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Message-Id: <1428323921-25832-3-git-send-email-grygorii.strashko@linaro.org>
Date: Mon, 6 Apr 2015 15:38:40 +0300
From: <grygorii.strashko@...aro.org>
To: Wolfram Sang <wsa@...-dreams.de>, Sekhar Nori <nsekhar@...com>,
Uwe Kleine-König
<u.kleine-koenig@...gutronix.de>
Cc: grygorii.strashko@...com, linux-i2c@...r.kernel.org,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>,
Kevin Hilman <khilman@...prootsystems.com>,
Santosh Shilimkar <ssantosh@...nel.org>,
Murali Karicheri <m-karicheri2@...com>,
Alexander Sverdlin <alexander.sverdlin@...ia.com>
Subject: [PATCH v4 2/3] i2c: davinci: use bus recovery infrastructure
From: Grygorii Strashko <grygorii.strashko@...com>
This patch converts Davinci I2C driver to use I2C bus recovery
infrastructure, introduced by commit 5f9296ba21b3 ("i2c: Add
bus recovery infrastructure").
The i2c_bus_recovery_info is configured for Davinci I2C adapter
only in case scl_pin is provided in platform data.
As the controller must be held in reset while doing so, the
recovery routine must re-init the controller. Since this was already
being done after each call to i2c_recover_bus, move those calls into
the recovery_prepare/unprepare routines and as well.
CC: Sekhar Nori <nsekhar@...com>
CC: Kevin Hilman <khilman@...prootsystems.com>
CC: Santosh Shilimkar <ssantosh@...nel.org>
CC: Murali Karicheri <m-karicheri2@...com>
CC: Alexander Sverdlin <alexander.sverdlin@...ia.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
---
drivers/i2c/busses/i2c-davinci.c | 77 +++++++++++++++++++---------------------
1 file changed, 36 insertions(+), 41 deletions(-)
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 120a4ef..54819fb 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -129,43 +129,6 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
return readw_relaxed(i2c_dev->base + reg);
}
-/* Generate a pulse on the i2c clock pin. */
-static void davinci_i2c_clock_pulse(unsigned int scl_pin)
-{
- u16 i;
-
- if (scl_pin) {
- /* Send high and low on the SCL line */
- for (i = 0; i < 9; i++) {
- gpio_set_value(scl_pin, 0);
- udelay(20);
- gpio_set_value(scl_pin, 1);
- udelay(20);
- }
- }
-}
-
-/* This routine does i2c bus recovery as specified in the
- * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
- */
-static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev)
-{
- u32 flag = 0;
- struct davinci_i2c_platform_data *pdata = dev->pdata;
-
- dev_err(dev->dev, "initiating i2c bus recovery\n");
- /* Send NACK to the slave */
- flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
- flag |= DAVINCI_I2C_MDR_NACK;
- /* write the data into mode register */
- davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
- davinci_i2c_clock_pulse(pdata->scl_pin);
- /* Send STOP */
- flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
- flag |= DAVINCI_I2C_MDR_STP;
- davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
-}
-
static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
int val)
{
@@ -263,6 +226,34 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
}
/*
+ * This routine does i2c bus recovery by using i2c_generic_gpio_recovery
+ * which is provided by I2C Bus recovery infrastructure.
+ */
+static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ /* Disable interrupts */
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);
+
+ /* put I2C into reset */
+ davinci_i2c_reset_ctrl(dev, 0);
+}
+
+static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ i2c_davinci_init(dev);
+}
+
+static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
+ .recover_bus = i2c_generic_gpio_recovery,
+ .prepare_recovery = davinci_i2c_prepare_recovery,
+ .unprepare_recovery = davinci_i2c_unprepare_recovery,
+};
+
+/*
* Waiting for bus not busy
*/
static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
@@ -282,8 +273,7 @@ static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
return -ETIMEDOUT;
} else {
to_cnt = 0;
- davinci_i2c_recover_bus(dev);
- i2c_davinci_init(dev);
+ i2c_recover_bus(&dev->adapter);
}
}
if (allow_sleep)
@@ -372,8 +362,7 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
dev->adapter.timeout);
if (!time_left) {
dev_err(dev->dev, "controller timed out\n");
- davinci_i2c_recover_bus(dev);
- i2c_davinci_init(dev);
+ i2c_recover_bus(adap);
dev->buf_len = 0;
return -ETIMEDOUT;
}
@@ -712,6 +701,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
adap->timeout = DAVINCI_I2C_TIMEOUT;
adap->dev.of_node = pdev->dev.of_node;
+ if (dev->pdata->scl_pin) {
+ adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info;
+ adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin;
+ adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin;
+ }
+
adap->nr = pdev->id;
r = i2c_add_numbered_adapter(adap);
if (r) {
--
1.9.1
--
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