[coreboot-gerrit] New patch to review for coreboot: i2c/generic: Enable support for adding PowerResource for device

[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/17081

-gerrit

commit a84a82198313b9b5287cb295c92b67b4cc37ce1d
Author: Furquan Shaikh <furquan at chromium.org>
Date:   Thu Oct 20 16:01:04 2016 -0700

    i2c/generic: Enable support for adding PowerResource for device
    
    Add support to allow a device to define PowerResource in its SSDT AML
    code. PowerResouce ACPI generation expects SoC to define the
    callbacks for generating AML code for GPIO manipulation.
    
    Device requiring PowerResource needs to define following parameters:
    1. Reset GPIO - Mandatory if PowerResource needs to be defined
    2. Reset delay - Delay after reset GPIO is de-asserted (default 0)
    3. Enable GPIO - Optional if a separate GPIO exists for enable
    4. Enable delay - Delay after enable GPIO is asserted (default 0)
    
    BUG=chrome-os-partner:55988
    
    Change-Id: Ieb2dd95fc1f555f5de66f3dda425172ac5b75dad
    Signed-off-by: Furquan Shaikh <furquan at chromium.org>
---
 src/drivers/i2c/generic/chip.h    |  9 +++++++++
 src/drivers/i2c/generic/generic.c | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+)

diff --git a/src/drivers/i2c/generic/chip.h b/src/drivers/i2c/generic/chip.h
index d84097f..e84fc38 100644
--- a/src/drivers/i2c/generic/chip.h
+++ b/src/drivers/i2c/generic/chip.h
@@ -22,4 +22,13 @@ struct drivers_i2c_generic_config {
 	/* GPIO used to indicate if this device is present */
 	unsigned device_present_gpio;
 	unsigned device_present_gpio_invert;
+
+	/* GPIO used to take device out of reset or to put it into reset. */
+        unsigned reset_gpio;
+	/* Delay to be inserted after device is taken out of reset. */
+	unsigned reset_delay_ms;
+	/* GPIO used to enable device. */
+	unsigned enable_gpio;
+	/* Delay to be inserted after device is enabled. */
+	unsigned enable_delay_ms;
 };
diff --git a/src/drivers/i2c/generic/generic.c b/src/drivers/i2c/generic/generic.c
index c11a889..7f078b0 100644
--- a/src/drivers/i2c/generic/generic.c
+++ b/src/drivers/i2c/generic/generic.c
@@ -25,6 +25,42 @@
 #include "chip.h"
 
 #if IS_ENABLED(CONFIG_HAVE_ACPI_TABLES)
+
+static void i2c_generic_add_power_res(struct drivers_i2c_generic_config *config)
+{
+	if (!config->reset_gpio)
+		return;
+
+	const char *power_res_dev_states[] = { "_PR0", "_PR3" };
+
+	/* PowerResource (PRIC, 0, 0) */
+	acpigen_write_power_res("PRIC", 0, 0, power_res_dev_states,
+				ARRAY_SIZE(power_res_dev_states));
+
+	/* Method (_STA, 0, NotSerialized) { Return (0x1) } */
+	acpigen_write_STA(0x1);
+
+	/* Method (_ON, 0, Serialized) */
+	acpigen_write_method_serialized("_ON", 0);
+	acpigen_soc_set_tx_gpio(config->reset_gpio);
+	if (config->enable_gpio) {
+		acpigen_soc_set_tx_gpio(config->enable_gpio);
+		acpigen_write_sleep(config->enable_delay_ms);
+	}
+	acpigen_soc_clear_tx_gpio(config->reset_gpio);
+	acpigen_write_sleep(config->reset_delay_ms);
+	acpigen_pop_len();		/* _ON method */
+
+	/* Method (_OFF, 0, Serialized) */
+	acpigen_write_method_serialized("_OFF", 0);
+	acpigen_soc_set_tx_gpio(config->reset_gpio);
+	if (config->enable_gpio)
+		acpigen_soc_clear_tx_gpio(config->enable_gpio);
+	acpigen_pop_len();		/* _OFF method */
+
+	acpigen_pop_len();		/* PowerResource PRIC */
+}
+
 static void i2c_generic_fill_ssdt(struct device *dev)
 {
 	struct drivers_i2c_generic_config *config = dev->chip_info;
@@ -72,6 +108,9 @@ static void i2c_generic_fill_ssdt(struct device *dev)
 		acpi_dp_write(dsd);
 	}
 
+	/* Power Resource */
+	i2c_generic_add_power_res(config);
+
 	acpigen_pop_len(); /* Device */
 	acpigen_pop_len(); /* Scope */