From: Grygorii Strashko <[email protected]>
This series converts driver to use I2C bus recovery infrastructure and
adds Davinci I2C bus recovery mechanizm based on using ICPFUNC registers.
These patches are combination of two patches from Ben Gardiner [1] and
Mike Looijmans [2] which i've reworked to use I2C bus recovery infrastructure
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2011-April/047305.html
"[PATCH 0/6] i2c-davinci gpio pulsed SCL recovery with ICPFUNC"
[2] https://lkml.org/lkml/2014/2/28/133
"[PATCH] i2c-davinci: Implement a bus recovery that actually works"
Changes in v4:
- no changes, re-besed on top of i2c/for-next, K4.1
Changes in v3:
- minor comments applied
Changes in v2:
- patch 1: error handling improved
- patch 2: commit message updated
- patch 4: minor comments applied
- patch 5: added new optional DT property "ti,has-pfunc"
Links
v3: http://www.spinics.net/lists/linux-i2c/msg17835.html
v2: https://lkml.org/lkml/2014/11/26/252
v1: http://www.spinics.net/lists/linux-i2c/msg17601.html
CC: Sekhar Nori <[email protected]>
CC: Kevin Hilman <[email protected]>
CC: Santosh Shilimkar <[email protected]>
CC: Murali Karicheri <[email protected]>
CC: Alexander Sverdlin <[email protected]>
Grygorii Strashko (3):
i2c: recovery: change input parameter to i2c_adapter for prepare/unprepare_recovery
i2c: davinci: use bus recovery infrastructure
i2c: davinci: use ICPFUNC to toggle I2C as gpio for bus recovery
.../devicetree/bindings/i2c/i2c-davinci.txt | 3 +
drivers/i2c/busses/i2c-davinci.c | 177 ++++++++++++++++-----
drivers/i2c/i2c-core.c | 4 +-
include/linux/i2c.h | 4 +-
include/linux/platform_data/i2c-davinci.h | 1 +
5 files changed, 144 insertions(+), 45 deletions(-)
--
1.9.1
From: Grygorii Strashko <[email protected]>
This patch changes type of input parameter for .prepare/unprepare_recovery()
callbacks from struct i2c_bus_recovery_info * to struct i2c_adapter *.
This allows to simplify implementation of these callbacks and avoid
type conversations from i2c_bus_recovery_info to i2c_adapter.
The i2c_bus_recovery_info can be simply retrieved from struct i2c_adapter
which contains pointer on it.
CC: Sekhar Nori <[email protected]>
CC: Kevin Hilman <[email protected]>
CC: Santosh Shilimkar <[email protected]>
CC: Murali Karicheri <[email protected]>
Acked-by: Uwe Kleine-König <[email protected]>
Acked-by: Alexander Sverdlin <[email protected]>
Signed-off-by: Grygorii Strashko <[email protected]>
---
drivers/i2c/i2c-core.c | 4 ++--
include/linux/i2c.h | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index fe80f85..617a19a 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -561,7 +561,7 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
int i = 0, val = 1, ret = 0;
if (bri->prepare_recovery)
- bri->prepare_recovery(bri);
+ bri->prepare_recovery(adap);
/*
* By this time SCL is high, as we need to give 9 falling-rising edges
@@ -586,7 +586,7 @@ static int i2c_generic_recovery(struct i2c_adapter *adap)
}
if (bri->unprepare_recovery)
- bri->unprepare_recovery(bri);
+ bri->unprepare_recovery(adap);
return ret;
}
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index c5e4bb2..898033f 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -435,8 +435,8 @@ struct i2c_bus_recovery_info {
void (*set_scl)(struct i2c_adapter *, int val);
int (*get_sda)(struct i2c_adapter *);
- void (*prepare_recovery)(struct i2c_bus_recovery_info *bri);
- void (*unprepare_recovery)(struct i2c_bus_recovery_info *bri);
+ void (*prepare_recovery)(struct i2c_adapter *);
+ void (*unprepare_recovery)(struct i2c_adapter *);
/* gpio recovery */
int scl_gpio;
--
1.9.1
From: Grygorii Strashko <[email protected]>
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 <[email protected]>
CC: Kevin Hilman <[email protected]>
CC: Santosh Shilimkar <[email protected]>
CC: Murali Karicheri <[email protected]>
CC: Alexander Sverdlin <[email protected]>
Acked-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Grygorii Strashko <[email protected]>
---
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
From: Grygorii Strashko <[email protected]>
Having a board where the I2C bus locks up occasionally made it clear
that the bus recovery in the i2c-davinci driver will only work on
some boards, because on regular boards, this will only toggle GPIO
lines that aren't muxed to the actual pins.
