* Timo Karjalainen <timo.o.karjalainen@xxxxxxxxx> [081002 02:09]:
> This patch fixes two problems in LM8323 PWM control. One is that
> locking is needed when setting and reading pwm->desired_brightness
> asynchronously. The other is that LM8323 may stop a PWM script only
> after the current instruction has finished. If it is a long RAMP,
> the chip would keep executing the old instruction and new
> settings were effectively ignored.
Yet another driver to go to mainline.. Pushing to l-o.
Tony
> Signed-off-by: Timo Karjalainen <timo.o.karjalainen@xxxxxxxxx>
> Signed-off-by: Daniel Stone <daniel.stone@xxxxxxxxx>
> ---
> drivers/input/keyboard/lm8323.c | 129 +++++++++++++++++++++------------------
> 1 files changed, 69 insertions(+), 60 deletions(-)
>
> diff --git a/drivers/input/keyboard/lm8323.c b/drivers/input/keyboard/lm8323.c
> index 72bb587..342ef6a 100644
> --- a/drivers/input/keyboard/lm8323.c
> +++ b/drivers/input/keyboard/lm8323.c
> @@ -141,6 +141,8 @@ struct lm8323_pwm {
> int fade_time;
> int brightness;
> int desired_brightness;
> + int running;
> + struct mutex lock;
> struct work_struct work;
> struct led_classdev cdev;
> };
> @@ -384,6 +386,15 @@ static int lm8323_configure(struct lm8323_chip *lm)
> return 0;
> }
>
> +static void pwm_done(struct lm8323_pwm *pwm)
> +{
> + mutex_lock(&pwm->lock);
> + pwm->running = 0;
> + if (pwm->desired_brightness != pwm->brightness)
> + schedule_work(&pwm->work);
> + mutex_unlock(&pwm->lock);
> +}
> +
> /*
> * Bottom half: handle the interrupt by posting key events, or dealing with
> * errors appropriately.
> @@ -411,12 +422,18 @@ static void lm8323_work(struct work_struct *work)
> "reinitialising\n");
> lm8323_configure(lm);
> }
> - if (ints & INT_PWM1)
> + if (ints & INT_PWM1) {
> debug(&lm->client->dev, "pwm1 engine completed\n");
> - if (ints & INT_PWM2)
> + pwm_done(&lm->pwm1);
> + }
> + if (ints & INT_PWM2) {
> debug(&lm->client->dev, "pwm2 engine completed\n");
> - if (ints & INT_PWM3)
> + pwm_done(&lm->pwm2);
> + }
> + if (ints & INT_PWM3) {
> debug(&lm->client->dev, "pwm3 engine completed\n");
> + pwm_done(&lm->pwm3);
> + }
> }
>
> mutex_unlock(&lm->lock);
> @@ -458,92 +475,80 @@ static void lm8323_write_pwm_one(struct lm8323_pwm *pwm, int pos, u16 cmd)
>
> /*
> * Write a script into a given PWM engine, concluding with PWM_END.
> - * If 'keepalive' is specified, the engine will be kept running
> - * indefinitely.
> + * If 'kill' is nonzero, the engine will be shut down at the end
> + * of the script, producing a zero output. Otherwise the engine
> + * will be kept running at the final PWM level indefinitely.
> */
> -static void lm8323_write_pwm(struct lm8323_pwm *pwm, int keepalive,
> - int len, ...)
> +static void lm8323_write_pwm(struct lm8323_pwm *pwm, int kill,
> + int len, const u16 *cmds)
> {
> struct lm8323_chip *lm = pwm_to_lm8323(pwm);
> - int i, cmd;
> - va_list ap;
> -
> - /*
> - * If there are any scripts running at the moment, terminate them
> - * and make sure the duty cycle is as if it finished.
> - */
> - lm8323_write(lm, 2, LM8323_CMD_STOP_PWM, pwm->id);
> -
> - va_start(ap, len);
> - for (i = 0; i < len; i++) {
> - cmd = va_arg(ap, int);
> - lm8323_write_pwm_one(pwm, i, cmd);
> - }
> - va_end(ap);
> + int i;
>
> - /* Wait for a trigger from any channel. This keeps the engine alive. */
> - if (keepalive)
> - lm8323_write_pwm_one(pwm, i++, PWM_WAIT_TRIG(0xe));
> - else
> - lm8323_write_pwm_one(pwm, i++, PWM_END(1));
> + for (i = 0; i < len; i++)
> + lm8323_write_pwm_one(pwm, i, cmds[i]);
>
> + lm8323_write_pwm_one(pwm, i++, PWM_END(kill));
> lm8323_write(lm, 2, LM8323_CMD_START_PWM, pwm->id);
> + pwm->running = 1;
> }
>
> static void lm8323_pwm_work(struct work_struct *work)
> {
> struct lm8323_pwm *pwm = work_to_pwm(work);
> - int div, perstep, steps, hz, direction, keepalive;
> + int div512, perstep, steps, hz, up, kill;
> + u16 pwm_cmds[3];
> + int num_cmds = 0;
> +
> + mutex_lock(&pwm->lock);
>
> - /* Do nothing if we're already at the requested level. */
> - if (pwm->desired_brightness == pwm->brightness)
> + /*
> + * Do nothing if we're already at the requested level,
> + * or previous setting is not yet complete. In the latter
> + * case we will be called again when the previous PWM script
> + * finishes.
