Input: add touchscreen support for TS-4800

On this board, the touchscreen, an ads7843, is not handled directly by
Linux but by a companion FPGA. This FPGA is memory-mapped and the IP
design is very similar to the mk712.

This commit adds the support for this IP.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/Documentation/devicetree/bindings/input/touchscreen/ts4800-ts.txt b/Documentation/devicetree/bindings/input/touchscreen/ts4800-ts.txt
new file mode 100644 (file)
index 0000000..4c1c092
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/ts4800-ts.txt
@@ -0,0 +1,11 @@
+* TS-4800 Touchscreen bindings
+
+Required properties:
+- compatible: must be "technologic,ts4800-ts"
+- reg: physical base address of the controller and length of memory mapped
+  region.
+- syscon: phandle / integers array that points to the syscon node which
+          describes the FPGA's syscon registers.
+          - phandle to FPGA's syscon
+          - offset to the touchscreen register
+          - offset to the touchscreen enable bit

diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 9bcb718668b2376881e0a58ade088d921ae263c5..f986e8b44b5fad235162eada48b780fd7bdcb5d7 100644 (file)
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -937,6 +937,22 @@ config TOUCHSCREEN_TOUCHIT213
          To compile this driver as a module, choose M here: the
          module will be called touchit213.
 
+config TOUCHSCREEN_TS4800
+       tristate "TS-4800 touchscreen"
+       depends on HAS_IOMEM && OF
+       select MFD_SYSCON
+       select INPUT_POLLDEV
+       help
+         Say Y here if you have a touchscreen on a TS-4800 board.
+
+         On TS-4800, the touchscreen is not handled directly by Linux but by
+         a companion FPGA.
+
+         If unsure, say N.
+
+         To compile this driver as a module, choose M here: the
+         module will be called ts4800_ts.
+
 config TOUCHSCREEN_TSC_SERIO
        tristate "TSC-10/25/40 serial touchscreen support"
        select SERIO

diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 001357c3f73f9e4ef585584832f0ced8a8d76010..968ff12e31325bec720c38608864a7af58c75d8d 100644 (file)
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_TOUCHSCREEN_TI_AM335X_TSC)       += ti_am335x_tsc.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHIT213)   += touchit213.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHRIGHT)   += touchright.o
 obj-$(CONFIG_TOUCHSCREEN_TOUCHWIN)     += touchwin.o
+obj-$(CONFIG_TOUCHSCREEN_TS4800)       += ts4800-ts.o
 obj-$(CONFIG_TOUCHSCREEN_TSC_SERIO)    += tsc40.o
 obj-$(CONFIG_TOUCHSCREEN_TSC200X_CORE) += tsc200x-core.o
 obj-$(CONFIG_TOUCHSCREEN_TSC2004)      += tsc2004.o

