* 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.
+ * 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.
+ * 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.
+ * 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'.
+ * 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:
+ * 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.
+ * 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.
+ * 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.
+ * 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.
*
- * 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.
+ * 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 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.
+ * 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.
*
+ * An led-tca6507 device must be provided with platform data or
+ * configured via devicetree.
+ *
+ * The platform-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_GPIO, 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.
+ *
+ * When configured via devicetree there is one child for each output.
+ * The "reg" determines the output number and "compatible" determines
+ * whether it is an LED or a GPIO. "linux,default-trigger" can set a
+ * default trigger.
*/
#include <linux/module.h>
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).
+ * 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;
}
/*
- * Update the register file with the appropriate 3-bit state for
- * the given led.
+ * 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)
{
}
}
-/* 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.
+/* 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)
{
tca->bank[bank].level = level;
}
-/* Record all relevant time code for a given bank */
+/* Record all relevant time codes for a given bank */
static void set_times(struct tca6507_chip *tca, int bank)
{
int c1, c2;
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],
+ "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);
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],
+ "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);
static int led_prepare(struct tca6507_led *led)
{
- /* Assign this led to a bank, configuring that bank if necessary. */
+ /* 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;
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.
+ * 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;
}
/*
- * 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.
+ * 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;
err = led_prepare(led);
if (err) {
/*
- * Can only fail on timer setup. In that case we need to
- * re-establish as steady level.
+ * Can only fail on timer setup. In that case we need
+ * to re-establish as steady level.
*/
led->ontime = 0;
led->offtime = 0;
spin_lock_irqsave(&tca->lock, flags);
/*
- * 'OFF' is floating high, and 'ON' is pulled down, so it has the
- * inverse sense of 'val'.
+ * '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);
git.openpandora.org / pandora-kernel.git / commitdiff