2015-08-24 06:01:59

by Vaibhav Hiremath

[permalink] [raw]
Subject: [PATCH-v5 RESEND 0/5] i2c: pxa: Add support for PXA910 family of device

Sorry for not following up on this aggressively, was quit busy with some
other stuff. Resending this patch with Robert's Tested-By.


This patch-series is subset of the original patch-series, submitted
on 14 Jul 2015.
Link to Original Patch-series - https://lkml.org/lkml/2015/7/14/80

The first six patches have been already queued up for upstream. So this
patch-series is respin of remaining 5 patches.

Testing:
- Basic testing on PMIC device on I2C-0 interface
- Boot tested on platform based on PXA1928
- Read few registers of PMIC (RTC, ID, etc...) during boot

V4 => V5
=======
Link to V3: https://lkml.org/lkml/2015/7/14/80
- Dropped First 6 patches as they are already accepted, queued for upstream
- Fixed a bug in PATCH [5/5], where for non PXA910 devices it as resulting into
NULL pointer dereference.


For the record, pasting all the details from original patch-series -

V3 => V4
=======
Link to V3: http://www.spinics.net/lists/devicetree/msg85904.html
- [PATCH 06/11] Removed unnecessary dev_err on devm_kzalloc() check
- [PATCH 06/11] Removed return check on platform_get_resource(), as
devm_ioremap_resource() does it for us.
Also, brought up the devm_ioremap_resource() function call in the execution
sequence, as no point in delaying it if we do not have resource.
It make sense, after this change.
- [PATCH 04/11] Typecast changed to 'enum pxa_i2c_types'
Also updated the subject line "Removed ==> Fix"

V2 => V3
=======
Link to V2: http://www.spinics.net/lists/linux-i2c/msg20059.html
- Removed PATCH [4/12] related to reset of I2C module.
Suggested by "Robert Jarzmik"
- Updated commit description for,
PATCH [11/12]: Mentioned reasoning about moment of clk_get code.
PATCH [12/12]: for DT property node.
- Added Acked by "Robert Jarzmik" to patched which he acked.

V1 => V2:
========
Link to V1 - http://lists.infradead.org/pipermail/linux-arm-kernel/2015-May/347012.html
- Fixed all comments from "Robert Jarzmik" and "Wolfram Sang"
- Dropped Patch
05/12: using core bus reset implementation - under work.
08/12: NAKed and dropped
- Separated DT binding patch from driver changes, for easy merge


Vaibhav Hiremath (4):
Documentation: binding: add new property 'disable_after_xfer' to
i2c-pxa
i2c: pxa: Add support for pxa910/988 & new configuration features
Documentation: binding: add sclk adjustment properties to i2c-pxa
i2c: pxa: Add ILCR (tLow & tHigh) configuration support

Yi Zhang (1):
i2c: pxa: enable/disable i2c module across msg xfer

Documentation/devicetree/bindings/i2c/i2c-pxa.txt | 18 +++
drivers/i2c/busses/i2c-pxa.c | 154 ++++++++++++++++++++--
2 files changed, 163 insertions(+), 9 deletions(-)

--
1.9.1


2015-08-24 06:02:06

by Vaibhav Hiremath

[permalink] [raw]
Subject: [PATCH-v5 RESEND 1/5] Documentation: binding: add new property 'disable_after_xfer' to i2c-pxa

Driver will now supports enable/disable across msg xfer, which user
can control it by new DT property -

i2c-disable-after-xfer : If set, driver will disable I2C module after msg
xfer and enable it back before xfer.

Signed-off-by: Vaibhav Hiremath <[email protected]>
---
Documentation/devicetree/bindings/i2c/i2c-pxa.txt | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-pxa.txt b/Documentation/devicetree/bindings/i2c/i2c-pxa.txt
index 12b78ac..9657db5 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-pxa.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-pxa.txt
@@ -18,6 +18,11 @@ Recommended properties :
status register of i2c controller instead.
- mrvl,i2c-fast-mode : Enable fast mode of i2c controller.

+Optional properties :
+
+ - i2c-disable-after-xfer : If set, driver will disable I2C module
+ after msg xfer and enable it again before xfer.
+
Examples:
twsi1: i2c@d4011000 {
compatible = "mrvl,mmp-twsi";
--
1.9.1

2015-08-24 06:02:12

by Vaibhav Hiremath

[permalink] [raw]
Subject: [PATCH-v5 RESEND 2/5] i2c: pxa: enable/disable i2c module across msg xfer

From: Yi Zhang <[email protected]>

Enable i2c module/unit before transmission and disable when it
finishes.

why?
It's because the i2c bus may be disturbed if the slave device,
typically a touch, powers on.

