/leds.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/gpio.h> +#include <linux/workqueue.h> +#include <linux/leds-tca6507.h> + +/* LED select registers determine the source that drives LED outputs */ +#define TCA6507_LS_LED_OFF 0x0 /* Output HI-Z (off) */ +#define TCA6507_LS_LED_OFF1 0x1 /* Output HI-Z (off) - not used */ +#define TCA6507_LS_LED_PWM0 0x2 /* Output LOW with Bank0 rate */ +#define TCA6507_LS_LED_PWM1 0x3 /* Output LOW with Bank1 rate */ +#define TCA6507_LS_LED_ON 0x4 /* Output LOW (on) */ +#define TCA6507_LS_LED_MIR 0x5 /* Output LOW with Master Intensity */ +#define TCA6507_LS_BLINK0 0x6 /* Blink at Bank0 rate */ +#define TCA6507_LS_BLINK1 0x7 /* Blink at Bank1 rate */ + +enum { + BANK0, + BANK1, + MASTER, +}; +static int bank_source[3] = { + TCA6507_LS_LED_PWM0, + TCA6507_LS_LED_PWM1, + TCA6507_LS_LED_MIR, +}; +static int blink_source[2] = { + TCA6507_LS_BLINK0, + TCA6507_LS_BLINK1, +}; + +/* PWM registers */ +#define TCA6507_REG_CNT 11 + +/* + * 0x00, 0x01, 0x02 encode the TCA6507_LS_* values, each output + * owns one bit in each register + */ +#define TCA6507_FADE_ON 0x03 +#define TCA6507_FULL_ON 0x04 +#define TCA6507_FADE_OFF 0x05 +#define TCA6507_FIRST_OFF 0x06 +#define TCA6507_SECOND_OFF 0x07 +#define TCA6507_MAX_INTENSITY 0x08 +#define TCA6507_MASTER_INTENSITY 0x09 +#define TCA6507_INITIALIZE 0x0A + +#define INIT_CODE 0x8 + +#define TIMECODES 16 +static int time_codes[TIMECODES] = { + 0, 64, 128, 192, 256, 384, 512, 768, + 1024, 1536, 2048, 3072, 4096, 5760, 8128, 16320 +}; + +/* Convert an led.brightness level (0..255) to a TCA6507 level (0..15) */ +static inline int TO_LEVEL(int brightness) +{ + return brightness >> 4; +} + +/* ...and convert back */ +static inline int TO_BRIGHT(int level) +{ + if (level) + return (level << 4) | 0xf; + return 0; +} + +#define NUM_LEDS 7 +struct tca6507_chip { + int reg_set; /* One bit per register where + * a '1' means the register + * should be written */ + u8 reg_file[TCA6507_REG_CNT]; + /* Bank 2 is Master Intensity and doesn't use times */ + struct bank { + int level; + int ontime, offtime; + int on_dflt, off_dflt; + int time_use, level_use; + } bank[3]; + struct i2c_client *client; + struct work_struct work; + spinlock_t lock; + + struct tca6507_led { + struct tca6507_chip *chip; + struct led_classdev led_cdev; + int num; + int ontime, offtime; + int on_dflt, off_dflt; + int bank; /* Bank used, or -1 */ + int blink; /* Set if hardware-blinking */ + } leds[NUM_LEDS]; +#ifdef CONFIG_GPIOLIB + struct gpio_chip gpio; + const char *gpio_name[NUM_LEDS]; + int gpio_map[NUM_LEDS]; +#endif +}; + +static const struct i2c_device_id tca6507_id[] = { + { "tca6507" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, tca6507_id); + +static int choose_times(int msec, int *c1p, int *c2p) +{ + /* + * Choose two timecodes which add to 'msec' as near as possible. + * The first returned is the 'on' or 'off' time. The second is to be + * used as a 'fade-on' or 'fade-off' time. If 'msec' is even, + * the first will not be smaller than the second. If 'msec' is odd, + * the first will not be larger than the second. + * If we cannot get a sum within 1/8 of 'msec' fail with -EINVAL, + * otherwise return the sum that was achieved, plus 1 if the first is + * smaller. + * If two possibilities are equally good (e.g. 512+0, 256+256), choose + * the