[PATCH v3 3/8] wifi: ath10k: snoc: support powering on the device via pwrseq

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

The WCN39xx family of WiFi/BT chips incorporates a simple PMU, spreading
voltages over internal rails. Implement support for using powersequencer
for this family of ATH10k devices in addition to using regulators.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
---
 drivers/net/wireless/ath/ath10k/snoc.c | 53 ++++++++++++++++++++++++++++++++--
 drivers/net/wireless/ath/ath10k/snoc.h |  3 ++
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
index b3f6424c17d3..f72f236fb9eb 100644
--- a/drivers/net/wireless/ath/ath10k/snoc.c
+++ b/drivers/net/wireless/ath/ath10k/snoc.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: ISC
 /*
  * Copyright (c) 2018 The Linux Foundation. All rights reserved.
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
  */
 
 #include <linux/bits.h>
@@ -11,6 +12,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
+#include <linux/pwrseq/consumer.h>
 #include <linux/regulator/consumer.h>
 #include <linux/remoteproc/qcom_rproc.h>
 #include <linux/of_reserved_mem.h>
@@ -1023,10 +1025,14 @@ static int ath10k_hw_power_on(struct ath10k *ar)
 
 	ath10k_dbg(ar, ATH10K_DBG_SNOC, "soc power on\n");
 
-	ret = regulator_bulk_enable(ar_snoc->num_vregs, ar_snoc->vregs);
+	ret = pwrseq_power_on(ar_snoc->pwrseq);
 	if (ret)
 		return ret;
 
+	ret = regulator_bulk_enable(ar_snoc->num_vregs, ar_snoc->vregs);
+	if (ret)
+		goto pwrseq_off;
+
 	ret = clk_bulk_prepare_enable(ar_snoc->num_clks, ar_snoc->clks);
 	if (ret)
 		goto vreg_off;
@@ -1035,18 +1041,28 @@ static int ath10k_hw_power_on(struct ath10k *ar)
 
 vreg_off:
 	regulator_bulk_disable(ar_snoc->num_vregs, ar_snoc->vregs);
+pwrseq_off:
+	pwrseq_power_off(ar_snoc->pwrseq);
+
 	return ret;
 }
 
 static int ath10k_hw_power_off(struct ath10k *ar)
 {
 	struct ath10k_snoc *ar_snoc = ath10k_snoc_priv(ar);
+	int ret_seq = 0;
+	int ret_vreg;
 
 	ath10k_dbg(ar, ATH10K_DBG_SNOC, "soc power off\n");
 
 	clk_bulk_disable_unprepare(ar_snoc->num_clks, ar_snoc->clks);
 
-	return regulator_bulk_disable(ar_snoc->num_vregs, ar_snoc->vregs);
+	ret_vreg = regulator_bulk_disable(ar_snoc->num_vregs, ar_snoc->vregs);
+
+	if (ar_snoc->pwrseq)
+		ret_seq = pwrseq_power_off(ar_snoc->pwrseq);
+
+	return ret_vreg ? : ret_seq;
 }
 
 static void ath10k_snoc_wlan_disable(struct ath10k *ar)
@@ -1762,7 +1778,38 @@ static int ath10k_snoc_probe(struct platform_device *pdev)
 		goto err_release_resource;
 	}
 
-	ar_snoc->num_vregs = ARRAY_SIZE(ath10k_regulators);
+	/*
+	 * devm_pwrseq_get() can return -EPROBE_DEFER in two cases:
+	 * - it is not supposed to be used
+	 * - it is supposed to be used, but the driver hasn't probed yet.
+	 *
+	 * There is no simple way to distinguish between these two cases, but:
+	 * - if it is not supposed to be used, then regulator_bulk_get() will
+	 *   return all regulators as expected, continuing the probe
+	 * - if it is supposed to be used, but wasn't probed yet, we will get
+	 *   -EPROBE_DEFER from regulator_bulk_get() too.
+	 *
+	 * For backwards compatibility with DTs specifying regulators directly
+	 * rather than using the PMU device, ignore the defer error from
+	 * pwrseq.
+	 */
+	ar_snoc->pwrseq = devm_pwrseq_get(&pdev->dev, "wlan");
+	if (IS_ERR(ar_snoc->pwrseq)) {
+		ret = PTR_ERR(ar_snoc->pwrseq);
+		ar_snoc->pwrseq = NULL;
+		if (ret != -EPROBE_DEFER)
+			goto err_free_irq;
+
+		ar_snoc->num_vregs = ARRAY_SIZE(ath10k_regulators);
+	} else {
+		/*
+		 * The first regulator (vdd-0.8-cx-mx) is used to power on part
+		 * of the SoC rather than the PMU on WCN399x, the rest are
+		 * handled via pwrseq.
+		 */
+		ar_snoc->num_vregs = 1;
+	}
+
 	ar_snoc->vregs = devm_kcalloc(&pdev->dev, ar_snoc->num_vregs,
 				      sizeof(*ar_snoc->vregs), GFP_KERNEL);
 	if (!ar_snoc->vregs) {
diff --git a/drivers/net/wireless/ath/ath10k/snoc.h b/drivers/net/wireless/ath/ath10k/snoc.h
index d4bce1707696..1ecae34687c2 100644
--- a/drivers/net/wireless/ath/ath10k/snoc.h
+++ b/drivers/net/wireless/ath/ath10k/snoc.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: ISC */
 /*
  * Copyright (c) 2018 The Linux Foundation. All rights reserved.
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
  */
 
 #ifndef _SNOC_H_
@@ -53,6 +54,7 @@ enum ath10k_snoc_flags {
 };
 
 struct clk_bulk_data;
+struct pwrseq_desc;
 struct regulator_bulk_data;
 
 struct ath10k_snoc {
@@ -73,6 +75,7 @@ struct ath10k_snoc {
 	struct ath10k_snoc_ce_irq ce_irqs[CE_COUNT_MAX];
 	struct ath10k_ce ce;
 	struct timer_list rx_post_retry;
+	struct pwrseq_desc *pwrseq;
 	struct regulator_bulk_data *vregs;
 	size_t num_vregs;
 	struct clk_bulk_data *clks;

-- 
2.47.3