Change in coreboot[master]: driver/i2c: Add sx9360 driver

[Gwendal Grignou (Code Review)]

Attention is currently required from: SH Kim.
Hello SH Kim,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/coreboot/+/59608

to review the following change.

Change subject: driver/i2c: Add sx9360 driver
......................................................................

driver/i2c: Add sx9360 driver

Add driver for setting up Semtech sx9360 SAR sensor.

Registers are documented in the kernel tree:
Documentation/devicetree/bindings/iio/proximity/semtech,sx9360.yaml

Signed-off-by: Seunghwan Kim 
Signed-off-by: Gwendal Grignou 
Change-Id: I0a912f184e6f3501f894cca24c0d71a2c3087516
---
A src/drivers/i2c/sx9360/Kconfig
A src/drivers/i2c/sx9360/Makefile.inc
A src/drivers/i2c/sx9360/chip.h
A src/drivers/i2c/sx9360/sx9360.c
4 files changed, 162 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/08/59608/1

diff --git a/src/drivers/i2c/sx9360/Kconfig b/src/drivers/i2c/sx9360/Kconfig
new file mode 100644
index 0000000..ea28564
--- /dev/null
+++ b/src/drivers/i2c/sx9360/Kconfig
@@ -0,0 +1,6 @@
+config DRIVERS_I2C_SX9360
+	bool
+	default n
+	depends on HAVE_ACPI_TABLES
+	help
+	  Board has a Semtech SX9360 proximity sensor.
diff --git a/src/drivers/i2c/sx9360/Makefile.inc b/src/drivers/i2c/sx9360/Makefile.inc
new file mode 100644
index 0000000..695bb52
--- /dev/null
+++ b/src/drivers/i2c/sx9360/Makefile.inc
@@ -0,0 +1 @@
+ramstage-$(CONFIG_DRIVERS_I2C_SX9360) += sx9360.c
diff --git a/src/drivers/i2c/sx9360/chip.h b/src/drivers/i2c/sx9360/chip.h
new file mode 100644
index 0000000..3b928b0
--- /dev/null
+++ b/src/drivers/i2c/sx9360/chip.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __DRIVERS_I2C_SX9360_CHIP_H__
+#define __DRIVERS_I2C_SX9360_CHIP_H__
+
+#include <acpi/acpi_device.h>
+#include <device/i2c_simple.h>
+
+struct drivers_i2c_sx9360_config {
+	/* Device Description */
+	const char *desc;
+
+	/* ACPI _UID */
+	unsigned int uid;
+
+	/* Bus speed in Hz, default is I2C_SPEED_FAST */
+	enum i2c_speed speed;
+
+	/* Use GPIO-based interrupt instead of IO-APIC */
+	struct acpi_gpio irq_gpio;
+
+	/* IO-APIC interrupt */
+	struct acpi_irq irq;
+
+      /*
+       * Registers definition in the kernel source tree at:
+       * Documentation/devicetree/bindings/iio/proximity/semtech,sx9310.yaml
+       */
+
+      /* Raw Proximity filter strength: When not set, disabled. */
+      uint32_t proxraw_strength;
+
+      /* Average Proximity filter strength: When not set, disabled. */
+      uint32_t avg_pos_strength;
+
+      /* Capacitance measure resolution. Driver default: 128. */
+      uint32_t resolution;
+};
+
+#endif /* __DRIVERS_I2C_SX9360_CHIP_H__ */
diff --git a/src/drivers/i2c/sx9360/sx9360.c b/src/drivers/i2c/sx9360/sx9360.c
new file mode 100644
index 0000000..b06882a
--- /dev/null
+++ b/src/drivers/i2c/sx9360/sx9360.c
@@ -0,0 +1,115 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <acpi/acpi_device.h>
