[PATCH v2 1/2] mfd: da9062: enable being a system-power-controller

* [PATCH v2 1/2] mfd: da9062: enable being a system-power-controller
@ 2022-04-22  6:16 Helmut Grohne
  2022-04-22  6:16 ` [PATCH v2 2/2] dt-bindings: mfd: da9062 can be a system power controller Helmut Grohne
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Helmut Grohne @ 2022-04-22  6:16 UTC (permalink / raw)
  To: Support Opensource, Lee Jones
  Cc: linux-kernel, Adam Thomson, Mark Brown, Wolfram Sang

The DA9062 can be the device used to power the CPU. In that case, it can
be used to power off the system. In the CONTROL_A register, the M_*_EN
bits must be zero for the corresponding *_EN bits to have an effect. We
zero them all to turn off the system.

Signed-off-by: Helmut Grohne <helmut.grohne@intenta.de>
---
 drivers/mfd/da9062-core.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

This series effectively is a rebased resend. The earlier posting was
https://lore.kernel.org/all/20200107120559.GA700@laureti-dev/. At that time,
Adam Thomson critisized the use of regmap and i2c inside a pm_power_off hook
since irqs are disabled. He reached out to Lee Jones, who asked Mark Brown and
Wolfram Sang, but never got any reply. I noted that a fair number of other
drivers do use regmap and i2c despite this issue. In the mean time, more
instances were added:
 * drivers/mfd/acer-ec-a500.c uses i2c
 * drivers/mfd/ntxec.c uses i2c
 * drivers/mfd/rk808.c uses regmap and i2c
Given that we proceeded with accepting the use of i2c and regmap inside
pm_power_off hooks, I think we can proceed with this patch as well.

Helmut

diff --git a/drivers/mfd/da9062-core.c b/drivers/mfd/da9062-core.c
index 2774b2cbaea6..e7af5b5f16e0 100644
--- a/drivers/mfd/da9062-core.c
+++ b/drivers/mfd/da9062-core.c
@@ -620,6 +620,23 @@ static const struct of_device_id da9062_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, da9062_dt_ids);
 
+/* Hold client since pm_power_off is global. */
+static struct i2c_client *da9062_i2c_client;
+
+static void da9062_power_off(void)
+{
+	struct da9062 *chip = i2c_get_clientdata(da9062_i2c_client);
+	const unsigned int mask = DA9062AA_SYSTEM_EN_MASK |
+		DA9062AA_POWER_EN_MASK | DA9062AA_POWER1_EN_MASK |
+		DA9062AA_M_SYSTEM_EN_MASK | DA9062AA_M_POWER_EN_MASK |
+		DA9062AA_M_POWER1_EN_MASK;
+	int ret = regmap_update_bits(chip->regmap, DA9062AA_CONTROL_A, mask, 0);
+
+	if (ret < 0)
+		dev_err(&da9062_i2c_client->dev,
+			"DA9062AA_CONTROL_A update failed, %d\n", ret);
+}
+
 static int da9062_i2c_probe(struct i2c_client *i2c,
 	const struct i2c_device_id *id)
 {
@@ -720,6 +737,15 @@ static int da9062_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	if (of_device_is_system_power_controller(i2c->dev.of_node)) {
+		if (!pm_power_off) {
+			da9062_i2c_client = i2c;
+			pm_power_off = da9062_power_off;
+		} else {
+			dev_warn(&i2c->dev, "Poweroff callback already assigned\n");
+		}
+	}
+
 	return ret;
 }
 
@@ -727,6 +753,11 @@ static int da9062_i2c_remove(struct i2c_client *i2c)
 {
 	struct da9062 *chip = i2c_get_clientdata(i2c);
 
+	if (pm_power_off == da9062_power_off)
+		pm_power_off = NULL;
+	if (da9062_i2c_client)
+		da9062_i2c_client = NULL;
+
 	mfd_remove_devices(chip->dev);
 	regmap_del_irq_chip(i2c->irq, chip->regmap_irq);
 
-- 
2.20.1

Dipl.-Inf. Helmut Grohne
Research and Development
Application Engineering
 
Phone: +49 (371) 24354 0 ∙ Fax:  +49 (371) 24354 020
helmut.grohne@intenta.de ∙ https://www.intenta.de
 
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