linux-kernel - [PATCH 1/2] gpio: gpio-74x164: add support for CDx4HC4094

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Message-Id: <20220721093422.2173982-1-marcus.folkesson@gmail.com>
Date:   Thu, 21 Jul 2022 11:34:21 +0200
From:   Marcus Folkesson <marcus.folkesson@...il.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Maxime Ripard <mripard@...nel.org>
Cc:     linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Marcus Folkesson <marcus.folkesson@...il.com>
Subject: [PATCH 1/2] gpio: gpio-74x164: add support for CDx4HC4094

74hc4094 and 75hc4094 works similar to 74x164 but has an additional
storage latch associated with each stage for strobing data from the
serial input to parallell buffer tri-state output.

Add support for an optional strobe pin.

Signed-off-by: Marcus Folkesson <marcus.folkesson@...il.com>
---
 drivers/gpio/gpio-74x164.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpio/gpio-74x164.c b/drivers/gpio/gpio-74x164.c
index e00c33310517..4a1c4de358e4 100644
--- a/drivers/gpio/gpio-74x164.c
+++ b/drivers/gpio/gpio-74x164.c
@@ -21,6 +21,7 @@ struct gen_74x164_chip {
 	struct gpio_chip	gpio_chip;
 	struct mutex		lock;
 	struct gpio_desc	*gpiod_oe;
+	struct gpio_desc	*gpiod_strobe;
 	u32			registers;
 	/*
 	 * Since the registers are chained, every byte sent will make
@@ -66,6 +67,10 @@ static void gen_74x164_set_value(struct gpio_chip *gc,
 		chip->buffer[bank] &= ~(1 << pin);
 
 	__gen_74x164_write_config(chip);
+
+	/*  Latch data to output pins*/
+	gpiod_set_value_cansleep(chip->gpiod_strobe, 1);
+	gpiod_set_value_cansleep(chip->gpiod_strobe, 0);
 	mutex_unlock(&chip->lock);
 }
 
@@ -87,6 +92,10 @@ static void gen_74x164_set_multiple(struct gpio_chip *gc, unsigned long *mask,
 		chip->buffer[bank] |= bitmask;
 	}
 	__gen_74x164_write_config(chip);
+
+	/*  Latch data to output pins*/
+	gpiod_set_value_cansleep(chip->gpiod_strobe, 1);
+	gpiod_set_value_cansleep(chip->gpiod_strobe, 0);
 	mutex_unlock(&chip->lock);
 }
 
@@ -129,6 +138,12 @@ static int gen_74x164_probe(struct spi_device *spi)
 
 	gpiod_set_value_cansleep(chip->gpiod_oe, 1);
 
+	chip->gpiod_strobe = devm_gpiod_get_optional(&spi->dev, "strobe",
+			GPIOD_OUT_LOW);
+	if (IS_ERR(chip->gpiod_strobe))
+		return PTR_ERR(chip->gpiod_strobe);
+
+
 	spi_set_drvdata(spi, chip);
 
 	chip->gpio_chip.label = spi->modalias;
@@ -153,6 +168,10 @@ static int gen_74x164_probe(struct spi_device *spi)
 		goto exit_destroy;
 	}
 
+	/*  Latch data to output pins*/
+	gpiod_set_value_cansleep(chip->gpiod_strobe, 1);
+	gpiod_set_value_cansleep(chip->gpiod_strobe, 0);
+
 	ret = gpiochip_add_data(&chip->gpio_chip, chip);
 	if (!ret)
 		return 0;
@@ -182,6 +201,8 @@ MODULE_DEVICE_TABLE(spi, gen_74x164_spi_ids);
 static const struct of_device_id gen_74x164_dt_ids[] = {
 	{ .compatible = "fairchild,74hc595" },
 	{ .compatible = "nxp,74lvc594" },
+	{ .compatible = "ti,cd54hc4094" },
+	{ .compatible = "ti,cd74hc4094" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, gen_74x164_dt_ids);
-- 
2.36.1