[PATCH v2 2/5] input: misc: introduce Atmel PTC driver

[Ludovic Desroches]

The Atmel Peripheral Touch Controller subsystem offers built-in hardware
for capacitive touch measurement on sensors that function as buttons,
sliders and wheels.

Two files are loaded when probing the driver:
- a firmware for the Pico Power Processor that computes raw data from
  the ADC front end to provide high level information as button touch or
  untouch, slider position, etc.
- a configuration file that describe the topology and the parameters of
  the sensors.

Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
---
 drivers/input/misc/Kconfig     |  12 +
 drivers/input/misc/Makefile    |   1 +
 drivers/input/misc/atmel_ptc.c | 723 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 736 insertions(+)
 create mode 100644 drivers/input/misc/atmel_ptc.c

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 79d0be9..5e27378 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -96,6 +96,18 @@ config INPUT_ATMEL_CAPTOUCH
 	  To compile this driver as a module, choose M here: the
 	  module will be called atmel_captouch.
 
+config INPUT_ATMEL_PTC
+	tristate "Atmel PTC Driver"
+	depends on OF || COMPILE_TEST
+	depends on SOC_SAMA5D2
+	help
+	  Say Y to enable support for the Atmel PTC Subsystem.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called atmel_ptc.
+	  If you compile it as a built-in driver, you have to build the
+	  firmware into the kernel or to use an initrd.
+
 config INPUT_BMA150
 	tristate "BMA150/SMB380 acceleration sensor support"
 	depends on I2C
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index b10523f..9470ec7 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_INPUT_ARIZONA_HAPTICS)	+= arizona-haptics.o
 obj-$(CONFIG_INPUT_ATI_REMOTE2)		+= ati_remote2.o
 obj-$(CONFIG_INPUT_ATLAS_BTNS)		+= atlas_btns.o
 obj-$(CONFIG_INPUT_ATMEL_CAPTOUCH)	+= atmel_captouch.o
+obj-$(CONFIG_INPUT_ATMEL_PTC)		+= atmel_ptc.o
 obj-$(CONFIG_INPUT_BFIN_ROTARY)		+= bfin_rotary.o
 obj-$(CONFIG_INPUT_BMA150)		+= bma150.o
 obj-$(CONFIG_INPUT_CM109)		+= cm109.o
diff --git a/drivers/input/misc/atmel_ptc.c b/drivers/input/misc/atmel_ptc.c
new file mode 100644
index 0000000..612eaed
--- /dev/null
+++ b/drivers/input/misc/atmel_ptc.c
@@ -0,0 +1,723 @@
+/*
+ * Atmel PTC subsystem driver for SAMA5D2 devices and compatible.
+ *
+ * Copyright (C) 2017 Microchip,
+ *               2017 Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/cdev.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/firmware.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#define ATMEL_PTC_MAX_NODES	64
+#define ATMEL_PTC_MAX_SCROLLERS	4
+
+/* ----- PPP ----- */
