All of lore.kernel.org
 help / color / mirror / Atom feed
From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [PATCH 3/4] i2c: Add option to send start condition after deblocking
Date: Fri,  7 Feb 2020 16:57:51 +0100	[thread overview]
Message-ID: <20200207155752.40930-3-marex@denx.de> (raw)
In-Reply-To: <20200207155752.40930-1-marex@denx.de>

Add option to send start condition after deblocking SDA.

Signed-off-by: Marek Vasut <marex@denx.de>
---
 drivers/i2c/i2c-uclass.c | 23 ++++++++++++++++++++---
 include/i2c.h            |  4 +++-
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index 86f529241f..e9ec388576 100644
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -504,9 +504,10 @@ static int i2c_gpio_get_pin(struct gpio_desc *pin)
 int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin,
 			  struct gpio_desc *scl_pin,
 			  unsigned int scl_count,
+			  unsigned int start_count,
 			  unsigned int delay)
 {
-	int ret = 0;
+	int i, ret = -EREMOTEIO;
 
 	i2c_gpio_set_pin(sda_pin, 1);
 	i2c_gpio_set_pin(scl_pin, 1);
@@ -518,8 +519,24 @@ int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin,
 		udelay(delay);
 		i2c_gpio_set_pin(scl_pin, 0);
 		udelay(delay);
-		if (i2c_gpio_get_pin(sda_pin))
+		if (i2c_gpio_get_pin(sda_pin)) {
+			ret = 0;
 			break;
+		}
+	}
+
+	if (!ret && start_count) {
+		for (i = 0; i < start_count; i++) {
+			/* Send start condition */
+			udelay(delay);
+			i2c_gpio_set_pin(sda_pin, 1);
+			udelay(delay);
+			i2c_gpio_set_pin(scl_pin, 1);
+			udelay(delay);
+			i2c_gpio_set_pin(sda_pin, 0);
+			udelay(delay);
+			i2c_gpio_set_pin(scl_pin, 0);
+		}
 	}
 
 	/* Then, send I2C stop */
@@ -562,7 +579,7 @@ static int i2c_deblock_gpio(struct udevice *bus)
 		goto out_no_pinctrl;
 	}
 
-	ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 5);
+	ret0 = i2c_deblock_gpio_loop(&gpios[PIN_SDA], &gpios[PIN_SCL], 9, 0, 5);
 
 	ret = pinctrl_select_state(bus, "default");
 	if (ret) {
diff --git a/include/i2c.h b/include/i2c.h
index 7c92042c58..059200115a 100644
--- a/include/i2c.h
+++ b/include/i2c.h
@@ -339,12 +339,14 @@ int i2c_deblock(struct udevice *bus);
  * @sda_pin:	SDA GPIO
  * @scl_pin:	SCL GPIO
  * @scl_count:	Number of SCL clock cycles generated to deblock SDA
+ * @start_count:Number of I2C start conditions sent after deblocking SDA
  * @delay:	Delay between SCL clock line changes
  * @return 0 if OK, -ve on error
  */
 struct gpio_desc;
 int i2c_deblock_gpio_loop(struct gpio_desc *sda_pin, struct gpio_desc *scl_pin,
-			  unsigned int scl_count, unsigned int delay);
+			  unsigned int scl_count, unsigned int start_count,
+			  unsigned int delay);
 
 /**
  * struct dm_i2c_ops - driver operations for I2C uclass
-- 
2.24.1

  parent reply	other threads:[~2020-02-07 15:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-07 15:57 [PATCH 1/4] i2c: Make deblock delay and SCL clock configurable Marek Vasut
2020-02-07 15:57 ` [PATCH 2/4] i2c: Export i2c_deblock_gpio_loop() Marek Vasut
2020-02-18  7:05   ` Heiko Schocher
2020-03-17  5:10   ` Heiko Schocher
2020-02-07 15:57 ` Marek Vasut [this message]
2020-02-18  7:07   ` [PATCH 3/4] i2c: Add option to send start condition after deblocking Heiko Schocher
2020-02-18 17:21     ` Marek Vasut
2020-03-17  5:11   ` Heiko Schocher
2020-02-07 15:57 ` [PATCH 4/4] i2c: gpio: Run deblock sequence on probe Marek Vasut
2020-02-18  7:11   ` Heiko Schocher
2020-02-18 17:25     ` Marek Vasut
2020-03-17  5:11   ` Heiko Schocher
2020-02-18  7:04 ` [PATCH 1/4] i2c: Make deblock delay and SCL clock configurable Heiko Schocher
2020-03-17  5:10 ` Heiko Schocher

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200207155752.40930-3-marex@denx.de \
    --to=marex@denx.de \
    --cc=u-boot@lists.denx.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.