[PATCH v3 16/57] i2c: Add a generic driver to generate ACPI info

Simon Glass
2020-09-06T21:43:24Z

Many I2C devices produce roughly the same ACPI data with just things like
the GPIO/interrupt information being different.

This can be handled by a generic driver along with some information in the
device tree.

Add a generic i2c driver for this purpose.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
---

(no changes since v2)

Changes in v2:
- Fix incorrect space in enable-off-delay-ms

Changes in v1:
- Adjust implementation to match new ACPI GPIO generation
- Capitalise ACPI_OPS_PTR
- Rename acpi-probed to linux,probed
- Support hid-over-i2c separately as well
- Use acpi,ddn instead of acpi,desc
- Use updated acpi_device_write_dsm_i2c_hid() function

doc/device-tree-bindings/i2c/generic-acpi.txt | 42 ++++
drivers/i2c/Makefile | 3 +
drivers/i2c/acpi_i2c.c | 226 ++++++++++++++++++
drivers/i2c/acpi_i2c.h | 15 ++
drivers/i2c/i2c-uclass.c | 17 ++
include/acpi/acpi_device.h | 55 +++++
include/i2c.h | 23 ++
7 files changed, 381 insertions(+)
create mode 100644 doc/device-tree-bindings/i2c/generic-acpi.txt
create mode 100644 drivers/i2c/acpi_i2c.c
create mode 100644 drivers/i2c/acpi_i2c.h