+#define ATMEL_PPP_FIRMWARE_NAME	"atmel_ptc.bin"
+
+#define ATMEL_PPP_CONFIG	0x20
+#define ATMEL_PPP_CTRL		0x24
+#define ATMEL_PPP_CMD		0x28
+#define		ATMEL_PPP_CMD_STOP		0x1
+#define		ATMEL_PPP_CMD_RESET		0x2
+#define		ATMEL_PPP_CMD_RESTART		0x3
+#define		ATMEL_PPP_CMD_ABORT		0x4
+#define		ATMEL_PPP_CMD_RUN		0x5
+#define		ATMEL_PPP_CMD_RUN_LOCKED	0x6
+#define		ATMEL_PPP_CMD_RUN_OCD		0x7
+#define		ATMEL_PPP_CMD_UNLOCK		0x8
+#define		ATMEL_PPP_CMD_NMI		0x9
+#define		ATMEL_PPP_CMD_HOST_OCD_RESUME	0xB
+#define ATMEL_PPP_ISR		0x33
+#define		ATMEL_PPP_IRQ_MASK	GENMASK(7, 4)
+#define		ATMEL_PPP_IRQ0		BIT(4)
+#define		ATMEL_PPP_IRQ1		BIT(5)
+#define		ATMEL_PPP_IRQ2		BIT(6)
+#define		ATMEL_PPP_IRQ3		BIT(7)
+#define		ATMEL_PPP_NOTIFY_MASK	GENMASK(3, 0)
+#define		ATMEL_PPP_NOTIFY0	BIT(0)
+#define		ATMEL_PPP_NOTIFY1	BIT(1)
+#define		ATMEL_PPP_NOTIFY2	BIT(2)
+#define		ATMEL_PPP_NOTIFY3	BIT(3)
+#define ATMEL_PPP_IDR		0x34
+#define ATMEL_PPP_IER		0x35
+
+#define atmel_ppp_readb(ptc, reg)	readb_relaxed(ptc->ppp_regs + reg)
+#define atmel_ppp_writeb(ptc, reg, val)	writeb_relaxed(val, ptc->ppp_regs + reg)
+#define atmel_ppp_readl(ptc, reg)	readl_relaxed(ptc->ppp_regs + reg)
+#define atmel_ppp_writel(ptc, reg, val)	writel_relaxed(val, ptc->ppp_regs + reg)
+
+/* ----- QTM ----- */
+#define ATMEL_QTM_CONF_NAME		"atmel_ptc.conf"
+
+#define ATMEL_QTM_MB_OFFSET			0x4000
+#define ATMEL_QTM_MB_SIZE			0x1000
+
+#define ATMEL_QTM_MB_CMD_OFFSET			0x0
+#define		ATMEL_QTM_CMD_FIRM_VERSION		8
+#define		ATMEL_QTM_CMD_INIT			18
+#define		ATMEL_QTM_CMD_RUN			19
+#define		ATMEL_QTM_CMD_STOP			21
+#define		ATMEL_QTM_CMD_SET_ACQ_MODE_TIMER	24
+#define ATMEL_QTM_MB_NODE_GROUP_CONFIG_OFFSET	0x100
+#define ATMEL_QTM_MB_SCROLLER_CONFIG_OFFSET	0x81a
+#define		ATMEL_QTM_SCROLLER_TYPE_SLIDER		0x0
+#define		ATMEL_QTM_SCROLLER_TYPE_WHEEL		0x1
+#define ATMEL_QTM_MB_SCROLLER_DATA_OFFSET	0x842
+#define ATMEL_QTM_MB_TOUCH_EVENTS_OFFSET	0x880
+
+#define atmel_qtm_get_scroller_config(buf, id) \
+	memcpy(buf, \
+	       ptc->qtm_mb + ATMEL_QTM_MB_SCROLLER_CONFIG_OFFSET \
+	       + (id) * sizeof(struct atmel_qtm_scroller_config), \
+	       sizeof(struct atmel_qtm_scroller_config))
+
+#define atmel_qtm_get_scroller_data(buf, id) \
+	memcpy(buf, \
+	       ptc->qtm_mb + ATMEL_QTM_MB_SCROLLER_DATA_OFFSET \
+	       + (id) * sizeof(struct atmel_qtm_scroller_data), \
+	       sizeof(struct atmel_qtm_scroller_data))
+
+#define get_scroller_resolution(scroller_config) \
+	(1 << (scroller_config.resol_deadband >> 4))
+
+struct atmel_qtm_cmd {
+	u16	id;
+	u16	addr;
+	u32	data;
+} __packed;
+
+struct atmel_qtm_node_group_config {
+	u16	count;
+	u8	ptc_type;
+	u8	freq_option;
