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-rw-r--r--Documentation/devicetree/bindings/input/ads7846.txt91
-rw-r--r--drivers/input/touchscreen/ads7846.c115
2 files changed, 195 insertions, 11 deletions
diff --git a/Documentation/devicetree/bindings/input/ads7846.txt b/Documentation/devicetree/bindings/input/ads7846.txt
new file mode 100644
index 000000000000..5f7619c22743
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/ads7846.txt
@@ -0,0 +1,91 @@
+Device tree bindings for TI's ADS7843, ADS7845, ADS7846, ADS7873, TSC2046
+SPI driven touch screen controllers.
+
+The node for this driver must be a child node of a SPI controller, hence
+all mandatory properties described in
+
+ Documentation/devicetree/bindings/spi/spi-bus.txt
+
+must be specified.
+
+Additional required properties:
+
+ compatible Must be one of the following, depending on the
+ model:
+ "ti,tsc2046"
+ "ti,ads7843"
+ "ti,ads7845"
+ "ti,ads7846"
+ "ti,ads7873"
+
+ interrupt-parent
+ interrupts An interrupt node describing the IRQ line the chip's
+ !PENIRQ pin is connected to.
+ vcc-supply A regulator node for the supply voltage.
+
+
+Optional properties:
+
+ ti,vref-delay-usecs vref supply delay in usecs, 0 for
+ external vref (u16).
+ ti,vref-mv The VREF voltage, in millivolts (u16).
+ ti,keep-vref-on set to keep vref on for differential
+ measurements as well
+ ti,swap-xy swap x and y axis
+ ti,settle-delay-usec Settling time of the analog signals;
+ a function of Vcc and the capacitance
+ on the X/Y drivers. If set to non-zero,
+ two samples are taken with settle_delay
+ us apart, and the second one is used.
+ ~150 uSec with 0.01uF caps (u16).
+ ti,penirq-recheck-delay-usecs If set to non-zero, after samples are
+ taken this delay is applied and penirq
+ is rechecked, to help avoid false
+ events. This value is affected by the
+ material used to build the touch layer
+ (u16).
+ ti,x-plate-ohms Resistance of the X-plate,
+ in Ohms (u16).
+ ti,y-plate-ohms Resistance of the Y-plate,
+ in Ohms (u16).
+ ti,x-min Minimum value on the X axis (u16).
+ ti,y-min Minimum value on the Y axis (u16).
+ ti,x-max Maximum value on the X axis (u16).
+ ti,y-max Minimum value on the Y axis (u16).
+ ti,pressure-min Minimum reported pressure value
+ (threshold) - u16.
+ ti,pressure-max Maximum reported pressure value (u16).
+ ti,debounce-max Max number of additional readings per
+ sample (u16).
+ ti,debounce-tol Tolerance used for filtering (u16).
+ ti,debounce-rep Additional consecutive good readings
+ required after the first two (u16).
+ ti,pendown-gpio-debounce Platform specific debounce time for the
+ pendown-gpio (u32).
+ pendown-gpio GPIO handle describing the pin the !PENIRQ
+ line is connected to.
+ linux,wakeup use any event on touchscreen as wakeup event.
+
+
+Example for a TSC2046 chip connected to an McSPI controller of an OMAP SoC::
+
+ spi_controller {
+ tsc2046@0 {
+ reg = <0>; /* CS0 */
+ compatible = "ti,tsc2046";
+ interrupt-parent = <&gpio1>;
+ interrupts = <8 0>; /* BOOT6 / GPIO 8 */
+ spi-max-frequency = <1000000>;
+ pendown-gpio = <&gpio1 8 0>;
+ vcc-supply = <&reg_vcc3>;
+
+ ti,x-min = /bits/ 16 <0>;
+ ti,x-max = /bits/ 16 <8000>;
+ ti,y-min = /bits/ 16 <0>;
+ ti,y-max = /bits/ 16 <4800>;
+ ti,x-plate-ohms = /bits/ 16 <40>;
+ ti,pressure-max = /bits/ 16 <255>;
+
+ linux,wakeup;
+ };
+ };
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 5ff041995198..ea195360747e 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -27,6 +27,9 @@
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/pm.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_device.h>
#include <linux/gpio.h>
#include <linux/spi/spi.h>
#include <linux/spi/ads7846.h>
@@ -1201,9 +1204,87 @@ static void ads7846_setup_spi_msg(struct ads7846 *ts,
spi_message_add_tail(x, m);
}
+#ifdef CONFIG_OF
+static const struct of_device_id ads7846_dt_ids[] = {
+ { .compatible = "ti,tsc2046", .data = (void *) 7846 },
+ { .compatible = "ti,ads7843", .data = (void *) 7843 },
+ { .compatible = "ti,ads7845", .data = (void *) 7845 },
+ { .compatible = "ti,ads7846", .data = (void *) 7846 },
+ { .compatible = "ti,ads7873", .data = (void *) 7873 },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
+
+static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
+{
+ struct ads7846_platform_data *pdata;
