[coreboot-gerrit] New patch to review for coreboot: i2c/generic: Add support for passing reset-gpio in ACPI

[Furquan Shaikh (furquan@google.com)]

Furquan Shaikh (furquan at google.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/16872

-gerrit

commit fb0c74ad2f6a217e096c9d7d22973d98cd75095a
Author: Furquan Shaikh <furquan at chromium.org>
Date:   Mon Oct 3 23:43:06 2016 -0700

    i2c/generic: Add support for passing reset-gpio in ACPI
    
    There are two things required to pass reset-gpio via ACPI:
    1. Add GPIO to _CRS
    2. Add reset-gpio property in _DSD with index in _CRS to the
    corresponding gpio.
    
    Add function to add gpio to _CRS and return appropriate index. This can
    be useful if later we need to add more gpio properties with appropriate
    indices.
    
    BUG=chrome-os-partner:55988
    BRANCH=None
    TEST=Verified that reset-gpio property appears in SSDT on reef.
    
    Change-Id: Ibbf7d6f3916fb43bd722de21391e635c07dd81f7
    Signed-off-by: Furquan Shaikh <furquan at chromium.org>
---
 src/drivers/i2c/generic/chip.h    |  1 +
 src/drivers/i2c/generic/generic.c | 32 ++++++++++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/src/drivers/i2c/generic/chip.h b/src/drivers/i2c/generic/chip.h
index d84097f..69774fe 100644
--- a/src/drivers/i2c/generic/chip.h
+++ b/src/drivers/i2c/generic/chip.h
@@ -22,4 +22,5 @@ struct drivers_i2c_generic_config {
 	/* GPIO used to indicate if this device is present */
 	unsigned device_present_gpio;
 	unsigned device_present_gpio_invert;
+	struct acpi_gpio reset_gpio;
 };
diff --git a/src/drivers/i2c/generic/generic.c b/src/drivers/i2c/generic/generic.c
index 30a280b..587e6aa 100644
--- a/src/drivers/i2c/generic/generic.c
+++ b/src/drivers/i2c/generic/generic.c
@@ -25,6 +25,21 @@
 #include "chip.h"
 
 #if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+
+static int i2c_generic_device_write_gpio(struct acpi_gpio *gpio)
+{
+	static int gpio_index = 0;
+	int ret = -1;
+
+	if (gpio->pin_count) {
+		acpi_device_write_gpio(gpio);
+		ret = gpio_index;
+		gpio_index++;
+	}
+
+	return ret;
+}
+
 static void i2c_generic_fill_ssdt(struct device *dev)
 {
 	struct drivers_i2c_generic_config *config = dev->chip_info;
@@ -54,10 +69,13 @@ static void i2c_generic_fill_ssdt(struct device *dev)
 	acpigen_write_STA(ACPI_STATUS_DEVICE_ALL_ON);
 
 	/* Resources */
+	int reset_index = 0;
+
 	acpigen_write_name("_CRS");
 	acpigen_write_resourcetemplate_header();
 	acpi_device_write_i2c(&i2c);
 	acpi_device_write_interrupt(&config->irq);
+	reset_index = i2c_generic_device_write_gpio(&config->reset_gpio);
 	acpigen_write_resourcetemplate_footer();
 
 	/* Wake capabilities */
@@ -66,11 +84,21 @@ static void i2c_generic_fill_ssdt(struct device *dev)
 		acpigen_write_PRW(config->wake, 3);
 	}
 
-	if (config->probed) {
+	/* Device-specific data */
+	const char *path = acpi_device_path(dev);
+
+	/* Decide if _DSD is required. */
+	if (config->probed || (reset_index != -1))
 		dsd = acpi_dp_new_table("_DSD");
+
+	if (config->probed)
 		acpi_dp_add_integer(dsd, "linux,probed", 1);
+
+	if (reset_index != -1)
+		acpi_dp_add_gpio(dsd, "reset-gpio", path, reset_index, 0, 0);
+
+	if (dsd)
 		acpi_dp_write(dsd);
-	}
 
 	acpigen_pop_len(); /* Device */
 	acpigen_pop_len(); /* Scope */