[PATCH 1/2 v1] dt-bindings: touchscreen: Add CY8CTMA140 bindings

[PATCH 1/2 v1] dt-bindings: touchscreen: Add CY8CTMA140 bindings

[Linus Walleij]

This adds device tree bindings for the Cypress CY8CTMA140
touchscreen.

Cc: devicetree@vger.kernel.org
Cc: Ferruh Yigit <fery@cypress.com>
Cc: Henrik Rydberg <rydberg@bitmath.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 .../input/touchscreen/cypress,cy8ctma140.yaml | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml

diff --git a/Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml b/Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml
new file mode 100644
index 000000000000..66b488e48b74
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml
@@ -0,0 +1,72 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/cypress,cy8ctma140.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Cypress CY8CTMA140 series touchscreen controller bindings
+
+maintainers:
+  - Linus Walleij <linus.walleij@linaro.org>
+
+allOf:
+  - $ref: touchscreen.yaml#
+
+properties:
+  compatible:
+    const: cypress,cy8ctma140
+
+  reg:
+    description: I2C client address, defined by hardware
+    const: 0x20
+
+  clock-frequency:
+    description: I2C client max frequency, defined by hardware
+    const: 400000
+
+  interrupts:
+    maxItems: 1
+
+  vcpin-supply:
+    description: Analog power supply regulator on VCPIN pin
+
+  vdd-supply:
+    description: Digital power supply regulator on VDD pin
+
+  touchscreen-inverted-x: true
+  touchscreen-inverted-y: true
+  touchscreen-size-x: true
+  touchscreen-size-y: true
+  touchscreen-swapped-x-y: true
+  touchscreen-max-pressure: true
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - touchscreen-size-x
+  - touchscreen-size-y
+  - touchscreen-max-pressure
+
+examples:
+- |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    i2c@00000000 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      touchscreen@20 {
+        compatible = "cypress,cy8ctma140";
+        reg = <0x20>;
+        touchscreen-size-x = <480>;
+        touchscreen-size-y = <800>;
+        touchscreen-max-pressure = <255>;
+        interrupt-parent = <&gpio6>;
+        interrupts = <26 IRQ_TYPE_EDGE_FALLING>;
+        vdd-supply = <&ab8500_ldo_aux2_reg>;
+        vcpin-supply = <&ab8500_ldo_aux2_reg>;
+      };
+    };
+
+...
-- 
2.21.1

[PATCH 2/2 v1] Input: cy8ctma140 - add driver

[Linus Walleij]

This adds a new driver for the Cypress CY8CTMA140 touchscreen.

This driver is inspired by out-of-tree code for the Samsung
GT-S7710 mobile phone.

I have tried to compare the structure and behaviour of this
touchscreen to the existing CYTTSP and CYTTSP4 generics and
it seems pretty different. It is also different in character
from the cy8ctmg110_ts.c. It appears to rather be vaguely
related to the Melfas MMS114 driver, yet distinctly
different.

Cc: Ferruh Yigit <fery@cypress.com>
Cc: Henrik Rydberg <rydberg@bitmath.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 MAINTAINERS                            |   6 +
 drivers/input/touchscreen/Kconfig      |  13 +
 drivers/input/touchscreen/Makefile     |   1 +
 drivers/input/touchscreen/cy8ctma140.c | 380 +++++++++++++++++++++++++
 4 files changed, 400 insertions(+)
 create mode 100644 drivers/input/touchscreen/cy8ctma140.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8e7433d74530..39163de1a082 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4628,6 +4628,12 @@ T:	git git://linuxtv.org/anttip/media_tree.git
 S:	Maintained
 F:	drivers/media/common/cypress_firmware*
 
+CYPRESS CY8CTMA140 TOUCHSCREEN DRIVER
+M:	Linus Walleij <linus.walleij@linaro.org>
+L:	linux-input@vger.kernel.org
+S:	Maintained
+F:	drivers/input/touchscreen/cy8ctma140.c
+
 CYTTSP TOUCHSCREEN DRIVER
 M:	Ferruh Yigit <fery@cypress.com>
 L:	linux-input@vger.kernel.org
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index c071f7c407b6..279b96d1761a 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -214,6 +214,19 @@ config TOUCHSCREEN_CY8CTMG110
 	  To compile this driver as a module, choose M here: the
 	  module will be called cy8ctmg110_ts.
 
