sandbox: cros-ec: Add tests for the Chromium OS EC PWM driver

This patch adds a limited pulse-width modulator to sandbox's Chromium OS
Embedded Controller emulation. The emulated PWM device supports multiple
channels but can only set a duty cycle for each, as the actual EC
doesn't expose any functionality or information other than that. Though
the EC supports specifying the PWM channel by its type (e.g. display
backlight, keyboard backlight), this is not implemented in the emulation
as nothing in U-Boot uses this type specification.

This emulated PWM device is then used to test the Chromium OS PWM driver
in sandbox. Adding the required device node to the sandbox test
device-tree unfortunately makes it the first PWM device, so this also
touches some other tests to make sure they still use the sandbox PWM.

Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/sandbox/dts/test.dts b/arch/sandbox/dts/test.dts
index 8e7eaf2..d85bb46 100644
--- a/arch/sandbox/dts/test.dts
+++ b/arch/sandbox/dts/test.dts
@@ -139,6 +139,12 @@
 				size = <0x10000>;
 			};
 		};
+
+		cros_ec_pwm: cros-ec-pwm {
+			compatible = "google,cros-ec-pwm";
+			#pwm-cells = <1>;
+		};
+
 	};
 
 	dsi_host: dsi_host {
diff --git a/arch/sandbox/include/asm/test.h b/arch/sandbox/include/asm/test.h
index 1cb960a..dab1a4e 100644
--- a/arch/sandbox/include/asm/test.h
+++ b/arch/sandbox/include/asm/test.h
@@ -275,4 +275,14 @@
  */
 void sandbox_cros_ec_set_test_flags(struct udevice *dev, uint flags);
 
+/**
+ * sandbox_cros_ec_get_pwm_duty() - Get EC PWM config for testing purposes
+ *
+ * @dev: Device to check
+ * @index: PWM channel index
+ * @duty: Current duty cycle in 0..EC_PWM_MAX_DUTY range.
+ * @return 0 if OK, -ENOSPC if the PWM number is invalid
+ */
+int sandbox_cros_ec_get_pwm_duty(struct udevice *dev, uint index, uint *duty);
+
 #endif
diff --git a/configs/sandbox64_defconfig b/configs/sandbox64_defconfig
index a8bb560..674b660 100644
--- a/configs/sandbox64_defconfig
+++ b/configs/sandbox64_defconfig
@@ -188,6 +188,7 @@
 CONFIG_DM_REGULATOR_SANDBOX=y
 CONFIG_REGULATOR_TPS65090=y
 CONFIG_DM_PWM=y
+CONFIG_PWM_CROS_EC=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
 CONFIG_REMOTEPROC_SANDBOX=y
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index f16e2d5..df14506 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -226,6 +226,7 @@
 CONFIG_REGULATOR_TPS65090=y
 CONFIG_DM_REGULATOR_SCMI=y
 CONFIG_DM_PWM=y
+CONFIG_PWM_CROS_EC=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
 CONFIG_REMOTEPROC_SANDBOX=y
diff --git a/configs/sandbox_flattree_defconfig b/configs/sandbox_flattree_defconfig
index 1c39a54..aaa6720 100644
--- a/configs/sandbox_flattree_defconfig
+++ b/configs/sandbox_flattree_defconfig
@@ -165,6 +165,7 @@
 CONFIG_DM_REGULATOR_SANDBOX=y
 CONFIG_REGULATOR_TPS65090=y
 CONFIG_DM_PWM=y
+CONFIG_PWM_CROS_EC=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
 CONFIG_REMOTEPROC_SANDBOX=y
diff --git a/configs/sandbox_noinst_defconfig b/configs/sandbox_noinst_defconfig
index 9f415cd..3dc3a36 100644
--- a/configs/sandbox_noinst_defconfig
+++ b/configs/sandbox_noinst_defconfig
@@ -181,6 +181,7 @@
 CONFIG_DM_REGULATOR_SANDBOX=y
 CONFIG_REGULATOR_TPS65090=y
 CONFIG_DM_PWM=y
+CONFIG_PWM_CROS_EC=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
 CONFIG_REMOTEPROC_SANDBOX=y
diff --git a/configs/sandbox_spl_defconfig b/configs/sandbox_spl_defconfig
index 8bc1373..c7d15de 100644
--- a/configs/sandbox_spl_defconfig
+++ b/configs/sandbox_spl_defconfig
@@ -183,6 +183,7 @@
 CONFIG_DM_REGULATOR_SANDBOX=y
 CONFIG_REGULATOR_TPS65090=y
 CONFIG_DM_PWM=y
+CONFIG_PWM_CROS_EC=y
 CONFIG_PWM_SANDBOX=y
 CONFIG_RAM=y
 CONFIG_REMOTEPROC_SANDBOX=y
diff --git a/drivers/misc/cros_ec_sandbox.c b/drivers/misc/cros_ec_sandbox.c
index bc01df0..db5e3b0 100644
--- a/drivers/misc/cros_ec_sandbox.c
+++ b/drivers/misc/cros_ec_sandbox.c
@@ -64,6 +64,7 @@
 