diff --git a/drivers/input/touchscreen/ts4800-ts.c b/drivers/input/touchscreen/ts4800-ts.c
new file mode 100644 (file)
index 0000000..3c3dd78
--- /dev/null
+++ b/drivers/input/touchscreen/ts4800-ts.c
@@ -0,0 +1,216 @@
+/*
+ * Touchscreen driver for the TS-4800 board
+ *
+ * Copyright (c) 2015 - Savoir-faire Linux
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/bitops.h>
+#include <linux/input.h>
+#include <linux/input-polldev.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* polling interval in ms */
+#define POLL_INTERVAL          3
+
+#define DEBOUNCE_COUNT         1
+
+/* sensor values are 12-bit wide */
+#define MAX_12BIT              ((1 << 12) - 1)
+
+#define PENDOWN_MASK           0x1
+
+#define X_OFFSET               0x0
+#define Y_OFFSET               0x2
+
+struct ts4800_ts {
+       struct input_polled_dev *poll_dev;
+       struct device           *dev;
+       char                    phys[32];
+
+       void __iomem            *base;
+       struct regmap           *regmap;
+       unsigned int            reg;
+       unsigned int            bit;
+
+       bool                    pendown;
+       int                     debounce;
+};
+
+static void ts4800_ts_open(struct input_polled_dev *dev)
+{
+       struct ts4800_ts *ts = dev->private;
+       int ret;
+
+       ts->pendown = false;
+       ts->debounce = DEBOUNCE_COUNT;
+
+       ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
+       if (ret)
+               dev_warn(ts->dev, "Failed to enable touchscreen\n");
+}
+
+static void ts4800_ts_close(struct input_polled_dev *dev)
+{
+       struct ts4800_ts *ts = dev->private;
+       int ret;
+
+       ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
+       if (ret)
+               dev_warn(ts->dev, "Failed to disable touchscreen\n");
+
+}
+
+static void ts4800_ts_poll(struct input_polled_dev *dev)
+{
+       struct input_dev *input_dev = dev->input;
+       struct ts4800_ts *ts = dev->private;
+       u16 last_x = readw(ts->base + X_OFFSET);
+       u16 last_y = readw(ts->base + Y_OFFSET);
+       bool pendown = last_x & PENDOWN_MASK;
+
+       if (pendown) {
+               if (ts->debounce) {
+                       ts->debounce--;
+                       return;
+               }
+
+               if (!ts->pendown) {
+                       input_report_key(input_dev, BTN_TOUCH, 1);
+                       ts->pendown = true;
+               }
+
+               last_x = ((~last_x) >> 4) & MAX_12BIT;
+               last_y = ((~last_y) >> 4) & MAX_12BIT;
+
+               input_report_abs(input_dev, ABS_X, last_x);
+               input_report_abs(input_dev, ABS_Y, last_y);
+               input_sync(input_dev);
+       } else if (ts->pendown) {
+               ts->pendown = false;
+               ts->debounce = DEBOUNCE_COUNT;
+               input_report_key(input_dev, BTN_TOUCH, 0);
+               input_sync(input_dev);
+       }
+}
+
+static int ts4800_parse_dt(struct platform_device *pdev,
+                          struct ts4800_ts *ts)
+{
+       struct device *dev = &pdev->dev;
+       struct device_node *np = dev->of_node;
+       struct device_node *syscon_np;
+       u32 reg, bit;
+       int error;
+
+       syscon_np = of_parse_phandle(np, "syscon", 0);
+       if (!syscon_np) {
+               dev_err(dev, "no syscon property\n");
+               return -ENODEV;
+       }
+
+       error = of_property_read_u32_index(np, "syscon", 1, &reg);
+       if (error < 0) {
+               dev_err(dev, "no offset in syscon\n");
+               return error;
+       }
+
+       ts->reg = reg;
+
+       error = of_property_read_u32_index(np, "syscon", 2, &bit);
+       if (error < 0) {
+               dev_err(dev, "no bit in syscon\n");
+               return error;
+       }
+
+       ts->bit = BIT(bit);
+
+       ts->regmap = syscon_node_to_regmap(syscon_np);
+       if (IS_ERR(ts->regmap)) {
+               dev_err(dev, "cannot get parent's regmap\n");
+               return PTR_ERR(ts->regmap);
+       }
+
+       return 0;
+}
+
+static int ts4800_ts_probe(struct platform_device *pdev)
+{
+       struct input_polled_dev *poll_dev;
+       struct ts4800_ts *ts;
+       struct resource *res;
+       int error;
+
+       ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
+       if (!ts)
+               return -ENOMEM;
+
+       error = ts4800_parse_dt(pdev, ts);
+       if (error)
+               return error;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       ts->base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(ts->base))
+               return PTR_ERR(ts->base);
+
+       poll_dev = devm_input_allocate_polled_device(&pdev->dev);
+       if (!poll_dev)
+               return -ENOMEM;
+
+       snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
+       ts->poll_dev = poll_dev;
+       ts->dev = &pdev->dev;
+
+       poll_dev->private = ts;
+       poll_dev->poll_interval = POLL_INTERVAL;
+       poll_dev->open = ts4800_ts_open;
+       poll_dev->close = ts4800_ts_close;
+       poll_dev->poll = ts4800_ts_poll;
+
+       poll_dev->input->name = "TS-4800 Touchscreen";
+       poll_dev->input->phys = ts->phys;
+
+       input_set_capability(poll_dev->input, EV_KEY, BTN_TOUCH);
+       input_set_abs_params(poll_dev->input, ABS_X, 0, MAX_12BIT, 0, 0);
+       input_set_abs_params(poll_dev->input, ABS_Y, 0, MAX_12BIT, 0, 0);
+
+       error = input_register_polled_device(poll_dev);
+       if (error) {
+               dev_err(&pdev->dev,
+                       "Unabled to register polled input device (%d)\n",
+                       error);
+               return error;
+       }
+
+       return 0;
+}
+
+static const struct of_device_id ts4800_ts_of_match[] = {
+       { .compatible = "technologic,ts4800-ts", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
+
+static struct platform_driver ts4800_ts_driver = {
+       .driver = {
+               .name = "ts4800-ts",
+               .of_match_table = ts4800_ts_of_match,
+       },
+       .probe = ts4800_ts_probe,
+};
+module_platform_driver(ts4800_ts_driver);
+
+MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
+MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:ts4800_ts");