diff --git a/doc/device-tree-bindings/i2c/generic-acpi.txt b/doc/device-tree-bindings/i2c/generic-acpi.txt
new file mode 100644
index 00000000000..3510a71b570
--- /dev/null
+++ b/doc/device-tree-bindings/i2c/generic-acpi.txt
@@ -0,0 +1,42 @@
+I2C generic device
+==================
+
+This is used only to generate ACPI tables for an I2C device.
+
+Required properties :
+
+ - compatible : "i2c-chip";
+ - reg : I2C chip address
+ - acpi,hid : HID name for the device
+
+Optional properies in addition to device.txt:
+
+ - reset-gpios : GPIO used to assert reset to the device
+ - irq-gpios : GPIO used for interrupt (if Interrupt is not used)
+ - stop-gpios : GPIO used to stop the device
+ - interrupts-extended : Interrupt to use for the device
+ - reset-delay-ms : Delay after de-asserting reset, in ms
+ - reset-off-delay-ms : Delay after asserting reset (during power off)
+ - enable-delay-ms : Delay after asserting enable
+ - enable-off-delay-ms : Delay after de-asserting enable (during power off)
+ - stop-delay-ms : Delay after de-aserting stop
+ - stop-off-delay-ms : Delay after asserting stop (during power off)
+ - hid-descr-addr : HID register offset (for Human Interface Devices)
+
+Example
+-------
+
+ elan-touchscreen at 10 {
+ compatible = "i2c-chip";
+ reg = <0x10>;
+ acpi,hid = "ELAN0001";
+ acpi,ddn = "ELAN Touchscreen";
+ interrupts-extended = <&acpi_gpe GPIO_21_IRQ
+ IRQ_TYPE_EDGE_FALLING>;
+ linux,probed;
+ reset-gpios = <&gpio_n GPIO_36 GPIO_ACTIVE_HIGH>;
+ reset-delay-ms = <20>;
+ enable-gpios = <&gpio_n GPIO_152 GPIO_ACTIVE_HIGH>;
+ enable-delay-ms = <1>;
+ acpi,has-power-resource;
+ };
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index f7b27864488..bd248cbf52b 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -3,6 +3,9 @@
# (C) Copyright 2000-2007
# Wolfgang Denk, DENX Software Engineering, wd at denx.de.
obj-$(CONFIG_DM_I2C) += i2c-uclass.o
+ifdef CONFIG_ACPIGEN
+obj-$(CONFIG_DM_I2C) += acpi_i2c.o
+endif
obj-$(CONFIG_DM_I2C_GPIO) += i2c-gpio.o
obj-$(CONFIG_$(SPL_)I2C_CROS_EC_TUNNEL) += cros_ec_tunnel.o
obj-$(CONFIG_$(SPL_)I2C_CROS_EC_LDO) += cros_ec_ldo.o
diff --git a/drivers/i2c/acpi_i2c.c b/drivers/i2c/acpi_i2c.c
new file mode 100644
index 00000000000..57d29683cbf
--- /dev/null
+++ b/drivers/i2c/acpi_i2c.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <log.h>
+#include <acpi/acpi_device.h>
+#include <acpi/acpigen.h>
+#include <acpi/acpi_dp.h>
+#ifdef CONFIG_X86
+#include <asm/intel_pinctrl_defs.h>
+#endif
+#include <asm-generic/gpio.h>
+#include <dm/acpi.h>
+
+static bool acpi_i2c_add_gpios_to_crs(struct acpi_i2c_priv *priv)
+{
+ /*
+ * Return false if:
+ * 1. Request to explicitly disable export of GPIOs in CRS, or
+ * 2. Both reset and enable GPIOs are not provided.
+ */
+ if (priv->disable_gpio_export_in_crs ||
+ (!dm_gpio_is_valid(&priv->reset_gpio) &&
+ !dm_gpio_is_valid(&priv->enable_gpio)))
+ return false;
+
+ return true;
+}
+
+static int acpi_i2c_write_gpio(struct acpi_ctx *ctx, struct gpio_desc *gpio,
+ int *curindex)
+{
+ int ret;
+
+ if (!dm_gpio_is_valid(gpio))
+ return -ENOENT;
+
+ acpi_device_write_gpio_desc(ctx, gpio);
+ ret = *curindex;
+ (*curindex)++;
+
+ return ret;
+}
+
+int acpi_i2c_fill_ssdt(const struct udevice *dev, struct acpi_ctx *ctx)
+{
+ int reset_gpio_index = -1, enable_gpio_index = -1, irq_gpio_index = -1;
+ enum i2c_device_t type = dev_get_driver_data(dev);
+ struct acpi_i2c_priv *priv = dev_get_priv(dev);
+ struct acpi_dp *dsd = NULL;
+ char scope[ACPI_PATH_MAX];
+ char name[ACPI_NAME_MAX];
+ int tx_state_val;
+ int curindex = 0;
+ int ret;
+
+#ifdef CONFIG_X86
+ tx_state_val = PAD_CFG0_TX_STATE;
+#elif defined(CONFIG_SANDBOX)
+ tx_state_val = BIT(7); /* test value */
+#else
+#error "Not supported on this architecture"
+#endif
+ ret = acpi_get_name(dev, name);
+ if (ret)
+ return log_msg_ret("name", ret);
+ ret = acpi_device_scope(dev, scope, sizeof(scope));
+ if (ret)
+ return log_msg_ret("scope", ret);
+
+ /* Device */
+ acpigen_write_scope(ctx, scope);
+ acpigen_write_device(ctx, name);
+ acpigen_write_name_string(ctx, "_HID", priv->hid);
+ if (type == I2C_DEVICE_HID_OVER_I2C)
+ acpigen_write_name_string(ctx, "_CID", "PNP0C50");
+ acpigen_write_name_integer(ctx, "_UID", priv->uid);
+ acpigen_write_name_string(ctx, "_DDN", priv->desc);
+ acpigen_write_sta(ctx, acpi_device_status(dev));
+
+ /* Resources */
+ acpigen_write_name(ctx, "_CRS");
+ acpigen_write_resourcetemplate_header(ctx);
+ acpi_device_write_i2c_dev(ctx, dev);
+
+ /* Use either Interrupt() or GpioInt() */
+ if (dm_gpio_is_valid(&priv->irq_gpio)) {
+ irq_gpio_index = acpi_i2c_write_gpio(ctx, &priv->irq_gpio,
+ &curindex);
+ } else {
+ ret = acpi_device_write_interrupt_irq(ctx, &priv->irq);
+ if (ret < 0)
+ return log_msg_ret("irq", ret);
+ }
+
+ if (acpi_i2c_add_gpios_to_crs(priv)) {
