[PATCH v4 2/2] Input: cap11xx - add advanced sensitivity settings

From: Jiri Valek - 2N
Date: Tue Jun 27 2023 - 02:54:10 EST


Add support for advanced sensitivity settings that allows more precise
tunig of touch buttons. Input-treshold allows to set the sensitivity for
each channel separately. Also add signal guard feature for CAP129x chips.

Signed-off-by: Jiri Valek - 2N <jiriv@xxxxxxxx>
---
drivers/input/keyboard/cap11xx.c | 250 ++++++++++++++++++++++++-------
1 file changed, 197 insertions(+), 53 deletions(-)

diff --git a/drivers/input/keyboard/cap11xx.c b/drivers/input/keyboard/cap11xx.c
index 040696d0e49c..5972415cc549 100644
--- a/drivers/input/keyboard/cap11xx.c
+++ b/drivers/input/keyboard/cap11xx.c
@@ -14,6 +14,7 @@
#include <linux/regmap.h>
#include <linux/i2c.h>
#include <linux/gpio/consumer.h>
+#include <linux/bitfield.h>

#define CAP11XX_REG_MAIN_CONTROL 0x00
#define CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT (6)
@@ -24,6 +25,7 @@
#define CAP11XX_REG_NOISE_FLAG_STATUS 0x0a
#define CAP11XX_REG_SENOR_DELTA(X) (0x10 + (X))
#define CAP11XX_REG_SENSITIVITY_CONTROL 0x1f
+#define CAP11XX_REG_SENSITIVITY_CONTROL_DELTA_SENSE_MASK 0x70
#define CAP11XX_REG_CONFIG 0x20
#define CAP11XX_REG_SENSOR_ENABLE 0x21
#define CAP11XX_REG_SENSOR_CONFIG 0x22
@@ -32,6 +34,7 @@
#define CAP11XX_REG_CALIBRATION 0x26
#define CAP11XX_REG_INT_ENABLE 0x27
#define CAP11XX_REG_REPEAT_RATE 0x28
+#define CAP11XX_REG_SIGNAL_GUARD_ENABLE 0x29
#define CAP11XX_REG_MT_CONFIG 0x2a
#define CAP11XX_REG_MT_PATTERN_CONFIG 0x2b
#define CAP11XX_REG_MT_PATTERN 0x2d
@@ -47,6 +50,8 @@
#define CAP11XX_REG_SENSOR_BASE_CNT(X) (0x50 + (X))
#define CAP11XX_REG_LED_POLARITY 0x73
#define CAP11XX_REG_LED_OUTPUT_CONTROL 0x74
+#define CAP11XX_REG_CALIB_SENSITIVITY_CONFIG 0x80
+#define CAP11XX_REG_CALIB_SENSITIVITY_CONFIG2 0x81

#define CAP11XX_REG_LED_DUTY_CYCLE_1 0x90
#define CAP11XX_REG_LED_DUTY_CYCLE_2 0x91
@@ -78,12 +83,20 @@ struct cap11xx_led {

struct cap11xx_priv {
struct regmap *regmap;
+ struct device *dev;
struct input_dev *idev;
+ const struct cap11xx_hw_model *model;
+ u8 id;

struct cap11xx_led *leds;
int num_leds;

/* config */
+ u8 analog_gain;
+ u8 sensitivity_delta_sense;
+ u8 signal_guard_inputs_mask;
+ u32 thresholds[8];
+ u32 calib_sensitivities[8];
u32 keycodes[];
};

@@ -181,6 +194,178 @@ static const struct regmap_config cap11xx_regmap_config = {
.volatile_reg = cap11xx_volatile_reg,
};

