input: ti_am33x_tsc: Order of TSC wires, made configurable

The current driver expected touchscreen input
wires(XP,XN,YP,YN) to be connected in a particular order.
Making changes to accept this as platform data.

Sebastian reworked the original patch and removed a lot of the not
required pieces.

Signed-off-by: Patil, Rachna <rachna@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

3 files changed, 98 insertions, 19 deletions

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 23d6a4dacc88..2bdd66cd76a7 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -33,6 +33,13 @@
 #define SEQ_SETTLE              275
 #define MAX_12BIT               ((1 << 12) - 1)
 
+static const int config_pins[] = {
+        STEPCONFIG_XPP,
+        STEPCONFIG_XNN,
+        STEPCONFIG_YPP,
+        STEPCONFIG_YNN,
+};
+
 struct titsc {
         struct input_dev        *input;
         struct ti_tscadc_dev    *mfd_tscadc;
@@ -41,6 +48,9 @@ struct titsc {
         unsigned int            x_plate_resistance;
         bool                    pen_down;
         int                     steps_to_configure;
+        u32                     config_inp[4];
+        u32                     bit_xp, bit_xn, bit_yp, bit_yn;
+        u32                     inp_xp, inp_xn, inp_yp, inp_yn;
 };
 
 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
@@ -54,6 +64,58 @@ static void titsc_writel(struct titsc *tsc, unsigned int reg,
         writel(val, tsc->mfd_tscadc->tscadc_base + reg);
 }
 
+static int titsc_config_wires(struct titsc *ts_dev)
+{
+        u32 analog_line[4];
+        u32 wire_order[4];
+        int i, bit_cfg;
+
+        for (i = 0; i < 4; i++) {
+                /*
+                 * Get the order in which TSC wires are attached
+                 * w.r.t. each of the analog input lines on the EVM.
+                 */
+                analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
+                wire_order[i] = ts_dev->config_inp[i] & 0x0F;
+                if (WARN_ON(analog_line[i] > 7))
+                        return -EINVAL;
+                if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
+                        return -EINVAL;
+        }
+
+        for (i = 0; i < 4; i++) {
+                int an_line;
+                int wi_order;
+
+                an_line = analog_line[i];
+                wi_order = wire_order[i];
+                bit_cfg = config_pins[wi_order];
+                if (bit_cfg == 0)
+                        return -EINVAL;
+                switch (wi_order) {
+                case 0:
+                        ts_dev->bit_xp = bit_cfg;
+                        ts_dev->inp_xp = an_line;
+                        break;
+
+                case 1:
+                        ts_dev->bit_xn = bit_cfg;
+                        ts_dev->inp_xn = an_line;
+                        break;
+
+                case 2:
+                        ts_dev->bit_yp = bit_cfg;
+                        ts_dev->inp_yp = an_line;
+                        break;
+                case 3:
+                        ts_dev->bit_yn = bit_cfg;
+                        ts_dev->inp_yn = an_line;
+                        break;
+                }
+        }
+        return 0;
+}
+
 static void titsc_step_config(struct titsc *ts_dev)
 {
         unsigned int    config;
@@ -64,18 +126,18 @@ static void titsc_step_config(struct titsc *ts_dev)
         total_steps = 2 * ts_dev->steps_to_configure;
 
         config = STEPCONFIG_MODE_HWSYNC |
-                        STEPCONFIG_AVG_16 | STEPCONFIG_XPP;
+                        STEPCONFIG_AVG_16 | ts_dev->bit_xp;
         switch (ts_dev->wires) {
         case 4:
-                config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
+                config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
                 break;
         case 5:
-                config |= STEPCONFIG_YNN |
-                                STEPCONFIG_INP_AN4 | STEPCONFIG_XNN |
-                                STEPCONFIG_YPP;
+                config |= ts_dev->bit_yn |
+                                STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
+                                ts_dev->bit_yp;
                 break;
         case 8:
-                config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
+                config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
                 break;
         }
 
@@ -86,18 +148,18 @@ static void titsc_step_config(struct titsc *ts_dev)
 
         config = 0;
         config = STEPCONFIG_MODE_HWSYNC |
-                        STEPCONFIG_AVG_16 | STEPCONFIG_YNN |
+                        STEPCONFIG_AVG_16 | ts_dev->bit_yn |
                         STEPCONFIG_INM_ADCREFM | STEPCONFIG_FIFO1;
         switch (ts_dev->wires) {
         case 4:
-                config |= STEPCONFIG_YPP;
+                config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
                 break;
         case 5:
-                config |= STEPCONFIG_XPP | STEPCONFIG_INP_AN4 |
-                                STEPCONFIG_XNP | STEPCONFIG_YPN;
+                config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
+                                ts_dev->bit_xn | ts_dev->bit_yp;
                 break;
         case 8:
-                config |= STEPCONFIG_YPP;
+                config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
                 break;
         }
 