+config TOUCHSCREEN_CY8CTMA140
+	tristate "cy8ctma140 touchscreen"
+	depends on I2C
+	depends on GPIOLIB || COMPILE_TEST
+	help
+	  Say Y here if you have a Cypress CY8CTMA140 capacitive
+	  touchscreen also just known as "TMA140"
+
+	  If unsure, say N.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cy8ctma140.
+
 config TOUCHSCREEN_CYTTSP_CORE
 	tristate "Cypress TTSP touchscreen"
 	help
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 94c6162409b3..006444c8f87b 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_TOUCHSCREEN_BU21029)	+= bu21029_ts.o
 obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8318)	+= chipone_icn8318.o
 obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8505)	+= chipone_icn8505.o
 obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110)	+= cy8ctmg110_ts.o
+obj-$(CONFIG_TOUCHSCREEN_CY8CTMA140)	+= cy8ctma140.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_CORE)	+= cyttsp_core.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_I2C)	+= cyttsp_i2c.o cyttsp_i2c_common.o
 obj-$(CONFIG_TOUCHSCREEN_CYTTSP_SPI)	+= cyttsp_spi.o
diff --git a/drivers/input/touchscreen/cy8ctma140.c b/drivers/input/touchscreen/cy8ctma140.c
new file mode 100644
index 000000000000..fb79f4251122
--- /dev/null
+++ b/drivers/input/touchscreen/cy8ctma140.c
@@ -0,0 +1,380 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Cypress CY8CTMA140 (TMA140) touchscreen
+ * (C) 2020 Linus Walleij <linus.walleij@linaro.org>
+ * (C) 2007 Cypress
+ * (C) 2007 Google, Inc.
+ *
+ * Inspired by the tma140_skomer.c driver in the Samsung GT-S7710 code
+ * drop. The GT-S7710 is codenamed "Skomer", the code also indicates
+ * that the same touchscreen was used in a product called "Lucas".
+ *
+ * The code drop for GT-S7710 also contains a firmware downloader and
+ * 15 (!) versions of the firmware drop from Cypress. But here we assume
+ * the firmware got downloaded to the touchscreen flash successfully and
+ * just use it to read the fingers. The shipped vendor driver does the
+ * same.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/input.h>
+#include <linux/input/touchscreen.h>
+#include <linux/input/mt.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/i2c.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+#include <linux/delay.h>
+
+/* Used for driver name etc */
+#define CY8CTMA140_NAME "cy8ctma140"
+
+/*
+ * The datasheet claims the device supports 4 fingers but the firmware
+ * I've seen certainly only supports 2 fingers.
+ */
+#define CY8CTMA140_MAX_FINGERS 2
+#define CY8CTMA140_GET_FINGERS 0x00
+#define CY8CTMA140_GET_FW_INFO 0x19
+
+struct cy8ctma140 {
+	struct input_dev *input;
+	struct touchscreen_properties props;
+	struct device *dev;
+	struct i2c_client *client;
+	struct regulator *vcpin;
+	struct regulator *vdd;
+	struct gpio_desc *irq;
+};
+
+static irqreturn_t cy8ctma140_irq_thread(int irq, void *d)
+{
+	struct cy8ctma140 *ts = d;
+	u8 msgbuf0[1];
+	u8 buf[31];
+	struct i2c_msg msg[2] = {
+		{
+			.addr = ts->client->addr,
+			.flags = 0,
+			.len = 1,
+			.buf = msgbuf0,
+		}, {
+			.addr = ts->client->addr,
+			.flags = I2C_M_RD,
+			.len = sizeof(buf),
+			.buf = buf,
+		},
+	};
+	u8 fingers;
+	u16 f1x, f1y, f1z;
+	u16 f2x, f2y, f2z;
+	int ret;
+	int slots[CY8CTMA140_MAX_FINGERS];
+	struct input_mt_pos pos[CY8CTMA140_MAX_FINGERS];
+
+	msgbuf0[0] = CY8CTMA140_GET_FINGERS;
+	ret = __i2c_transfer(ts->client->adapter, msg, 2);
+	if (ret < 0) {
+		dev_err(ts->dev, "error reading message\n");
+		goto evt_out;
+	}
+	if (ret != 2) {
+		dev_err(ts->dev, "wrong number of messages\n");
+		goto evt_out;
+	}
+	if (buf[1] & 0x20) {
+		dev_info(ts->dev, "invalid event\n");
+		goto evt_out;
+	}
+
+	f1x = buf[3] << 8 | buf[4];
+	f1y = buf[5] << 8 | buf[6];
+	f1z = buf[7];
+
+	f2x = buf[9] << 8 | buf[10];
+	f2y = buf[11] << 8 | buf[12];
+	f2z = buf[13];
+
+	fingers = buf[2] & 0x0f;
+	if (fingers == 0) {
+		dev_info(ts->dev, "no fingers\n");
+		goto evt_out;
+	}
+
+	input_mt_assign_slots(ts->input, slots, pos, fingers, 0);
+
+	/*
+	 * When just handling two fingers this code is simple and we do not
+	 * need a loop increasing the complexity. If you need to modify
+	 * this driver for some firmware handling more than 2 fingers,
+	 * this is where you put in an array of coordinated and a loop
+	 * instead.
+	 */
+	if (fingers >= 1) {
+		dev_dbg(ts->dev, "%d fingers: finger 1 ID: %02x (%d, %d, %d)\n",
+			fingers, buf[8] >> 4, f1x, f1y, f1z);
+		input_mt_slot(ts->input, slots[0]);
+		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
+		input_report_abs(ts->input, ABS_MT_POSITION_X, f1x);
+		input_report_abs(ts->input, ABS_MT_POSITION_Y, f1y);
+		input_report_abs(ts->input, ABS_MT_PRESSURE, f1z);
+	}
+	if (fingers >= 2) {
+		dev_dbg(ts->dev, "%d fingers: finger 2 ID %02x (%d, %d, %d)\n",
+			fingers, buf[8] & 0x0f, f2x, f2y, f2z);
+		input_mt_slot(ts->input, slots[1]);
+		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
+		input_report_abs(ts->input, ABS_MT_POSITION_X, f2x);
+		input_report_abs(ts->input, ABS_MT_POSITION_Y, f2y);
+		input_report_abs(ts->input, ABS_MT_PRESSURE, f2z);
+	}
+	if (fingers > 2)
+		dev_err(ts->dev, "%d fingers - unsupported!\n", fingers);
+
+	input_mt_sync_frame(ts->input);
+	input_sync(ts->input);
+
+evt_out:
+	return IRQ_HANDLED;
+}
+
+static int cy8ctma140_init(struct cy8ctma140 *ts)
+{
+	u8 addr[1];
+	u8 buf[5];
+	int ret;
+
+	addr[0] = CY8CTMA140_GET_FW_INFO;
+	ret = i2c_master_send(ts->client, addr, 1);
+	if (ret < 0) {
+		dev_err(ts->dev, "error sending FW info message\n");
+		return ret;
+	}
+	ret = i2c_master_recv(ts->client, buf, 5);
+	if (ret < 0) {
+		dev_err(ts->dev, "error recieveing FW info message\n");
+		return ret;
+	}
+	if (ret != 5) {
+		dev_err(ts->dev, "got only %d bytes\n", ret);
+		return -EIO;
+	}
+
+	dev_info(ts->dev, "vendor %c%c, HW ID %.2d, FW ver %.4d\n",
+		 buf[0], buf[1], buf[3], buf[4]);
+	return 0;
+}
+
+static int cy8ctma140_power_up(struct cy8ctma140 *ts)
+{
+	int ret;
+
+	ret = regulator_enable(ts->vcpin);
+	if (ret) {
+		dev_err(ts->dev, "failed to enable VCPIN voltage\n");
+		return ret;
+	}
+	ret = regulator_enable(ts->vdd);
+	if (ret) {
+		dev_err(ts->dev, "failed to enable VDD voltage\n");
+		regulator_disable(ts->vcpin);
+		return ret;
+	}
+
+	msleep(250);
+
+	return 0;
+}
+
+static void cy8ctma140_power_down(struct cy8ctma140 *ts)
+{
+	regulator_disable(ts->vdd);
+	regulator_disable(ts->vcpin);
+}
+
+/* Called from the registered devm action */
+static void cy8ctma140_power_off_action(void *d)
+{
+	struct cy8ctma140 *ts = d;
+
+	cy8ctma140_power_down(ts);
+}
+
+static int cy8ctma140_probe(struct i2c_client *client,
+			    const struct i2c_device_id *id)
+{
+	struct cy8ctma140 *ts;
+	struct input_dev *input;
+	struct device *dev = &client->dev;
+	int ret;
+
+	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	input = devm_input_allocate_device(dev);
+	if (!input)
+		return -ENOMEM;
+
+	ts->dev = dev;
+	ts->client = client;
+	ts->input = input;
+
+	/*
+	 * This sets up event max/min capabilities and fuzz.
+	 * Some DT properties are compulsory so we do not need
+	 * to provide defaults for X/Y max or pressure max.
+	 *
+	 * We just initialize a very simple MT touchscreen here,
+	 * some devices use the capability of this touchscreen to
+	 * provide touchkeys, and in that case this needs to be
+	 * extended to handle touchkey input.
+	 *
+	 * The firmware takes care of finger tracking and dropping
+	 * invalid ranges.
+	 */
+	touchscreen_parse_properties(input, true, &ts->props);
+
+	ret = input_mt_init_slots(input, CY8CTMA140_MAX_FINGERS,
+				  INPUT_MT_DIRECT);
+	if (ret)
+		return ret;
+
+	input->name = CY8CTMA140_NAME;
+	input->phys = "inpus/ts";
+	input->id.bustype = BUS_I2C;
+	input_set_drvdata(input, ts);
+
+	/* VCPIN is the analog voltage supply */
+	ts->vcpin = devm_regulator_get(dev, "vcpin");
+	if (IS_ERR(ts->vcpin)) {
+		if (PTR_ERR(ts->vcpin) != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get VCPIN regulator %d\n",
+				(int)PTR_ERR(ts->vcpin));
+		return PTR_ERR(ts->vcpin);
+	}
+	/* According to datasheet this should be in the 2.7-3.6 V range */
+	ret = regulator_set_voltage(ts->vcpin, 2700000, 3600000);
+	if (ret) {
+		dev_err(dev, "failed to set VCPIN voltage\n");
+		return ret;
+	}
+
+	/*
+	 * VDD is the digital voltage supply
+	 * since the voltage range of VDD overlaps that of VCPIN,
+	 * many designs to just supply both with a single voltage
+	 * source of ~3.3 V.
+	 */
+	ts->vdd = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(ts->vdd)) {
+		if (PTR_ERR(ts->vdd) != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get VDD regulator %d\n",
+				(int)PTR_ERR(ts->vdd));
+		return PTR_ERR(ts->vdd);
+	}
+	/* According to datasheet this should be in the 1.71-3.6 V range */
+	ret = regulator_set_voltage(ts->vdd, 2700000, 3600000);
+	if (ret) {
+		dev_err(dev, "failed to set VDD voltage\n");
+		return ret;
+	}
+
+	ret = cy8ctma140_power_up(ts);
+	if (ret)
+		return ret;
+	ret = devm_add_action_or_reset(dev, cy8ctma140_power_off_action, ts);
+	if (ret) {
+		dev_err(dev, "failed to install power off handler\n");
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL,
+					cy8ctma140_irq_thread,
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					CY8CTMA140_NAME, ts);
+	if (ret) {
+		dev_err(dev, "irq %d busy? error %d\n", client->irq, ret);
+		goto err_reg_dis;
+	}
+
+	ret = cy8ctma140_init(ts);
+	if (ret)
+		return ret;
+
+	ret = input_register_device(input);
+	if (ret)
+		goto err_reg_dis;
+
+	i2c_set_clientdata(client, ts);
+
+	device_init_wakeup(dev, 1);
+	return 0;
+
+err_reg_dis:
+	cy8ctma140_power_down(ts);
+	return ret;
+}
+
+static int __maybe_unused cy8ctma140_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct cy8ctma140 *ts = i2c_get_clientdata(client);
+
+	if (device_may_wakeup(&client->dev))
+		enable_irq_wake(client->irq);
+	else
+		cy8ctma140_power_down(ts);
+
+	return 0;
+}
+
+static int __maybe_unused cy8ctma140_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct cy8ctma140 *ts = i2c_get_clientdata(client);
+	int ret;
+
+	if (device_may_wakeup(&client->dev)) {
+		disable_irq_wake(client->irq);
+	} else {
+		ret = cy8ctma140_power_up(ts);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(cy8ctma140_pm, cy8ctma140_suspend, cy8ctma140_resume);
+
+static const struct i2c_device_id cy8ctma140_idtable[] = {
+	{ CY8CTMA140_NAME, 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, cy8ctma140_idtable);
+
+static const struct of_device_id cy8ctma140_of_match[] = {
+	{
+		.compatible = "cypress,cy8ctma140",
+	},
+};
+MODULE_DEVICE_TABLE(of, cy8ctma140_of_match);
+
+static struct i2c_driver cy8ctma140_driver = {
+	.driver		= {
+		.name	= CY8CTMA140_NAME,
+		.pm	= &cy8ctma140_pm,
+		.of_match_table = cy8ctma140_of_match,
+	},
+	.id_table	= cy8ctma140_idtable,
+	.probe		= cy8ctma140_probe,
+};
+module_i2c_driver(cy8ctma140_driver);
+
+MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
+MODULE_DESCRIPTION("CY8CTMA140 TouchScreen Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.21.1