As we do not want to break slave mode support, this patch introduces
DT property to control disable of the I2C module after xfer in master
mode of operation.

i2c-disable-after-xfer : If set, driver will disable I2C module after
msg xfer

Signed-off-by: Yi Zhang <[email protected]>
Signed-off-by: Vaibhav Hiremath <[email protected]>
---
drivers/i2c/busses/i2c-pxa.c | 43 +++++++++++++++++++++++++++++++++++++++++--
1 file changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 66cf437..abf04f2 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -161,6 +161,7 @@ struct pxa_i2c {
unsigned char master_code;
unsigned long rate;
bool highmode_enter;
+ bool disable_after_xfer;
};

#define _IBMR(i2c) ((i2c)->reg_ibmr)
@@ -284,6 +285,24 @@ static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);
static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id);

+/* enable/disable i2c unit */
+static inline int i2c_pxa_is_enabled(struct pxa_i2c *i2c)
+{
+ return (readl(_ICR(i2c)) & ICR_IUE);
+}
+
+static inline void i2c_pxa_enable(struct pxa_i2c *i2c, bool enable)
+{
+ if (enable) {
+ if (!i2c_pxa_is_enabled(i2c)) {
+ writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
+ udelay(100);
+ }
+ } else {
+ writel(readl(_ICR(i2c)) & ~ICR_IUE, _ICR(i2c));
+ }
+}
+
static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
{
return !(readl(_ICR(i2c)) & ICR_SCLE);
@@ -480,8 +499,7 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c)
i2c_pxa_set_slave(i2c, 0);

/* enable unit */
- writel(readl(_ICR(i2c)) | ICR_IUE, _ICR(i2c));
- udelay(100);
+ i2c_pxa_enable(i2c, true);
}


@@ -832,6 +850,9 @@ static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
struct pxa_i2c *i2c = adap->algo_data;
int ret, i;

+ /* Enable i2c unit */
+ i2c_pxa_enable(i2c, true);
+
/* If the I2C controller is disabled we need to reset it
(probably due to a suspend/resume destroying state). We do
this here as we can then avoid worrying about resuming the
@@ -852,6 +873,11 @@ static int i2c_pxa_pio_xfer(struct i2c_adapter *adap,
ret = -EREMOTEIO;
out:
i2c_pxa_set_slave(i2c, ret);
+
+ /* disable i2c unit */
+ if (i2c->disable_after_xfer)
+ i2c_pxa_enable(i2c, false);
+
return ret;
}

@@ -1067,6 +1093,9 @@ static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num
struct pxa_i2c *i2c = adap->algo_data;
int ret, i;

+ /* Enable i2c unit */
+ i2c_pxa_enable(i2c, true);
+
for (i = adap->retries; i >= 0; i--) {
ret = i2c_pxa_do_xfer(i2c, msgs, num);
if (ret != I2C_RETRY)
@@ -1080,6 +1109,10 @@ static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num
ret = -EREMOTEIO;
out:
i2c_pxa_set_slave(i2c, ret);
+ /* disable i2c unit */
+ if (i2c->disable_after_xfer)
+ i2c_pxa_enable(i2c, false);
+
return ret;
}

@@ -1120,6 +1153,9 @@ static int i2c_pxa_probe_dt(struct platform_device *pdev, struct pxa_i2c *i2c,
/* For device tree we always use the dynamic or alias-assigned ID */
i2c->adap.nr = -1;

+ i2c->disable_after_xfer = of_property_read_bool(np,
+ "i2c-disable-after-xfer");
+
if (of_get_property(np, "mrvl,i2c-polling", NULL))
i2c->use_pio = 1;
if (of_get_property(np, "mrvl,i2c-fast-mode", NULL))
@@ -1264,6 +1300,9 @@ static int i2c_pxa_probe(struct platform_device *dev)

platform_set_drvdata(dev, i2c);

+ if (i2c->disable_after_xfer)
+ i2c_pxa_enable(i2c, false);
+
#ifdef CONFIG_I2C_PXA_SLAVE
dev_info(&i2c->adap.dev, " PXA I2C adapter, slave address %d\n",
i2c->slave_addr);
--
1.9.1

2015-08-24 06:02:58

by Vaibhav Hiremath

[permalink] [raw]
Subject: [PATCH-v5 RESEND 3/5] i2c: pxa: Add support for pxa910/988 & new configuration features

TWSI_ILCR & TWSI_IWCR registers are used to adjust clock rate
of standard & fast mode in pxa910/988; so this patch adds these two new
entries to "struct pxa_reg_layout" and "struct pxa_i2c".