+static int
+cap11xx_write_calib_sens_config_1(struct cap11xx_priv *priv)
+{
+ return regmap_write(priv->regmap,
+ CAP11XX_REG_CALIB_SENSITIVITY_CONFIG,
+ (priv->calib_sensitivities[3] << 6) |
+ (priv->calib_sensitivities[2] << 4) |
+ (priv->calib_sensitivities[1] << 2) |
+ priv->calib_sensitivities[0]);
+}
+
+static int
+cap11xx_write_calib_sens_config_2(struct cap11xx_priv *priv)
+{
+ return regmap_write(priv->regmap,
+ CAP11XX_REG_CALIB_SENSITIVITY_CONFIG2,
+ (priv->calib_sensitivities[7] << 6) |
+ (priv->calib_sensitivities[6] << 4) |
+ (priv->calib_sensitivities[5] << 2) |
+ priv->calib_sensitivities[4]);
+}
+
+static int
+cap11xx_init_keys(struct cap11xx_priv *priv)
+{
+ struct device_node *node = priv->dev->of_node;
+ struct device *dev = priv->dev;
+ int i, error;
+ u32 u32_val;
+
+ if (!node) {
+ dev_err(dev, "Corresponding DT entry is not available\n");
+ return -ENODEV;
+ }
+
+ if (!of_property_read_u32(node, "microchip,sensor-gain", &u32_val)) {
+ if (priv->model->no_gain) {
+ dev_warn(dev,
+ "This model doesn't support 'sensor-gain'\n");
+ } else if (is_power_of_2(u32_val) && u32_val <= 8) {
+ priv->analog_gain = (u8)ilog2(u32_val);
+
+ error = regmap_update_bits(priv->regmap,
+ CAP11XX_REG_MAIN_CONTROL,
+ CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
+ priv->analog_gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
+ if (error)
+ return error;
+ } else {
+ dev_err(dev, "Invalid sensor-gain value %u\n", u32_val);
+ return -EINVAL;
+ }
+ }
+
+ if (of_property_read_bool(node, "microchip,irq-active-high")) {
+ if (priv->id == CAP1106 ||
+ priv->id == CAP1126 ||
+ priv->id == CAP1188) {
+ error = regmap_update_bits(priv->regmap,
+ CAP11XX_REG_CONFIG2,
+ CAP11XX_REG_CONFIG2_ALT_POL,
+ 0);
+ if (error)
+ return error;
+ } else {
+ dev_warn(dev,
+ "This model doesn't support 'irq-active-high'\n");
+ }
+ }
+
+ if (!of_property_read_u32(node,
+ "microchip,sensitivity-delta-sense", &u32_val)) {
+ if (!is_power_of_2(u32_val) || u32_val > 128) {
+ dev_err(dev, "Invalid sensitivity-delta-sense value %u\n", u32_val);
+ return -EINVAL;
+ }
+
+ priv->sensitivity_delta_sense = (u8)ilog2(u32_val);
+ u32_val = ~(FIELD_PREP(CAP11XX_REG_SENSITIVITY_CONTROL_DELTA_SENSE_MASK,
+ priv->sensitivity_delta_sense));
+
+ error = regmap_update_bits(priv->regmap,
+ CAP11XX_REG_SENSITIVITY_CONTROL,
+ CAP11XX_REG_SENSITIVITY_CONTROL_DELTA_SENSE_MASK,
+ u32_val);
+ if (error)
+ return error;
+ }
+
+ if (!of_property_read_u32_array(node, "microchip,input-treshold",
+ priv->thresholds, priv->model->num_channels)) {
+ for (i = 0; i < priv->model->num_channels; i++) {
+ if (priv->thresholds[i] > 127) {
+ dev_err(dev, "Invalid input-treshold value %u\n",
+ priv->thresholds[i]);
+ return -EINVAL;
+ }
+
+ error = regmap_write(priv->regmap,
+ CAP11XX_REG_SENSOR_THRESH(i),
+ priv->thresholds[i]);
+ if (error)
+ return error;
+ }
+ }
+
+ if (!of_property_read_u32_array(node, "microchip,calib-sensitivity",
+ priv->calib_sensitivities, priv->model->num_channels)) {
+ if (priv->id == CAP1293 || priv->id == CAP1298) {
+ for (i = 0; i < priv->model->num_channels; i++) {
+ if (!is_power_of_2(priv->calib_sensitivities[i]) ||
+ priv->calib_sensitivities[i] > 4) {
+ dev_err(dev, "Invalid calib-sensitivity value %u\n",
+ priv->calib_sensitivities[i]);
+ return -EINVAL;
+ }
+ priv->calib_sensitivities[i] = ilog2(priv->calib_sensitivities[i]);
+ }
+
+ error = cap11xx_write_calib_sens_config_1(priv);
+ if (error)
+ return error;
+
+ if (priv->id == CAP1298) {
+ error = cap11xx_write_calib_sens_config_2(priv);
+ if (error)
+ return error;
+ }
+ } else {
+ dev_warn(dev,
+ "This model doesn't support 'calib-sensitivity'\n");
+ }
+ }
+
+ for (i = 0; i < priv->model->num_channels; i++) {
+ if (!of_property_read_u32_index(node, "microchip,signal-guard",
+ i, &u32_val)) {
+ if (u32_val > 1)
+ return -EINVAL;
+ if (u32_val)
+ priv->signal_guard_inputs_mask |= 0x01 << i;
+ }
+ }
+
+ if (priv->signal_guard_inputs_mask) {
+ if (priv->id == CAP1293 || priv->id == CAP1298) {
+ error = regmap_write(priv->regmap,
+ CAP11XX_REG_SIGNAL_GUARD_ENABLE,
+ priv->signal_guard_inputs_mask);
+ if (error)
+ return error;
+ } else {
+ dev_warn(dev,
+ "This model doesn't support 'signal-guard'\n");
+ }
+ }
+
+ /* Provide some useful defaults */
+ for (i = 0; i < priv->model->num_channels; i++)
+ priv->keycodes[i] = KEY_A + i;
+
+ of_property_read_u32_array(node, "linux,keycodes",
+ priv->keycodes, priv->model->num_channels);
+
+ /* Disable autorepeat. The Linux input system has its own handling. */
+ error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
+ if (error)
+ return error;
+
+ return 0;
+}
+
static irqreturn_t cap11xx_thread_func(int irq_num, void *data)
{
struct cap11xx_priv *priv = data;
@@ -332,11 +517,9 @@ static int cap11xx_i2c_probe(struct i2c_client *i2c_client)
const struct i2c_device_id *id = i2c_client_get_device_id(i2c_client);
struct device *dev = &i2c_client->dev;
struct cap11xx_priv *priv;
- struct device_node *node;
const struct cap11xx_hw_model *cap;
- int i, error, irq, gain = 0;
+ int i, error;
unsigned int val, rev;
- u32 gain32;

