Merge branch 'i2c/for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
 "I2C has the following changes for you:

   - new flag to mark DMA safe buffers in i2c_msg. Also, some
     infrastructure around it. And docs.

   - huge refactoring of the at24 driver led by the new maintainer
     Bartosz

   - update I2C bus recovery to send STOP after recovery

   - conversion from gpio to gpiod for I2C bus recovery

   - adding a fault-injector to the i2c-gpio driver

   - lots of small driver improvements, and bigger ones to
     i2c-sh_mobile"

* 'i2c/for-4.16' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (99 commits)
  i2c: mv64xxx: Add myself as maintainer for this driver
  i2c: mv64xxx: Fix clock resource by adding an optional bus clock
  i2c: mv64xxx: Remove useless test before clk_disable_unprepare
  i2c: mxs: use true and false for boolean values
  i2c: meson: update doc description to fix build warnings
  i2c: meson: add configurable divider factors
  dt-bindings: i2c: update documentation for the Meson-AXG
  i2c: imx-lpi2c: add runtime pm support
  i2c: rcar: fix some trivial typos in comments
  i2c: davinci: fix the cpufreq transition
  i2c: rk3x: add proper kerneldoc header
  i2c: rk3x: account for const type of of_device_id.data
  i2c: acorn: remove outdated path from file header
  i2c: acorn: add MODULE_LICENSE tag
  i2c: rcar: implement bus recovery
  i2c: send STOP after successful bus recovery
  i2c: ensure SDA is released in recovery if SDA is controllable
  i2c: add 'set_sda' to bus_recovery_info
  i2c: add identifier in declarations for i2c_bus_recovery
  i2c: make kerneldoc about bus recovery more precise
  ...

1 files changed, 96 insertions, 116 deletions

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index f7829a74140c..5a00bf443d06 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -27,7 +27,7 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/errno.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/i2c-smbus.h>
 #include <linux/idr.h>
@@ -134,52 +134,22 @@ static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 /* i2c bus recovery routines */
 static int get_scl_gpio_value(struct i2c_adapter *adap)
 {
-	return gpio_get_value(adap->bus_recovery_info->scl_gpio);
+	return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 }
 
 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 {
-	gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
+	gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 }
 
 static int get_sda_gpio_value(struct i2c_adapter *adap)
 {
-	return gpio_get_value(adap->bus_recovery_info->sda_gpio);
+	return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 }
 
-static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
+static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 {
-	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
-	struct device *dev = &adap->dev;
-	int ret = 0;
-
-	ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
-			GPIOF_OUT_INIT_HIGH, "i2c-scl");
-	if (ret) {
-		dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
-		return ret;
-	}
-
-	if (bri->get_sda) {
-		if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
-			/* work without SDA polling */
-			dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
-					bri->sda_gpio);
-			bri->get_sda = NULL;
-		}
-	}
-
-	return ret;
-}
-
-static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
-{
-	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
-
-	if (bri->get_sda)
-		gpio_free(bri->sda_gpio);
-
-	gpio_free(bri->scl_gpio);
+	gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 }
 
 /*
@@ -190,7 +160,7 @@ static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
 #define RECOVERY_NDELAY		5000
 #define RECOVERY_CLK_CNT	9
 
-static int i2c_generic_recovery(struct i2c_adapter *adap)
+int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 {
 	struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 	int i = 0, val = 1, ret = 0;
@@ -199,6 +169,8 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
 		bri->prepare_recovery(adap);
 
 	bri->set_scl(adap, val);
+	if (bri->set_sda)
+		bri->set_sda(adap, 1);
 	ndelay(RECOVERY_NDELAY);
 
 	/*
@@ -227,33 +199,25 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
 	if (bri->get_sda && !bri->get_sda(adap))
 		ret = -EBUSY;
 
+	/* If all went well, send STOP for a sane bus state. */
+	if (ret == 0 && bri->set_sda) {
+		bri->set_scl(adap, 0);
+		ndelay(RECOVERY_NDELAY / 2);
+		bri->set_sda(adap, 0);
+		ndelay(RECOVERY_NDELAY / 2);
+		bri->set_scl(adap, 1);
+		ndelay(RECOVERY_NDELAY / 2);
+		bri->set_sda(adap, 1);
+		ndelay(RECOVERY_NDELAY / 2);
+	}
+
 	if (bri->unprepare_recovery)
 		bri->unprepare_recovery(adap);
 
 	return ret;
 }
-
-int i2c_generic_scl_recovery(struct i2c_adapter *adap)
-{
-	return i2c_generic_recovery(adap);
-}
 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 
-int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
-{
-	int ret;
-
-	ret = i2c_get_gpios_for_recovery(adap);
-	if (ret)
-		return ret;
-
-	ret = i2c_generic_recovery(adap);
-	i2c_put_gpios_for_recovery(adap);
-
-	return ret;
-}
-EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
-
 int i2c_recover_bus(struct i2c_adapter *adap)
 {
 	if (!adap->bus_recovery_info)
@@ -277,21 +241,19 @@ static void i2c_init_recovery(struct i2c_adapter *adap)
 		goto err;
 	}
 