+	u8	calib_option;
+	u8	unused;
+} __packed;
+
+struct atmel_qtm_scroller_config {
+	u8	type;
+	u8	unused;
+	u16	key_start;
+	u8	key_count;
+	u8	resol_deadband;
+	u8	position_hysteresis;
+	u8	unused2;
+	u16	contact_min_threshold;
+} __packed;
+
+struct atmel_qtm_scroller_data {
+	u8	status;
+	u8	right_hyst;
+	u8	left_hyst;
+	u8	unused;
+	u16	raw_position;
+	u16	position;
+	u16	contact_size;
+} __packed;
+
+struct atmel_qtm_touch_events {
+	u32	key_event_id[2];
+	u32	key_enable_state[2];
+	u32	scroller_event_id;
+	u32	scroller_event_state;
+} __packed;
+
+struct atmel_ptc {
+	void __iomem		*ppp_regs;
+	void __iomem		*firmware;
+	int			irq;
+	u8			imr;
+	void __iomem		*qtm_mb;
+	struct clk		*clk_per;
+	struct clk		*clk_int_osc;
+	struct clk		*clk_slow;
+	struct device		*dev;
+	struct completion	ppp_ack;
+	unsigned int		button_keycode[ATMEL_PTC_MAX_NODES];
+	struct input_dev	*buttons_input;
+	struct input_dev	*scroller_input[ATMEL_PTC_MAX_SCROLLERS];
+	bool			buttons_registered;
+	bool			scroller_registered[ATMEL_PTC_MAX_SCROLLERS];
+	u32			button_event[ATMEL_PTC_MAX_NODES / 32];
+	u32			button_state[ATMEL_PTC_MAX_NODES / 32];
+	u32			scroller_event;
+	u32			scroller_state;
+};
+
+static void atmel_ppp_irq_enable(struct atmel_ptc *ptc, u8 mask)
+{
+	ptc->imr |= mask;
+	atmel_ppp_writeb(ptc, ATMEL_PPP_IER, mask & ATMEL_PPP_IRQ_MASK);
+}
+
+static void atmel_ppp_irq_disable(struct atmel_ptc *ptc, u8 mask)
+{
+	ptc->imr &= ~mask;
+	atmel_ppp_writeb(ptc, ATMEL_PPP_IDR, mask & ATMEL_PPP_IRQ_MASK);
+}
+
+static void atmel_ppp_notify(struct atmel_ptc *ptc, u8 mask)
+{
+	if (mask & ATMEL_PPP_NOTIFY_MASK) {
+		u8 notify = atmel_ppp_readb(ptc, ATMEL_PPP_ISR)
+			| (mask & ATMEL_PPP_NOTIFY_MASK);
+
+		atmel_ppp_writeb(ptc, ATMEL_PPP_ISR, notify);
+	}
+}
+
+static void atmel_ppp_irq_pending_clr(struct atmel_ptc *ptc, u8 mask)
+{
+	if (mask & ATMEL_PPP_IRQ_MASK) {
+		u8 irq = atmel_ppp_readb(ptc, ATMEL_PPP_ISR) & ~mask;
+
+		atmel_ppp_writeb(ptc, ATMEL_PPP_ISR, irq);
+	}
+}
+
+static void atmel_ppp_cmd_send(struct atmel_ptc *ptc, u32 cmd)
+{
+	atmel_ppp_writel(ptc, ATMEL_PPP_CMD, cmd);
+}
+
+static void atmel_ppp_irq_scroller_event(struct atmel_ptc *ptc)
+{
+	int i;
+
+	if (!ptc->scroller_event)
+		return;
+
+	for (i = 0; i < ATMEL_PTC_MAX_SCROLLERS; i++) {
+		u32 mask = 1 << i;
+		struct atmel_qtm_scroller_data scroller_data;
+		struct atmel_qtm_scroller_config scroller_config;
+
+		if (!(ptc->scroller_event & mask))
+			continue;
+
+		atmel_qtm_get_scroller_data(&scroller_data, i);
+		atmel_qtm_get_scroller_config(&scroller_config, i);
+
+		if (scroller_config.type == ATMEL_QTM_SCROLLER_TYPE_WHEEL)
+			input_report_abs(ptc->scroller_input[i],
