// SPDX-License-Identifier: GPL-2.0-only /* * 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 (pull-up resistor required) 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. */ #include #include #include #include #include #include #include #include /* 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 */ struct tca6507_platform_data { struct led_platform_data leds; }; #define TCA6507_MAKE_GPIO 1 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; 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) { swap(*c2p, *c1p); } 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 * initialization. */ 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 codes 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); if (result < 0) return; 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<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 = gpiochip_get_data(gc); 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 device *dev, 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_map[gpios] = i; gpios++; } if (!gpios) return 0; tca->gpio.label = "gpio-tca6507"; tca->gpio.ngpio = gpios; tca->gpio.base = -1; tca->gpio.owner = THIS_MODULE; tca->gpio.direction_output = tca6507_gpio_direction_output; tca->gpio.set = tca6507_gpio_set_value; tca->gpio.parent = dev; err = devm_gpiochip_add_data(dev, &tca->gpio, tca); if (err) { tca->gpio.ngpio = 0; return err; } return 0; } #else /* CONFIG_GPIOLIB */ static int tca6507_probe_gpios(struct device *dev, struct tca6507_chip *tca, struct tca6507_platform_data *pdata) { return 0; } #endif /* CONFIG_GPIOLIB */ static struct tca6507_platform_data * tca6507_led_dt_init(struct device *dev) { struct tca6507_platform_data *pdata; struct led_info *tca_leds; int count; count = device_get_child_node_count(dev); if (!count || count > NUM_LEDS) return ERR_PTR(-ENODEV); tca_leds = devm_kcalloc(dev, NUM_LEDS, sizeof(struct led_info), GFP_KERNEL); if (!tca_leds) return ERR_PTR(-ENOMEM); device_for_each_child_node_scoped(dev, child) { struct led_info led; u32 reg; int ret; if (fwnode_property_read_string(child, "label", &led.name)) led.name = fwnode_get_name(child); if (fwnode_property_read_string(child, "linux,default-trigger", &led.default_trigger)) led.default_trigger = NULL; led.flags = 0; if (fwnode_device_is_compatible(child, "gpio")) led.flags |= TCA6507_MAKE_GPIO; ret = fwnode_property_read_u32(child, "reg", ®); if (ret || reg >= NUM_LEDS) return ERR_PTR(ret ? : -EINVAL); tca_leds[reg] = led; } pdata = devm_kzalloc(dev, sizeof(struct tca6507_platform_data), GFP_KERNEL); if (!pdata) return ERR_PTR(-ENOMEM); pdata->leds.leds = tca_leds; pdata->leds.num_leds = NUM_LEDS; return pdata; } static const struct of_device_id __maybe_unused of_tca6507_leds_match[] = { { .compatible = "ti,tca6507", }, {}, }; MODULE_DEVICE_TABLE(of, of_tca6507_leds_match); static int tca6507_probe(struct i2c_client *client) { struct device *dev = &client->dev; struct i2c_adapter *adapter; struct tca6507_chip *tca; struct tca6507_platform_data *pdata; int err; int i = 0; adapter = client->adapter; if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) return -EIO; pdata = tca6507_led_dt_init(dev); if (IS_ERR(pdata)) { dev_err(dev, "Need %d entries in platform-data list\n", NUM_LEDS); return PTR_ERR(pdata); } tca = devm_kzalloc(dev, sizeof(*tca), GFP_KERNEL); if (!tca) return -ENOMEM; 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 = devm_led_classdev_register(dev, &l->led_cdev); if (err < 0) return err; } } err = tca6507_probe_gpios(dev, tca, pdata); if (err) return err; /* set all registers to known state - zero */ tca->reg_set = 0x7f; schedule_work(&tca->work); return 0; } static void tca6507_remove(struct i2c_client *client) { struct tca6507_chip *tca = i2c_get_clientdata(client); cancel_work_sync(&tca->work); } static struct i2c_driver tca6507_driver = { .driver = { .name = "leds-tca6507", .of_match_table = of_match_ptr(of_tca6507_leds_match), }, .probe = tca6507_probe, .remove = tca6507_remove, .id_table = tca6507_id, }; module_i2c_driver(tca6507_driver); MODULE_AUTHOR("NeilBrown "); MODULE_DESCRIPTION("TCA6507 LED/GPO driver"); MODULE_LICENSE("GPL v2");