diff options
| -rw-r--r-- | drivers/leds/leds-pca955x.c | 224 |
1 files changed, 172 insertions, 52 deletions
diff --git a/drivers/leds/leds-pca955x.c b/drivers/leds/leds-pca955x.c index eb268e6ee2a8..156649e1e1c4 100644 --- a/drivers/leds/leds-pca955x.c +++ b/drivers/leds/leds-pca955x.c @@ -62,6 +62,8 @@ #define PCA955X_GPIO_HIGH LED_OFF #define PCA955X_GPIO_LOW LED_FULL +#define PCA955X_BLINK_DEFAULT_MS 1000 + enum pca955x_type { pca9550, pca9551, @@ -74,6 +76,7 @@ struct pca955x_chipdef { int bits; u8 slv_addr; /* 7-bit slave address mask */ int slv_addr_shift; /* Number of bits to ignore */ + int blink_div; /* PSC divider */ }; static const struct pca955x_chipdef pca955x_chipdefs[] = { @@ -81,26 +84,31 @@ static const struct pca955x_chipdef pca955x_chipdefs[] = { .bits = 2, .slv_addr = /* 110000x */ 0x60, .slv_addr_shift = 1, + .blink_div = 44, }, [pca9551] = { .bits = 8, .slv_addr = /* 1100xxx */ 0x60, .slv_addr_shift = 3, + .blink_div = 38, }, [pca9552] = { .bits = 16, .slv_addr = /* 1100xxx */ 0x60, .slv_addr_shift = 3, + .blink_div = 44, }, [ibm_pca9552] = { .bits = 16, .slv_addr = /* 0110xxx */ 0x30, .slv_addr_shift = 3, + .blink_div = 44, }, [pca9553] = { .bits = 4, .slv_addr = /* 110001x */ 0x62, .slv_addr_shift = 1, + .blink_div = 44, }, }; @@ -109,7 +117,9 @@ struct pca955x { struct pca955x_led *leds; const struct pca955x_chipdef *chipdef; struct i2c_client *client; + unsigned long active_blink; unsigned long active_pins; + unsigned long blink_period; #ifdef CONFIG_LEDS_PCA955X_GPIO struct gpio_chip gpio; #endif @@ -154,7 +164,8 @@ static inline int pca955x_ledstate(u8 ls, int led_num) /* * Write to frequency prescaler register, used to program the - * period of the PWM output. period = (PSCx + 1) / 38 + * period of the PWM output. period = (PSCx + 1) / coeff + * Where for pca9551 chips coeff = 38 and for all other chips coeff = 44 */ static int pca955x_write_psc(struct pca955x *pca955x, int n, u8 val) { @@ -235,6 +246,21 @@ static int pca955x_read_pwm(struct pca955x *pca955x, int n, u8 *val) return 0; } +static int pca955x_read_psc(struct pca955x *pca955x, int n, u8 *val) +{ + int ret; + u8 cmd; + + cmd = pca955x_num_input_regs(pca955x->chipdef->bits) + (2 * n); + ret = i2c_smbus_read_byte_data(pca955x->client, cmd); + if (ret < 0) { + dev_err(&pca955x->client->dev, "%s: reg 0x%x, err %d\n", __func__, n, ret); + return ret; + } + *val = (u8)ret; + return 0; +} + static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev) { struct pca955x_led *pca955x_led = led_to_pca955x(led_cdev); @@ -248,14 +274,12 @@ static enum led_brightness pca955x_led_get(struct led_classdev *led_cdev) switch (pca955x_ledstate(ls, pca955x_led->led_num % 4)) { case PCA955X_LS_LED_ON: + case PCA955X_LS_BLINK0: ret = LED_FULL; break; case PCA955X_LS_LED_OFF: ret = LED_OFF; break; - case PCA955X_LS_BLINK0: - ret = LED_HALF; - break; case PCA955X_LS_BLINK1: ret = pca955x_read_pwm(pca955x, 1, &pwm); if (ret) @@ -283,29 +307,36 @@ static int pca955x_led_set(struct led_classdev *led_cdev, if (ret) goto out; - switch (value) { - case LED_FULL: - ls = pca955x_ledsel(ls, bit, PCA955X_LS_LED_ON); - break; - case LED_OFF: - ls = pca955x_ledsel(ls, bit, PCA955X_LS_LED_OFF); - break; - case LED_HALF: - ls = pca955x_ledsel(ls, bit, PCA955X_LS_BLINK0); - break; - default: - /* - * Use PWM1 for all other values. This has the unwanted - * side effect of making all LEDs on the chip share the - * same brightness level if set to a value other than - * OFF, HALF, or FULL. But, this is probably better than - * just turning off for all other values. - */ - ret = pca955x_write_pwm(pca955x, 1, 255 - value); - if (ret) + if (test_bit(pca955x_led->led_num, &pca955x->active_blink)) { + if (value == LED_OFF) { + clear_bit(pca955x_led->led_num, &pca955x->active_blink); + ls = pca955x_ledsel(ls, bit, PCA955X_LS_LED_OFF); + } else { + /* No variable brightness for blinking LEDs */ goto out; - ls = pca955x_ledsel(ls, bit, PCA955X_LS_BLINK1); - break; + } + } else { + switch (value) { + case LED_FULL: + ls = pca955x_ledsel(ls, bit, PCA955X_LS_LED_ON); + break; + case LED_OFF: + ls = pca955x_ledsel(ls, bit, PCA955X_LS_LED_OFF); + break; + default: + /* + * Use PWM1 for all other values. This has the unwanted + * side effect of making all LEDs on the chip share the + * same brightness level if set to a value other than + * OFF or FULL. But, this is probably better than just + * turning off for all other values. + */ + ret = pca955x_write_pwm(pca955x, 1, 255 - value); + if (ret) + goto out; + ls = pca955x_ledsel(ls, bit, PCA955X_LS_BLINK1); + break; + } } ret = pca955x_write_ls(pca955x, reg, ls); @@ -316,6 +347,104 @@ out: return ret; } +static u8 pca955x_period_to_psc(struct pca955x *pca955x, unsigned long period) +{ + /* psc register value = (blink period * coeff) - 1 */ + period *= pca955x->chipdef->blink_div; + period /= MSEC_PER_SEC; + period -= 1; + + return period; +} + +static unsigned long pca955x_psc_to_period(struct pca955x *pca955x, u8 psc) +{ + unsigned long period = psc; + + /* blink period = (psc register value + 1) / coeff */ + period += 1; + period *= MSEC_PER_SEC; + period /= pca955x->chipdef->blink_div; + + return period; +} + +static int pca955x_led_blink(struct led_classdev *led_cdev, + unsigned long *delay_on, unsigned long *delay_off) +{ + struct pca955x_led *pca955x_led = led_to_pca955x(led_cdev); + struct pca955x *pca955x = pca955x_led->pca955x; + unsigned long period = *delay_on + *delay_off; + int ret = 0; + + mutex_lock(&pca955x->lock); + + if (period) { + if (*delay_on != *delay_off) { + ret = -EINVAL; + goto out; + } + + if (period < pca955x_psc_to_period(pca955x, 0) || + period > pca955x_psc_to_period(pca955x, 0xff)) { + ret = -EINVAL; + goto out; + } + } else { + period = pca955x->active_blink ? pca955x->blink_period : + PCA955X_BLINK_DEFAULT_MS; + } + + if (!pca955x->active_blink || + pca955x->active_blink == BIT(pca955x_led->led_num) || + pca955x->blink_period == period) { + u8 psc = pca955x_period_to_psc(pca955x, period); + + if (!test_and_set_bit(pca955x_led->led_num, + &pca955x->active_blink)) { + u8 ls; + int reg = pca955x_led->led_num / 4; + int bit = pca955x_led->led_num % 4; + + ret = pca955x_read_ls(pca955x, reg, &ls); + if (ret) + goto out; + + ls = pca955x_ledsel(ls, bit, PCA955X_LS_BLINK0); + ret = pca955x_write_ls(pca955x, reg, ls); + if (ret) + goto out; + + /* + * Force 50% duty cycle to maintain the specified + * blink rate. + */ + ret = pca955x_write_pwm(pca955x, 0, 128); + if (ret) + goto out; + } + + if (pca955x->blink_period != period) { + pca955x->blink_period = period; + ret = pca955x_write_psc(pca955x, 0, psc); + if (ret) + goto out; + } + + period = pca955x_psc_to_period(pca955x, psc); + period /= 2; + *delay_on = period; + *delay_off = period; + } else { + ret = -EBUSY; + } + +out: + mutex_unlock(&pca955x->lock); + + return ret; +} + #ifdef CONFIG_LEDS_PCA955X_GPIO /* * Read the INPUT register, which contains the state of LEDs. @@ -450,8 +579,9 @@ static int pca955x_probe(struct i2c_client *client) u8 ls1[4]; u8 ls2[4]; struct pca955x_platform_data *pdata; + u8 psc0; + bool keep_psc0 = false; bool set_default_label = false; - bool keep_pwm = false; char default_label[8]; chip = i2c_get_match_data(client); @@ -502,6 +632,7 @@ static int pca955x_probe(struct i2c_client *client) mutex_init(&pca955x->lock); pca955x->client = client; pca955x->chipdef = chip; + pca955x->blink_period = PCA955X_BLINK_DEFAULT_MS; init_data.devname_mandatory = false; init_data.devicename = "pca955x"; @@ -533,11 +664,16 @@ static int pca955x_probe(struct i2c_client *client) led = &pca955x_led->led_cdev; led->brightness_set_blocking = pca955x_led_set; led->brightness_get = pca955x_led_get; + led->blink_set = pca955x_led_blink; if (pdata->leds[i].default_state == LEDS_DEFSTATE_OFF) ls2[reg] = pca955x_ledsel(ls2[reg], bit, PCA955X_LS_LED_OFF); else if (pdata->leds[i].default_state == LEDS_DEFSTATE_ON) ls2[reg] = pca955x_ledsel(ls2[reg], bit, PCA955X_LS_LED_ON); + else if (pca955x_ledstate(ls2[reg], bit) == PCA955X_LS_BLINK0) { + keep_psc0 = true; + set_bit(i, &pca955x->active_blink); + } init_data.fwnode = pdata->leds[i].fwnode; @@ -565,19 +701,6 @@ static int pca955x_probe(struct i2c_client *client) return err; set_bit(i, &pca955x->active_pins); - - /* - * For default-state == "keep", let the core update the - * brightness from the hardware, then check the - * brightness to see if it's using PWM1. If so, PWM1 - * should not be written below. - */ - if (pdata->leds[i].default_state == LEDS_DEFSTATE_KEEP) { - if (led->brightness != LED_FULL && - led->brightness != LED_OFF && - led->brightness != LED_HALF) - keep_pwm = true; - } } } @@ -589,22 +712,19 @@ static int pca955x_probe(struct i2c_client *client) } } - /* PWM0 is used for half brightness or 50% duty cycle */ - err = pca955x_write_pwm(pca955x, 0, 255 - LED_HALF); - if (err) - return err; - - if (!keep_pwm) { - /* PWM1 is used for variable brightness, default to OFF */ - err = pca955x_write_pwm(pca955x, 1, 0); - if (err) - return err; + if (keep_psc0) { + err = pca955x_read_psc(pca955x, 0, &psc0); + } else { + psc0 = pca955x_period_to_psc(pca955x, pca955x->blink_period); + err = pca955x_write_psc(pca955x, 0, psc0); } - /* Set to fast frequency so we do not see flashing */ - err = pca955x_write_psc(pca955x, 0, 0); if (err) return err; + + pca955x->blink_period = pca955x_psc_to_period(pca955x, psc0); + + /* Set PWM1 to fast frequency so we do not see flashing */ err = pca955x_write_psc(pca955x, 1, 0); if (err) return err; |