 enum {
 	VSTORE_SLOT_COUNT	= 4,
+	PWM_CHANNEL_COUNT	= 4,
 };
 
 struct vstore_slot {
@@ -71,6 +72,10 @@
 	u8 data[EC_VSTORE_SLOT_SIZE];
 };
 
+struct ec_pwm_channel {
+	uint duty;	/* not ns, EC_PWM_MAX_DUTY = 100% */
+};
+
 /**
  * struct ec_state - Information about the EC state
  *
@@ -85,6 +90,7 @@
  * @recovery_req: Keyboard recovery requested
  * @test_flags: Flags that control behaviour for tests
  * @slot_locked: Locked vstore slots (mask)
+ * @pwm: Information per PWM channel
  */
 struct ec_state {
 	u8 vbnv_context[EC_VBNV_BLOCK_SIZE_V2];
@@ -98,6 +104,7 @@
 	bool recovery_req;
 	uint test_flags;
 	struct vstore_slot slot[VSTORE_SLOT_COUNT];
+	struct ec_pwm_channel pwm[PWM_CHANNEL_COUNT];
 } s_state, *g_state;
 
 /**
@@ -554,6 +561,33 @@
 		len = sizeof(*resp);
 		break;
 	}
+	case EC_CMD_PWM_GET_DUTY: {
+		const struct ec_params_pwm_get_duty *req = req_data;
+		struct ec_response_pwm_get_duty *resp = resp_data;
+		struct ec_pwm_channel *pwm;
+
+		if (req->pwm_type != EC_PWM_TYPE_GENERIC)
+			return -EINVAL;
+		if (req->index >= PWM_CHANNEL_COUNT)
+			return -EINVAL;
+		pwm = &ec->pwm[req->index];
+		resp->duty = pwm->duty;
+		len = sizeof(*resp);
+		break;
+	}
+	case EC_CMD_PWM_SET_DUTY: {
+		const struct ec_params_pwm_set_duty *req = req_data;
+		struct ec_pwm_channel *pwm;
+
+		if (req->pwm_type != EC_PWM_TYPE_GENERIC)
+			return -EINVAL;
+		if (req->index >= PWM_CHANNEL_COUNT)
+			return -EINVAL;
+		pwm = &ec->pwm[req->index];
+		pwm->duty = req->duty;
+		len = 0;
+		break;
+	}
 	default:
 		printf("   ** Unknown EC command %#02x\n", req_hdr->command);
 		return -1;
@@ -619,6 +653,19 @@
 	ec->test_flags = flags;
 }
 