As discussed in the previous patch-series, the idea here is to add standard
DT properties for ilcr and iwcr configuration fields.
In case of Master ilcr is used for low/high time and in case of slave mode
of operation iwcr is used for setup/hold time.

Signed-off-by: Jett.Zhou <[email protected]>
Signed-off-by: Yi Zhang <[email protected]>
Signed-off-by: Vaibhav Hiremath <[email protected]>
Tested-by: Robert Jarzmik <[email protected]>
---
drivers/i2c/busses/i2c-pxa.c | 42 +++++++++++++++++++++++++++++++++++++++++-
1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index abf04f2..8d76197 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -46,12 +46,15 @@ struct pxa_reg_layout {
u32 icr;
u32 isr;
u32 isar;
+ u32 ilcr;
+ u32 iwcr;
};

enum pxa_i2c_types {
REGS_PXA2XX,
REGS_PXA3XX,
REGS_CE4100,
+ REGS_PXA910,
};

/*
@@ -79,12 +82,22 @@ static struct pxa_reg_layout pxa_reg_layout[] = {
.isr = 0x04,
/* no isar register */
},
+ [REGS_PXA910] = {
+ .ibmr = 0x00,
+ .idbr = 0x08,
+ .icr = 0x10,
+ .isr = 0x18,
+ .isar = 0x20,
+ .ilcr = 0x28,
+ .iwcr = 0x30,
+ },
};

static const struct platform_device_id i2c_pxa_id_table[] = {
{ "pxa2xx-i2c", REGS_PXA2XX },
{ "pxa3xx-pwri2c", REGS_PXA3XX },
{ "ce4100-i2c", REGS_CE4100 },
+ { "pxa910-i2c", REGS_PXA910 },
{ },
};
MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
@@ -124,6 +137,24 @@ MODULE_DEVICE_TABLE(platform, i2c_pxa_id_table);
#define ISR_SAD (1 << 9) /* slave address detected */
#define ISR_BED (1 << 10) /* bus error no ACK/NAK */

+/* bit field shift & mask */
+#define ILCR_SLV_SHIFT 0
+#define ILCR_SLV_MASK (0x1FF << ILCR_SLV_SHIFT)
+#define ILCR_FLV_SHIFT 9
+#define ILCR_FLV_MASK (0x1FF << ILCR_FLV_SHIFT)
+#define ILCR_HLVL_SHIFT 18
+#define ILCR_HLVL_MASK (0x1FF << ILCR_HLVL_SHIFT)
+#define ILCR_HLVH_SHIFT 27
+#define ILCR_HLVH_MASK (0x1F << ILCR_HLVH_SHIFT)
+
+#define IWCR_CNT_SHIFT 0
+#define IWCR_CNT_MASK (0x1F << IWCR_CNT_SHIFT)
+#define IWCR_HS_CNT1_SHIFT 5
+#define IWCR_HS_CNT1_MASK (0x1F << IWCR_HS_CNT1_SHIFT)
+#define IWCR_HS_CNT2_SHIFT 10
+#define IWCR_HS_CNT2_MASK (0x1F << IWCR_HS_CNT2_SHIFT)
+
+
struct pxa_i2c {
spinlock_t lock;
wait_queue_head_t wait;
@@ -150,6 +181,8 @@ struct pxa_i2c {
void __iomem *reg_icr;
void __iomem *reg_isr;
void __iomem *reg_isar;
+ void __iomem *reg_ilcr;
+ void __iomem *reg_iwcr;

unsigned long iobase;
unsigned long iosize;
@@ -169,6 +202,8 @@ struct pxa_i2c {
#define _ICR(i2c) ((i2c)->reg_icr)
#define _ISR(i2c) ((i2c)->reg_isr)
#define _ISAR(i2c) ((i2c)->reg_isar)
+#define _ILCR(i2c) ((i2c)->reg_ilcr)
+#define _IWCR(i2c) ((i2c)->reg_iwcr)

/*
* I2C Slave mode address
@@ -1135,7 +1170,7 @@ static const struct i2c_algorithm i2c_pxa_pio_algorithm = {
static const struct of_device_id i2c_pxa_dt_ids[] = {
{ .compatible = "mrvl,pxa-i2c", .data = (void *)REGS_PXA2XX },
{ .compatible = "mrvl,pwri2c", .data = (void *)REGS_PXA3XX },
- { .compatible = "mrvl,mmp-twsi", .data = (void *)REGS_PXA2XX },
+ { .compatible = "mrvl,mmp-twsi", .data = (void *)REGS_PXA910 },
{}
};
MODULE_DEVICE_TABLE(of, i2c_pxa_dt_ids);
@@ -1243,6 +1278,11 @@ static int i2c_pxa_probe(struct platform_device *dev)
if (i2c_type != REGS_CE4100)
i2c->reg_isar = i2c->reg_base + pxa_reg_layout[i2c_type].isar;