+					 ABS_WHEEL, scroller_data.position);
+		else
+			input_report_abs(ptc->scroller_input[i],
+					 ABS_X, scroller_data.position);
+
+		input_report_key(ptc->scroller_input[i], BTN_TOUCH,
+				 scroller_data.status & 0x1);
+		input_sync(ptc->scroller_input[i]);
+	}
+}
+
+static void atmel_ppp_irq_button_event(struct atmel_ptc *ptc)
+{
+	int i, j;
+
+	for (i = 0; i < ATMEL_PTC_MAX_NODES / 32; i++) {
+		if (!ptc->button_event[i])
+			continue;
+
+		for (j = 0; j < 32; j++) {
+			u32 mask = 1 << j;
+			u32 state = ptc->button_state[i] & mask;
+			unsigned int key_id = i * 32 + j;
+
+			if (!(ptc->button_event[i] & mask))
+				continue;
+
+			input_report_key(ptc->buttons_input,
+					 ptc->button_keycode[key_id], !!state);
+			input_sync(ptc->buttons_input);
+		}
+	}
+}
+
+static void atmel_ppp_irq_touch_event(struct atmel_ptc *ptc)
+{
+	atmel_ppp_irq_scroller_event(ptc);
+	atmel_ppp_irq_button_event(ptc);
+}
+
+static irqreturn_t atmel_ppp_irq_handler(int irq, void *data)
+{
+	struct atmel_ptc *ptc = data;
+	u32 isr = atmel_ppp_readb(ptc, ATMEL_PPP_ISR) & ptc->imr;
+
+	/* QTM CMD acknowledgment */
+	if (isr & ATMEL_PPP_IRQ0) {
+		atmel_ppp_irq_disable(ptc, ATMEL_PPP_IRQ0);
+		atmel_ppp_irq_pending_clr(ptc, ATMEL_PPP_IRQ0);
+		complete(&ptc->ppp_ack);
+	}
+	/* QTM touch event */
+	if (isr & ATMEL_PPP_IRQ1) {
+		struct atmel_qtm_touch_events touch_events;
+		int i;
+
+		memcpy(&touch_events,
+		       ptc->qtm_mb + ATMEL_QTM_MB_TOUCH_EVENTS_OFFSET,
+		       sizeof(touch_events));
+
+		for (i = 0; i < ATMEL_PTC_MAX_NODES / 32; i++) {
+			ptc->button_event[i] = touch_events.key_event_id[i];
+			ptc->button_state[i] = touch_events.key_enable_state[i];
+		}
+		ptc->scroller_event = touch_events.scroller_event_id;
+		ptc->scroller_state = touch_events.scroller_event_state;
+
+		atmel_ppp_irq_pending_clr(ptc, ATMEL_PPP_IRQ1);
+
+		atmel_ppp_irq_touch_event(ptc);
+	}
+	/* Debug event */
+	if (isr & ATMEL_PPP_IRQ2)
+		atmel_ppp_irq_pending_clr(ptc, ATMEL_PPP_IRQ2);
+
+	return IRQ_HANDLED;
+}
+
+void atmel_qtm_cmd_send(struct atmel_ptc *ptc, struct atmel_qtm_cmd *cmd)
+{
+	int i, ret;
+
+	dev_dbg(ptc->dev, "%s: cmd=0x%x, addr=0x%x, data=0x%x\n",
+		__func__, cmd->id, cmd->addr, cmd->data);
+
+	memcpy(ptc->qtm_mb, cmd, sizeof(*cmd));
+
+	/* Once command performed, we'll get an IRQ. */
+	atmel_ppp_irq_enable(ptc, ATMEL_PPP_IRQ0);
+	/* Notify PPP that we have sent a command. */
+	atmel_ppp_notify(ptc, ATMEL_PPP_NOTIFY0);
+	/* Wait for IRQ from PPP. */
+	wait_for_completion(&ptc->ppp_ack);
+
+	/*
+	 * Register input devices only when QTM is started since we need some
+	 * information from the QTM configuration.
