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BeagleBone: Add support for Element14 BB-VIEW LCD touchscreens
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Software came from http://www.element14.com/community/docs/DOC-67958?ICID=BBB-feature-viewpanel
Hints came from http://armsdr.blogspot.com/2014/01/element14-bb-view-and-debian-beta.html
Testing on BB-VIEW 7" LCD display
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Jason Kridner committed Jan 15, 2015
1 parent 41b0051 commit bc8f3d7
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Showing 4 changed files with 654 additions and 37 deletions.
129 changes: 92 additions & 37 deletions drivers/input/touchscreen/ti_am335x_tsc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,7 +32,7 @@
#include <linux/mfd/ti_am335x_tscadc.h>

#define ADCFSM_STEPID 0x10
#define SEQ_SETTLE 275
#define SEQ_SETTLE 315
#define MAX_12BIT ((1 << 12) - 1)

static const int config_pins[] = {
Expand All @@ -53,14 +53,31 @@ struct titsc {
u32 config_inp[4];
u32 bit_xp, bit_xn, bit_yp, bit_yn;
u32 inp_xp, inp_xn, inp_yp, inp_yn;
unsigned int prevZ;
#define TOUCH_TYPE_LCD_NORM 0
#define TOUCH_TYPE_LCD43 1
#define TOUCH_TYPE_LCD7 2
int touch_type;
unsigned bckup_x, bckup_y;
};

static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
{
return readl(ts->mfd_tscadc->tscadc_base + reg);
}

static u32 reg_read(unsigned addr) { return readl((const volatile void*)addr); }
static int dump_regs(char* name, unsigned addr, int size) {
int i;
u32 reg;

for (i = 0; i < size; i += sizeof(int)) {
reg = reg_read(addr + i);
printk("%s[%.4X] = 0x%.8X\n", name, i, reg);
}
return 0;
}


static void titsc_writel(struct titsc *tsc, unsigned int reg,
unsigned int val)
{
Expand Down Expand Up @@ -176,15 +193,15 @@ static void titsc_step_config(struct titsc *ts_dev)
/* Charge step configuration */
config = ts_dev->bit_xp | ts_dev->bit_yn |
STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);
STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_xn);

titsc_writel(ts_dev, REG_CHARGECONFIG, config);
titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);

/* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */
config = STEPCONFIG_MODE_HWSYNC |
STEPCONFIG_AVG_16 | ts_dev->bit_yp |
ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
STEPCONFIG_AVG_16 | STEPCONFIG_YPN |
STEPCONFIG_XNP | STEPCONFIG_INM_ADCREFM |
STEPCONFIG_INP(ts_dev->inp_xp);
titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
titsc_writel(ts_dev, REG_STEPDELAY(end_step),
Expand All @@ -205,10 +222,11 @@ 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 read;
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 creads = ts_dev->coordinate_readouts;
unsigned int nX, nY;

*z1 = *z2 = 0;
if (fifocount % (creads * 2 + 2))
Expand All @@ -221,34 +239,34 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
* algorithm compares the difference with that of a present value,
* if true the value is reported to the sub system.
*/
*x=0;
*y=0;
nX=0;
nY=0;
for (i = 0; i < fifocount; i++) {
read = titsc_readl(ts_dev, REG_FIFO0);

channel = (read & 0xf0000) >> 16;
read &= 0xfff;
if (channel < creads) {
(*x)+=read;
nX++;
diff = abs(read - prev_val_x);
if (diff < prev_diff_x) {
prev_diff_x = diff;
*x = read;
}
prev_val_x = read;

} else if (channel < creads * 2) {
(*y)+=read;
nY++;
diff = abs(read - prev_val_y);
if (diff < prev_diff_y) {
prev_diff_y = diff;
*y = read;
}
prev_val_y = read;

} else if (channel < creads * 2 + 1) {
*z1 = read;

} else if (channel < creads * 2 + 2) {
*z2 = read;
}
}
if (nX != 0) {
(*x)/=nX;
}
if (nY != 0) {
(*y)/=nY;
}
}

static irqreturn_t titsc_irq(int irq, void *dev)
Expand All @@ -258,8 +276,8 @@ static irqreturn_t titsc_irq(int irq, void *dev)
unsigned int status, irqclr = 0;
unsigned int x = 0, y = 0;
unsigned int z1, z2, z;
int deltaZ;
unsigned int fsm;
unsigned int config;

status = titsc_readl(ts_dev, REG_IRQSTATUS);
/*
Expand All @@ -273,31 +291,61 @@ static irqreturn_t titsc_irq(int irq, void *dev)
(status & IRQENB_FIFO1OVRRUN) ||
(status & IRQENB_FIFO1UNDRFLW))
return IRQ_NONE;
else if (status & IRQENB_FIFO0THRES) {
else if ((status & IRQENB_FIFO0OVRRUN) ||
(status & IRQENB_FIFO0UNDRFLW)) {
config = titsc_readl(ts_dev, REG_CTRL);
config &= ~(CNTRLREG_TSCSSENB);
titsc_writel(ts_dev, REG_CTRL, config);