+ if (i2c_type == REGS_PXA910) {
+ i2c->reg_ilcr = i2c->reg_base + pxa_reg_layout[i2c_type].ilcr;
+ i2c->reg_iwcr = i2c->reg_base + pxa_reg_layout[i2c_type].iwcr;
+ }
+
i2c->iobase = res->start;
i2c->iosize = resource_size(res);

--
1.9.1

2015-08-24 06:02:19

by Vaibhav Hiremath

[permalink] [raw]
Subject: [PATCH-v5 RESEND 4/5] Documentation: binding: add sclk adjustment properties to i2c-pxa

With addition of PXA910 family of devices, the TWSI module supports
new feature which allows us to adjust SCLK. i2c-pxa driver takes input
configuration in nsec and converts it to respective bit-fields,

- i2c-sclk-low-time-ns : SCLK low time (tlow)
This property is used along with mode selection.
- i2c-sclk-high-time-ns : SCLK high time (thigh)
- i2c-start-hold-time-ns : Used in case of high speed mode for start bit
hold/setup wait counter.
- i2c-stop-hold-time-ns : Used in case of high speed mode for stop bit
hold/setup wait counter.
- i2c-sda-hold-time-ns : Used to calculate hold/setup wait counter for
standard and fast mode.

Signed-off-by: Vaibhav Hiremath <[email protected]>
---
Documentation/devicetree/bindings/i2c/i2c-pxa.txt | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-pxa.txt b/Documentation/devicetree/bindings/i2c/i2c-pxa.txt
index 9657db5..bb4df60 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-pxa.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-pxa.txt
@@ -23,12 +23,25 @@ Optional properties :
- i2c-disable-after-xfer : If set, driver will disable I2C module
after msg xfer and enable it again before xfer.

+ (Applicable to PXA910 family):
+
+ - i2c-sclk-low-time-ns : SCLK low time (tlow), for standard/fast/high
+ speed mode.
+ This property is used along with mode selection. Driver uses this property
+ to set low/high time for standard and fast speed mode, as HW counter
+ bit-field is same for both.
+ - i2c-sclk-high-time-ns : SCLK high time (thigh), Used in case of high speed
+ mode only.
+
Examples:
twsi1: i2c@d4011000 {
compatible = "mrvl,mmp-twsi";
reg = <0xd4011000 0x1000>;
interrupts = <7>;
mrvl,i2c-fast-mode;
+
+ i2c-sclk-low-time-ns = <988>;
+ i2c-sclk-high-time-ns = <988>;
};

twsi2: i2c@d4025000 {
--
1.9.1

2015-08-24 06:02:27

by Vaibhav Hiremath

[permalink] [raw]
Subject: [PATCH-v5 RESEND 5/5] i2c: pxa: Add ILCR (tLow & tHigh) configuration support

With addition of PXA910 family of devices, the TWSI module supports
SCL clock adjustment using ILCR register.

This patch enables the control and configuration of ICLR through DT
properties,

i2c-sclk-high-time-ns:
SCLK high time (tHigh), for standard/fast/high speed mode
i2c-sclk-low-time-ns:
SCLK low time (tLow), for standard/fast/high speed mode

Note that in case of standard and fast mod, the tLow and tHigh counters
are same, and software will use tLow value.

Also, brought up devm_clk_get() fn above i2c_pxa_probe_dt(), as it
uses clk rate for timing calculations.

Signed-off-by: Vaibhav Hiremath <[email protected]>
Signed-off-by: Jett.Zhou <[email protected]>
Signed-off-by: Yi Zhang <[email protected]>
Tested-by: Robert Jarzmik <[email protected]>
---
drivers/i2c/busses/i2c-pxa.c | 69 ++++++++++++++++++++++++++++++++++++++++----
1 file changed, 63 insertions(+), 6 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 8d76197..6012ae5 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -195,6 +195,9 @@ struct pxa_i2c {
unsigned long rate;
bool highmode_enter;
bool disable_after_xfer;
+
+ unsigned int sclk_thigh_load_cnt;
+ unsigned int sclk_tlow_load_cnt;
};

#define _IBMR(i2c) ((i2c)->reg_ibmr)
@@ -507,6 +510,36 @@ static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
#define i2c_pxa_set_slave(i2c, err) do { } while (0)
#endif