+ reset_gpio_index = acpi_i2c_write_gpio(ctx, &priv->reset_gpio,
+ &curindex);
+ enable_gpio_index = acpi_i2c_write_gpio(ctx, &priv->enable_gpio,
+ &curindex);
+ }
+ acpigen_write_resourcetemplate_footer(ctx);
+
+ /* Wake capabilities */
+ if (priv->wake) {
+ acpigen_write_name_integer(ctx, "_S0W", 4);
+ acpigen_write_prw(ctx, priv->wake, 3);
+ }
+
+ /* DSD */
+ if (priv->probed || priv->property_count || priv->compat_string ||
+ reset_gpio_index >= 0 || enable_gpio_index >= 0 ||
+ irq_gpio_index >= 0) {
+ char path[ACPI_PATH_MAX];
+
+ ret = acpi_device_path(dev, path, sizeof(path));
+ if (ret)
+ return log_msg_ret("path", ret);
+
+ dsd = acpi_dp_new_table("_DSD");
+ if (priv->compat_string)
+ acpi_dp_add_string(dsd, "compatible",
+ priv->compat_string);
+ if (priv->probed)
+ acpi_dp_add_integer(dsd, "linux,probed", 1);
+ if (irq_gpio_index >= 0)
+ acpi_dp_add_gpio(dsd, "irq-gpios", path,
+ irq_gpio_index, 0,
+ priv->irq_gpio.flags &
+ GPIOD_ACTIVE_LOW ?
+ ACPI_GPIO_ACTIVE_LOW : 0);
+ if (reset_gpio_index >= 0)
+ acpi_dp_add_gpio(dsd, "reset-gpios", path,
+ reset_gpio_index, 0,
+ priv->reset_gpio.flags &
+ GPIOD_ACTIVE_LOW ?
+ ACPI_GPIO_ACTIVE_LOW : 0);
+ if (enable_gpio_index >= 0)
+ acpi_dp_add_gpio(dsd, "enable-gpios", path,
+ enable_gpio_index, 0,
+ priv->enable_gpio.flags &
+ GPIOD_ACTIVE_LOW ?
+ ACPI_GPIO_ACTIVE_LOW : 0);
+ /* Generic property list is not supported */
+ acpi_dp_write(ctx, dsd);
+ }
+
+ /* Power Resource */
+ if (priv->has_power_resource) {
+ ret = acpi_device_add_power_res(ctx, tx_state_val,
+ "\\_SB.GPC0", "\\_SB.SPC0",
+ &priv->reset_gpio, priv->reset_delay_ms,
+ priv->reset_off_delay_ms, &priv->enable_gpio,
+ priv->enable_delay_ms, priv->enable_off_delay_ms,
+ &priv->stop_gpio, priv->stop_delay_ms,
+ priv->stop_off_delay_ms);
+ if (ret)
+ return log_msg_ret("power", ret);
+ }
+ if (priv->hid_desc_reg_offset) {
+ ret = acpi_device_write_dsm_i2c_hid(ctx,
+ priv->hid_desc_reg_offset);
+ if (ret)
+ return log_msg_ret("dsm", ret);
+ }
+
+ acpigen_pop_len(ctx); /* Device */
+ acpigen_pop_len(ctx); /* Scope */
+
+ return 0;
+}
+
+int acpi_i2c_ofdata_to_platdata(struct udevice *dev)
+{
+ struct acpi_i2c_priv *priv = dev_get_priv(dev);
+
+ gpio_request_by_name(dev, "reset-gpios", 0, &priv->reset_gpio,
+ GPIOD_IS_OUT);
+ gpio_request_by_name(dev, "enable-gpios", 0, &priv->enable_gpio,
+ GPIOD_IS_OUT);
+ gpio_request_by_name(dev, "irq-gpios", 0, &priv->irq_gpio, GPIOD_IS_IN);
+ gpio_request_by_name(dev, "stop-gpios", 0, &priv->stop_gpio,
+ GPIOD_IS_OUT);
+ irq_get_by_index(dev, 0, &priv->irq);
+ priv->hid = dev_read_string(dev, "acpi,hid");
+ if (!priv->hid)
+ return log_msg_ret("hid", -EINVAL);
+ dev_read_u32(dev, "acpi,uid", &priv->uid);
+ priv->desc = dev_read_string(dev, "acpi,ddn");
+ dev_read_u32(dev, "acpi,wake", &priv->wake);
+ priv->probed = dev_read_bool(dev, "linux,probed");
+ priv->compat_string = dev_read_string(dev, "acpi,compatible");
+ priv->has_power_resource = dev_read_bool(dev,
+ "acpi,has-power-resource");
+ dev_read_u32(dev, "hid-descr-addr", &priv->hid_desc_reg_offset);
+ dev_read_u32(dev, "reset-delay-ms", &priv->reset_delay_ms);
+ dev_read_u32(dev, "reset-off-delay-ms", &priv->reset_off_delay_ms);
+ dev_read_u32(dev, "enable-delay-ms", &priv->enable_delay_ms);
+ dev_read_u32(dev, "enable-off-delay-ms", &priv->enable_off_delay_ms);
+ dev_read_u32(dev, "stop-delay-ms", &priv->stop_delay_ms);
+ dev_read_u32(dev, "stop-off-delay-ms", &priv->stop_off_delay_ms);
+
+ return 0;
+}
+
+/* Use name specified in priv or build one from I2C address */
+static int acpi_i2c_get_name(const struct udevice *dev, char *out_name)
+{
+ struct dm_i2c_chip *chip = dev_get_parent_platdata(dev);
+ struct acpi_i2c_priv *priv = dev_get_priv(dev);
+
+ snprintf(out_name, ACPI_NAME_MAX,
+ priv->hid_desc_reg_offset ? "H%03X" : "D%03X",
+ chip->chip_addr);
+
+ return 0;
+}
+
+struct acpi_ops acpi_i2c_ops = {
+ .fill_ssdt = acpi_i2c_fill_ssdt,
+ .get_name = acpi_i2c_get_name,
+};
diff --git a/drivers/i2c/acpi_i2c.h b/drivers/i2c/acpi_i2c.h
new file mode 100644
index 00000000000..1f4be296016
--- /dev/null
+++ b/drivers/i2c/acpi_i2c.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef __ACPI_I2C_H
+#define __ACPI_I2C_H
+
+#include <dm/acpi.h>
+
+extern struct acpi_ops acpi_i2c_ops;
+
+int acpi_i2c_ofdata_to_platdata(struct udevice *dev);
+
+#endif
diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index 2373aa2ea4c..5c4626b0442 100644
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -9,6 +9,8 @@
#include <i2c.h>
#include <log.h>
#include <malloc.h>
+#include <acpi/acpi_device.h>
+#include <dm/acpi.h>
#include <dm/device-internal.h>
#include <dm/lists.h>
#include <dm/pinctrl.h>
@@ -16,6 +18,7 @@
#include <asm/gpio.h>
#endif
#include <linux/delay.h>
+#include "acpi_i2c.h"

