[PATCH v3 04/11] power: sequencing: pcie-m2: Report power controllability

[Loic Poulain]

The M.2 Key E connector gates its functions through the W_DISABLE1#
(PCIe/WiFi) and W_DISABLE2# (Bluetooth) signals. When a signal is not
routed to a host GPIO, the corresponding enable/disable callbacks are
no-ops, so the host cannot gate that function's power on its own.

Implement the per-unit .is_controllable() callback on the "uart-enable"
and "pcie-enable" units so that consumers can query this per instance
(based on the runtime presence of the W_DISABLE2#/W_DISABLE1# GPIOs) via
pwrseq_power_is_controllable().

Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxxxxxxxx>
---
 drivers/power/sequencing/pwrseq-pcie-m2.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
index e3ba9169144dabbf0c553c0a4302c3b511fcaaa1..4bcd5078609da1be966ab30c73cffae5e578934f 100644
--- a/drivers/power/sequencing/pwrseq-pcie-m2.c
+++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
@@ -84,11 +84,24 @@ static int pwrseq_pci_m2_e_uart_disable(struct pwrseq_device *pwrseq)
 	return gpiod_set_value_cansleep(ctx->w_disable2_gpio, 1);
 }
 
+static bool pwrseq_pci_m2_e_uart_is_controllable(struct pwrseq_device *pwrseq)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	/*
+	 * The UART enable is driven through the W_DISABLE2# line. When it is not
+	 * wired up on this connector the enable/disable callbacks are no-ops, so
+	 * the host cannot gate the Bluetooth function on its own.
+	 */
+	return !!ctx->w_disable2_gpio;
+}
+
 static const struct pwrseq_unit_data pwrseq_pcie_m2_e_uart_unit_data = {
 	.name = "uart-enable",
 	.deps = pwrseq_pcie_m2_unit_deps,
 	.enable = pwrseq_pci_m2_e_uart_enable,
 	.disable = pwrseq_pci_m2_e_uart_disable,
+	.is_controllable = pwrseq_pci_m2_e_uart_is_controllable,
 };
 
 static int pwrseq_pci_m2_e_pcie_enable(struct pwrseq_device *pwrseq)
@@ -105,11 +118,24 @@ static int pwrseq_pci_m2_e_pcie_disable(struct pwrseq_device *pwrseq)
 	return gpiod_set_value_cansleep(ctx->w_disable1_gpio, 1);
 }
 
+static bool pwrseq_pci_m2_e_pcie_is_controllable(struct pwrseq_device *pwrseq)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	/*
+	 * The PCIe/WiFi enable is driven through the W_DISABLE1# line. When it
+	 * is not wired up on this connector the enable/disable callbacks are
+	 * no-ops, so the host cannot gate the PCIe/WiFi function on its own.
+	 */
+	return !!ctx->w_disable1_gpio;
+}
+
 static const struct pwrseq_unit_data pwrseq_pcie_m2_e_pcie_unit_data = {
 	.name = "pcie-enable",
 	.deps = pwrseq_pcie_m2_unit_deps,
 	.enable = pwrseq_pci_m2_e_pcie_enable,
 	.disable = pwrseq_pci_m2_e_pcie_disable,
+	.is_controllable = pwrseq_pci_m2_e_pcie_is_controllable,
 };
 
 static const struct pwrseq_unit_data pwrseq_pcie_m2_m_pcie_unit_data = {

-- 
2.34.1