Re: [PATCH 2/2 v1] Input: cy8ctma140 - add driver

[Dmitry Torokhov]

Hi Linus,

On Tue, Mar 10, 2020 at 03:28:18PM +0100, Linus Walleij wrote:
> This adds a new driver for the Cypress CY8CTMA140 touchscreen.
> 
> This driver is inspired by out-of-tree code for the Samsung
> GT-S7710 mobile phone.
> 
> I have tried to compare the structure and behaviour of this
> touchscreen to the existing CYTTSP and CYTTSP4 generics and
> it seems pretty different. It is also different in character
> from the cy8ctmg110_ts.c. It appears to rather be vaguely
> related to the Melfas MMS114 driver, yet distinctly
> different.
> 
> Cc: Ferruh Yigit <fery@cypress.com>
> Cc: Henrik Rydberg <rydberg@bitmath.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  MAINTAINERS                            |   6 +
>  drivers/input/touchscreen/Kconfig      |  13 +
>  drivers/input/touchscreen/Makefile     |   1 +
>  drivers/input/touchscreen/cy8ctma140.c | 380 +++++++++++++++++++++++++
>  4 files changed, 400 insertions(+)
>  create mode 100644 drivers/input/touchscreen/cy8ctma140.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8e7433d74530..39163de1a082 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4628,6 +4628,12 @@ T:	git git://linuxtv.org/anttip/media_tree.git
>  S:	Maintained
>  F:	drivers/media/common/cypress_firmware*
>  
> +CYPRESS CY8CTMA140 TOUCHSCREEN DRIVER
> +M:	Linus Walleij <linus.walleij@linaro.org>
> +L:	linux-input@vger.kernel.org
> +S:	Maintained
> +F:	drivers/input/touchscreen/cy8ctma140.c
> +
>  CYTTSP TOUCHSCREEN DRIVER
>  M:	Ferruh Yigit <fery@cypress.com>
>  L:	linux-input@vger.kernel.org
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index c071f7c407b6..279b96d1761a 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -214,6 +214,19 @@ config TOUCHSCREEN_CY8CTMG110
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called cy8ctmg110_ts.
>  
> +config TOUCHSCREEN_CY8CTMA140
> +	tristate "cy8ctma140 touchscreen"
> +	depends on I2C
> +	depends on GPIOLIB || COMPILE_TEST
> +	help
> +	  Say Y here if you have a Cypress CY8CTMA140 capacitive
> +	  touchscreen also just known as "TMA140"
> +
> +	  If unsure, say N.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called cy8ctma140.
> +
>  config TOUCHSCREEN_CYTTSP_CORE
>  	tristate "Cypress TTSP touchscreen"
>  	help
> diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> index 94c6162409b3..006444c8f87b 100644
> --- a/drivers/input/touchscreen/Makefile
> +++ b/drivers/input/touchscreen/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_TOUCHSCREEN_BU21029)	+= bu21029_ts.o
>  obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8318)	+= chipone_icn8318.o
>  obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8505)	+= chipone_icn8505.o
>  obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110)	+= cy8ctmg110_ts.o
> +obj-$(CONFIG_TOUCHSCREEN_CY8CTMA140)	+= cy8ctma140.o
>  obj-$(CONFIG_TOUCHSCREEN_CYTTSP_CORE)	+= cyttsp_core.o
>  obj-$(CONFIG_TOUCHSCREEN_CYTTSP_I2C)	+= cyttsp_i2c.o cyttsp_i2c_common.o
>  obj-$(CONFIG_TOUCHSCREEN_CYTTSP_SPI)	+= cyttsp_spi.o
> diff --git a/drivers/input/touchscreen/cy8ctma140.c b/drivers/input/touchscreen/cy8ctma140.c
> new file mode 100644
> index 000000000000..fb79f4251122
> --- /dev/null
> +++ b/drivers/input/touchscreen/cy8ctma140.c
> @@ -0,0 +1,380 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Driver for Cypress CY8CTMA140 (TMA140) touchscreen
> + * (C) 2020 Linus Walleij <linus.walleij@linaro.org>
> + * (C) 2007 Cypress
> + * (C) 2007 Google, Inc.
> + *
> + * Inspired by the tma140_skomer.c driver in the Samsung GT-S7710 code
> + * drop. The GT-S7710 is codenamed "Skomer", the code also indicates
> + * that the same touchscreen was used in a product called "Lucas".
> + *
> + * The code drop for GT-S7710 also contains a firmware downloader and
> + * 15 (!) versions of the firmware drop from Cypress. But here we assume
> + * the firmware got downloaded to the touchscreen flash successfully and
> + * just use it to read the fingers. The shipped vendor driver does the
> + * same.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/input.h>
> +#include <linux/input/touchscreen.h>
> +#include <linux/input/mt.h>
> +#include <linux/slab.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/i2c.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/delay.h>
> +
> +/* Used for driver name etc */
> +#define CY8CTMA140_NAME "cy8ctma140"
> +
> +/*
> + * The datasheet claims the device supports 4 fingers but the firmware
> + * I've seen certainly only supports 2 fingers.
> + */
> +#define CY8CTMA140_MAX_FINGERS 2
> +#define CY8CTMA140_GET_FINGERS 0x00
> +#define CY8CTMA140_GET_FW_INFO 0x19
> +
> +struct cy8ctma140 {
> +	struct input_dev *input;
> +	struct touchscreen_properties props;
> +	struct device *dev;
> +	struct i2c_client *client;
> +	struct regulator *vcpin;
> +	struct regulator *vdd;
> +	struct gpio_desc *irq;
> +};
> +
> +static irqreturn_t cy8ctma140_irq_thread(int irq, void *d)
> +{
> +	struct cy8ctma140 *ts = d;
> +	u8 msgbuf0[1];
> +	u8 buf[31];
> +	struct i2c_msg msg[2] = {

Drop explicit size?