@@ -108,9 +170,9 @@ static void titsc_step_config(struct titsc *ts_dev)
 
         config = 0;
         /* Charge step configuration */
-        config = STEPCONFIG_XPP | STEPCONFIG_YNN |
+        config = ts_dev->bit_xp | ts_dev->bit_yn |
                         STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
-                        STEPCHARGE_INM_AN1 | STEPCHARGE_INP_AN1;
+                        STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);
 
         titsc_writel(ts_dev, REG_CHARGECONFIG, config);
         titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
@@ -118,13 +180,14 @@ static void titsc_step_config(struct titsc *ts_dev)
         config = 0;
         /* Configure to calculate pressure */
         config = STEPCONFIG_MODE_HWSYNC |
-                        STEPCONFIG_AVG_16 | STEPCONFIG_YPP |
-                        STEPCONFIG_XNN | STEPCONFIG_INM_ADCREFM;
+                        STEPCONFIG_AVG_16 | ts_dev->bit_yp |
+                        ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
+                        STEPCONFIG_INP(ts_dev->inp_xp);
         titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 1), config);
         titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 1),
                         STEPCONFIG_OPENDLY);
 
-        config |= STEPCONFIG_INP_AN3 | STEPCONFIG_FIFO1;
+        config |= STEPCONFIG_INP(ts_dev->inp_yn) | STEPCONFIG_FIFO1;
         titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 2), config);
         titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 2),
                         STEPCONFIG_OPENDLY);
@@ -292,6 +355,8 @@ static int titsc_probe(struct platform_device *pdev)
         ts_dev->wires = pdata->tsc_init->wires;
         ts_dev->x_plate_resistance = pdata->tsc_init->x_plate_resistance;
         ts_dev->steps_to_configure = pdata->tsc_init->steps_to_configure;
+        memcpy(ts_dev->config_inp, pdata->tsc_init->wire_config,
+                        sizeof(pdata->tsc_init->wire_config));
 
         err = request_irq(ts_dev->irq, titsc_irq,
                           0, pdev->dev.driver->name, ts_dev);
@@ -301,6 +366,11 @@ static int titsc_probe(struct platform_device *pdev)
         }
 
         titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
+        err = titsc_config_wires(ts_dev);
+        if (err) {
+                dev_err(&pdev->dev, "wrong i/p wire configuration\n");
+                goto err_free_irq;
+        }
         titsc_step_config(ts_dev);
         titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->steps_to_configure);
 
diff --git a/include/linux/input/ti_am335x_tsc.h b/include/linux/input/ti_am335x_tsc.h
index 49269a2aa329..6a66b4d1ac2c 100644
--- a/include/linux/input/ti_am335x_tsc.h
+++ b/include/linux/input/ti_am335x_tsc.h
@@ -12,12 +12,24 @@
  *                      A step configured to read a single
  *                      co-ordinate value, can be applied
  *                      more number of times for better results.
+ * @wire_config:        Different EVM's could have a different order
+ *                      for connecting wires on touchscreen.
+ *                      We need to provide an 8 bit number where in
+ *                      the 1st four bits represent the analog lines
+ *                      and the next 4 bits represent positive/
+ *                      negative terminal on that input line.
+ *                      Notations to represent the input lines and
+ *                      terminals resoectively is as follows:
+ *                      AIN0 = 0, AIN1 = 1 and so on till AIN7 = 7.
+ *                      XP  = 0, XN = 1, YP = 2, YN = 3.
+ *
  */
 
 struct tsc_data {
         int wires;
         int x_plate_resistance;
         int steps_to_configure;
+        int wire_config[10];
 };
 
 #endif
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index 4258627d076a..e36ae4184917 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -71,8 +71,6 @@
 #define STEPCONFIG_INM_ADCREFM  STEPCONFIG_INM(8)
 #define STEPCONFIG_INP_MASK     (0xF << 19)
 #define STEPCONFIG_INP(val)     ((val) << 19)
-#define STEPCONFIG_INP_AN2      STEPCONFIG_INP(2)
-#define STEPCONFIG_INP_AN3      STEPCONFIG_INP(3)
 #define STEPCONFIG_INP_AN4      STEPCONFIG_INP(4)
 #define STEPCONFIG_INP_ADCREFM  STEPCONFIG_INP(8)
 #define STEPCONFIG_FIFO1        BIT(26)
@@ -94,7 +92,6 @@
 #define STEPCHARGE_INM_AN1      STEPCHARGE_INM(1)
 #define STEPCHARGE_INP_MASK     (0xF << 19)
 #define STEPCHARGE_INP(val)     ((val) << 19)
-#define STEPCHARGE_INP_AN1      STEPCHARGE_INP(1)
 #define STEPCHARGE_RFM_MASK     (3 << 23)
 #define STEPCHARGE_RFM(val)     ((val) << 23)
 #define STEPCHARGE_RFM_XNUR     STEPCHARGE_RFM(1)