if (status & IRQENB_FIFO0UNDRFLW)
titsc_writel(ts_dev, REG_IRQSTATUS,
(status | IRQENB_FIFO0UNDRFLW));
else
titsc_writel(ts_dev, REG_IRQSTATUS,
(status | IRQENB_FIFO0OVRRUN));

titsc_writel(ts_dev, REG_CTRL,
(config | CNTRLREG_TSCSSENB));
return IRQ_HANDLED;
} else if (status & IRQENB_FIFO0THRES) {
unsigned int diffx = 0, diffy = 0;

titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);

diffx = abs(x - ts_dev->bckup_x);
diffy = abs(y - ts_dev->bckup_y);
ts_dev->bckup_x = x;
ts_dev->bckup_y = y;

if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
/*
* Calculate pressure using formula
* Resistance(touch) = x plate resistance *
* x postion/4096 * ((z2 / z1) - 1)
*/
z = z1 - z2;
z = z2 - z1;
z *= x;
z *= ts_dev->x_plate_resistance;
z /= z2;
z /= z1;
z = (z + 2047) >> 12;

// calculate the deltaZ :
deltaZ= z - ts_dev->prevZ;
// save the last z calculated :
ts_dev->prevZ=z;
pr_debug("x %d y %d deltaZ %d\n", x, y, deltaZ);

if (z <= MAX_12BIT && deltaZ>=0 && deltaZ<=10 ) {
if (diffx < 30 && diffy < 30 && z <= MAX_12BIT) {
if (ts_dev->touch_type != TOUCH_TYPE_LCD_NORM) {
x &= ~0x0007;
y &= ~0x0007;
}
#if 0
if (ts_dev->touch_type == TOUCH_TYPE_LCD7) {
input_report_abs(input_dev, ABS_X, 4096 - y);
input_report_abs(input_dev, ABS_Y, x - 256);
} else if (ts_dev->touch_type == TOUCH_TYPE_LCD43) {
input_report_abs(input_dev, ABS_X, 4096 - x);
input_report_abs(input_dev, ABS_Y, 3840 - y);
} else {
#endif
input_report_abs(input_dev, ABS_X, x);
input_report_abs(input_dev, ABS_Y, y);
//}
input_report_abs(input_dev, ABS_PRESSURE, z);
input_report_key(input_dev, BTN_TOUCH, 1);
input_sync(input_dev);
Expand All @@ -318,6 +366,8 @@ static irqreturn_t titsc_irq(int irq, void *dev)
fsm = titsc_readl(ts_dev, REG_ADCFSM);
if (fsm == ADCFSM_STEPID) {
ts_dev->pen_down = false;
ts_dev->bckup_x = 0;
ts_dev->bckup_y = 0;
input_report_key(input_dev, BTN_TOUCH, 0);
input_report_abs(input_dev, ABS_PRESSURE, 0);
input_sync(input_dev);
Expand All @@ -326,9 +376,9 @@ static irqreturn_t titsc_irq(int irq, void *dev)
}
irqclr |= IRQENB_PENUP;
}
irqclr |= IRQENB_HW_PEN;

if (status & IRQENB_HW_PEN) {

titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
}
Expand Down Expand Up @@ -372,6 +422,11 @@ static int titsc_parse_dt(struct ti_tscadc_dev *tscadc_dev,
if (err < 0)
return err;

err = of_property_read_u32(node, "ti,touch-type", &ts_dev->touch_type);
if (err < 0) {
ts_dev->touch_type = TOUCH_TYPE_LCD_NORM;
}

return of_property_read_u32_array(node, "ti,wire-config",
ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
}
Expand Down Expand Up @@ -432,7 +487,8 @@ static int titsc_probe(struct platform_device *pdev)
goto err_free_mem;
}

titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES
| IRQENB_FIFO0OVRRUN | IRQENB_FIFO0UNDRFLW);
err = titsc_config_wires(ts_dev);
if (err) {
dev_err(&pdev->dev, "wrong i/p wire configuration\n");
Expand All @@ -452,15 +508,14 @@ static int titsc_probe(struct platform_device *pdev)
input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);

/*init prev Z*/
ts_dev->prevZ=0;

/* register to the input system */
err = input_register_device(input_dev);
if (err)
goto err_free_irq;

platform_set_drvdata(pdev, ts_dev);

dump_regs("TSC", (unsigned)ts_dev->mfd_tscadc->tscadc_base, REG_FIFO0);
return 0;

err_free_irq:
Expand Down
2 changes: 2 additions & 0 deletions firmware/Makefile
View file
Original file line number Diff line number Diff line change
Expand Up @@ -157,6 +157,8 @@ fw-shipped-$(CONFIG_CAPE_BEAGLEBONE) += \
BB-BONE-LCD7-01-00A2.dtbo \
BB-BONE-LCD7-01-00A3.dtbo \
BB-BONE-LCD7-01-00A4.dtbo \
BB-VIEW-LCD4-01-00A0.dtbo \
BB-VIEW-LCD7-01-00A0.dtbo \
BB-BONE-eMMC1-01-00A0.dtbo \
BB-BONE-GPEVT-00A0.dtbo \
BB-BONE-RTC-00A0.dtbo \
Expand Down
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