> +		{
> +			.addr = ts->client->addr,
> +			.flags = 0,
> +			.len = 1,
> +			.buf = msgbuf0,
> +		}, {
> +			.addr = ts->client->addr,
> +			.flags = I2C_M_RD,
> +			.len = sizeof(buf),
> +			.buf = buf,
> +		},
> +	};
> +	u8 fingers;
> +	u16 f1x, f1y, f1z;
> +	u16 f2x, f2y, f2z;
> +	int ret;
> +	int slots[CY8CTMA140_MAX_FINGERS];
> +	struct input_mt_pos pos[CY8CTMA140_MAX_FINGERS];
> +
> +	msgbuf0[0] = CY8CTMA140_GET_FINGERS;
> +	ret = __i2c_transfer(ts->client->adapter, msg, 2);

ARRAY_SIZE() instead of 2 here and below.

Who is taking the adapter lock so that __i2c_transfer() can be used?
Why can't normal i2c_transfer() be used here?


> +	if (ret < 0) {
> +		dev_err(ts->dev, "error reading message\n");
> +		goto evt_out;
> +	}
> +	if (ret != 2) {
> +		dev_err(ts->dev, "wrong number of messages\n");
> +		goto evt_out;
> +	}
> +	if (buf[1] & 0x20) {
> +		dev_info(ts->dev, "invalid event\n");
> +		goto evt_out;
> +	}
> +
> +	f1x = buf[3] << 8 | buf[4];

get_unaligned_be16() here and below.

> +	f1y = buf[5] << 8 | buf[6];
> +	f1z = buf[7];
> +
> +	f2x = buf[9] << 8 | buf[10];
> +	f2y = buf[11] << 8 | buf[12];
> +	f2z = buf[13];
> +
> +	fingers = buf[2] & 0x0f;
> +	if (fingers == 0) {
> +		dev_info(ts->dev, "no fingers\n");
> +		goto evt_out;
> +	}
> +
> +	input_mt_assign_slots(ts->input, slots, pos, fingers, 0);
> +
> +	/*
> +	 * When just handling two fingers this code is simple and we do not
> +	 * need a loop increasing the complexity. If you need to modify
> +	 * this driver for some firmware handling more than 2 fingers,
> +	 * this is where you put in an array of coordinated and a loop
> +	 * instead.
> +	 */
> +	if (fingers >= 1) {
> +		dev_dbg(ts->dev, "%d fingers: finger 1 ID: %02x (%d, %d, %d)\n",
> +			fingers, buf[8] >> 4, f1x, f1y, f1z);
> +		input_mt_slot(ts->input, slots[0]);
> +		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
> +		input_report_abs(ts->input, ABS_MT_POSITION_X, f1x);
> +		input_report_abs(ts->input, ABS_MT_POSITION_Y, f1y);
> +		input_report_abs(ts->input, ABS_MT_PRESSURE, f1z);
> +	}
> +	if (fingers >= 2) {
> +		dev_dbg(ts->dev, "%d fingers: finger 2 ID %02x (%d, %d, %d)\n",
> +			fingers, buf[8] & 0x0f, f2x, f2y, f2z);
> +		input_mt_slot(ts->input, slots[1]);
> +		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
> +		input_report_abs(ts->input, ABS_MT_POSITION_X, f2x);
> +		input_report_abs(ts->input, ABS_MT_POSITION_Y, f2y);
> +		input_report_abs(ts->input, ABS_MT_PRESSURE, f2z);


Please use touchscreen_set_mt_pos()/touchscreen_report_pos() so that we
can support common transformation device properties from
of_touchscreen.c

> +	}
> +	if (fingers > 2)
> +		dev_err(ts->dev, "%d fingers - unsupported!\n", fingers);
> +
> +	input_mt_sync_frame(ts->input);
> +	input_sync(ts->input);
> +
> +evt_out:
> +	return IRQ_HANDLED;
> +}
> +
> +static int cy8ctma140_init(struct cy8ctma140 *ts)
> +{
> +	u8 addr[1];
> +	u8 buf[5];
> +	int ret;
> +
> +	addr[0] = CY8CTMA140_GET_FW_INFO;
> +	ret = i2c_master_send(ts->client, addr, 1);
> +	if (ret < 0) {
> +		dev_err(ts->dev, "error sending FW info message\n");
> +		return ret;
> +	}
> +	ret = i2c_master_recv(ts->client, buf, 5);
> +	if (ret < 0) {
> +		dev_err(ts->dev, "error recieveing FW info message\n");
> +		return ret;
> +	}
> +	if (ret != 5) {
> +		dev_err(ts->dev, "got only %d bytes\n", ret);
> +		return -EIO;
> +	}
> +
> +	dev_info(ts->dev, "vendor %c%c, HW ID %.2d, FW ver %.4d\n",
> +		 buf[0], buf[1], buf[3], buf[4]);
> +	return 0;
> +}
> +
> +static int cy8ctma140_power_up(struct cy8ctma140 *ts)
> +{
> +	int ret;
> +
> +	ret = regulator_enable(ts->vcpin);
> +	if (ret) {
> +		dev_err(ts->dev, "failed to enable VCPIN voltage\n");
> +		return ret;
> +	}
> +	ret = regulator_enable(ts->vdd);
> +	if (ret) {
> +		dev_err(ts->dev, "failed to enable VDD voltage\n");
> +		regulator_disable(ts->vcpin);
> +		return ret;
> +	}

Use bulk regulator API?

> +
> +	msleep(250);
> +
> +	return 0;
> +}
> +
> +static void cy8ctma140_power_down(struct cy8ctma140 *ts)
> +{
> +	regulator_disable(ts->vdd);
> +	regulator_disable(ts->vcpin);
> +}
> +
> +/* Called from the registered devm action */
> +static void cy8ctma140_power_off_action(void *d)
> +{
> +	struct cy8ctma140 *ts = d;
> +
> +	cy8ctma140_power_down(ts);
> +}
> +
> +static int cy8ctma140_probe(struct i2c_client *client,
> +			    const struct i2c_device_id *id)
> +{
> +	struct cy8ctma140 *ts;
> +	struct input_dev *input;
> +	struct device *dev = &client->dev;
> +	int ret;
> +
> +	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
> +	if (!ts)
> +		return -ENOMEM;
> +
> +	input = devm_input_allocate_device(dev);
> +	if (!input)
> +		return -ENOMEM;
> +
> +	ts->dev = dev;
> +	ts->client = client;
> +	ts->input = input;
> +
> +	/*
> +	 * This sets up event max/min capabilities and fuzz.
> +	 * Some DT properties are compulsory so we do not need
> +	 * to provide defaults for X/Y max or pressure max.
> +	 *
> +	 * We just initialize a very simple MT touchscreen here,
> +	 * some devices use the capability of this touchscreen to
> +	 * provide touchkeys, and in that case this needs to be
> +	 * extended to handle touchkey input.
> +	 *
> +	 * The firmware takes care of finger tracking and dropping
> +	 * invalid ranges.
> +	 */
> +	touchscreen_parse_properties(input, true, &ts->props);
> +
> +	ret = input_mt_init_slots(input, CY8CTMA140_MAX_FINGERS,
> +				  INPUT_MT_DIRECT);
> +	if (ret)
> +		return ret;

Since this holds and returns error codes, can we call this variable
"error" please?

> +
> +	input->name = CY8CTMA140_NAME;
> +	input->phys = "inpus/ts";

Umm... If there is not a better physical location string, maybe just
omit it?

> +	input->id.bustype = BUS_I2C;
> +	input_set_drvdata(input, ts);
> +
> +	/* VCPIN is the analog voltage supply */
> +	ts->vcpin = devm_regulator_get(dev, "vcpin");
> +	if (IS_ERR(ts->vcpin)) {
> +		if (PTR_ERR(ts->vcpin) != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get VCPIN regulator %d\n",
> +				(int)PTR_ERR(ts->vcpin));
> +		return PTR_ERR(ts->vcpin);
> +	}
> +	/* According to datasheet this should be in the 2.7-3.6 V range */
> +	ret = regulator_set_voltage(ts->vcpin, 2700000, 3600000);
> +	if (ret) {
> +		dev_err(dev, "failed to set VCPIN voltage\n");
> +		return ret;
> +	}

Shouldn't this already be in DT? We typically do not configure voltage
on various rail unless in very specific circumstances.