> + */
> + if (pwm->running || pwm->desired_brightness == pwm->brightness) {
> + mutex_unlock(&pwm->lock);
> return;
> + }
>
> - keepalive = (pwm->desired_brightness > 0);
> - direction = (pwm->desired_brightness > pwm->brightness);
> + kill = (pwm->desired_brightness == 0);
> + up = (pwm->desired_brightness > pwm->brightness);
> steps = abs(pwm->desired_brightness - pwm->brightness);
>
> /*
> * Convert time (in ms) into a divisor (512 or 16 on a refclk of
> * 32768Hz), and number of ticks per step.
> */
> - if ((pwm->fade_time / steps) > (32768 / 512))
> - div = 512;
> - else
> - div = 16;
> + if ((pwm->fade_time / steps) > (32768 / 512)) {
> + div512 = 1;
> + hz = 32768 / 512;
> + }
> + else {
> + div512 = 0;
> + hz = 32768 / 16;
> + }
>
> - hz = 32768 / div;
> - if (pwm->fade_time < ((steps * 1000) / hz))
> - perstep = 1;
> - else
> - perstep = (hz * pwm->fade_time) / (steps * 1000);
> + perstep = (hz * pwm->fade_time) / (steps * 1000);
>
> if (perstep == 0)
> perstep = 1;
> else if (perstep > 63)
> perstep = 63;
>
> - if (steps > 252) {
> - lm8323_write_pwm(pwm, keepalive, 3,
> - PWM_RAMP((div == 512), perstep, 126,
> - direction),
> - PWM_RAMP((div == 512), perstep, 126,
> - direction),
> - PWM_RAMP((div == 512), perstep, steps - 252,
> - direction));
> - } else if (steps > 126) {
> - lm8323_write_pwm(pwm, keepalive, 2,
> - PWM_RAMP((div == 512), perstep, 126,
> - direction),
> - PWM_RAMP((div == 512), perstep, steps - 126,
> - direction));
> - } else {
> - lm8323_write_pwm(pwm, keepalive, 1,
> - PWM_RAMP((div == 512), perstep, steps,
> - direction));
> + while (steps) {
> + int s;
> +
> + s = min(126, steps);
> + pwm_cmds[num_cmds++] = PWM_RAMP(div512, perstep, s, up);
> + steps -= s;
> }
>
> + lm8323_write_pwm(pwm, kill, num_cmds, pwm_cmds);
> +
> pwm->brightness = pwm->desired_brightness;
> + mutex_unlock(&pwm->lock);
> }
>
> static void lm8323_pwm_set_brightness(struct led_classdev *led_cdev,
> @@ -552,7 +557,9 @@ static void lm8323_pwm_set_brightness(struct led_classdev *led_cdev,
> struct lm8323_pwm *pwm = cdev_to_pwm(led_cdev);
> struct lm8323_chip *lm = pwm_to_lm8323(pwm);
>
> + mutex_lock(&pwm->lock);
> pwm->desired_brightness = brightness;
> + mutex_unlock(&pwm->lock);
>
> if (in_interrupt()) {
> schedule_work(&pwm->work);
> @@ -620,6 +627,8 @@ static int init_pwm(struct lm8323_chip *lm, int id, struct device *dev,
> pwm->fade_time = 0;
> pwm->brightness = 0;
> pwm->desired_brightness = 0;
> + pwm->running = 0;
> + mutex_init(&pwm->lock);
> if (name) {
> pwm->cdev.name = name;
> pwm->cdev.brightness_set = lm8323_pwm_set_brightness;
> @@ -917,7 +926,7 @@ static void __exit lm8323_exit(void)
> i2c_del_driver(&lm8323_i2c_driver);
> }
>
> -MODULE_AUTHOR("Daniel Stone");
> +MODULE_AUTHOR("Timo O. Karjalainen <timo.o.karjalainen@xxxxxxxxx>, Daniel Stone");
> MODULE_DESCRIPTION("LM8323 keypad driver");
> MODULE_LICENSE("GPL");
>
> --
> 1.6.0
>
> --
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