+#include <acpi/acpigen.h>
+#include <console/console.h>
+#include <device/i2c_simple.h>
+#include <device/device.h>
+#include <device/path.h>
+#include <string.h>
+#include "chip.h"
+
+#define I2C_SX9360_ACPI_ID	"STH9360"
+#define I2C_SX9360_CHIP_NAME	"Semtech SX9360"
+
+#define REGISTER(NAME) acpi_dp_add_integer(dsd, \
+					I2C_SX9360_ACPI_ID "," #NAME, \
+					config->NAME)
+
+static void i2c_sx9360_fill_ssdt(const struct device *dev)
+{
+	struct drivers_i2c_sx9360_config *config = dev->chip_info;
+	const char *scope = acpi_device_scope(dev);
+	struct acpi_i2c i2c = {
+		.address = dev->path.i2c.device,
+		.mode_10bit = dev->path.i2c.mode_10bit,
+		.speed = I2C_SPEED_FAST,
+		.resource = scope,
+	};
+	struct acpi_dp *dsd;
+
+	if (!scope || !config)
+		return;
+
+	if (config->speed)
+		i2c.speed = config->speed;
+
+	/* Device */
+	acpigen_write_scope(scope);
+	acpigen_write_device(acpi_device_name(dev));
+	acpigen_write_name_string("_HID", I2C_SX9360_ACPI_ID);
+	acpigen_write_name_integer("_UID", config->uid);
+	acpigen_write_name_string("_DDN", config->desc);
+	acpigen_write_STA(acpi_device_status(dev));
+
+	/* Resources */
+	acpigen_write_name("_CRS");
+	acpigen_write_resourcetemplate_header();
+	acpi_device_write_i2c(&i2c);
+
+	if (config->irq_gpio.pin_count)
+		acpi_device_write_gpio(&config->irq_gpio);
+	else
+		acpi_device_write_interrupt(&config->irq);
+
+	acpigen_write_resourcetemplate_footer();
+
+	/* DSD */
+	dsd = acpi_dp_new_table("_DSD");
+
+	/*
+	 * Format describe in linux kernel documentation. See
+	 * https://www.kernel.org/doc/Documentation/devicetree/bindings/iio/proximity/s...
+	 */
+	acpi_dp_add_integer(dsd, "semtech,proxraw-strength",
+			    config->proxraw_strength);
+	acpi_dp_add_integer(dsd, "semtech,avg-pos-strength",
+			    config->avg_pos_strength);
+	acpi_dp_add_integer(dsd, "semtech,resolution",
+			    config->resolution);
+
+	acpi_dp_write(dsd);
+
+	acpigen_pop_len(); /* Device */
+	acpigen_pop_len(); /* Scope */
+
+	printk(BIOS_INFO, "%s: %s at %s\n", acpi_device_path(dev),
+	       config->desc ? : dev->chip_ops->name, dev_path(dev));
+}
+
+#undef REGISTER
+
+static const char *i2c_sx9360_acpi_name(const struct device *dev)
+{
+	static char name[5];
+
+	snprintf(name, sizeof(name), "SX%02.2X", dev->path.i2c.device);
+	return name;
+}
+
+static struct device_operations i2c_sx9360_ops = {
+	.read_resources		= noop_read_resources,
+	.set_resources		= noop_set_resources,
+	.acpi_name		= i2c_sx9360_acpi_name,
+	.acpi_fill_ssdt		= i2c_sx9360_fill_ssdt,
+};
+
+static void i2c_sx9360_enable(struct device *dev)
+{
+	struct drivers_i2c_sx9360_config *config = dev->chip_info;
+
+	if (!config) {
+		dev->enabled = 0;
+		return;
+	}
+
+	dev->ops = &i2c_sx9360_ops;
+
+	if (config->desc)
+		dev->name = config->desc;
+}
+
+struct chip_operations drivers_i2c_sx9360_ops = {
+	CHIP_NAME(I2C_SX9360_CHIP_NAME)
+	.enable_dev = i2c_sx9360_enable
+};