acpi: Add support for writing a GPIO power sequence

Power to some devices is controlled by GPIOs. Add a way to generate ACPI
code to enable and disable a GPIO so that this can be handled within an
ACPI method.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 85 insertions, 0 deletions

diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index 70d734245b..45216c1f9d 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -13,6 +13,7 @@
 #include <log.h>
 #include <uuid.h>
 #include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
 #include <dm/acpi.h>
 
 u8 *acpigen_get_current(struct acpi_ctx *ctx)
@@ -395,3 +396,87 @@ void acpigen_write_debug_string(struct acpi_ctx *ctx, const char *str)
 	acpigen_write_string(ctx, str);
 	acpigen_emit_ext_op(ctx, DEBUG_OP);
 }
+
+/**
+ * acpigen_get_dw0_in_local5() - Generate code to put dw0 cfg0 in local5
+ *
+ * Store (\_SB.GPC0 (addr), Local5)
+ *
+ * \_SB.GPC0 is used to read cfg0 value from dw0. It is typically defined in
+ * the board's gpiolib.asl
+ *
+ * The value needs to be stored in a local variable so that it can be used in
+ * expressions in the ACPI code.
+ *
+ * @ctx: ACPI context pointer
+ * @dw0_read: Name to use to read dw0, e.g. "\\_SB.GPC0"
+ * @addr: GPIO pin configuration register address
+ *
+ */
+static void acpigen_get_dw0_in_local5(struct acpi_ctx *ctx,
+				      const char *dw0_read, ulong addr)
+{
+	acpigen_write_store(ctx);
+	acpigen_emit_namestring(ctx, dw0_read);
+	acpigen_write_integer(ctx, addr);
+	acpigen_emit_byte(ctx, LOCAL5_OP);
+}
+
+/**
+ * acpigen_set_gpio_val() - Emit code to set value of TX GPIO to on/off
+ *
+ * @ctx: ACPI context pointer
+ * @dw0_read: Method name to use to read dw0, e.g. "\\_SB.GPC0"
+ * @dw0_write: Method name to use to read dw0, e.g. "\\_SB.SPC0"
+ * @gpio_num: GPIO number to adjust
+ * @vaL: true to set on, false to set off
+ */
+static int acpigen_set_gpio_val(struct acpi_ctx *ctx, u32 tx_state_val,
+				const char *dw0_read, const char *dw0_write,
+				struct acpi_gpio *gpio, bool val)
+{
+	acpigen_get_dw0_in_local5(ctx, dw0_read, gpio->pin0_addr);
+
+	/* Store (0x40, Local0) */
+	acpigen_write_store(ctx);
+	acpigen_write_integer(ctx, tx_state_val);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+
+	if (val) {
+		/* Or (Local5, PAD_CFG0_TX_STATE, Local5) */
+		acpigen_write_or(ctx, LOCAL5_OP, LOCAL0_OP, LOCAL5_OP);
+	} else {
+		/* Not (PAD_CFG0_TX_STATE, Local6) */
+		acpigen_write_not(ctx, LOCAL0_OP, LOCAL6_OP);
+
+		/* And (Local5, Local6, Local5) */
+		acpigen_write_and(ctx, LOCAL5_OP, LOCAL6_OP, LOCAL5_OP);
+	}
+
+	/*
+	 * \_SB.SPC0 (addr, Local5)
+	 * \_SB.SPC0 is used to write cfg0 value in dw0. It is defined in
+	 * gpiolib.asl.
+	 */
+	acpigen_emit_namestring(ctx, dw0_write);
+	acpigen_write_integer(ctx, gpio->pin0_addr);
+	acpigen_emit_byte(ctx, LOCAL5_OP);
+
+	return 0;
+}
+
+int acpigen_set_enable_tx_gpio(struct acpi_ctx *ctx, u32 tx_state_val,
+			       const char *dw0_read, const char *dw0_write,
+			       struct acpi_gpio *gpio, bool enable)
+{
+	bool set;
+	int ret;
+
+	set = gpio->polarity == ACPI_GPIO_ACTIVE_HIGH ? enable : !enable;
+	ret = acpigen_set_gpio_val(ctx, tx_state_val, dw0_read, dw0_write, gpio,
+				   set);
+	if (ret)
+		return log_msg_ret("call", ret);
+
+	return 0;
+}