The I2C controller on SoCs like da850 (and da830), Keystone 2 has the
built-in capability to bit-bang its lines by using the ICPFUNC registers
of the i2c controller.
Implement the suggested procedure by toggling SCL and checking SDA using
the ICPFUNC registers of the I2C controller when present. Allow platforms
to indicate the presence of the ICPFUNC registers with a has_pfunc platform
data flag and add optional DT property "ti,has-pfunc" to indicate
the same in DT.
CC: Sekhar Nori <[email protected]>
CC: Kevin Hilman <[email protected]>
CC: Santosh Shilimkar <[email protected]>
CC: Murali Karicheri <[email protected]>
CC: Mike Looijmans <[email protected]>
CC: <[email protected]>
Reviewed-by: Uwe Kleine-König <[email protected]>
Acked-by: Alexander Sverdlin <[email protected]>
Tested-by: Michael Lawnick <[email protected]>
Signed-off-by: Ben Gardiner <[email protected]>
Signed-off-by: Mike Looijmans <[email protected]>
[[email protected]: combined patches from Ben Gardiner and
Mike Looijmans and reimplemented ICPFUNC bus recovery using I2C
bus recovery infrastructure]
Signed-off-by: Grygorii Strashko <[email protected]>
---
.../devicetree/bindings/i2c/i2c-davinci.txt | 3 +
drivers/i2c/busses/i2c-davinci.c | 102 ++++++++++++++++++++-
include/linux/platform_data/i2c-davinci.h | 1 +
3 files changed, 105 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-davinci.txt b/Documentation/devicetree/bindings/i2c/i2c-davinci.txt
index 2dc935b..a4e1cbc 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-davinci.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-davinci.txt
@@ -10,6 +10,9 @@ Required properties:
Recommended properties :
- interrupts : standard interrupt property.
- clock-frequency : desired I2C bus clock frequency in Hz.
+- ti,has-pfunc: boolean; if defined, it indicates that SoC supports PFUNC
+ registers. PFUNC registers allow to switch I2C pins to function as
+ GPIOs, so they can by toggled manually.
Example (enbw_cmc board):
i2c@1c22000 {
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 54819fb..4788a32 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -60,6 +60,12 @@
#define DAVINCI_I2C_IVR_REG 0x28
#define DAVINCI_I2C_EMDR_REG 0x2c
#define DAVINCI_I2C_PSC_REG 0x30
+#define DAVINCI_I2C_FUNC_REG 0x48
+#define DAVINCI_I2C_DIR_REG 0x4c
+#define DAVINCI_I2C_DIN_REG 0x50
+#define DAVINCI_I2C_DOUT_REG 0x54
+#define DAVINCI_I2C_DSET_REG 0x58
+#define DAVINCI_I2C_DCLR_REG 0x5c
#define DAVINCI_I2C_IVR_AAS 0x07
#define DAVINCI_I2C_IVR_SCD 0x06
@@ -93,6 +99,29 @@
#define DAVINCI_I2C_IMR_NACK BIT(1)
#define DAVINCI_I2C_IMR_AL BIT(0)
+/* set SDA and SCL as GPIO */
+#define DAVINCI_I2C_FUNC_PFUNC0 BIT(0)
+
+/* set SCL as output when used as GPIO*/
+#define DAVINCI_I2C_DIR_PDIR0 BIT(0)
+/* set SDA as output when used as GPIO*/
+#define DAVINCI_I2C_DIR_PDIR1 BIT(1)
+
+/* read SCL GPIO level */
+#define DAVINCI_I2C_DIN_PDIN0 BIT(0)
+/* read SDA GPIO level */
+#define DAVINCI_I2C_DIN_PDIN1 BIT(1)
+
+/*set the SCL GPIO high */
+#define DAVINCI_I2C_DSET_PDSET0 BIT(0)
+/*set the SDA GPIO high */
+#define DAVINCI_I2C_DSET_PDSET1 BIT(1)
+
+/* set the SCL GPIO low */
+#define DAVINCI_I2C_DCLR_PDCLR0 BIT(0)
+/* set the SDA GPIO low */
+#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)
+
struct davinci_i2c_dev {
struct device *dev;
void __iomem *base;
@@ -253,6 +282,71 @@ static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
.unprepare_recovery = davinci_i2c_unprepare_recovery,
};
+static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ if (val)
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG,
+ DAVINCI_I2C_DSET_PDSET0);
+ else
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG,