if (id->driver_data >= ARRAY_SIZE(cap11xx_devices)) {
dev_err(dev, "Invalid device ID %lu\n", id->driver_data);
@@ -355,6 +538,8 @@ static int cap11xx_i2c_probe(struct i2c_client *i2c_client)
if (!priv)
return -ENOMEM;

+ priv->dev = dev;
+
priv->regmap = devm_regmap_init_i2c(i2c_client, &cap11xx_regmap_config);
if (IS_ERR(priv->regmap))
return PTR_ERR(priv->regmap);
@@ -384,50 +569,15 @@ static int cap11xx_i2c_probe(struct i2c_client *i2c_client)
return error;

dev_info(dev, "CAP11XX detected, model %s, revision 0x%02x\n",
- id->name, rev);
- node = dev->of_node;
-
- if (!of_property_read_u32(node, "microchip,sensor-gain", &gain32)) {
- if (cap->no_gain)
- dev_warn(dev,
- "This version doesn't support sensor gain\n");
- else if (is_power_of_2(gain32) && gain32 <= 8)
- gain = ilog2(gain32);
- else
- dev_err(dev, "Invalid sensor-gain value %d\n", gain32);
- }
+ id->name, rev);

- if (id->driver_data == CAP1106 ||
- id->driver_data == CAP1126 ||
- id->driver_data == CAP1188) {
- if (of_property_read_bool(node, "microchip,irq-active-high")) {
- error = regmap_update_bits(priv->regmap,
- CAP11XX_REG_CONFIG2,
- CAP11XX_REG_CONFIG2_ALT_POL,
- 0);
- if (error)
- return error;
- }
- }
-
- /* Provide some useful defaults */
- for (i = 0; i < cap->num_channels; i++)
- priv->keycodes[i] = KEY_A + i;
-
- of_property_read_u32_array(node, "linux,keycodes",
- priv->keycodes, cap->num_channels);
+ priv->model = cap;
+ priv->id = id->driver_data;

- if (!cap->no_gain) {
- error = regmap_update_bits(priv->regmap,
- CAP11XX_REG_MAIN_CONTROL,
- CAP11XX_REG_MAIN_CONTROL_GAIN_MASK,
- gain << CAP11XX_REG_MAIN_CONTROL_GAIN_SHIFT);
- if (error)
- return error;
- }
+ dev_info(dev, "CAP11XX device detected, model %s, revision 0x%02x\n",
+ id->name, rev);

- /* Disable autorepeat. The Linux input system has its own handling. */
- error = regmap_write(priv->regmap, CAP11XX_REG_REPEAT_RATE, 0);
+ error = cap11xx_init_keys(priv);
if (error)
return error;

@@ -439,7 +589,7 @@ static int cap11xx_i2c_probe(struct i2c_client *i2c_client)
priv->idev->id.bustype = BUS_I2C;
priv->idev->evbit[0] = BIT_MASK(EV_KEY);

- if (of_property_read_bool(node, "autorepeat"))
+ if (of_property_read_bool(dev->of_node, "autorepeat"))
__set_bit(EV_REP, priv->idev->evbit);

for (i = 0; i < cap->num_channels; i++)
@@ -474,14 +624,8 @@ static int cap11xx_i2c_probe(struct i2c_client *i2c_client)
if (error)
return error;

- irq = irq_of_parse_and_map(node, 0);
- if (!irq) {
- dev_err(dev, "Unable to parse or map IRQ\n");
- return -ENXIO;
- }
-
- error = devm_request_threaded_irq(dev, irq, NULL, cap11xx_thread_func,
- IRQF_ONESHOT, dev_name(dev), priv);
+ error = devm_request_threaded_irq(dev, i2c_client->irq, NULL,
+ cap11xx_thread_func, IRQF_ONESHOT, dev_name(dev), priv);
if (error)
return error;

--
2.25.1