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From: Maciej Purski <m.purski@samsung.com>
To: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Cc: Mark Brown <broonie@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Doug Anderson <dianders@chromium.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Maciej Purski <m.purski@samsung.com>
Subject: [PATCH v4 5/7] regulator: core: Resolve coupled regulators
Date: Mon, 22 Jan 2018 15:30:10 +0100	[thread overview]
Message-ID: <1516631412-17542-6-git-send-email-m.purski@samsung.com> (raw)
In-Reply-To: <1516631412-17542-1-git-send-email-m.purski@samsung.com>

On Odroid XU3/4 and other Exynos5422 based boards there is a case, that
different devices on the board are supplied by different regulators
with non-fixed voltages. If one of these devices temporarily requires
higher voltage, there might occur a situation that the spread between
two devices' voltages is so high, that there is a risk of changing
'high' and 'low' states on the interconnection between devices powered
by those regulators.

Fill coupling descriptor with data obtained from DTS using previously
defined of_functions. Fail to register a regulator, if some data
inconsistency occurs. If some coupled regulators are not yet registered,
don't fail to register, but try to resolve them in late init call.

Signed-off-by: Maciej Purski <m.purski@samsung.com>
---
 drivers/regulator/core.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 1118527..3628949 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3945,6 +3945,88 @@ static int regulator_register_resolve_supply(struct device *dev, void *data)
 	return 0;
 }
 
+static int regulator_fill_coupling_array(struct regulator_dev *rdev)
+{
+	struct coupling_desc *c_desc = &rdev->coupling_desc;
+	int n_coupled = c_desc->n_coupled;
+	struct regulator_dev *c_rdev;
+	int i;
+
+	for (i = 1; i < n_coupled; i++) {
+		/* already resolved */
+		if (c_desc->coupled_rdevs[i])
+			continue;
+
+		c_rdev = of_parse_coupled_regulator(rdev, i - 1);
+
+		if (c_rdev) {
+			c_desc->coupled_rdevs[i] = c_rdev;
+			c_desc->n_resolved++;
+		}
+	}
+
+	if (rdev->coupling_desc.n_resolved < n_coupled)
+		return -1;
+	else
+		return 0;
+}
+
+static int regulator_register_fill_coupling_array(struct device *dev,
+						  void *data)
+{
+	struct regulator_dev *rdev = dev_to_rdev(dev);
+
+	if (regulator_fill_coupling_array(rdev))
+		rdev_dbg(rdev, "unable to resolve coupling\n");
+
+	return 0;
+}
+
+static int regulator_resolve_coupling(struct regulator_dev *rdev)
+{
+	int n_phandles = of_get_n_coupled(rdev);
+
+	if (n_phandles + 1 > MAX_COUPLED) {
+		rdev_err(rdev, "too many regulators coupled\n");
+		return -EPERM;
+	}
+
+	/*
+	 * Every regulator should always have coupling descriptor filled with
+	 * at least pointer to itself.
+	 */
+	rdev->coupling_desc.coupled_rdevs[0] = rdev;
+	rdev->coupling_desc.n_coupled = n_phandles + 1;
+	rdev->coupling_desc.n_resolved++;
+
+	/* regulator isn't coupled */
+	if (n_phandles == 0)
+		return 0;
+
+	/* regulator, which can't change its voltage, can't be coupled */
+	if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_VOLTAGE)) {
+		rdev_err(rdev, "voltage operation not allowed\n");
+		return -EPERM;
+	}
+
+	if (rdev->constraints->max_spread <= 0) {
+		rdev_err(rdev, "wrong max_spread value\n");
+		return -EPERM;
+	}
+
+	if (!of_check_coupling_data(rdev))
+		return -EPERM;
+
+	/*
+	 * After everything has been checked, try to fill rdevs array
+	 * with pointers to regulators parsed from device tree. If some
+	 * regulators are not registered yet, retry in late init call
+	 */
+	regulator_fill_coupling_array(rdev);
+
+	return 0;
+}
+
 /**
  * regulator_register - register regulator
  * @regulator_desc: regulator to register
@@ -4077,6 +4159,13 @@ regulator_register(const struct regulator_desc *regulator_desc,
 	if (ret < 0)
 		goto wash;
 
+	mutex_lock(&regulator_list_mutex);
+	ret = regulator_resolve_coupling(rdev);
+	mutex_unlock(&regulator_list_mutex);
+
+	if (ret != 0)
+		goto wash;
+
 	/* add consumers devices */
 	if (init_data) {
 		mutex_lock(&regulator_list_mutex);
@@ -4565,6 +4654,9 @@ static int __init regulator_init_complete(void)
 	class_for_each_device(&regulator_class, NULL, NULL,
 			      regulator_late_cleanup);
 
+	class_for_each_device(&regulator_class, NULL, NULL,
+			      regulator_register_fill_coupling_array);
+
 	return 0;
 }
 late_initcall_sync(regulator_init_complete);
-- 
2.7.4

  parent reply	other threads:[~2018-01-22 14:30 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20180122143019eucas1p213b852c98cde3fb8a77b96ab0d372ee6@eucas1p2.samsung.com>
2018-01-22 14:30 ` [PATCH v4 0/7] Add coupled regulators mechanism Maciej Purski
     [not found]   ` <CGME20180122143029eucas1p284202b6e60a86b428b3aa1e6eef62bda@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 1/7] regulator: core: Move of_find_regulator_by_node() to of_regulator.c Maciej Purski
     [not found]   ` <CGME20180122143030eucas1p2eb1054dd14902eb0be83e5c9efb11d98@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 2/7] regulator: core: Refactor regulator_list_voltage() Maciej Purski
2018-01-26 17:35       ` Applied "regulator: core: Refactor regulator_list_voltage()" to the regulator tree Mark Brown
     [not found]   ` <CGME20180122143031eucas1p205647b3821760ad7e7a3bef5f8873d14@eucas1p2.samsung.com>
     [not found]     ` <1516631412-17542-1-git-send-email-m.purski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2018-01-22 14:30       ` [PATCH v4 3/7] regulator: bindings: Add properties for coupled regulators Maciej Purski
2018-01-22 14:30       ` [PATCH v4 6/7] regulator: core: Add voltage balancing mechanism Maciej Purski
2018-03-02 12:55         ` Applied "regulator: core: Add voltage balancing mechanism" to the regulator tree Mark Brown
2018-05-17 16:41         ` Mark Brown
2018-01-22 14:30       ` [PATCH v4 7/7] regulator: core: Change voltage setting path Maciej Purski
     [not found]   ` <CGME20180122143032eucas1p229e2ec741318df3e716e736796bbb9c1@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 4/7] regulator: core: Parse coupled regulators properties Maciej Purski
     [not found]   ` <CGME20180122143033eucas1p2adb3b39af238b2449486389d214a3a68@eucas1p2.samsung.com>
2018-01-22 14:30     ` Maciej Purski [this message]
2018-03-02 12:55       ` Applied "regulator: core: Resolve coupled regulators" to the regulator tree Mark Brown
2018-01-26 17:31   ` [PATCH v4 0/7] Add coupled regulators mechanism Mark Brown
2018-03-01 19:38   ` Mark Brown

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