diff options
| -rw-r--r-- | drivers/input/touchscreen/ti_am335x_tsc.c | 92 |
1 files changed, 52 insertions, 40 deletions
diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c index 7c0f6b21559d..191a1b87895f 100644 --- a/drivers/input/touchscreen/ti_am335x_tsc.c +++ b/drivers/input/touchscreen/ti_am335x_tsc.c @@ -26,6 +26,7 @@ #include <linux/delay.h> #include <linux/of.h> #include <linux/of_device.h> +#include <linux/sort.h> #include <linux/mfd/ti_am335x_tscadc.h> @@ -204,56 +205,61 @@ static void titsc_step_config(struct titsc *ts_dev) am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask); } +static int titsc_cmp_coord(const void *a, const void *b) +{ + return *(int *)a - *(int *)b; +} + static void titsc_read_coordinates(struct titsc *ts_dev, u32 *x, u32 *y, u32 *z1, u32 *z2) { - unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT); - unsigned int prev_val_x = ~0, prev_val_y = ~0; - unsigned int prev_diff_x = ~0, prev_diff_y = ~0; - unsigned int read, diff; - unsigned int i, channel; + unsigned int yvals[7], xvals[7]; + unsigned int i, xsum = 0, ysum = 0; unsigned int creads = ts_dev->coordinate_readouts; - unsigned int first_step = TOTAL_STEPS - (creads * 2 + 2); - *z1 = *z2 = 0; - if (fifocount % (creads * 2 + 2)) - fifocount -= fifocount % (creads * 2 + 2); - /* - * Delta filter is used to remove large variations in sampled - * values from ADC. The filter tries to predict where the next - * coordinate could be. This is done by taking a previous - * coordinate and subtracting it form current one. Further the - * algorithm compares the difference with that of a present value, - * if true the value is reported to the sub system. - */ - for (i = 0; i < fifocount; i++) { - read = titsc_readl(ts_dev, REG_FIFO0); - - channel = (read & 0xf0000) >> 16; - read &= 0xfff; - if (channel > first_step + creads + 2) { - diff = abs(read - prev_val_x); - if (diff < prev_diff_x) { - prev_diff_x = diff; - *x = read; - } - prev_val_x = read; + for (i = 0; i < creads; i++) { + yvals[i] = titsc_readl(ts_dev, REG_FIFO0); + yvals[i] &= 0xfff; + } - } else if (channel == first_step + creads + 1) { - *z1 = read; + *z1 = titsc_readl(ts_dev, REG_FIFO0); + *z1 &= 0xfff; + *z2 = titsc_readl(ts_dev, REG_FIFO0); + *z2 &= 0xfff; - } else if (channel == first_step + creads + 2) { - *z2 = read; + for (i = 0; i < creads; i++) { + xvals[i] = titsc_readl(ts_dev, REG_FIFO0); + xvals[i] &= 0xfff; + } - } else if (channel > first_step) { - diff = abs(read - prev_val_y); - if (diff < prev_diff_y) { - prev_diff_y = diff; - *y = read; - } - prev_val_y = read; + /* + * If co-ordinates readouts is less than 4 then + * report the average. In case of 4 or more + * readouts, sort the co-ordinate samples, drop + * min and max values and report the average of + * remaining values. + */ + if (creads <= 3) { + for (i = 0; i < creads; i++) { + ysum += yvals[i]; + xsum += xvals[i]; } + ysum /= creads; + xsum /= creads; + } else { + sort(yvals, creads, sizeof(unsigned int), + titsc_cmp_coord, NULL); + sort(xvals, creads, sizeof(unsigned int), + titsc_cmp_coord, NULL); + for (i = 1; i < creads - 1; i++) { + ysum += yvals[i]; + xsum += xvals[i]; + } + ysum /= creads - 2; + xsum /= creads - 2; } + *y = ysum; + *x = xsum; } static irqreturn_t titsc_irq(int irq, void *dev) @@ -369,6 +375,12 @@ static int titsc_parse_dt(struct platform_device *pdev, if (err < 0) return err; + if (ts_dev->coordinate_readouts <= 0) { + dev_warn(&pdev->dev, + "invalid co-ordinate readouts, resetting it to 5\n"); + ts_dev->coordinate_readouts = 5; + } + err = of_property_read_u32(node, "ti,charge-delay", &ts_dev->charge_delay); /* |