> +
> +	/*
> +	 * VDD is the digital voltage supply
> +	 * since the voltage range of VDD overlaps that of VCPIN,
> +	 * many designs to just supply both with a single voltage
> +	 * source of ~3.3 V.
> +	 */
> +	ts->vdd = devm_regulator_get(dev, "vdd");
> +	if (IS_ERR(ts->vdd)) {
> +		if (PTR_ERR(ts->vdd) != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get VDD regulator %d\n",
> +				(int)PTR_ERR(ts->vdd));
> +		return PTR_ERR(ts->vdd);
> +	}
> +	/* According to datasheet this should be in the 1.71-3.6 V range */
> +	ret = regulator_set_voltage(ts->vdd, 2700000, 3600000);
> +	if (ret) {
> +		dev_err(dev, "failed to set VDD voltage\n");
> +		return ret;
> +	}
> +
> +	ret = cy8ctma140_power_up(ts);
> +	if (ret)
> +		return ret;
> +	ret = devm_add_action_or_reset(dev, cy8ctma140_power_off_action, ts);
> +	if (ret) {
> +		dev_err(dev, "failed to install power off handler\n");
> +		return ret;
> +	}
> +
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> +					cy8ctma140_irq_thread,
> +					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,

The trigger (edge, level) should come from DT.

> +					CY8CTMA140_NAME, ts);
> +	if (ret) {
> +		dev_err(dev, "irq %d busy? error %d\n", client->irq, ret);
> +		goto err_reg_dis;
> +	}
> +
> +	ret = cy8ctma140_init(ts);
> +	if (ret)
> +		return ret;
> +
> +	ret = input_register_device(input);
> +	if (ret)
> +		goto err_reg_dis;
> +
> +	i2c_set_clientdata(client, ts);
> +
> +	device_init_wakeup(dev, 1);

We should not mark device as wakeup source unconditionally. If there is
"wakeup-source" property in DT, i2c core will do the right thing
automatically. Please drop.

> +	return 0;
> +
> +err_reg_dis:
> +	cy8ctma140_power_down(ts);
> +	return ret;
> +}
> +
> +static int __maybe_unused cy8ctma140_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct cy8ctma140 *ts = i2c_get_clientdata(client);
> +
> +	if (device_may_wakeup(&client->dev))
> +		enable_irq_wake(client->irq);

No need as i2c core manages wake irq if there is "wakeup-source"
property. So it should read:

	if (!device_may_wakeup(&client->dev))
		cy8ctma140_power_down(ts);

> +	else
> +		cy8ctma140_power_down(ts);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused cy8ctma140_resume(struct device *dev)
> +{
> +	struct i2c_client *client = to_i2c_client(dev);
> +	struct cy8ctma140 *ts = i2c_get_clientdata(client);
> +	int ret;
> +
> +	if (device_may_wakeup(&client->dev)) {
> +		disable_irq_wake(client->irq);
> +	} else {
> +		ret = cy8ctma140_power_up(ts);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(cy8ctma140_pm, cy8ctma140_suspend, cy8ctma140_resume);
> +
> +static const struct i2c_device_id cy8ctma140_idtable[] = {
> +	{ CY8CTMA140_NAME, 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, cy8ctma140_idtable);
> +
> +static const struct of_device_id cy8ctma140_of_match[] = {
> +	{
> +		.compatible = "cypress,cy8ctma140",
> +	},
> +};
> +MODULE_DEVICE_TABLE(of, cy8ctma140_of_match);
> +
> +static struct i2c_driver cy8ctma140_driver = {
> +	.driver		= {
> +		.name	= CY8CTMA140_NAME,
> +		.pm	= &cy8ctma140_pm,
> +		.of_match_table = cy8ctma140_of_match,
> +	},
> +	.id_table	= cy8ctma140_idtable,
> +	.probe		= cy8ctma140_probe,
> +};
> +module_i2c_driver(cy8ctma140_driver);
> +
> +MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
> +MODULE_DESCRIPTION("CY8CTMA140 TouchScreen Driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.21.1
> 

Thanks.

-- 
Dmitry

Re: [PATCH 2/2 v1] Input: cy8ctma140 - add driver

[Dmitry Torokhov]

On Tue, Mar 10, 2020 at 10:08:09AM -0700, Dmitry Torokhov wrote:
> Hi Linus,
> 
> On Tue, Mar 10, 2020 at 03:28:18PM +0100, Linus Walleij wrote:
> > This adds a new driver for the Cypress CY8CTMA140 touchscreen.
> > 
> > This driver is inspired by out-of-tree code for the Samsung
> > GT-S7710 mobile phone.
> > 
> > I have tried to compare the structure and behaviour of this
> > touchscreen to the existing CYTTSP and CYTTSP4 generics and
> > it seems pretty different. It is also different in character
> > from the cy8ctmg110_ts.c. It appears to rather be vaguely
> > related to the Melfas MMS114 driver, yet distinctly
> > different.
> > 
> > Cc: Ferruh Yigit <fery@cypress.com>
> > Cc: Henrik Rydberg <rydberg@bitmath.org>
> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> > ---
> >  MAINTAINERS                            |   6 +
> >  drivers/input/touchscreen/Kconfig      |  13 +
> >  drivers/input/touchscreen/Makefile     |   1 +
> >  drivers/input/touchscreen/cy8ctma140.c | 380 +++++++++++++++++++++++++
> >  4 files changed, 400 insertions(+)
> >  create mode 100644 drivers/input/touchscreen/cy8ctma140.c
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 8e7433d74530..39163de1a082 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -4628,6 +4628,12 @@ T:	git git://linuxtv.org/anttip/media_tree.git
> >  S:	Maintained
> >  F:	drivers/media/common/cypress_firmware*
> >  
> > +CYPRESS CY8CTMA140 TOUCHSCREEN DRIVER
> > +M:	Linus Walleij <linus.walleij@linaro.org>
> > +L:	linux-input@vger.kernel.org
> > +S:	Maintained
> > +F:	drivers/input/touchscreen/cy8ctma140.c
> > +
> >  CYTTSP TOUCHSCREEN DRIVER
> >  M:	Ferruh Yigit <fery@cypress.com>
> >  L:	linux-input@vger.kernel.org
> > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > index c071f7c407b6..279b96d1761a 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -214,6 +214,19 @@ config TOUCHSCREEN_CY8CTMG110
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called cy8ctmg110_ts.
> >  
> > +config TOUCHSCREEN_CY8CTMA140
> > +	tristate "cy8ctma140 touchscreen"
> > +	depends on I2C
> > +	depends on GPIOLIB || COMPILE_TEST
> > +	help
> > +	  Say Y here if you have a Cypress CY8CTMA140 capacitive
> > +	  touchscreen also just known as "TMA140"
> > +
> > +	  If unsure, say N.
> > +
> > +	  To compile this driver as a module, choose M here: the
> > +	  module will be called cy8ctma140.
> > +
> >  config TOUCHSCREEN_CYTTSP_CORE
> >  	tristate "Cypress TTSP touchscreen"
> >  	help
> > diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
> > index 94c6162409b3..006444c8f87b 100644
> > --- a/drivers/input/touchscreen/Makefile
> > +++ b/drivers/input/touchscreen/Makefile
> > @@ -23,6 +23,7 @@ obj-$(CONFIG_TOUCHSCREEN_BU21029)	+= bu21029_ts.o
> >  obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8318)	+= chipone_icn8318.o
> >  obj-$(CONFIG_TOUCHSCREEN_CHIPONE_ICN8505)	+= chipone_icn8505.o
> >  obj-$(CONFIG_TOUCHSCREEN_CY8CTMG110)	+= cy8ctmg110_ts.o
> > +obj-$(CONFIG_TOUCHSCREEN_CY8CTMA140)	+= cy8ctma140.o
> >  obj-$(CONFIG_TOUCHSCREEN_CYTTSP_CORE)	+= cyttsp_core.o
> >  obj-$(CONFIG_TOUCHSCREEN_CYTTSP_I2C)	+= cyttsp_i2c.o cyttsp_i2c_common.o
> >  obj-$(CONFIG_TOUCHSCREEN_CYTTSP_SPI)	+= cyttsp_spi.o
> > diff --git a/drivers/input/touchscreen/cy8ctma140.c b/drivers/input/touchscreen/cy8ctma140.c
> > new file mode 100644
> > index 000000000000..fb79f4251122
> > --- /dev/null
> > +++ b/drivers/input/touchscreen/cy8ctma140.c
> > @@ -0,0 +1,380 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Driver for Cypress CY8CTMA140 (TMA140) touchscreen
> > + * (C) 2020 Linus Walleij <linus.walleij@linaro.org>
> > + * (C) 2007 Cypress
> > + * (C) 2007 Google, Inc.
> > + *
> > + * Inspired by the tma140_skomer.c driver in the Samsung GT-S7710 code
> > + * drop. The GT-S7710 is codenamed "Skomer", the code also indicates
> > + * that the same touchscreen was used in a product called "Lucas".
> > + *
> > + * The code drop for GT-S7710 also contains a firmware downloader and
> > + * 15 (!) versions of the firmware drop from Cypress. But here we assume
> > + * the firmware got downloaded to the touchscreen flash successfully and
> > + * just use it to read the fingers. The shipped vendor driver does the
> > + * same.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/kernel.h>
> > +#include <linux/input.h>
> > +#include <linux/input/touchscreen.h>
> > +#include <linux/input/mt.h>
> > +#include <linux/slab.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/i2c.h>
> > +#include <linux/gpio/consumer.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/delay.h>
> > +
> > +/* Used for driver name etc */
> > +#define CY8CTMA140_NAME "cy8ctma140"
> > +
> > +/*
> > + * The datasheet claims the device supports 4 fingers but the firmware
> > + * I've seen certainly only supports 2 fingers.
> > + */
> > +#define CY8CTMA140_MAX_FINGERS 2
> > +#define CY8CTMA140_GET_FINGERS 0x00
> > +#define CY8CTMA140_GET_FW_INFO 0x19
> > +
> > +struct cy8ctma140 {
> > +	struct input_dev *input;
> > +	struct touchscreen_properties props;
> > +	struct device *dev;
> > +	struct i2c_client *client;
> > +	struct regulator *vcpin;
> > +	struct regulator *vdd;
> > +	struct gpio_desc *irq;