+	 */
+	if (cmd->id == ATMEL_QTM_CMD_RUN) {
+		if (ptc->buttons_input && !ptc->buttons_registered) {
+			ret = input_register_device(ptc->buttons_input);
+			if (ret)
+				dev_err(ptc->dev, "can't register input button device.\n");
+			else
+				ptc->buttons_registered = true;
+		}
+
+		for (i = 0; i < ATMEL_PTC_MAX_SCROLLERS; i++) {
+			struct input_dev *scroller = ptc->scroller_input[i];
+			struct atmel_qtm_scroller_config scroller_config;
+
+			if (!scroller || ptc->scroller_registered[i])
+				continue;
+
+			atmel_qtm_get_scroller_config(&scroller_config, i);
+
+			if (scroller_config.type ==
+			    ATMEL_QTM_SCROLLER_TYPE_SLIDER) {
+				unsigned int max = get_scroller_resolution(scroller_config);
+
+				input_set_abs_params(scroller, 0, 0, max, 0, 0);
+			}
+			ret = input_register_device(scroller);
+			if (ret)
+				dev_err(ptc->dev, "can't register input scroller device.\n");
+			else
+				ptc->scroller_registered[i] = true;
+		}
+	}
+
+	memcpy(cmd, ptc->qtm_mb, sizeof(*cmd));
+}
+
+static inline struct atmel_ptc *kobj_to_atmel_ptc(struct kobject *kobj)
+{
+	struct device *dev = kobj_to_dev(kobj);
+
+	return dev->driver_data;
+}
+
+static ssize_t atmel_qtm_mb_read(struct file *filp, struct kobject *kobj,
+				 struct bin_attribute *attr,
+				 char *buf, loff_t off, size_t count)
+{
+	struct atmel_ptc *ptc = kobj_to_atmel_ptc(kobj);
+	char *qtm_mb = (char *)ptc->qtm_mb;
+
+	dev_dbg(ptc->dev, "%s: off=0x%llx, count=%zu\n", __func__, off, count);
+
+	memcpy(buf, qtm_mb + off, count);
+
+	return count;
+}
+
+static ssize_t atmel_qtm_mb_write(struct file *filp, struct kobject *kobj,
+				  struct bin_attribute *attr,
+				  char *buf, loff_t off, size_t count)
+{
+	struct atmel_ptc *ptc = kobj_to_atmel_ptc(kobj);
+	char *qtm_mb = (char *)ptc->qtm_mb;
+
+	dev_dbg(ptc->dev, "%s: off=0x%llx, count=%zu\n", __func__, off, count);
+
+	if (off == 0 && count == sizeof(struct atmel_qtm_cmd))
+		atmel_qtm_cmd_send(ptc, (struct atmel_qtm_cmd *)buf);
+	else
+		memcpy(qtm_mb + off, buf, count);
+
+	return count;
+}
+
+static struct bin_attribute atmel_ptc_qtm_mb_attr = {
+	.attr = {
+		.name = "qtm_mb",
+		.mode = 0644,
+	},
+	.size = ATMEL_QTM_MB_SIZE,
+	.read = atmel_qtm_mb_read,
+	.write = atmel_qtm_mb_write,
+};
+
+/*
+ * From QTM MB configuration, we can't retrieve all the information needed
+ * to setup correctly input devices: buttons key codes and slider axis are
+ * missing.