+int sandbox_cros_ec_get_pwm_duty(struct udevice *dev, uint index, uint *duty)
+{
+	struct ec_state *ec = dev_get_priv(dev);
+	struct ec_pwm_channel *pwm;
+
+	if (index >= PWM_CHANNEL_COUNT)
+		return -ENOSPC;
+	pwm = &ec->pwm[index];
+	*duty = pwm->duty;
+
+	return 0;
+}
+
 int cros_ec_probe(struct udevice *dev)
 {
 	struct ec_state *ec = dev_get_priv(dev);
diff --git a/test/cmd/pwm.c b/test/cmd/pwm.c
index 5343af8..2fc0b5e 100644
--- a/test/cmd/pwm.c
+++ b/test/cmd/pwm.c
@@ -18,16 +18,20 @@
 {
 	struct udevice *dev;
 
+	/* cros-ec-pwm */
 	ut_assertok(uclass_get_device(UCLASS_PWM, 0, &dev));
 	ut_assertnonnull(dev);
 
 	ut_assertok(console_record_reset_enable());
 
 	/* pwm <invert> <pwm_dev_num> <channel> <polarity> */
-	ut_assertok(run_command("pwm invert 0 0 1", 0));
+	/* cros-ec-pwm doesn't support invert */
+	ut_asserteq(1, run_command("pwm invert 0 0 1", 0));
+	ut_assert_nextline("error(-38)")
 	ut_assert_console_end();
 
-	ut_assertok(run_command("pwm invert 0 0 0", 0));
+	ut_asserteq(1, run_command("pwm invert 0 0 0", 0));
+	ut_assert_nextline("error(-38)")
 	ut_assert_console_end();
 
 	/* pwm <config> <pwm_dev_num> <channel> <period_ns> <duty_ns> */
@@ -41,6 +45,30 @@
 	ut_assertok(run_command("pwm disable 0 0", 0));
 	ut_assert_console_end();
 
+	/* sandbox-pwm */
+	ut_assertok(uclass_get_device(UCLASS_PWM, 1, &dev));
+	ut_assertnonnull(dev);
+
+	ut_assertok(console_record_reset_enable());
+
+	/* pwm <invert> <pwm_dev_num> <channel> <polarity> */
+	ut_assertok(run_command("pwm invert 1 0 1", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("pwm invert 1 0 0", 0));
+	ut_assert_console_end();
+
+	/* pwm <config> <pwm_dev_num> <channel> <period_ns> <duty_ns> */
+	ut_assertok(run_command("pwm config 1 0 10 50", 0));
+	ut_assert_console_end();
+
+	/* pwm <enable/disable> <pwm_dev_num> <channel> */
+	ut_assertok(run_command("pwm enable 1 0", 0));
+	ut_assert_console_end();
+
+	ut_assertok(run_command("pwm disable 1 0", 0));
+	ut_assert_console_end();
+
 	return 0;
 }
 
