Input: synaptics-rmi4 - add support for F55 sensor tuning

Sensor tuning support is needed to determine the number of enabled
tx and rx electrodes for use in F54 functions.

The number of enabled electrodes is not identical to the total number
of electrodes as reported with F55:Query0 and F55:Query1. It has to be
calculated by analyzing F55:Ctrl1 (sensor receiver assignment) and
F55:Ctrl2 (sensor transmitter assignment).

Support for additional sensor tuning functions may be added later.

Fixes: 3a762dbd53 ("[media] Input: synaptics-rmi4 - add support for F54 ...")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Nick Dyer <nick@shmanahar.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/rmi4/Kconfig

@@ -95,3 +95,12 @@ config RMI4_F54
 
 	  Function 54 provides access to various diagnostic features in certain
 	  RMI4 touch sensors.
+
+config RMI4_F55
+	bool "RMI4 Function 55 (Sensor tuning)"
+	depends on RMI4_CORE
+	help
+	  Say Y here if you want to add support for RMI4 function 55
+
+	  Function 55 provides access to the RMI4 touch sensor tuning
+	  mechanism.

drivers/input/rmi4/Makefile

@@ -9,6 +9,7 @@ rmi_core-$(CONFIG_RMI4_F12) += rmi_f12.o
 rmi_core-$(CONFIG_RMI4_F30) += rmi_f30.o
 rmi_core-$(CONFIG_RMI4_F34) += rmi_f34.o
 rmi_core-$(CONFIG_RMI4_F54) += rmi_f54.o
+rmi_core-$(CONFIG_RMI4_F55) += rmi_f55.o
 
 # Transports
 obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o

drivers/input/rmi4/rmi_bus.c

@@ -321,6 +321,9 @@ static struct rmi_function_handler *fn_handlers[] = {
 #ifdef CONFIG_RMI4_F54
 	&rmi_f54_handler,
 #endif
+#ifdef CONFIG_RMI4_F55
+	&rmi_f55_handler,
+#endif
 };
 
 static void __rmi_unregister_function_handlers(int start_idx)

drivers/input/rmi4/rmi_driver.h

@@ -127,4 +127,5 @@ extern struct rmi_function_handler rmi_f12_handler;
 extern struct rmi_function_handler rmi_f30_handler;
 extern struct rmi_function_handler rmi_f34_handler;
 extern struct rmi_function_handler rmi_f54_handler;
+extern struct rmi_function_handler rmi_f55_handler;
 #endif

drivers/input/rmi4/rmi_f55.c

@@ -0,0 +1,124 @@
+/*
+ * Copyright (c) 2012-2015 Synaptics Incorporated
+ * Copyright (C) 2016 Zodiac Inflight Innovations
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/rmi.h>
+#include <linux/slab.h>
+#include "rmi_driver.h"
+
+#define F55_NAME		"rmi4_f55"
+
+/* F55 data offsets */
+#define F55_NUM_RX_OFFSET	0
+#define F55_NUM_TX_OFFSET	1
+#define F55_PHYS_CHAR_OFFSET	2
+
+/* Only read required query registers */
+#define F55_QUERY_LEN		3
+
+/* F55 capabilities */
+#define F55_CAP_SENSOR_ASSIGN	BIT(0)
+
+struct f55_data {
+	struct rmi_function *fn;
+
+	u8 qry[F55_QUERY_LEN];
+	u8 num_rx_electrodes;
+	u8 cfg_num_rx_electrodes;
+	u8 num_tx_electrodes;
+	u8 cfg_num_tx_electrodes;
+};
+
+static int rmi_f55_detect(struct rmi_function *fn)
+{
+	struct f55_data *f55;
+	int error;
+
+	f55 = dev_get_drvdata(&fn->dev);
+
+	error = rmi_read_block(fn->rmi_dev, fn->fd.query_base_addr,
+			       &f55->qry, sizeof(f55->qry));
+	if (error) {
+		dev_err(&fn->dev, "%s: Failed to query F55 properties\n",
+			__func__);
+		return error;
+	}
+
+	f55->num_rx_electrodes = f55->qry[F55_NUM_RX_OFFSET];
+	f55->num_tx_electrodes = f55->qry[F55_NUM_TX_OFFSET];
+
+	f55->cfg_num_rx_electrodes = f55->num_rx_electrodes;
+	f55->cfg_num_tx_electrodes = f55->num_rx_electrodes;
+
+	if (f55->qry[F55_PHYS_CHAR_OFFSET] & F55_CAP_SENSOR_ASSIGN) {
+		int i, total;
+		u8 buf[256];
+
+		/*
+		 * Calculate the number of enabled receive and transmit
+		 * electrodes by reading F55:Ctrl1 (sensor receiver assignment)
+		 * and F55:Ctrl2 (sensor transmitter assignment). The number of
+		 * enabled electrodes is the sum of all field entries with a
+		 * value other than 0xff.
+		 */
+		error = rmi_read_block(fn->rmi_dev,
+				       fn->fd.control_base_addr + 1,
+				       buf, f55->num_rx_electrodes);
+		if (!error) {
+			total = 0;
+			for (i = 0; i < f55->num_rx_electrodes; i++) {
+				if (buf[i] != 0xff)
+					total++;
+			}
+			f55->cfg_num_rx_electrodes = total;
+		}
+
+		error = rmi_read_block(fn->rmi_dev,
+				       fn->fd.control_base_addr + 2,
+				       buf, f55->num_tx_electrodes);
+		if (!error) {
+			total = 0;
+			for (i = 0; i < f55->num_tx_electrodes; i++) {
+				if (buf[i] != 0xff)
+					total++;
+			}
+			f55->cfg_num_tx_electrodes = total;
+		}
+	}
+
+	rmi_dbg(RMI_DEBUG_FN, &fn->dev, "F55 num_rx_electrodes: %d (raw %d)\n",
+		f55->cfg_num_rx_electrodes, f55->num_rx_electrodes);
+	rmi_dbg(RMI_DEBUG_FN, &fn->dev, "F55 num_tx_electrodes: %d (raw %d)\n",
+		f55->cfg_num_tx_electrodes, f55->num_tx_electrodes);
+
+	return 0;
+}
+
+static int rmi_f55_probe(struct rmi_function *fn)
+{
+	struct f55_data *f55;
+
+	f55 = devm_kzalloc(&fn->dev, sizeof(struct f55_data), GFP_KERNEL);
+	if (!f55)
+		return -ENOMEM;
+
+	f55->fn = fn;
+	dev_set_drvdata(&fn->dev, f55);
+
+	return rmi_f55_detect(fn);
+}
+
+struct rmi_function_handler rmi_f55_handler = {
+	.driver = {
+		.name = F55_NAME,
+	},
+	.func = 0x55,
+	.probe = rmi_f55_probe,
+};