BTW, I do not think you are using this GPIO descriptor anywhere.

> > +};
> > +
> > +static irqreturn_t cy8ctma140_irq_thread(int irq, void *d)
> > +{
> > +	struct cy8ctma140 *ts = d;
> > +	u8 msgbuf0[1];
> > +	u8 buf[31];
> > +	struct i2c_msg msg[2] = {
> 
> Drop explicit size?
> 
> > +		{
> > +			.addr = ts->client->addr,
> > +			.flags = 0,
> > +			.len = 1,
> > +			.buf = msgbuf0,
> > +		}, {
> > +			.addr = ts->client->addr,
> > +			.flags = I2C_M_RD,
> > +			.len = sizeof(buf),
> > +			.buf = buf,
> > +		},
> > +	};
> > +	u8 fingers;
> > +	u16 f1x, f1y, f1z;
> > +	u16 f2x, f2y, f2z;
> > +	int ret;
> > +	int slots[CY8CTMA140_MAX_FINGERS];
> > +	struct input_mt_pos pos[CY8CTMA140_MAX_FINGERS];
> > +
> > +	msgbuf0[0] = CY8CTMA140_GET_FINGERS;
> > +	ret = __i2c_transfer(ts->client->adapter, msg, 2);
> 
> ARRAY_SIZE() instead of 2 here and below.
> 
> Who is taking the adapter lock so that __i2c_transfer() can be used?
> Why can't normal i2c_transfer() be used here?
> 
> 
> > +	if (ret < 0) {
> > +		dev_err(ts->dev, "error reading message\n");
> > +		goto evt_out;
> > +	}
> > +	if (ret != 2) {
> > +		dev_err(ts->dev, "wrong number of messages\n");
> > +		goto evt_out;
> > +	}
> > +	if (buf[1] & 0x20) {
> > +		dev_info(ts->dev, "invalid event\n");
> > +		goto evt_out;
> > +	}
> > +
> > +	f1x = buf[3] << 8 | buf[4];
> 
> get_unaligned_be16() here and below.
> 
> > +	f1y = buf[5] << 8 | buf[6];
> > +	f1z = buf[7];
> > +
> > +	f2x = buf[9] << 8 | buf[10];
> > +	f2y = buf[11] << 8 | buf[12];
> > +	f2z = buf[13];
> > +
> > +	fingers = buf[2] & 0x0f;
> > +	if (fingers == 0) {
> > +		dev_info(ts->dev, "no fingers\n");
> > +		goto evt_out;
> > +	}
> > +
> > +	input_mt_assign_slots(ts->input, slots, pos, fingers, 0);
> > +
> > +	/*
> > +	 * When just handling two fingers this code is simple and we do not
> > +	 * need a loop increasing the complexity. If you need to modify
> > +	 * this driver for some firmware handling more than 2 fingers,
> > +	 * this is where you put in an array of coordinated and a loop
> > +	 * instead.
> > +	 */
> > +	if (fingers >= 1) {
> > +		dev_dbg(ts->dev, "%d fingers: finger 1 ID: %02x (%d, %d, %d)\n",
> > +			fingers, buf[8] >> 4, f1x, f1y, f1z);
> > +		input_mt_slot(ts->input, slots[0]);
> > +		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
> > +		input_report_abs(ts->input, ABS_MT_POSITION_X, f1x);
> > +		input_report_abs(ts->input, ABS_MT_POSITION_Y, f1y);
> > +		input_report_abs(ts->input, ABS_MT_PRESSURE, f1z);
> > +	}
> > +	if (fingers >= 2) {
> > +		dev_dbg(ts->dev, "%d fingers: finger 2 ID %02x (%d, %d, %d)\n",
> > +			fingers, buf[8] & 0x0f, f2x, f2y, f2z);
> > +		input_mt_slot(ts->input, slots[1]);
> > +		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
> > +		input_report_abs(ts->input, ABS_MT_POSITION_X, f2x);
> > +		input_report_abs(ts->input, ABS_MT_POSITION_Y, f2y);
> > +		input_report_abs(ts->input, ABS_MT_PRESSURE, f2z);
> 
> 
> Please use touchscreen_set_mt_pos()/touchscreen_report_pos() so that we
> can support common transformation device properties from
> of_touchscreen.c
> 
> > +	}
> > +	if (fingers > 2)
> > +		dev_err(ts->dev, "%d fingers - unsupported!\n", fingers);
> > +
> > +	input_mt_sync_frame(ts->input);
> > +	input_sync(ts->input);
> > +
> > +evt_out:
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int cy8ctma140_init(struct cy8ctma140 *ts)
> > +{
> > +	u8 addr[1];
> > +	u8 buf[5];
> > +	int ret;
> > +
> > +	addr[0] = CY8CTMA140_GET_FW_INFO;
> > +	ret = i2c_master_send(ts->client, addr, 1);
> > +	if (ret < 0) {
> > +		dev_err(ts->dev, "error sending FW info message\n");
> > +		return ret;
> > +	}
> > +	ret = i2c_master_recv(ts->client, buf, 5);
> > +	if (ret < 0) {
> > +		dev_err(ts->dev, "error recieveing FW info message\n");
> > +		return ret;
> > +	}
> > +	if (ret != 5) {
> > +		dev_err(ts->dev, "got only %d bytes\n", ret);
> > +		return -EIO;
> > +	}
> > +
> > +	dev_info(ts->dev, "vendor %c%c, HW ID %.2d, FW ver %.4d\n",
> > +		 buf[0], buf[1], buf[3], buf[4]);
> > +	return 0;
> > +}
> > +
> > +static int cy8ctma140_power_up(struct cy8ctma140 *ts)
> > +{
> > +	int ret;
> > +
> > +	ret = regulator_enable(ts->vcpin);
> > +	if (ret) {
> > +		dev_err(ts->dev, "failed to enable VCPIN voltage\n");
> > +		return ret;
> > +	}
> > +	ret = regulator_enable(ts->vdd);
> > +	if (ret) {
> > +		dev_err(ts->dev, "failed to enable VDD voltage\n");
> > +		regulator_disable(ts->vcpin);
> > +		return ret;
> > +	}
> 
> Use bulk regulator API?
> 
> > +
> > +	msleep(250);
> > +
> > +	return 0;
> > +}
> > +
> > +static void cy8ctma140_power_down(struct cy8ctma140 *ts)
> > +{
> > +	regulator_disable(ts->vdd);
> > +	regulator_disable(ts->vcpin);
> > +}
> > +
> > +/* Called from the registered devm action */
> > +static void cy8ctma140_power_off_action(void *d)
> > +{
> > +	struct cy8ctma140 *ts = d;
> > +
> > +	cy8ctma140_power_down(ts);
> > +}
> > +
> > +static int cy8ctma140_probe(struct i2c_client *client,
> > +			    const struct i2c_device_id *id)
> > +{
> > +	struct cy8ctma140 *ts;
> > +	struct input_dev *input;
> > +	struct device *dev = &client->dev;
> > +	int ret;
> > +
> > +	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
> > +	if (!ts)
> > +		return -ENOMEM;
> > +
> > +	input = devm_input_allocate_device(dev);
> > +	if (!input)
> > +		return -ENOMEM;
> > +
> > +	ts->dev = dev;
> > +	ts->client = client;
> > +	ts->input = input;
> > +
> > +	/*
> > +	 * This sets up event max/min capabilities and fuzz.
