linux-kernel - [PATCH v5 02/11] leds: aw200xx: support HWEN hardware control

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231125200519.1750-3-ddrokosov@salutedevices.com>
Date:   Sat, 25 Nov 2023 23:05:10 +0300
From:   Dmitry Rokosov <ddrokosov@...utedevices.com>
To:     <lee@...nel.org>, <pavel@....cz>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <andy.shevchenko@...il.com>
CC:     <kernel@...rdevices.ru>, <rockosov@...il.com>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-leds@...r.kernel.org>,
        Dmitry Rokosov <ddrokosov@...utedevices.com>
Subject: [PATCH v5 02/11] leds: aw200xx: support HWEN hardware control

HWEN is hardware control, which is used for enable/disable aw200xx chip.
It's high active, internally pulled down to GND.

After HWEN pin set high the chip begins to load the OTP information,
which takes 200us to complete. About 200us wait time is needed for
internal oscillator startup and display SRAM initialization. After
display SRAM initialization, the registers in page 1 to page 5 can be
configured via i2c interface.

Signed-off-by: Dmitry Rokosov <ddrokosov@...utedevices.com>
---
 drivers/leds/leds-aw200xx.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/leds/leds-aw200xx.c b/drivers/leds/leds-aw200xx.c
index 842a22087b16..d8f2fe57cbb7 100644
--- a/drivers/leds/leds-aw200xx.c
+++ b/drivers/leds/leds-aw200xx.c
@@ -10,6 +10,7 @@
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/container_of.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/leds.h>
 #include <linux/mod_devicetable.h>
@@ -116,6 +117,7 @@ struct aw200xx {
 	struct mutex mutex;
 	u32 num_leds;
 	u32 display_rows;
+	struct gpio_desc *hwen;
 	struct aw200xx_led leds[] __counted_by(num_leds);
 };
 
@@ -358,6 +360,25 @@ static int aw200xx_chip_check(const struct aw200xx *const chip)
 	return 0;
 }
 
+static void aw200xx_enable(const struct aw200xx *const chip)
+{
+	gpiod_set_value_cansleep(chip->hwen, 1);
+
+	/*
+	 * After HWEN pin set high the chip begins to load the OTP information,
+	 * which takes 200us to complete. About 200us wait time is needed for
+	 * internal oscillator startup and display SRAM initialization. After
+	 * display SRAM initialization, the registers in page1 to page5 can be
+	 * configured via i2c interface.
+	 */
+	fsleep(400);
+}
+
+static void aw200xx_disable(const struct aw200xx *const chip)
+{
+	return gpiod_set_value_cansleep(chip->hwen, 0);
+}
+
 static int aw200xx_probe_fw(struct device *dev, struct aw200xx *chip)
 {
 	struct fwnode_handle *child;
@@ -517,6 +538,14 @@ static int aw200xx_probe(struct i2c_client *client)
 	if (IS_ERR(chip->regmap))
 		return PTR_ERR(chip->regmap);
 
+	chip->hwen = devm_gpiod_get_optional(&client->dev, "enable",
+					     GPIOD_OUT_HIGH);
+	if (IS_ERR(chip->hwen))
+		return dev_err_probe(&client->dev, PTR_ERR(chip->hwen),
+				     "Cannot get enable GPIO");
+
+	aw200xx_enable(chip);
+
 	ret = aw200xx_chip_check(chip);
 	if (ret)
 		return ret;
@@ -537,6 +566,9 @@ static int aw200xx_probe(struct i2c_client *client)
 	ret = aw200xx_chip_init(chip);
 
 out_unlock:
+	if (ret)
+		aw200xx_disable(chip);
+
 	mutex_unlock(&chip->mutex);
 	return ret;
 }
@@ -546,6 +578,7 @@ static void aw200xx_remove(struct i2c_client *client)
 	struct aw200xx *chip = i2c_get_clientdata(client);
 
 	aw200xx_chip_reset(chip);
+	aw200xx_disable(chip);
 	mutex_destroy(&chip->mutex);
 }
 
-- 
2.36.0