[PATCH v1 24/35] acpi: Add support for writing a GPIO power sequence

[Simon Glass <sjg@chromium.org>]

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>
---

Changes in v1: None

 include/acpi/acpigen.h | 12 +++++++
 lib/acpi/acpigen.c     | 80 ++++++++++++++++++++++++++++++++++++++++++
 test/dm/acpigen.c      | 54 ++++++++++++++++++++++++++++
 3 files changed, 146 insertions(+)

diff --git a/include/acpi/acpigen.h b/include/acpi/acpigen.h
index 7d9a02805b..1205836f58 100644
--- a/include/acpi/acpigen.h
+++ b/include/acpi/acpigen.h
@@ -13,6 +13,7 @@
 #include <linux/types.h>
 
 struct acpi_ctx;
+struct acpi_gpio;
 
 /* ACPI Op/Prefix codes */
 enum {
@@ -332,4 +333,15 @@ void acpigen_write_power_res(struct acpi_ctx *ctx, const char *name, uint level,
 			     uint order, const char *const dev_states[],
 			     size_t dev_states_count);
 
+/*
+ * Helper functions for enabling/disabling Tx GPIOs based on the GPIO
+ * polarity. These functions end up calling acpigen_soc_{set,clear}_tx_gpio to
+ * make callbacks into SoC acpigen code.
+ *
+ * Returns 0 on success and -1 on error.
+ */
+int acpigen_set_enable_tx_gpio(struct acpi_ctx *ctx, u32 tx_state_val,
+			       const char *dw0_name, struct acpi_gpio *gpio,
+			       bool enable);
+
 #endif
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
index 265048e656..19b531e872 100644
--- a/lib/acpi/acpigen.c
+++ b/lib/acpi/acpigen.c
@@ -11,6 +11,7 @@
 #include <common.h>
 #include <dm.h>
 #include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
 #include <dm/acpi.h>
 
 /* CPU path format */
@@ -393,3 +394,82 @@ 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
+ *
+ * @ctx: ACPI context pointer
+ * @dw0_name: Name to use (e.g. "\\_SB.GPC0")
+ * @addr: GPIO pin configuration register address
+ *
+ * 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
+ */
+static void acpigen_get_dw0_in_local5(struct acpi_ctx *ctx,
+				      const char *dw0_name, ulong addr)
+{
+	acpigen_write_store(ctx);
+	acpigen_emit_namestring(ctx, dw0_name);
+	acpigen_write_integer(ctx, addr);
+	acpigen_emit_byte(ctx, LOCAL5_OP);
+}
+
+/**
+ * acpigen_set_gpio_val() - Set value of TX GPIO to on/off
+ *
+ * @ctx: ACPI context pointer
+ * @dw0_name: Name to use (e.g. "\\_SB.GPC0")
+ * @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_name, struct acpi_gpio *gpio,
+				bool val)
+{
+	acpigen_get_dw0_in_local5(ctx, dw0_name, gpio->pin0_addr);
+
+	if (val) {
+		/* Or (Local5, PAD_CFG0_TX_STATE, Local5) */
+		acpigen_write_or(ctx, LOCAL5_OP, tx_state_val, LOCAL5_OP);
+	} else {
+		/* Not (PAD_CFG0_TX_STATE, Local6) */
+		acpigen_write_not(ctx, tx_state_val, 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_name);
+	acpigen_write_integer(ctx, gpio->pin0_addr);
+	acpigen_emit_byte(ctx, LOCAL5_OP);
+
+	return 0;
+}
+
+/*
+ * Helper functions for enabling/disabling Tx GPIOs based on the GPIO
+ * polarity. These functions end up calling acpigen_{set,clear}_tx_gpio to
+ * make callbacks into SoC acpigen code.
+ *
+ * Returns 0 on success and -1 on error.
+ */
+int acpigen_set_enable_tx_gpio(struct acpi_ctx *ctx, u32 tx_state_val,
+			       const char *dw0_name, 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_name, gpio, set);
+	if (ret)
+		return log_msg_ret("call", ret);
+
+	return 0;
+}
diff --git a/test/dm/acpigen.c b/test/dm/acpigen.c
index c92f6cdb0b..06bdd63739 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -737,3 +737,57 @@ static int dm_test_acpi_power_res(struct unit_test_state *uts)
 	return 0;
 }
 DM_TEST(dm_test_acpi_power_res, 0);
+
+/* Test writing ACPI code to toggle a GPIO */
+static int dm_test_acpi_gpio_toggle(struct unit_test_state *uts)
+{
+	const uint addr = 0x80012;
+	const int txbit = BIT(2);
+	struct gpio_desc desc;
+	struct acpi_gpio gpio;
+	struct acpi_ctx *ctx;
+	struct udevice *dev;
+	u8 *ptr;
+
+	ut_assertok(alloc_context(&ctx));
+
+	ut_assertok(uclass_get_device(UCLASS_TEST_FDT, 0, &dev));
+	ut_asserteq_str("a-test", dev->name);
+	ut_assertok(gpio_request_by_name(dev, "test2-gpios", 2, &desc, 0));
+	ut_assertok(gpio_get_acpi(&desc, &gpio));
+
+	/* Spot-check the results - see sb_gpio_get_acpi() */
+	ptr = acpigen_get_current(ctx);
+	acpigen_set_enable_tx_gpio(ctx, txbit, "\\_SB.GPC0", &gpio, true);
+	acpigen_set_enable_tx_gpio(ctx, txbit, "\\_SB.GPC0", &gpio, false);
+
+	/* Since this GPIO is active low, we expect it to be cleared here */
+	ut_asserteq(STORE_OP, ptr[0]);
+	ut_asserteq_strn("_SB_GPC0", (char *)ptr + 3);
+	ut_asserteq(addr + desc.offset, get_unaligned((u32 *)(ptr + 0xc)));
+	ut_asserteq(LOCAL5_OP, ptr[0x10]);
+
+	ut_asserteq(NOT_OP, ptr[0x11]);
+	ut_asserteq(txbit, ptr[0x12]);
+	ut_asserteq(AND_OP, ptr[0x14]);
+	ut_asserteq_strn("_SB_GPC0", (char *)ptr + 0x1a);
+	ut_asserteq(addr + desc.offset, get_unaligned((u32 *)(ptr + 0x23)));
+	ut_asserteq(LOCAL5_OP, ptr[0x27]);
+
+	/* Now the second one, which should be set */
+	ut_asserteq_strn("_SB_GPC0", (char *)ptr + 0x2b);
+	ut_asserteq(addr + desc.offset, get_unaligned((u32 *)(ptr + 0x34)));
+	ut_asserteq(LOCAL5_OP, ptr[0x38]);
+
+	ut_asserteq(OR_OP, ptr[0x39]);
+	ut_asserteq(txbit, ptr[0x3b]);
+	ut_asserteq_strn("_SB_GPC0", (char *)ptr + 0x3f);
+	ut_asserteq(addr + desc.offset, get_unaligned((u32 *)(ptr + 0x48)));
+	ut_asserteq(LOCAL5_OP, ptr[0x4c]);
+	ut_asserteq(0x4d, acpigen_get_current(ctx) - ptr);
+
+	free_context(&ctx);
+
+	return 0;
+}
+DM_TEST(dm_test_acpi_gpio_toggle, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);
-- 
2.26.2.303.gf8c07b1a785-goog