> > +	 * Some DT properties are compulsory so we do not need
> > +	 * to provide defaults for X/Y max or pressure max.
> > +	 *
> > +	 * We just initialize a very simple MT touchscreen here,
> > +	 * some devices use the capability of this touchscreen to
> > +	 * provide touchkeys, and in that case this needs to be
> > +	 * extended to handle touchkey input.
> > +	 *
> > +	 * The firmware takes care of finger tracking and dropping
> > +	 * invalid ranges.
> > +	 */
> > +	touchscreen_parse_properties(input, true, &ts->props);
> > +
> > +	ret = input_mt_init_slots(input, CY8CTMA140_MAX_FINGERS,
> > +				  INPUT_MT_DIRECT);
> > +	if (ret)
> > +		return ret;
> 
> Since this holds and returns error codes, can we call this variable
> "error" please?
> 
> > +
> > +	input->name = CY8CTMA140_NAME;
> > +	input->phys = "inpus/ts";
> 
> Umm... If there is not a better physical location string, maybe just
> omit it?
> 
> > +	input->id.bustype = BUS_I2C;
> > +	input_set_drvdata(input, ts);
> > +
> > +	/* VCPIN is the analog voltage supply */
> > +	ts->vcpin = devm_regulator_get(dev, "vcpin");
> > +	if (IS_ERR(ts->vcpin)) {
> > +		if (PTR_ERR(ts->vcpin) != -EPROBE_DEFER)
> > +			dev_err(dev, "Failed to get VCPIN regulator %d\n",
> > +				(int)PTR_ERR(ts->vcpin));
> > +		return PTR_ERR(ts->vcpin);
> > +	}
> > +	/* According to datasheet this should be in the 2.7-3.6 V range */
> > +	ret = regulator_set_voltage(ts->vcpin, 2700000, 3600000);
> > +	if (ret) {
> > +		dev_err(dev, "failed to set VCPIN voltage\n");
> > +		return ret;
> > +	}
> 
> Shouldn't this already be in DT? We typically do not configure voltage
> on various rail unless in very specific circumstances.
> 
> > +
> > +	/*
> > +	 * VDD is the digital voltage supply
> > +	 * since the voltage range of VDD overlaps that of VCPIN,
> > +	 * many designs to just supply both with a single voltage
> > +	 * source of ~3.3 V.
> > +	 */
> > +	ts->vdd = devm_regulator_get(dev, "vdd");
> > +	if (IS_ERR(ts->vdd)) {
> > +		if (PTR_ERR(ts->vdd) != -EPROBE_DEFER)
> > +			dev_err(dev, "Failed to get VDD regulator %d\n",
> > +				(int)PTR_ERR(ts->vdd));
> > +		return PTR_ERR(ts->vdd);
> > +	}
> > +	/* According to datasheet this should be in the 1.71-3.6 V range */
> > +	ret = regulator_set_voltage(ts->vdd, 2700000, 3600000);
> > +	if (ret) {
> > +		dev_err(dev, "failed to set VDD voltage\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = cy8ctma140_power_up(ts);
> > +	if (ret)
> > +		return ret;
> > +	ret = devm_add_action_or_reset(dev, cy8ctma140_power_off_action, ts);
> > +	if (ret) {
> > +		dev_err(dev, "failed to install power off handler\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> > +					cy8ctma140_irq_thread,
> > +					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> 
> The trigger (edge, level) should come from DT.
> 
> > +					CY8CTMA140_NAME, ts);
> > +	if (ret) {
> > +		dev_err(dev, "irq %d busy? error %d\n", client->irq, ret);
> > +		goto err_reg_dis;
> > +	}
> > +
> > +	ret = cy8ctma140_init(ts);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = input_register_device(input);
> > +	if (ret)
> > +		goto err_reg_dis;
> > +
> > +	i2c_set_clientdata(client, ts);
> > +
> > +	device_init_wakeup(dev, 1);
> 
> We should not mark device as wakeup source unconditionally. If there is
> "wakeup-source" property in DT, i2c core will do the right thing
> automatically. Please drop.
> 
> > +	return 0;
> > +
> > +err_reg_dis:
> > +	cy8ctma140_power_down(ts);
> > +	return ret;
> > +}
> > +
> > +static int __maybe_unused cy8ctma140_suspend(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct cy8ctma140 *ts = i2c_get_clientdata(client);
> > +
> > +	if (device_may_wakeup(&client->dev))
> > +		enable_irq_wake(client->irq);
> 
> No need as i2c core manages wake irq if there is "wakeup-source"
> property. So it should read:
> 
> 	if (!device_may_wakeup(&client->dev))
> 		cy8ctma140_power_down(ts);
> 
> > +	else
> > +		cy8ctma140_power_down(ts);
> > +
> > +	return 0;
> > +}
> > +
> > +static int __maybe_unused cy8ctma140_resume(struct device *dev)
> > +{
> > +	struct i2c_client *client = to_i2c_client(dev);
> > +	struct cy8ctma140 *ts = i2c_get_clientdata(client);
> > +	int ret;
> > +
> > +	if (device_may_wakeup(&client->dev)) {
> > +		disable_irq_wake(client->irq);
> > +	} else {
> > +		ret = cy8ctma140_power_up(ts);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(cy8ctma140_pm, cy8ctma140_suspend, cy8ctma140_resume);
> > +
> > +static const struct i2c_device_id cy8ctma140_idtable[] = {
> > +	{ CY8CTMA140_NAME, 0 },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(i2c, cy8ctma140_idtable);
> > +
> > +static const struct of_device_id cy8ctma140_of_match[] = {
> > +	{
> > +		.compatible = "cypress,cy8ctma140",
> > +	},
> > +};
> > +MODULE_DEVICE_TABLE(of, cy8ctma140_of_match);
> > +
> > +static struct i2c_driver cy8ctma140_driver = {
> > +	.driver		= {
> > +		.name	= CY8CTMA140_NAME,
> > +		.pm	= &cy8ctma140_pm,
> > +		.of_match_table = cy8ctma140_of_match,
> > +	},
> > +	.id_table	= cy8ctma140_idtable,
> > +	.probe		= cy8ctma140_probe,
> > +};
> > +module_i2c_driver(cy8ctma140_driver);
> > +
> > +MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
> > +MODULE_DESCRIPTION("CY8CTMA140 TouchScreen Driver");
> > +MODULE_LICENSE("GPL v2");
> > -- 
> > 2.21.1
> > 
> 
> Thanks.
> 
> -- 
> Dmitry

-- 
Dmitry

Re: [PATCH 2/2 v1] Input: cy8ctma140 - add driver

[Linus Walleij]

Hi Dmitry,

thanks for the quick review!