+ DAVINCI_I2C_DCLR_PDCLR0);
+}
+
+static int davinci_i2c_get_scl(struct i2c_adapter *adap)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+ int val;
+
+ /* read the state of SCL */
+ val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
+ return val & DAVINCI_I2C_DIN_PDIN0;
+}
+
+static int davinci_i2c_get_sda(struct i2c_adapter *adap)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+ int val;
+
+ /* read the state of SDA */
+ val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
+ return val & DAVINCI_I2C_DIN_PDIN1;
+}
+
+static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ davinci_i2c_prepare_recovery(adap);
+
+ /* SCL output, SDA input */
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
+
+ /* change to GPIO mode */
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG,
+ DAVINCI_I2C_FUNC_PFUNC0);
+}
+
+static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap)
+{
+ struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
+
+ /* change back to I2C mode */
+ davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0);
+
+ davinci_i2c_unprepare_recovery(adap);
+}
+
+static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
+ .recover_bus = i2c_generic_scl_recovery,
+ .set_scl = davinci_i2c_set_scl,
+ .get_scl = davinci_i2c_get_scl,
+ .get_sda = davinci_i2c_get_sda,
+ .prepare_recovery = davinci_i2c_scl_prepare_recovery,
+ .unprepare_recovery = davinci_i2c_scl_unprepare_recovery,
+};
+
/*
* Waiting for bus not busy
*/
@@ -660,6 +754,10 @@ static int davinci_i2c_probe(struct platform_device *pdev)
if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&prop))
dev->pdata->bus_freq = prop / 1000;
+
+ dev->pdata->has_pfunc =
+ of_property_read_bool(pdev->dev.of_node,
+ "ti,has-pfunc");
} else if (!dev->pdata) {
dev->pdata = &davinci_i2c_platform_data_default;
}
@@ -701,7 +799,9 @@ 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) {
+ if (dev->pdata->has_pfunc)
+ adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
+ else 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;
diff --git a/include/linux/platform_data/i2c-davinci.h b/include/linux/platform_data/i2c-davinci.h
index 2312d19..89fd347 100644
--- a/include/linux/platform_data/i2c-davinci.h
+++ b/include/linux/platform_data/i2c-davinci.h
@@ -18,6 +18,7 @@ struct davinci_i2c_platform_data {
unsigned int bus_delay; /* post-transaction delay (usec) */
unsigned int sda_pin; /* GPIO pin ID to use for SDA */
unsigned int scl_pin; /* GPIO pin ID to use for SCL */
+ bool has_pfunc; /*chip has a ICPFUNC register */
};
/* for board setup code */
--
1.9.1
On Mon, Apr 06, 2015 at 03:38:38PM +0300, [email protected] wrote:
> From: Grygorii Strashko <[email protected]>
>
> This series converts driver to use I2C bus recovery infrastructure and
> adds Davinci I2C bus recovery mechanizm based on using ICPFUNC registers.
> These patches are combination of two patches from Ben Gardiner [1] and
> Mike Looijmans [2] which i've reworked to use I2C bus recovery infrastructure
Applied to for-next, thanks for keeping at it and providing useful info!
On 04/10/2015 06:59 PM, Wolfram Sang wrote:
> On Mon, Apr 06, 2015 at 03:38:38PM +0300, [email protected] wrote:
>> From: Grygorii Strashko <[email protected]>
>>
>> This series converts driver to use I2C bus recovery infrastructure and
>> adds Davinci I2C bus recovery mechanizm based on using ICPFUNC registers.
>> These patches are combination of two patches from Ben Gardiner [1] and
>> Mike Looijmans [2] which i've reworked to use I2C bus recovery infrastructure
>
> Applied to for-next, thanks for keeping at it and providing useful info!
>
Thanks
--
regards,
-grygorii