drivers: Defer probe if firmware is not ready

Driver needs ZynqMP firmware interface to call EEMI
APIs. In case firmware is not ready, dependent drivers
should wait until the firmware is ready.

Signed-off-by: Rajan Vaja <[e-mail]>
Signed-off-by: Jolly Shah <[e-mail]>
Signed-off-by: Michal Simek <[e-mail]>

Documentation/xilinx/eemi.txt

···
 	int ret;
 
 	eemi_ops = zynqmp_pm_get_eemi_ops();
-	if (!eemi_ops)
-		return -ENXIO;
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	ret = eemi_ops->query_data(qdata, ret_payload);
 

drivers/clk/zynqmp/clkc.c

···
 	struct device *dev = &pdev->dev;
 
 	eemi_ops = zynqmp_pm_get_eemi_ops();
-	if (!eemi_ops)
-		return -ENXIO;
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	ret = zynqmp_clk_setup(dev->of_node);
 

drivers/firmware/xilinx/zynqmp-debug.c

···
 	int ret;
 	struct zynqmp_pm_query_data qdata = {0};
 
-	if (!eemi_ops)
-		return -ENXIO;
-
 	switch (pm_id) {
 	case PM_GET_API_VERSION:
 		ret = eemi_ops->get_api_version(&pm_api_version);

drivers/firmware/xilinx/zynqmp.c

···
 #include <linux/firmware/xlnx-zynqmp.h>
 #include "zynqmp-debug.h"
 
+static const struct zynqmp_eemi_ops *eemi_ops_tbl;
+
 static const struct mfd_cell firmware_devs[] = {
 	{
 		.name = "zynqmp_power_controller",
···
  */
 const struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
 {
-	return &eemi_ops;
+	if (eemi_ops_tbl)
+		return eemi_ops_tbl;
+	else
+		return ERR_PTR(-EPROBE_DEFER);
+
 }
 EXPORT_SYMBOL_GPL(zynqmp_pm_get_eemi_ops);
 
···
 
 	pr_info("%s Trustzone version v%d.%d\n", __func__,
 		pm_tz_version >> 16, pm_tz_version & 0xFFFF);
+
+	/* Assign eemi_ops_table */
+	eemi_ops_tbl = &eemi_ops;
 
 	zynqmp_pm_api_debugfs_init();
 

drivers/nvmem/zynqmp_nvmem.c

···
 	struct nvmem_device *nvmem;
 };
 
+static const struct zynqmp_eemi_ops *eemi_ops;
+
 static int zynqmp_nvmem_read(void *context, unsigned int offset,
 			     void *val, size_t bytes)
 {
···
 	int idcode, version;
 	struct zynqmp_nvmem_data *priv = context;
 
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
-
-	if (!eemi_ops || !eemi_ops->get_chipid)
+	if (!eemi_ops->get_chipid)
 		return -ENXIO;
 
 	ret = eemi_ops->get_chipid(&idcode, &version);
···
 	priv = devm_kzalloc(dev, sizeof(struct zynqmp_nvmem_data), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
+
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	priv->dev = dev;
 	econfig.dev = dev;

drivers/reset/reset-zynqmp.c

···
 	if (!priv)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, priv);
-
 	priv->eemi_ops = zynqmp_pm_get_eemi_ops();
-	if (!priv->eemi_ops)
-		return -ENXIO;
+	if (IS_ERR(priv->eemi_ops))
+		return PTR_ERR(priv->eemi_ops);
+
+	platform_set_drvdata(pdev, priv);
 
 	priv->rcdev.ops = &zynqmp_reset_ops;
 	priv->rcdev.owner = THIS_MODULE;

drivers/soc/xilinx/zynqmp_pm_domains.c

···
 /* Flag stating if PM nodes mapped to the PM domain has been requested */
 #define ZYNQMP_PM_DOMAIN_REQUESTED	BIT(0)
 
+static const struct zynqmp_eemi_ops *eemi_ops;
+
 /**
  * struct zynqmp_pm_domain - Wrapper around struct generic_pm_domain
  * @gpd:		Generic power domain
···
 {
 	int ret;
 	struct zynqmp_pm_domain *pd;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->set_requirement)
+	if (!eemi_ops->set_requirement)
 		return -ENXIO;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
···
 	struct zynqmp_pm_domain *pd;
 	u32 capabilities = 0;
 	bool may_wakeup;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->set_requirement)
+	if (!eemi_ops->set_requirement)
 		return -ENXIO;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
···
 {
 	int ret;
 	struct zynqmp_pm_domain *pd;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->request_node)
+	if (!eemi_ops->request_node)
 		return -ENXIO;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
···
 {
 	int ret;
 	struct zynqmp_pm_domain *pd;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->release_node)
+	if (!eemi_ops->release_node)
 		return;
 
 	pd = container_of(domain, struct zynqmp_pm_domain, gpd);
···
 	struct generic_pm_domain **domains;
 	struct zynqmp_pm_domain *pd;
 	struct device *dev = &pdev->dev;
+
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	pd = devm_kcalloc(dev, ZYNQMP_NUM_DOMAINS, sizeof(*pd), GFP_KERNEL);
 	if (!pd)

drivers/soc/xilinx/zynqmp_power.c

···
 };
 
 static enum pm_suspend_mode suspend_mode = PM_SUSPEND_MODE_STD;
+static const struct zynqmp_eemi_ops *eemi_ops;
 
 enum pm_api_cb_id {
 	PM_INIT_SUSPEND_CB = 30,
···
 				  const char *buf, size_t count)
 {
 	int md, ret = -EINVAL;
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
 
-	if (!eemi_ops || !eemi_ops->set_suspend_mode)
+	if (!eemi_ops->set_suspend_mode)
 		return ret;
 
 	for (md = PM_SUSPEND_MODE_FIRST; md < ARRAY_SIZE(suspend_modes); md++)
···
 	int ret, irq;
 	u32 pm_api_version;
 
-	const struct zynqmp_eemi_ops *eemi_ops = zynqmp_pm_get_eemi_ops();
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
-	if (!eemi_ops || !eemi_ops->get_api_version || !eemi_ops->init_finalize)
+	if (!eemi_ops->get_api_version || !eemi_ops->init_finalize)
 		return -ENXIO;
 
 	eemi_ops->init_finalize();

drivers/spi/spi-zynqmp-gqspi.c

···
 
 #define SPI_AUTOSUSPEND_TIMEOUT		3000
 enum mode_type {GQSPI_MODE_IO, GQSPI_MODE_DMA};
+static const struct zynqmp_eemi_ops *eemi_ops;
 
 /**
  * struct zynqmp_qspi - Defines qspi driver instance
···
 	struct zynqmp_qspi *xqspi;
 	struct resource *res;
 	struct device *dev = &pdev->dev;
+
+	eemi_ops = zynqmp_pm_get_eemi_ops();
+	if (IS_ERR(eemi_ops))
+		return PTR_ERR(eemi_ops);
 
 	master = spi_alloc_master(&pdev->dev, sizeof(*xqspi));
 	if (!master)

include/linux/firmware/xlnx-zynqmp.h

···
 #else
 static inline struct zynqmp_eemi_ops *zynqmp_pm_get_eemi_ops(void)
 {
-	return NULL;
+	return ERR_PTR(-ENODEV);
 }
 #endif