I fixed most stuff, just one minor comment:

On Tue, Mar 10, 2020 at 6:08 PM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:

> > +     /* According to datasheet this should be in the 2.7-3.6 V range */
> > +     ret = regulator_set_voltage(ts->vcpin, 2700000, 3600000);
> > +     if (ret) {
> > +             dev_err(dev, "failed to set VCPIN voltage\n");
> > +             return ret;
> > +     }
>
> Shouldn't this already be in DT? We typically do not configure voltage
> on various rail unless in very specific circumstances.

Certainly the DT defines the voltage range on the regulator
on the producer side.

This is the consumer range, and DT has no facility to put
restrictions on the consumer voltage window.

I think it is pretty natural to do in the code.

The typical usecase is when two components share the
same line, and in this case two voltage consumer inputs
*may* be connected to the same producer regulator.

The regulator framework will the infer that the producer
can produce a voltage that fulfil the constraints on all the
consumers.

The fact that few devices issue regulator_set_voltage()
is a combination of "good enough" and general sloppiness,
I think it should reflect the operation voltages of the component
and stop people from shooting themselves in the foot.

But I CC Mark on this and see what he says. (I might be wrong.)

Yours,
Linus Walleij

Re: [PATCH 2/2 v1] Input: cy8ctma140 - add driver

[Dmitry Torokhov]

On Sun, Mar 15, 2020 at 05:12:29PM +0100, Linus Walleij wrote:
> Hi Dmitry,
> 
> thanks for the quick review!
> 
> I fixed most stuff, just one minor comment:
> 
> On Tue, Mar 10, 2020 at 6:08 PM Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> 
> > > +     /* According to datasheet this should be in the 2.7-3.6 V range */
> > > +     ret = regulator_set_voltage(ts->vcpin, 2700000, 3600000);
> > > +     if (ret) {
> > > +             dev_err(dev, "failed to set VCPIN voltage\n");
> > > +             return ret;
> > > +     }
> >
> > Shouldn't this already be in DT? We typically do not configure voltage
> > on various rail unless in very specific circumstances.
> 
> Certainly the DT defines the voltage range on the regulator
> on the producer side.
> 
> This is the consumer range, and DT has no facility to put
> restrictions on the consumer voltage window.
> 
> I think it is pretty natural to do in the code.

That means we will have essentially a boilerplate code in many many
drivers.

If we indeed want to do this (although I am not sure if practically this
makes much sense - nobody creates a rail delivering 24 volts by default
and saying "oh well, when driver loads it will request us to lower the
voltage down to 1.5V that components attached to the rail require") can
we consider adding consumer side constraints to the DT so that
regulator_get() can set the voltage right there and driver does not have
to? I am just trying to limit the amount of custom code in the drivers.

> 
> The typical usecase is when two components share the
> same line, and in this case two voltage consumer inputs
> *may* be connected to the same producer regulator.
> 
> The regulator framework will the infer that the producer
> can produce a voltage that fulfil the constraints on all the
> consumers.
> 
> The fact that few devices issue regulator_set_voltage()
> is a combination of "good enough" and general sloppiness,
> I think it should reflect the operation voltages of the component
> and stop people from shooting themselves in the foot.
> 
> But I CC Mark on this and see what he says. (I might be wrong.)

Thanks.

-- 
Dmitry

Re: [PATCH 2/2 v1] Input: cy8ctma140 - add driver

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 1598 bytes --]

On Sun, Mar 15, 2020 at 03:22:48PM -0700, Dmitry Torokhov wrote:
> On Sun, Mar 15, 2020 at 05:12:29PM +0100, Linus Walleij wrote:

> > > > +     /* According to datasheet this should be in the 2.7-3.6 V range */
> > > > +     ret = regulator_set_voltage(ts->vcpin, 2700000, 3600000);
> > > > +     if (ret) {
> > > > +             dev_err(dev, "failed to set VCPIN voltage\n");
> > > > +             return ret;
> > > > +     }

> > > Shouldn't this already be in DT? We typically do not configure voltage
> > > on various rail unless in very specific circumstances.

> > This is the consumer range, and DT has no facility to put
> > restrictions on the consumer voltage window.

> > I think it is pretty natural to do in the code.

> That means we will have essentially a boilerplate code in many many
> drivers.

> If we indeed want to do this (although I am not sure if practically this
> makes much sense - nobody creates a rail delivering 24 volts by default
> and saying "oh well, when driver loads it will request us to lower the
> voltage down to 1.5V that components attached to the rail require") can
> we consider adding consumer side constraints to the DT so that
> regulator_get() can set the voltage right there and driver does not have
> to? I am just trying to limit the amount of custom code in the drivers.

Consumers shouldn't be setting the voltage at runtime unless they are
actively managing it and will be changing it repeatedly for some reason,
if it's just a case of ensuring that the supply voltage is within spec
for the device that's the job of the machine constraints.

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Re: [PATCH 1/2 v1] dt-bindings: touchscreen: Add CY8CTMA140 bindings

[Rob Herring]

On Tue, Mar 10, 2020 at 03:28:17PM +0100, Linus Walleij wrote:
> This adds device tree bindings for the Cypress CY8CTMA140
> touchscreen.
> 
> Cc: devicetree@vger.kernel.org
> Cc: Ferruh Yigit <fery@cypress.com>
> Cc: Henrik Rydberg <rydberg@bitmath.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  .../input/touchscreen/cypress,cy8ctma140.yaml | 72 +++++++++++++++++++
>  1 file changed, 72 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml b/Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml
> new file mode 100644
> index 000000000000..66b488e48b74
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/touchscreen/cypress,cy8ctma140.yaml
> @@ -0,0 +1,72 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/input/touchscreen/cypress,cy8ctma140.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Cypress CY8CTMA140 series touchscreen controller bindings
> +
> +maintainers:
> +  - Linus Walleij <linus.walleij@linaro.org>
> +
> +allOf:
> +  - $ref: touchscreen.yaml#
> +
> +properties:
> +  compatible:
> +    const: cypress,cy8ctma140
> +
> +  reg:
> +    description: I2C client address, defined by hardware

Can drop this. That's every 'reg'.

> +    const: 0x20
> +
> +  clock-frequency:
> +    description: I2C client max frequency, defined by hardware
> +    const: 400000

What if I have a board which can't do 400k? Perhaps 'maximum: 400000' 
instead.

With that,

Reviewed-by: Rob Herring <robh@kernel.org>

> +
> +  interrupts:
> +    maxItems: 1
> +
> +  vcpin-supply:
> +    description: Analog power supply regulator on VCPIN pin
> +
> +  vdd-supply:
> +    description: Digital power supply regulator on VDD pin
> +
> +  touchscreen-inverted-x: true
> +  touchscreen-inverted-y: true
> +  touchscreen-size-x: true
> +  touchscreen-size-y: true
> +  touchscreen-swapped-x-y: true
> +  touchscreen-max-pressure: true
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - touchscreen-size-x
> +  - touchscreen-size-y
> +  - touchscreen-max-pressure
> +
> +examples:
> +- |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    i2c@00000000 {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +      touchscreen@20 {
> +        compatible = "cypress,cy8ctma140";
> +        reg = <0x20>;
> +        touchscreen-size-x = <480>;
> +        touchscreen-size-y = <800>;
> +        touchscreen-max-pressure = <255>;
> +        interrupt-parent = <&gpio6>;
> +        interrupts = <26 IRQ_TYPE_EDGE_FALLING>;
> +        vdd-supply = <&ab8500_ldo_aux2_reg>;
> +        vcpin-supply = <&ab8500_ldo_aux2_reg>;
> +      };
> +    };
> +
> +...
> -- 
> 2.21.1
>