first pair so there is more change-time visible (i.e. it is + * softer). + */ + int c1, c2; + int tmax = msec * 9 / 8; + int tmin = msec * 7 / 8; + int diff = 65536; + + /* We start at '1' to ensure we never even think of choosing a + * total time of '0'. + */ + for (c1 = 1; c1 < TIMECODES; c1++) { + int t = time_codes[c1]; + if (t*2 < tmin) + continue; + if (t > tmax) + break; + for (c2 = 0; c2 <= c1; c2++) { + int tt = t + time_codes[c2]; + int d; + if (tt < tmin) + continue; + if (tt > tmax) + break; + /* This works! */ + d = abs(msec - tt); + if (d >= diff) + continue; + /* Best yet */ + *c1p = c1; + *c2p = c2; + diff = d; + if (d == 0) + return msec; + } + } + if (diff < 65536) { + int actual; + if (msec & 1) { + c1 = *c2p; + *c2p = *c1p; + *c1p = c1; + } + actual = time_codes[*c1p] + time_codes[*c2p]; + if (*c1p < *c2p) + return actual + 1; + else + return actual; + } + /* No close match */ + return -EINVAL; +} + +/* + * Update the register file with the appropriate 3-bit state for + * the given led. + */ +static void set_select(struct tca6507_chip *tca, int led, int val) +{ + int mask = (1 << led); + int bit; + + for (bit = 0; bit < 3; bit++) { + int n = tca->reg_file[bit] & ~mask; + if (val & (1 << bit)) + n |= mask; + if (tca->reg_file[bit] != n) { + tca->reg_file[bit] = n; + tca->reg_set |= (1 << bit); + } + } +} + +/* Update the register file with the appropriate 4-bit code for + * one bank or other. This can be used for timers, for levels, or + * for initialisation. + */ +static void set_code(struct tca6507_chip *tca, int reg, int bank, int new) +{ + int mask = 0xF; + int n; + if (bank) { + mask <<= 4; + new <<= 4; + } + n = tca->reg_file[reg] & ~mask; + n |= new; + if (tca->reg_file[reg] != n) { + tca->reg_file[reg] = n; + tca->reg_set |= 1 << reg; + } +} + +/* Update brightness level. */ +static void set_level(struct tca6507_chip *tca, int bank, int level) +{ + switch (bank) { + case BANK0: + case BANK1: + set_code(tca, TCA6507_MAX_INTENSITY, bank, level); + break; + case MASTER: + set_code(tca, TCA6507_MASTER_INTENSITY, 0, level); + break; + } + tca->bank[bank].level = level; +} + +/* Record all relevant time code for a given bank */ +static void set_times(struct tca6507_chip *tca, int bank) +{ + int c1, c2; + int result; + + result = choose_times(tca->bank[bank].ontime, &c1, &c2); + dev_dbg(&tca->client->dev, + "Chose on times %d(%d) %d(%d) for %dms\n", c1, time_codes[c1], + c2, time_codes[c2], tca->bank[bank].ontime); + set_code(tca, TCA6507_FADE_ON, bank, c2); + set_code(tca, TCA6507_FULL_ON, bank, c1); + tca->bank[bank].ontime = result; + + result = choose_times(tca->bank[bank].offtime, &c1, &c2); + dev_dbg(&tca->client->dev, + "Chose off times %d(%d) %d(%d) for %dms\n", c1, time_codes[c1], + c2, time_codes[c2], tca->bank[bank].offtime); + set_code(tca, TCA6507_FADE_OFF, bank, c2); + set_code(tca, TCA6507_FIRST_OFF, bank, c1); + set_code(tca, TCA6507_SECOND_OFF, bank, c1); + tca->bank[bank].offtime = result; + + set_code(tca, TCA6507_INITIALIZE, bank, INIT_CODE); +} + +/* Write all needed register of tca6507 */ + +static void tca6507_work(struct work_struct *work) +{ + struct tca6507_chip *tca = container_of(work, struct tca6507_chip, + work); + struct i2c_client *cl = tca->client; + int set; + u8 file[TCA6507_REG_CNT]; + int r; + + spin_lock_irq(&tca->lock); + set = tca->reg_set; + memcpy(file, tca->reg_file, TCA6507_REG_CNT); + tca->reg_set = 0; + spin_unlock_irq(&tca->lock); + + for (r = 0; r < TCA6507_REG_CNT; r++) + if (set & (1<<r)) + i2c_smbus_write_byte_data(cl, r, file[r]); +} + +static void led_release(struct tca6507_led *led) +{ + /* If led owns any resource, release it. */ + struct tca6507_chip *tca = led->chip; + if (led->bank >= 0) { + struct bank *b = tca->bank + led->bank; + if (led->blink) + b->time_use--; + b->level_use--; + } + led->blink = 0; + led->bank = -1; +} + +static int led_prepare(struct tca6507_led *led) +{ + /* Assign this led to a bank, configuring that bank if necessary. */ + int level = TO_LEVEL(led->led_cdev.brightness); + struct tca6507_chip *tca = led->chip; + int c1, c2; + int i; + struct bank *b; + int need_init = 0; + + led->led_cdev.brightness = TO_BRIGHT(level); + if (level == 0) { + set_select(tca, led->num, TCA6507_LS_LED_OFF); + return 0; + } + + if (led->ontime == 0 || led->offtime == 0) { + /* + * Just set the brightness, choosing first usable bank. + * If none perfect, choose best. + * Count backwards so we check MASTER bank first + * to avoid wasting a timer. + */ + int best = -1;/* full-on */ + int diff = 15-level; + + if (level == 15) { + set_select(tca, led->num, TCA6507_LS_LED_ON); + return 0; + } + + for (i = MASTER; i >= BANK0; i--) { + int d; + if (tca->bank[i].level == level || + tca->bank[i].level_use == 0) { + best = i; + break; + } + d = abs(level - tca->bank[i].level); + if (d < diff) { + diff = d; + best = i; + } + } + if (best == -1) { + /* Best brightness is full-on */ + set_select(tca, led->num, TCA6507_LS_LED_ON); + led->led_cdev.brightness = LED_FULL; + return 0; + } + + if (!tca->bank[best].level_use) + set_level(tca, best, level); + + tca->bank[best].level_use++; + led->bank = best; + set_select(tca, led->num, bank_source[best]); + led->led_cdev.brightness = TO_BRIGHT(tca->bank[best].level); + return 0; + } + + /* + * We have on/off time so we need to try to allocate a timing bank. + * First check if times are compatible with hardware and give up if + * not. + */ + if (choose_times(led->ontime, &c1, &c2) < 0) + return -EINVAL; + if (choose_times(led->offtime, &c1, &c2) < 0) + return -EINVAL; + + for (i = BANK0; i <= BANK1; i++) { + if (tca->bank[i].level_use == 0) + /* not in use - it is ours! */ + break; + if (tca->bank[i].level != level) + /* Incompatible level - skip */ + /* FIX: if timer matches we maybe should consider + * this anyway... + */ + continue; + + if (tca->bank[i].time_use == 0) + /* Timer not in use, and level matches - use it */ + break; + + if (!(tca->bank[i].on_dflt || + led->on_dflt || + tca->bank[i].ontime == led->ontime)) + /* on time is incompatible */ + continue; + + if (!(tca->bank[i].off_dflt || + led->off_dflt || + tca->bank[i].offtime == led->offtime)) + /* off time is incompatible */ + continue; + + /* looks like a suitable match */ + break; + } + + if (i > BANK1) + /* Nothing matches - how sad */ + return -EINVAL; + + b = &tca->bank[i]; + if (b->level_use == 0) + set_level(tca, i, level); + b->level_use++; + led->bank = i; + + if (b->on_dflt || + !led->on_dflt || + b->time_use == 0) { + b->ontime = led->ontime; + b->on_dflt = led->on_dflt; + need_init = 1; + } + + if (b->off_dflt || + !led->off_dflt || + b->time_use == 0) { + b->offtime = led->offtime; + b->off_dflt = led->off_dflt; + need_init = 1; + } + + if (need_init) + set_times(tca, i); + + led->ontime = b->ontime; + led->offtime = b->offtime; + + b->time_use++; + led->blink = 1; + led->led_cdev.brightness = TO_BRIGHT(b->level); + set_select(tca, led->num, blink_source[i]); + return 0; +} + +static int led_assign(struct tca6507_led *led) +{ + struct tca6507_chip *tca = led->chip; + int err; + unsigned long flags; + + spin_lock_irqsave(&tca->lock, flags); + led_release(led); + err = led_prepare(led); + if (err) { + /* + * Can only fail on timer setup. In that case we need to + * re-establish as steady level. + */ + led->ontime = 0; + led->offtime = 0; + led_prepare(led); + } + spin_unlock_irqrestore(&tca->lock, flags); + + if (tca->reg_set) + schedule_work(&tca->work); + return err; +} + +static void tca6507_brightness_set(struct led_classdev *led_cdev, + enum led_brightness brightness) +{ + struct tca6507_led *led = container_of(led_cdev, struct tca6507_led, + led_cdev); + led->led_cdev.brightness = brightness; + led->ontime = 0; + led->offtime = 0; + led_assign(led); +} + +static int tca6507_blink_set(struct led_classdev *led_cdev, + unsigned long *delay_on, + unsigned long *delay_off) +{ + struct tca6507_led *led = container_of(led_cdev, struct tca6507_led, + led_cdev); + + if (*delay_on == 0) + led->on_dflt = 1; + else if (delay_on != &led_cdev->blink_delay_on) + led->on_dflt = 0; + led->ontime = *delay_on; + + if (*delay_off == 0) + led->off_dflt = 1; + else if (delay_off != &led_cdev->blink_delay_off) + led->off_dflt = 0; + led->offtime = *delay_off; + + if (led->ontime == 0) + led->ontime = 512; + if (led->offtime == 0) + led->offtime = 512; + + if (led->led_cdev.brightness == LED_OFF) + led->led_cdev.brightness = LED_FULL; + if (led_assign(led) < 0) { + led->ontime = 0; + led->offtime = 0; + led->led_cdev.brightness = LED_OFF; + return -EINVAL; + } + *delay_on = led->ontime; + *delay_off = led->offtime; + return 0; +} + +#ifdef CONFIG_GPIOLIB +static void tca6507_gpio_set_value(struct gpio_chip *gc, + unsigned offset, int val) +{ + struct tca6507_chip *tca = container_of(gc, struct tca6507_chip, gpio); + unsigned long flags; + + spin_lock_irqsave(&tca->lock, flags); + /* + * 'OFF' is floating high, and 'ON' is pulled down, so it has the + * inverse sense of 'val'. + */ + set_select(tca, tca->gpio_map[offset], + val ? TCA6507_LS_LED_OFF : TCA6507_LS_LED_ON); + spin_unlock_irqrestore(&tca->lock, flags); + if (tca->reg_set) + schedule_work(&tca->work); +} + +static int tca6507_gpio_direction_output(struct gpio_chip *gc, + unsigned offset, int val) +{ + tca6507_gpio_set_value(gc, offset, val); + return 0; +} + +static int tca6507_probe_gpios(struct i2c_client *client, + struct tca6507_chip *tca, + struct tca6507_platform_data *pdata) +{ + int err; + int i = 0; + int gpios = 0; + + for (i = 0; i < NUM_LEDS; i++) + if (pdata->leds.leds[i].name && pdata->leds.leds[i].flags) { + /* Configure as a gpio */ + tca->gpio_name[gpios] = pdata->leds.leds[i].name; + tca->gpio_map[gpios] = i; + gpios++; + } + + if (!gpios) + return 0; + + tca->gpio.label = "gpio-tca6507"; + tca->gpio.names = tca->gpio_name; + tca->gpio.ngpio = gpios; + tca->gpio.base = pdata->gpio_base; + tca->gpio.owner = THIS_MODULE; + tca->gpio.direction_output = tca6507_gpio_direction_output; + tca->gpio.set = tca6507_gpio_set_value; + tca->gpio.dev = &client->dev; + err = gpiochip_add(&tca->gpio); + if (err) { + tca->gpio.ngpio = 0; + return err; + } + if (pdata->setup) + pdata->setup(tca->gpio.base, tca->gpio.ngpio); + return 0; +} + +static void tca6507_remove_gpio(struct tca6507_chip *tca) +{ + if (tca->gpio.ngpio) { + int err = gpiochip_remove(&tca->gpio); + dev_err(&tca->client->dev, "%s failed, %d\n", + "gpiochip_remove()", err); + } +} +#else /* CONFIG_GPIOLIB */ +static int tca6507_probe_gpios(struct i2c_client *client, + struct tca6507_chip *tca, + struct tca6507_platform_data *pdata) +{ + return 0; +} +static void tca6507_remove_gpio(struct tca6507_chip *tca) +{ +} +#endif /* CONFIG_GPIOLIB */ + +static int __devinit tca6507_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct tca6507_chip *tca; + struct i2c_adapter *adapter; + struct tca6507_platform_data *pdata; + int err; + int i = 0; + + adapter = to_i2c_adapter(client->dev.parent); + pdata = client->dev.platform_data; + + if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) + return -EIO; + + if (!pdata || pdata->leds.num_leds != NUM_LEDS) { + dev_err(&client->dev, "Need %d entries in platform-data list\n", + NUM_LEDS); + return -ENODEV; + } + err = -ENOMEM; + tca = kzalloc(sizeof(*tca), GFP_KERNEL); + if (!tca) + goto exit; + + tca->client = client; + INIT_WORK(&tca->work, tca6507_work); + spin_lock_init(&tca->lock); + i2c_set_clientdata(client, tca); + + for (i = 0; i < NUM_LEDS; i++) { + struct tca6507_led *l = tca->leds + i; + + l->chip = tca; + l->num = i; + if (pdata->leds.leds[i].name && !pdata->leds.leds[i].flags) { + l->led_cdev.name = pdata->leds.leds[i].name; + l->led_cdev.default_trigger + = pdata->leds.leds[i].default_trigger; + l->led_cdev.brightness_set = tca6507_brightness_set; + l->led_cdev.blink_set = tca6507_blink_set; + l->bank = -1; + err = led_classdev_register(&client->dev, + &l->led_cdev); + if (err < 0) + goto exit; + } + } + err = tca6507_probe_gpios(client, tca, pdata); + if (err) + goto exit; + /* set all registers to known state - zero */ + tca->reg_set = 0x7f; + schedule_work(&tca->work); + + return 0; +exit: + while (i--) + if (tca->leds[i].led_cdev.name) + led_classdev_unregister(&tca->leds[i].led_cdev); + cancel_work_sync(&tca->work); + i2c_set_clientdata(client, NULL); + kfree(tca); + return err; +} + +static int __devexit tca6507_remove(struct i2c_client *client) +{ + int i; + struct tca6507_chip *tca = i2c_get_clientdata(client); + struct tca6507_led *tca_leds = tca->leds; + + for (i = 0; i < NUM_LEDS; i++) { + if (tca_leds[i].led_cdev.name) + led_classdev_unregister(&tca_leds[i].led_cdev); + } + tca6507_remove_gpio(tca); + cancel_work_sync(&tca->work); + i2c_set_clientdata(client, NULL); + kfree(tca); + + return 0; +} + +static struct i2c_driver tca6507_driver = { + .driver = { + .name = "leds-tca6507", + .owner = THIS_MODULE, + }, + .probe = tca6507_probe, + .remove = __devexit_p(tca6507_remove), + .id_table = tca6507_id, +}; + +static int __init tca6507_leds_init(void) +{ + return i2c_add_driver(&tca6507_driver); +} + +static void __exit tca6507_leds_exit(void) +{ + i2c_del_driver(&tca6507_driver); +} + +module_init(tca6507_leds_init); +module_exit(tca6507_leds_exit); + +MODULE_AUTHOR("NeilBrown <neilb@suse.de>"); +MODULE_DESCRIPTION("TCA6507 LED/GPO driver"); +MODULE_LICENSE("GPL v2"); |