[PATCH v4 8/9] power: sequencing: pcie-m2: Add support for PCIe M.2 Key E connectors

Manivannan Sadhasivam via B4 Relay
2026-01-12T16:28:34Z

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Add support for handling the power sequence of the PCIe M.2 Key E
connectors. These connectors are used to attach the Wireless Connectivity
devices to the host machine including combinations of WiFi, BT, NFC using
interfaces such as PCIe/SDIO for WiFi, USB/UART for BT and I2C for NFC.

Currently, this driver supports only the PCIe interface for WiFi and UART
interface for BT. The driver also only supports driving the 3.3v/1.8v power
supplies and W_DISABLE{1/2}# GPIOs. The optional signals of the Key E
connectors are not currently supported.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
drivers/power/sequencing/Kconfig | 1 +
drivers/power/sequencing/pwrseq-pcie-m2.c | 110 ++++++++++++++++++++++++++++--
2 files changed, 104 insertions(+), 7 deletions(-)

diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
index f5fff84566ba..29bd204319cc 100644
--- a/drivers/power/sequencing/Kconfig
+++ b/drivers/power/sequencing/Kconfig
@@ -38,6 +38,7 @@ config POWER_SEQUENCING_TH1520_GPU
config POWER_SEQUENCING_PCIE_M2
tristate "PCIe M.2 connector power sequencing driver"
depends on OF || COMPILE_TEST
+ depends on PCI
help
Say Y here to enable the power sequencing driver for PCIe M.2
connectors. This driver handles the power sequencing for the M.2
diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
index e01e19123415..4b85a40d7692 100644
--- a/drivers/power/sequencing/pwrseq-pcie-m2.c
+++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
@@ -4,12 +4,16 @@
* Author: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
*/

+#include <linux/err.h>
#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_graph.h>
#include <linux/of_platform.h>
+#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/pwrseq/provider.h>
#include <linux/regulator/consumer.h>
@@ -25,17 +29,19 @@ struct pwrseq_pcie_m2_ctx {
const struct pwrseq_pcie_m2_pdata *pdata;
struct regulator_bulk_data *regs;
size_t num_vregs;
- struct notifier_block nb;
+ struct gpio_desc *w_disable1_gpio;
+ struct gpio_desc *w_disable2_gpio;
+ struct device *dev;
};

-static int pwrseq_pcie_m2_m_vregs_enable(struct pwrseq_device *pwrseq)
+static int pwrseq_pcie_m2_vregs_enable(struct pwrseq_device *pwrseq)
{
struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);

return regulator_bulk_enable(ctx->num_vregs, ctx->regs);
}

-static int pwrseq_pcie_m2_m_vregs_disable(struct pwrseq_device *pwrseq)
+static int pwrseq_pcie_m2_vregs_disable(struct pwrseq_device *pwrseq)
{
struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);

@@ -44,18 +50,84 @@ static int pwrseq_pcie_m2_m_vregs_disable(struct pwrseq_device *pwrseq)

static const struct pwrseq_unit_data pwrseq_pcie_m2_vregs_unit_data = {
.name = "regulators-enable",
- .enable = pwrseq_pcie_m2_m_vregs_enable,
- .disable = pwrseq_pcie_m2_m_vregs_disable,
+ .enable = pwrseq_pcie_m2_vregs_enable,
+ .disable = pwrseq_pcie_m2_vregs_disable,
};

-static const struct pwrseq_unit_data *pwrseq_pcie_m2_m_unit_deps[] = {
+static const struct pwrseq_unit_data *pwrseq_pcie_m2_unit_deps[] = {
&pwrseq_pcie_m2_vregs_unit_data,
NULL
};