+ */
+static int atmel_ptc_of_parse(struct atmel_ptc *ptc)
+{
+	struct device_node *sensor;
+	bool first_button = true;
+
+	/* Parse sensors. */
+	for_each_child_of_node(ptc->dev->of_node, sensor) {
+		if (!strcmp(sensor->name, "button")) {
+			u32 key_id, keycode;
+			struct input_dev *buttons = ptc->buttons_input;
+
+			if (of_property_read_u32(sensor, "reg", &key_id)) {
+				dev_err(ptc->dev, "reg is missing (%s)\n",
+					sensor->full_name);
+				return -EINVAL;
+			}
+
+			if (of_property_read_u32(sensor, "linux,keycode", &keycode)) {
+				dev_err(ptc->dev, "linux,keycode is missing (%s)\n",
+					sensor->full_name);
+				return -EINVAL;
+			}
+			ptc->button_keycode[key_id] = keycode;
+
+			/* All buttons are put together in a keyboard device. */
+			if (first_button) {
+				buttons = devm_input_allocate_device(ptc->dev);
+				if (!buttons)
+					return -ENOMEM;
+				buttons->name = "atmel_ptc_buttons";
+				buttons->dev.parent = ptc->dev;
+				buttons->keycode = ptc->button_keycode;
+				buttons->keycodesize = sizeof(ptc->button_keycode[0]);
+				buttons->keycodemax = ATMEL_PTC_MAX_NODES;
+				ptc->buttons_input = buttons;
+				first_button = false;
+			}
+
+			input_set_capability(buttons, EV_KEY, keycode);
+		} else if (!strcmp(sensor->name, "slider") ||
+			   !strcmp(sensor->name, "wheel")) {
+			u32 scroller_id;
+			struct input_dev *scroller;
+
+			if (of_property_read_u32(sensor, "reg", &scroller_id)) {
+				dev_err(ptc->dev, "reg is missing (%s)\n",
+					sensor->full_name);
+				return -EINVAL;
+			}
+
+			if (scroller_id > ATMEL_PTC_MAX_SCROLLERS - 1) {
+				dev_err(ptc->dev, "wrong scroller id (%s)\n",
+					sensor->full_name);
+				return -EINVAL;
+			}
+
+			scroller = devm_input_allocate_device(ptc->dev);
+			if (!scroller)
+				return -ENOMEM;
+
+			scroller->dev.parent = ptc->dev;
+			ptc->scroller_input[scroller_id] = scroller;
+
+			if (!strcmp(sensor->name, "slider")) {
+				scroller->name = "atmel_ptc_slider";
+				input_set_capability(scroller, EV_ABS, ABS_X);
+				input_set_capability(scroller, EV_KEY, BTN_TOUCH);
+			} else {
+				scroller->name = "atmel_ptc_wheel";
+				input_set_capability(scroller, EV_ABS, ABS_WHEEL);
+				input_set_capability(scroller, EV_KEY, BTN_TOUCH);
+			}
+		} else {
+			dev_err(ptc->dev, "%s is not supported\n", sensor->name);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static void atmel_qtm_conf_callback(const struct firmware *conf, void *context)
+{
+	struct atmel_ptc *ptc = context;
+	struct atmel_qtm_cmd qtm_cmd;
+	char *dst;
+	struct atmel_qtm_node_group_config node_group_config;
+
+	if (!conf) {
+		dev_err(ptc->dev, "cannot load QTM configuration, it has to be set manually.\n");
+		return;
+	}
+
+	atmel_ppp_irq_enable(ptc, ATMEL_PPP_IRQ1);
+	atmel_ppp_irq_disable(ptc, ATMEL_PPP_IRQ2 | ATMEL_PPP_IRQ3);
+
+	qtm_cmd.id = ATMEL_QTM_CMD_STOP;
+	atmel_qtm_cmd_send(ptc, &qtm_cmd);
+
+	/* Load QTM configuration. */
+	dst = (char *)ptc->qtm_mb + ATMEL_QTM_MB_NODE_GROUP_CONFIG_OFFSET;
+	/* memcpy doesn't work for an unknown reason. */
+	_memcpy_toio(dst, conf->data, conf->size);
+	release_firmware(conf);
+
+	if (atmel_ptc_of_parse(ptc))
+		dev_err(ptc->dev, "ptc_of_parse failed\n");
+
+	memcpy(&node_group_config,
+	       ptc->qtm_mb + ATMEL_QTM_MB_NODE_GROUP_CONFIG_OFFSET,
+	       sizeof(node_group_config));
+
+	/* Start QTM. */