-	/* Generic GPIO recovery */
-	if (bri->recover_bus == i2c_generic_gpio_recovery) {
-		if (!gpio_is_valid(bri->scl_gpio)) {
-			err_str = "invalid SCL gpio";
-			goto err;
-		}
-
-		if (gpio_is_valid(bri->sda_gpio))
-			bri->get_sda = get_sda_gpio_value;
-		else
-			bri->get_sda = NULL;
-
+	if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 		bri->get_scl = get_scl_gpio_value;
 		bri->set_scl = set_scl_gpio_value;
-	} else if (bri->recover_bus == i2c_generic_scl_recovery) {
+		if (bri->sda_gpiod) {
+			bri->get_sda = get_sda_gpio_value;
+			/* FIXME: add proper flag instead of '0' once available */
+			if (gpiod_get_direction(bri->sda_gpiod) == 0)
+				bri->set_sda = set_sda_gpio_value;
+		}
+		return;
+	}
+
+	if (bri->recover_bus == i2c_generic_scl_recovery) {
 		/* Generic SCL recovery */
 		if (!bri->set_scl || !bri->get_scl) {
 			err_str = "no {get|set}_scl() found";
@@ -1976,63 +1938,35 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 EXPORT_SYMBOL(i2c_transfer);
 
 /**
- * i2c_master_send - issue a single I2C message in master transmit mode
- * @client: Handle to slave device
- * @buf: Data that will be written to the slave
- * @count: How many bytes to write, must be less than 64k since msg.len is u16
- *
- * Returns negative errno, or else the number of bytes written.
- */
-int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
-{
-	int ret;
-	struct i2c_adapter *adap = client->adapter;
-	struct i2c_msg msg;
-
-	msg.addr = client->addr;
-	msg.flags = client->flags & I2C_M_TEN;
-	msg.len = count;
-	msg.buf = (char *)buf;
-
-	ret = i2c_transfer(adap, &msg, 1);
-
-	/*
-	 * If everything went ok (i.e. 1 msg transmitted), return #bytes
-	 * transmitted, else error code.
-	 */
-	return (ret == 1) ? count : ret;
-}
-EXPORT_SYMBOL(i2c_master_send);
-
-/**
- * i2c_master_recv - issue a single I2C message in master receive mode
+ * i2c_transfer_buffer_flags - issue a single I2C message transferring data
+ *			       to/from a buffer
  * @client: Handle to slave device
- * @buf: Where to store data read from slave
- * @count: How many bytes to read, must be less than 64k since msg.len is u16
+ * @buf: Where the data is stored
+ * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
+ * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
  *
- * Returns negative errno, or else the number of bytes read.
+ * Returns negative errno, or else the number of bytes transferred.
  */
-int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
+int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
+			      int count, u16 flags)
 {
-	struct i2c_adapter *adap = client->adapter;
-	struct i2c_msg msg;
 	int ret;
+	struct i2c_msg msg = {
+		.addr = client->addr,
+		.flags = flags | (client->flags & I2C_M_TEN),
+		.len = count,
+		.buf = buf,
+	};
 
-	msg.addr = client->addr;
-	msg.flags = client->flags & I2C_M_TEN;
-	msg.flags |= I2C_M_RD;
-	msg.len = count;
-	msg.buf = buf;
-
-	ret = i2c_transfer(adap, &msg, 1);
+	ret = i2c_transfer(client->adapter, &msg, 1);
 
 	/*
-	 * If everything went ok (i.e. 1 msg received), return #bytes received,
-	 * else error code.
+	 * If everything went ok (i.e. 1 msg transferred), return #bytes
+	 * transferred, else error code.
 	 */
 	return (ret == 1) ? count : ret;
 }
-EXPORT_SYMBOL(i2c_master_recv);
+EXPORT_SYMBOL(i2c_transfer_buffer_flags);
 
 /* ----------------------------------------------------
  * the i2c address scanning function
@@ -2265,6 +2199,52 @@ void i2c_put_adapter(struct i2c_adapter *adap)
 }
 EXPORT_SYMBOL(i2c_put_adapter);
 
+/**
+ * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
+ * @msg: the message to be checked
+ * @threshold: the minimum number of bytes for which using DMA makes sense
+ *
+ * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
+ *	   Or a valid pointer to be used with DMA. After use, release it by
+ *	   calling i2c_release_dma_safe_msg_buf().
+ *
+ * This function must only be called from process context!
+ */
+u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
+{
+	if (msg->len < threshold)
+		return NULL;
+
+	if (msg->flags & I2C_M_DMA_SAFE)
+		return msg->buf;
+
+	pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
+		 msg->addr, msg->len);
+
+	if (msg->flags & I2C_M_RD)
+		return kzalloc(msg->len, GFP_KERNEL);
+	else
+		return kmemdup(msg->buf, msg->len, GFP_KERNEL);
+}
+EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
+
+/**
+ * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
+ * @msg: the message to be synced with
+ * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
+ */
+void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
+{
+	if (!buf || buf == msg->buf)
+		return;
+
+	if (msg->flags & I2C_M_RD)
+		memcpy(msg->buf, buf, msg->len);
+
+	kfree(buf);
+}
+EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
+
 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
 MODULE_DESCRIPTION("I2C-Bus main module");
 MODULE_LICENSE("GPL");