+static int pwrseq_pci_m2_e_uart_enable(struct pwrseq_device *pwrseq)
+{
+ struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+ return gpiod_set_value_cansleep(ctx->w_disable2_gpio, 0);
+}
+
+static int pwrseq_pci_m2_e_uart_disable(struct pwrseq_device *pwrseq)
+{
+ struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+ return gpiod_set_value_cansleep(ctx->w_disable2_gpio, 1);
+}
+
+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,
+};
+
+static int pwrseq_pci_m2_e_pcie_enable(struct pwrseq_device *pwrseq)
+{
+ struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+ return gpiod_set_value_cansleep(ctx->w_disable1_gpio, 0);
+}
+
+static int pwrseq_pci_m2_e_pcie_disable(struct pwrseq_device *pwrseq)
+{
+ struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+ return gpiod_set_value_cansleep(ctx->w_disable1_gpio, 1);
+}
+
+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,
+};
+
static const struct pwrseq_unit_data pwrseq_pcie_m2_m_pcie_unit_data = {
.name = "pcie-enable",
- .deps = pwrseq_pcie_m2_m_unit_deps,
+ .deps = pwrseq_pcie_m2_unit_deps,
+};
+
+static int pwrseq_pcie_m2_e_pwup_delay(struct pwrseq_device *pwrseq)
+{
+ /*
+ * FIXME: This delay is only required for some Qcom WLAN/BT cards like
+ * WCN7850 and not for all devices. But currently, there is no way to
+ * identify the device model before enumeration.
+ */
+ msleep(50);
+
+ return 0;
+}
+
+static const struct pwrseq_target_data pwrseq_pcie_m2_e_uart_target_data = {
+ .name = "uart",
+ .unit = &pwrseq_pcie_m2_e_uart_unit_data,
+ .post_enable = pwrseq_pcie_m2_e_pwup_delay,
+};
+
+static const struct pwrseq_target_data pwrseq_pcie_m2_e_pcie_target_data = {
+ .name = "pcie",
+ .unit = &pwrseq_pcie_m2_e_pcie_unit_data,
+ .post_enable = pwrseq_pcie_m2_e_pwup_delay,
};

static const struct pwrseq_target_data pwrseq_pcie_m2_m_pcie_target_data = {
@@ -63,11 +135,21 @@ static const struct pwrseq_target_data pwrseq_pcie_m2_m_pcie_target_data = {
.unit = &pwrseq_pcie_m2_m_pcie_unit_data,
};

+static const struct pwrseq_target_data *pwrseq_pcie_m2_e_targets[] = {
+ &pwrseq_pcie_m2_e_pcie_target_data,
+ &pwrseq_pcie_m2_e_uart_target_data,
+ NULL
+};
+
static const struct pwrseq_target_data *pwrseq_pcie_m2_m_targets[] = {
&pwrseq_pcie_m2_m_pcie_target_data,
NULL
};

+static const struct pwrseq_pcie_m2_pdata pwrseq_pcie_m2_e_of_data = {
+ .targets = pwrseq_pcie_m2_e_targets,
+};
+
static const struct pwrseq_pcie_m2_pdata pwrseq_pcie_m2_m_of_data = {
.targets = pwrseq_pcie_m2_m_targets,
};
@@ -126,6 +208,16 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
return dev_err_probe(dev, ret,
"Failed to get all regulators\n");

+ ctx->w_disable1_gpio = devm_gpiod_get_optional(dev, "w-disable1", GPIOD_OUT_HIGH);
+ if (IS_ERR(ctx->w_disable1_gpio))
+ return dev_err_probe(dev, PTR_ERR(ctx->w_disable1_gpio),
+ "Failed to get the W_DISABLE_1# GPIO\n");
+
+ ctx->w_disable2_gpio = devm_gpiod_get_optional(dev, "w-disable2", GPIOD_OUT_HIGH);
+ if (IS_ERR(ctx->w_disable2_gpio))
+ return dev_err_probe(dev, PTR_ERR(ctx->w_disable2_gpio),
+ "Failed to get the W_DISABLE_2# GPIO\n");
+
ctx->num_vregs = ret;

ret = devm_add_action_or_reset(dev, pwrseq_pcie_free_resources, ctx);
@@ -151,6 +243,10 @@ static const struct of_device_id pwrseq_pcie_m2_of_match[] = {
.compatible = "pcie-m2-m-connector",
.data = &pwrseq_pcie_m2_m_of_data,
},
+ {
+ .compatible = "pcie-m2-e-connector",
+ .data = &pwrseq_pcie_m2_e_of_data,
+ },
{ }
};
MODULE_DEVICE_TABLE(of, pwrseq_pcie_m2_of_match);

--
2.48.1