[PATCH v3 13/14] power: sequencing: pcie-m2: Add support for PCIe M.2 Key E connectors

[Manivannan Sadhasivam via B4 Relay <devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org>]

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 | 111 ++++++++++++++++++++++++++++--
 2 files changed, 105 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..ad94090bbdb2 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 +29,20 @@ 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 +51,84 @@ 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 +136,21 @@ 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 +209,16 @@ 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 +244,10 @@ 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