diff --git a/test/dm/Makefile b/test/dm/Makefile
index c964461..9ef9171 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -30,6 +30,7 @@
 obj-$(CONFIG_CLK) += clk.o clk_ccf.o
 obj-$(CONFIG_CPU) += cpu.o
 obj-$(CONFIG_CROS_EC) += cros_ec.o
+obj-$(CONFIG_PWM_CROS_EC) += cros_ec_pwm.o
 obj-$(CONFIG_DEVRES) += devres.o
 obj-$(CONFIG_DMA) += dma.o
 obj-$(CONFIG_VIDEO_MIPI_DSI) += dsi_host.o
diff --git a/test/dm/cros_ec_pwm.c b/test/dm/cros_ec_pwm.c
new file mode 100644
index 0000000..f8d6e1e
--- /dev/null
+++ b/test/dm/cros_ec_pwm.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <common.h>
+#include <cros_ec.h>
+#include <dm.h>
+#include <pwm.h>
+#include <asm/test.h>
+#include <dm/test.h>
+#include <test/test.h>
+#include <test/ut.h>
+
+static int dm_test_cros_ec_pwm(struct unit_test_state *uts)
+{
+	struct udevice *pwm;
+	struct udevice *ec;
+	uint duty;
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_PWM, "cros-ec-pwm", &pwm));
+	ut_assertnonnull(pwm);
+	ec = dev_get_parent(pwm);
+	ut_assertnonnull(ec);
+
+	ut_assertok(pwm_set_config(pwm, 0, 100, 50));
+	ut_assertok(pwm_set_enable(pwm, 0, true));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 0, &duty));
+	ut_asserteq(50 * EC_PWM_MAX_DUTY / 100, duty);
+
+	ut_assertok(pwm_set_config(pwm, 0, 15721, 2719));
+	ut_assertok(pwm_set_enable(pwm, 0, true));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 0, &duty));
+	ut_asserteq(2719 * EC_PWM_MAX_DUTY / 15721, duty);
+
+	ut_assertok(pwm_set_enable(pwm, 0, false));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 0, &duty));
+	ut_asserteq(0, duty);
+
+	ut_assertok(pwm_set_enable(pwm, 0, true));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 0, &duty));
+	ut_asserteq(2719 * EC_PWM_MAX_DUTY / 15721, duty);
+
+	ut_assertok(pwm_set_config(pwm, 1, 1000, 0));
+	ut_assertok(pwm_set_enable(pwm, 1, true));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 1, &duty));
+	ut_asserteq(0, duty);
+
+	ut_assertok(pwm_set_config(pwm, 2, 1000, 1024));
+	ut_assertok(pwm_set_enable(pwm, 2, true));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 2, &duty));
+	ut_asserteq(EC_PWM_MAX_DUTY, duty);
+
+	ut_assertok(pwm_set_config(pwm, 3, EC_PWM_MAX_DUTY, 0xABCD));
+	ut_assertok(pwm_set_enable(pwm, 3, true));
+	ut_assertok(sandbox_cros_ec_get_pwm_duty(ec, 3, &duty));
+	ut_asserteq(0xABCD, duty);
+
+	ut_asserteq(-EINVAL, pwm_set_enable(pwm, 4, true));
+
+	return 0;
+}
+DM_TEST(dm_test_cros_ec_pwm, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
diff --git a/test/dm/panel.c b/test/dm/panel.c
index 49f5ac7..4d435a0 100644
--- a/test/dm/panel.c
+++ b/test/dm/panel.c
@@ -28,7 +28,7 @@
 	bool polarity;
 
 	ut_assertok(uclass_first_device_err(UCLASS_PANEL, &dev));
-	ut_assertok(uclass_first_device_err(UCLASS_PWM, &pwm));
+	ut_assertok(uclass_get_device_by_name(UCLASS_PWM, "pwm", &pwm));
 	ut_assertok(uclass_get_device(UCLASS_GPIO, 1, &gpio));
 	ut_assertok(regulator_get_by_platname("VDD_EMMC_1.8V", &reg));
 	ut_assertok(sandbox_pwm_get_config(pwm, 0, &period_ns, &duty_ns,
diff --git a/test/dm/pwm.c b/test/dm/pwm.c
index b624cf3..dff626c 100644
--- a/test/dm/pwm.c
+++ b/test/dm/pwm.c
@@ -20,7 +20,7 @@
 	bool enable;
 	bool polarity;
 
-	ut_assertok(uclass_get_device(UCLASS_PWM, 0, &dev));
+	ut_assertok(uclass_get_device_by_name(UCLASS_PWM, "pwm", &dev));
 	ut_assertnonnull(dev);
 	ut_assertok(pwm_set_config(dev, 0, 100, 50));
 	ut_assertok(pwm_set_enable(dev, 0, true));
@@ -35,8 +35,10 @@
 	ut_asserteq(period_ns, 4096);
 	ut_asserteq(duty_ns, 50 * 4096 / 100);
 
+	ut_assertok(uclass_get_device(UCLASS_PWM, 0, &dev));
 	ut_assertok(uclass_get_device(UCLASS_PWM, 1, &dev));
-	ut_asserteq(-ENODEV, uclass_get_device(UCLASS_PWM, 2, &dev));
+	ut_assertok(uclass_get_device(UCLASS_PWM, 2, &dev));
+	ut_asserteq(-ENODEV, uclass_get_device(UCLASS_PWM, 3, &dev));
 
 	return 0;
 }