+	qtm_cmd.id = ATMEL_QTM_CMD_INIT;
+	qtm_cmd.data = node_group_config.count;
+	atmel_qtm_cmd_send(ptc, &qtm_cmd);
+	qtm_cmd.id = ATMEL_QTM_CMD_SET_ACQ_MODE_TIMER;
+	qtm_cmd.data = 20;
+	atmel_qtm_cmd_send(ptc, &qtm_cmd);
+	qtm_cmd.id = ATMEL_QTM_CMD_RUN;
+	qtm_cmd.data = node_group_config.count;
+	atmel_qtm_cmd_send(ptc, &qtm_cmd);
+}
+
+static void atmel_ppp_fw_callback(const struct firmware *fw, void *context)
+{
+	struct atmel_ptc *ptc = context;
+	int ret;
+	struct atmel_qtm_cmd cmd;
+
+	if (!fw || !fw->size) {
+		dev_err(ptc->dev, "cannot load firmware.\n");
+		release_firmware(fw);
+		device_release_driver(ptc->dev);
+		return;
+	}
+
+	/* Command sequence to start from a clean state. */
+	atmel_ppp_cmd_send(ptc, ATMEL_PPP_CMD_ABORT);
+	atmel_ppp_irq_pending_clr(ptc, ATMEL_PPP_IRQ_MASK);
+	atmel_ppp_cmd_send(ptc, ATMEL_PPP_CMD_RESET);
+
+	memcpy(ptc->firmware, fw->data, fw->size);
+	release_firmware(fw);
+
+	atmel_ppp_cmd_send(ptc, ATMEL_PPP_CMD_RUN);
+
+	cmd.id = ATMEL_QTM_CMD_FIRM_VERSION;
+	atmel_qtm_cmd_send(ptc, &cmd);
+	dev_info(ptc->dev, "firmware version: %u\n", cmd.data);
+
+	/* PPP is running, it's time to load the QTM configuration. */
+	ret = request_firmware_nowait(THIS_MODULE, 1, ATMEL_QTM_CONF_NAME, ptc->dev,
+				      GFP_KERNEL, ptc, atmel_qtm_conf_callback);
+	if (ret)
+		dev_err(ptc->dev, "QTM configuration loading failed.\n");
+}
+
+static int atmel_ptc_probe(struct platform_device *pdev)
+{
+	struct atmel_ptc *ptc;
+	struct resource	*res;
+	void *shared_memory;
+	int ret;
+
+	ptc = devm_kzalloc(&pdev->dev, sizeof(*ptc), GFP_KERNEL);
+	if (!ptc)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ptc);
+	ptc->dev = &pdev->dev;
+	ptc->dev->driver_data = ptc;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
+	shared_memory = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(shared_memory))
+		return PTR_ERR(shared_memory);
+
+	ptc->firmware = shared_memory;
+	ptc->qtm_mb = shared_memory + ATMEL_QTM_MB_OFFSET;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res)
+		return -EINVAL;
+
+	ptc->ppp_regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ptc->ppp_regs))
+		return PTR_ERR(ptc->ppp_regs);
+
+	ptc->irq = platform_get_irq(pdev, 0);
+	if (ptc->irq <= 0) {
+		if (!ptc->irq)
+			ptc->irq = -ENXIO;
+
+		return ptc->irq;
+	}
+
+	ptc->clk_per = devm_clk_get(&pdev->dev, "ptc_clk");
+	if (IS_ERR(ptc->clk_per))
+		return PTR_ERR(ptc->clk_per);
+
+	ptc->clk_int_osc = devm_clk_get(&pdev->dev, "ptc_int_osc");
+	if (IS_ERR(ptc->clk_int_osc))
+		return PTR_ERR(ptc->clk_int_osc);
+
+	ptc->clk_slow = devm_clk_get(&pdev->dev, "slow_clk");
+	if (IS_ERR(ptc->clk_slow))
+		return PTR_ERR(ptc->clk_slow);
+
+	ret = devm_request_irq(&pdev->dev, ptc->irq, atmel_ppp_irq_handler, 0,
+			       pdev->dev.driver->name, ptc);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(ptc->clk_int_osc);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(ptc->clk_per);
+	if (ret)
+		goto disable_clk_int_osc;
+
+	ret = clk_prepare_enable(ptc->clk_slow);
+	if (ret)
+		goto disable_clk_per;
+
+	/* Needed to avoid unexpected behaviors. */
+	memset(ptc->firmware, 0, ATMEL_QTM_MB_OFFSET + sizeof(*ptc->qtm_mb));
+	ptc->imr = 0;
+	init_completion(&ptc->ppp_ack);
+
+	/*
+	 * Expose a file to give an access to the QTM mailbox to a user space
+	 * application in order to configure it or to send commands.