#define I2C_MAX_OFFSET_LEN 4

@@ -749,7 +752,21 @@ UCLASS_DRIVER(i2c_generic) = {
.name = "i2c_generic",
};

+static const struct udevice_id generic_chip_i2c_ids[] = {
+ { .compatible = "i2c-chip", .data = I2C_DEVICE_GENERIC },
+#if CONFIG_IS_ENABLED(ACPIGEN)
+ { .compatible = "hid-over-i2c", .data = I2C_DEVICE_HID_OVER_I2C },
+#endif
+ { }
+};
+
U_BOOT_DRIVER(i2c_generic_chip_drv) = {
.name = "i2c_generic_chip_drv",
.id = UCLASS_I2C_GENERIC,
+ .of_match = generic_chip_i2c_ids,
+#if CONFIG_IS_ENABLED(ACPIGEN)
+ .ofdata_to_platdata = acpi_i2c_ofdata_to_platdata,
+ .priv_auto_alloc_size = sizeof(struct acpi_i2c_priv),
+#endif
+ ACPI_OPS_PTR(&acpi_i2c_ops)
};
diff --git a/include/acpi/acpi_device.h b/include/acpi/acpi_device.h
index a5b12217820..1b838fcb857 100644
--- a/include/acpi/acpi_device.h
+++ b/include/acpi/acpi_device.h
@@ -10,7 +10,9 @@
#define __ACPI_DEVICE_H