+ struct device_node *node = dev->of_node;
+ const struct of_device_id *match;
+
+ if (!node) {
+ dev_err(dev, "Device does not have associated DT data\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ match = of_match_device(ads7846_dt_ids, dev);
+ if (!match) {
+ dev_err(dev, "Unknown device model\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return ERR_PTR(-ENOMEM);
+
+ pdata->model = (unsigned long)match->data;
+
+ of_property_read_u16(node, "ti,vref-delay-usecs",
+ &pdata->vref_delay_usecs);
+ of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
+ pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
+
+ pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
+
+ of_property_read_u16(node, "ti,settle-delay-usec",
+ &pdata->settle_delay_usecs);
+ of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
+ &pdata->penirq_recheck_delay_usecs);
+
+ of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
+ of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
+
+ of_property_read_u16(node, "ti,x-min", &pdata->x_min);
+ of_property_read_u16(node, "ti,y-min", &pdata->y_min);
+ of_property_read_u16(node, "ti,x-max", &pdata->x_max);
+ of_property_read_u16(node, "ti,y-max", &pdata->y_max);
+
+ of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
+ of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
+
+ of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
+ of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
+ of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
+
+ of_property_read_u32(node, "ti,pendown-gpio-debounce",
+ &pdata->gpio_pendown_debounce);
+
+ pdata->wakeup = of_property_read_bool(node, "linux,wakeup");
+
+ pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
+
+ return pdata;
+}
+#else
+static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
+{
+ dev_err(dev, "no platform data defined\n");
+ return ERR_PTR(-EINVAL);
+}
+#endif
+
static int ads7846_probe(struct spi_device *spi)
{
- const struct ads7846_platform_data *pdata = dev_get_platdata(&spi->dev);
+ const struct ads7846_platform_data *pdata;
struct ads7846 *ts;
struct ads7846_packet *packet;
struct input_dev *input_dev;
@@ -1212,22 +1293,18 @@ static int ads7846_probe(struct spi_device *spi)
if (!spi->irq) {
dev_dbg(&spi->dev, "no IRQ?\n");
- return -ENODEV;
- }
-
- if (!pdata) {
- dev_dbg(&spi->dev, "no platform data?\n");
- return -ENODEV;
+ return -EINVAL;
}
/* don't exceed max specified sample rate */
if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
- dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
+ dev_err(&spi->dev, "f(sample) %d KHz?\n",
(spi->max_speed_hz/SAMPLE_BITS)/1000);
return -EINVAL;
}
- /* We'd set TX word size 8 bits and RX word size to 13 bits ... except
+ /*
+ * We'd set TX word size 8 bits and RX word size to 13 bits ... except
* that even if the hardware can do that, the SPI controller driver
* may not. So we stick to very-portable 8 bit words, both RX and TX.
*/
@@ -1250,17 +1327,25 @@ static int ads7846_probe(struct spi_device *spi)
ts->packet = packet;
ts->spi = spi;
ts->input = input_dev;
- ts->vref_mv = pdata->vref_mv;
- ts->swap_xy = pdata->swap_xy;
mutex_init(&ts->lock);
init_waitqueue_head(&ts->wait);
+ pdata = dev_get_platdata(&spi->dev);
+ if (!pdata) {
+ pdata = ads7846_probe_dt(&spi->dev);
+ if (IS_ERR(pdata))
+ return PTR_ERR(pdata);
+ }
+
ts->model = pdata->model ? : 7846;
ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
ts->pressure_max = pdata->pressure_max ? : ~0;
+ ts->vref_mv = pdata->vref_mv;
+ ts->swap_xy = pdata->swap_xy;
+
if (pdata->filter != NULL) {
if (pdata->filter_init != NULL) {
err = pdata->filter_init(pdata, &ts->filter_data);
@@ -1370,6 +1455,13 @@ static int ads7846_probe(struct spi_device *spi)
device_init_wakeup(&spi->dev, pdata->wakeup);
+ /*
+ * If device does not carry platform data we must have allocated it
+ * when parsing DT data.
+ */
+ if (!dev_get_platdata(&spi->dev))
+ devm_kfree(&spi->dev, (void *)pdata);
+
return 0;
err_remove_attr_group:
@@ -1437,6 +1529,7 @@ static struct spi_driver ads7846_driver = {
.name = "ads7846",
.owner = THIS_MODULE,
.pm = &ads7846_pm,
+ .of_match_table = of_match_ptr(ads7846_dt_ids),
},
.probe = ads7846_probe,
.remove = ads7846_remove,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.