input: ti_am33x_tsc: Add DT support

This patch adds DT support to touch driver. It also provides a binding
document which is used by the MFD and IIO part of the device.
This patch also renames steps_to_configure to coordinate_readouts
because the original name misleads the purpose of the variable.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
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>

1 files changed, 82 insertions, 23 deletions

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 7b7de6035af7..449c0fbbe1d6 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -26,6 +26,8 @@
 #include <linux/io.h>
 #include <linux/input/ti_am335x_tsc.h>
 #include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 #include <linux/mfd/ti_am335x_tscadc.h>
 
@@ -47,7 +49,7 @@ struct titsc {
         unsigned int            wires;
         unsigned int            x_plate_resistance;
         bool                    pen_down;
-        int                     steps_to_configure;
+        int                     coordinate_readouts;
         u32                     config_inp[4];
         u32                     bit_xp, bit_xn, bit_yp, bit_yn;
         u32                     inp_xp, inp_xn, inp_yp, inp_yn;
@@ -123,7 +125,7 @@ static void titsc_step_config(struct titsc *ts_dev)
         int i, total_steps;
 
         /* Configure the Step registers */
-        total_steps = 2 * ts_dev->steps_to_configure;
+        total_steps = 2 * ts_dev->coordinate_readouts;
 
         config = STEPCONFIG_MODE_HWSYNC |
                         STEPCONFIG_AVG_16 | ts_dev->bit_xp;
@@ -141,7 +143,7 @@ static void titsc_step_config(struct titsc *ts_dev)
                 break;
         }
 
-        for (i = 1; i <= ts_dev->steps_to_configure; i++) {
+        for (i = 1; i <= ts_dev->coordinate_readouts; i++) {
                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
         }
@@ -163,7 +165,7 @@ static void titsc_step_config(struct titsc *ts_dev)
                 break;
         }
 
-        for (i = (ts_dev->steps_to_configure + 1); i <= total_steps; i++) {
+        for (i = (ts_dev->coordinate_readouts + 1); i <= total_steps; i++) {
                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
         }
@@ -218,7 +220,7 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
                 read = titsc_readl(ts_dev, REG_FIFO0);
                 channel = read & 0xf0000;
                 channel = channel >> 0x10;
-                if ((channel >= 0) && (channel < ts_dev->steps_to_configure)) {
+                if ((channel >= 0) && (channel < ts_dev->coordinate_readouts)) {
                         read &= 0xfff;
                         diff = abs(read - prev_val_x);
                         if (diff < prev_diff_x) {
@@ -231,8 +233,8 @@ static void titsc_read_coordinates(struct titsc *ts_dev,
                 read = titsc_readl(ts_dev, REG_FIFO1);
                 channel = read & 0xf0000;
                 channel = channel >> 0x10;
-                if ((channel >= ts_dev->steps_to_configure) &&
-                        (channel < (2 * ts_dev->steps_to_configure - 1))) {
+                if ((channel >= ts_dev->coordinate_readouts) &&
+                        (channel < (2 * ts_dev->coordinate_readouts - 1))) {
                         read &= 0xfff;
                         diff = abs(read - prev_val_y);
                         if (diff < prev_diff_y) {
@@ -310,6 +312,59 @@ static irqreturn_t titsc_irq(int irq, void *dev)
         return IRQ_HANDLED;
 }
 
+static int titsc_parse_dt(struct platform_device *pdev,
+                                        struct titsc *ts_dev)
+{
+        struct device_node *node = pdev->dev.of_node;
+        int err;
+
+        if (!node)
+                return -EINVAL;
+
+        err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
+        if (err < 0)
+                return err;
+        switch (ts_dev->wires) {
+        case 4:
+        case 5:
+        case 8:
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        err = of_property_read_u32(node, "ti,x-plate-resistance",
+                        &ts_dev->x_plate_resistance);
+        if (err < 0)
+                return err;
+
+        err = of_property_read_u32(node, "ti,coordiante-readouts",
+                        &ts_dev->coordinate_readouts);
+        if (err < 0)
+                return err;
+
+        return of_property_read_u32_array(node, "ti,wire-config",
+                        ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
+}
+
+static int titsc_parse_pdata(struct ti_tscadc_dev *tscadc_dev,
+                                        struct titsc *ts_dev)
+{
+        struct mfd_tscadc_board *pdata = tscadc_dev->dev->platform_data;
+
+        if (!pdata)
+                return -EINVAL;
+
+        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));
+        return 0;
+}
+
 /*
  * The functions for inserting/removing driver as a module.
  */
@@ -319,16 +374,8 @@ static int titsc_probe(struct platform_device *pdev)
         struct titsc *ts_dev;
         struct input_dev *input_dev;
         struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
-        struct mfd_tscadc_board *pdata;
         int err;
 
-        pdata = tscadc_dev->dev->platform_data;
-
-        if (!pdata) {
-                dev_err(&pdev->dev, "Could not find platform data\n");
-                return -EINVAL;
-        }
-
         /* Allocate memory for device */
         ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
         input_dev = input_allocate_device();
@@ -342,11 +389,16 @@ static int titsc_probe(struct platform_device *pdev)
         ts_dev->mfd_tscadc = tscadc_dev;
         ts_dev->input = input_dev;
         ts_dev->irq = tscadc_dev->irq;
-        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));
+
+        if (tscadc_dev->dev->platform_data)
+                err = titsc_parse_pdata(tscadc_dev, ts_dev);
+        else
+                err = titsc_parse_dt(pdev, ts_dev);
+
+        if (err) {
+                dev_err(&pdev->dev, "Could not find valid DT data.\n");
+                goto err_free_mem;
+        }
 
         err = request_irq(ts_dev->irq, titsc_irq,
                           0, pdev->dev.driver->name, ts_dev);
@@ -362,7 +414,7 @@ static int titsc_probe(struct platform_device *pdev)
                 goto err_free_irq;
         }
         titsc_step_config(ts_dev);
-        titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->steps_to_configure);
+        titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->coordinate_readouts);
 
         input_dev->name = "ti-tsc";
         input_dev->dev.parent = &pdev->dev;
@@ -398,7 +450,7 @@ static int titsc_remove(struct platform_device *pdev)
         free_irq(ts_dev->irq, ts_dev);
 
         /* total steps followed by the enable mask */
-        steps = 2 * ts_dev->steps_to_configure + 2;
+        steps = 2 * ts_dev->coordinate_readouts + 2;
         steps = (1 << steps) - 1;
         am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
 
@@ -439,7 +491,7 @@ static int titsc_resume(struct device *dev)
         }
         titsc_step_config(ts_dev);
         titsc_writel(ts_dev, REG_FIFO0THR,
-                        ts_dev->steps_to_configure);
+                        ts_dev->coordinate_readouts);
         return 0;
 }
 
@@ -452,6 +504,12 @@ static const struct dev_pm_ops titsc_pm_ops = {
 #define TITSC_PM_OPS NULL
 #endif
 
+static const struct of_device_id ti_tsc_dt_ids[] = {
+        { .compatible = "ti,am3359-tsc", },
+        { }
+};
+MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
+
 static struct platform_driver ti_tsc_driver = {
         .probe  = titsc_probe,
         .remove = titsc_remove,
@@ -459,6 +517,7 @@ static struct platform_driver ti_tsc_driver = {
                 .name   = "tsc",
                 .owner  = THIS_MODULE,
                 .pm     = TITSC_PM_OPS,
+                .of_match_table = of_match_ptr(ti_tsc_dt_ids),
         },
 };
 module_platform_driver(ti_tsc_driver);