#include <i2c.h>
+#include <irq.h>
#include <spi.h>
+#include <asm-generic/gpio.h>
#include <linux/bitops.h>

struct acpi_ctx;
@@ -235,6 +237,59 @@ struct acpi_spi {
const char *resource;
};

+/**
+ * struct acpi_i2c_priv - Information read from device tree
+ *
+ * This is used by devices which want to specify various pieces of ACPI
+ * information, including power control. It allows a generic function to
+ * generate the information for ACPI, based on device-tree properties.
+ *
+ * @disable_gpio_export_in_crs: Don't export GPIOs in the CRS
+ * @reset_gpio: GPIO used to assert reset to the device
+ * @enable_gpio: GPIO used to enable the device
+ * @stop_gpio: GPIO used to stop the device
+ * @irq_gpio: GPIO used for interrupt (if @irq is not used)
+ * @irq: IRQ used for interrupt (if @irq_gpio is not used)
+ * @hid: _HID value for device (required)
+ * @uid: _UID value for device
+ * @desc: _DDN value for device
+ * @wake: Wake event, e.g. GPE0_DW1_15; 0 if none
+ * @property_count: Number of other DSD properties (currently always 0)
+ * @probed: true set set 'linux,probed' property
+ * @compat_string: Device tree compatible string to report through ACPI
+ * @has_power_resource: true if this device has a power resource
+ * @reset_delay_ms: Delay after de-asserting reset, in ms
+ * @reset_off_delay_ms: Delay after asserting reset (during power off)
+ * @enable_delay_ms: Delay after asserting enable
+ * @enable_off_delay_ms: Delay after de-asserting enable (during power off)
+ * @stop_delay_ms: Delay after de-aserting stop
+ * @stop_off_delay_ms: Delay after asserting stop (during power off)
+ * @hid_desc_reg_offset: HID register offset (for Human Interface Devices)
+ */
+struct acpi_i2c_priv {
+ bool disable_gpio_export_in_crs;
+ struct gpio_desc reset_gpio;
+ struct gpio_desc enable_gpio;
+ struct gpio_desc irq_gpio;
+ struct gpio_desc stop_gpio;
+ struct irq irq;
+ const char *hid;
+ u32 uid;
+ const char *desc;
+ u32 wake;
+ u32 property_count;
+ bool probed;
+ const char *compat_string;
+ bool has_power_resource;
+ u32 reset_delay_ms;
+ u32 reset_off_delay_ms;
+ u32 enable_delay_ms;
+ u32 enable_off_delay_ms;
+ u32 stop_delay_ms;
+ u32 stop_off_delay_ms;
+ u32 hid_desc_reg_offset;
+};
+
/**
* acpi_device_path() - Get the full path to an ACPI device
*
diff --git a/include/i2c.h b/include/i2c.h
index 1d792db454a..880aa8032b7 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -58,6 +58,12 @@ enum i2c_address_mode {
I2C_MODE_10_BIT
};

+/** enum i2c_device_t - Types of I2C devices, used for compatible strings */
+enum i2c_device_t {
+ I2C_DEVICE_GENERIC,
+ I2C_DEVICE_HID_OVER_I2C,
+};
+
struct udevice;
/**
* struct dm_i2c_chip - information about an i2c chip
@@ -558,6 +564,23 @@ int i2c_emul_find(struct udevice *dev, struct udevice **emulp);
*/
struct udevice *i2c_emul_get_device(struct udevice *emul);

+/* ACPI operations for generic I2C devices */
+extern struct acpi_ops i2c_acpi_ops;
+
+/**
+ * acpi_i2c_ofdata_to_platdata() - Read properties intended for ACPI
+ *
+ * This reads the generic I2C properties from the device tree, so that these
+ * can be used to create ACPI information for the device.
+ *
+ * See the i2c/generic-acpi.txt binding file for information about the
+ * properties.
+ *
+ * @dev: I2C device to process
+ * @return 0 if OK, -EINVAL if acpi,hid is not present
+ */
+int acpi_i2c_ofdata_to_platdata(struct udevice *dev);
+
#ifndef CONFIG_DM_I2C

/*
--
2.28.0.526.ge36021eeef-goog