+	 */
+	ret = sysfs_create_bin_file(&pdev->dev.kobj, &atmel_ptc_qtm_mb_attr);
+	if (ret)
+		goto disable_clk_slow;
+
+	ret = request_firmware_nowait(THIS_MODULE, 1, ATMEL_PPP_FIRMWARE_NAME,
+				      ptc->dev, GFP_KERNEL, ptc,
+				      atmel_ppp_fw_callback);
+	if (ret) {
+		dev_err(&pdev->dev, "firmware loading failed\n");
+		ret = -EPROBE_DEFER;
+		goto remove_qtm_mb;
+	}
+
+	return 0;
+
+remove_qtm_mb:
+	sysfs_remove_bin_file(&pdev->dev.kobj, &atmel_ptc_qtm_mb_attr);
+disable_clk_slow:
+	clk_disable_unprepare(ptc->clk_slow);
+disable_clk_per:
+	clk_disable_unprepare(ptc->clk_per);
+disable_clk_int_osc:
+	clk_disable_unprepare(ptc->clk_int_osc);
+
+	return ret;
+}
+
+static int atmel_ptc_remove(struct platform_device *pdev)
+{
+	struct atmel_ptc *ptc = platform_get_drvdata(pdev);
+	int i;
+
+	if (ptc->buttons_registered)
+		input_unregister_device(ptc->buttons_input);
+
+	for (i = 0; i < ATMEL_PTC_MAX_SCROLLERS; i++) {
+		struct input_dev *scroller = ptc->scroller_input[i];
+
+		if (!scroller || !ptc->scroller_registered[i])
+			continue;
+		input_unregister_device(scroller);
+	}
+
+	sysfs_remove_bin_file(&pdev->dev.kobj, &atmel_ptc_qtm_mb_attr);
+	clk_disable_unprepare(ptc->clk_slow);
+	clk_disable_unprepare(ptc->clk_per);
+	clk_disable_unprepare(ptc->clk_int_osc);
+
+	return 0;
+}
+
+static const struct of_device_id atmel_ptc_dt_match[] = {
+	{
+		.compatible = "atmel,sama5d2-ptc",
+	}, {
+		/* sentinel */
+	}
+};
+MODULE_DEVICE_TABLE(of, atmel_ptc_dt_match);
+
+static struct platform_driver atmel_ptc_driver = {
+	.probe = atmel_ptc_probe,
+	.remove = atmel_ptc_remove,
+	.driver = {
+		.name = "atmel_ptc",
+		.of_match_table = atmel_ptc_dt_match,
+	},
+};
+module_platform_driver(atmel_ptc_driver)
+
+MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Atmel PTC subsystem");
+MODULE_LICENSE("GPL v2");
+MODULE_FIRMWARE(ATMEL_PPP_FIRMWARE_NAME);
+MODULE_FIRMWARE(ATMEL_QTM_CONF_NAME);
-- 
2.9.0