+static void i2c_pxa_do_sclk_adj(struct pxa_i2c *i2c)
+{
+ unsigned int reg_ilcr;
+
+ if (!i2c->reg_ilcr)
+ return;
+
+ reg_ilcr = readl(_ILCR(i2c));
+
+ /* For standard/fast mode tlow and thigh counters are same */
+ if (i2c->sclk_tlow_load_cnt) {
+ unsigned int mask, shift;
+
+ mask = i2c->high_mode ? ILCR_HLVL_MASK :
+ i2c->fast_mode ? ILCR_FLV_MASK : ILCR_SLV_MASK;
+ shift = i2c->high_mode ? ILCR_HLVL_SHIFT :
+ i2c->fast_mode ? ILCR_FLV_SHIFT : ILCR_SLV_SHIFT;
+
+ reg_ilcr &= ~mask;
+ reg_ilcr |= i2c->sclk_tlow_load_cnt << shift;
+ }
+
+ if (i2c->high_mode && i2c->sclk_thigh_load_cnt) {
+ reg_ilcr &= ~ILCR_HLVH_MASK;
+ reg_ilcr |= i2c->sclk_thigh_load_cnt << ILCR_HLVH_SHIFT;
+ }
+
+ writel(reg_ilcr, _ILCR(i2c));
+}
+
static void i2c_pxa_reset(struct pxa_i2c *i2c)
{
pr_debug("Resetting I2C Controller Unit\n");
@@ -526,6 +559,8 @@ static void i2c_pxa_reset(struct pxa_i2c *i2c)
writel(I2C_ICR_INIT | (i2c->fast_mode ? ICR_FM : 0), _ICR(i2c));
writel(readl(_ICR(i2c)) | (i2c->high_mode ? ICR_HS : 0), _ICR(i2c));

+ i2c_pxa_do_sclk_adj(i2c);
+
#ifdef CONFIG_I2C_PXA_SLAVE
dev_info(&i2c->adap.dev, "Enabling slave mode\n");
writel(readl(_ICR(i2c)) | ICR_SADIE | ICR_ALDIE | ICR_SSDIE, _ICR(i2c));
@@ -1198,6 +1233,26 @@ static int i2c_pxa_probe_dt(struct platform_device *pdev, struct pxa_i2c *i2c,

*i2c_types = (enum pxa_i2c_types)(of_id->data);

+ /* optional properties */
+ if (of_device_is_compatible(np, "mrvl,mmp-twsi")) {
+ unsigned int tlow = 0, thigh = 0;
+ unsigned int clk_ns;
+
+ /* clock time in nsec */
+ clk_ns = 1000000 / (i2c->rate / 1000);
+
+ of_property_read_u32(np, "i2c-sclk-high-time-ns", &thigh);
+ i2c->sclk_thigh_load_cnt = thigh / clk_ns;
+
+ of_property_read_u32(np, "i2c-sclk-low-time-ns", &tlow);
+ i2c->sclk_tlow_load_cnt = tlow / clk_ns;
+
+ /* For std/fast mode tlow & thigh have same bit-fields */
+ if (!i2c->high_mode &&
+ (i2c->sclk_tlow_load_cnt != i2c->sclk_thigh_load_cnt))
+ dev_warn(&i2c->adap.dev,
+ "mismatch of tLow & tHigh values, using tLow\n");
+ }
return 0;
}

@@ -1248,6 +1303,14 @@ static int i2c_pxa_probe(struct platform_device *dev)
return irq;
}

+ i2c->clk = devm_clk_get(&dev->dev, NULL);
+ if (IS_ERR(i2c->clk)) {
+ dev_err(&dev->dev, "failed to get the clk: %ld\n", PTR_ERR(i2c->clk));
+ return PTR_ERR(i2c->clk);
+ }
+
+ i2c->rate = clk_get_rate(i2c->clk);
+
/* Default adapter num to device id; i2c_pxa_probe_dt can override. */
i2c->adap.nr = dev->id;

@@ -1265,12 +1328,6 @@ static int i2c_pxa_probe(struct platform_device *dev)

strlcpy(i2c->adap.name, "pxa_i2c-i2c", sizeof(i2c->adap.name));

- i2c->clk = devm_clk_get(&dev->dev, NULL);
- if (IS_ERR(i2c->clk)) {
- dev_err(&dev->dev, "failed to get the clk: %ld\n", PTR_ERR(i2c->clk));
- return PTR_ERR(i2c->clk);
- }
-
i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
i2c->reg_idbr = i2c->reg_base + pxa_reg_layout[i2c_type].idbr;
i2c->reg_icr = i2c->reg_base + pxa_reg_layout[i2c_type].icr;
--
1.9.1