diff mbox

[PATCH-v5,5/5] i2c: pxa: Add ILCR (tLow & tHigh) configuration support

Message ID 1437482466-16126-6-git-send-email-vaibhav.hiremath@linaro.org
State Superseded
Headers show

Commit Message

Vaibhav Hiremath July 21, 2015, 12:41 p.m. UTC 
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 <vaibhav.hiremath@linaro.org>
Signed-off-by: Jett.Zhou <jtzhou@marvell.com>
Signed-off-by: Yi Zhang <yizhang@marvell.com>
---
 drivers/i2c/busses/i2c-pxa.c | 69 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 63 insertions(+), 6 deletions(-)

Comments

Vaibhav Hiremath Aug. 5, 2015, 8:51 a.m. UTC | #1 
On Tuesday 21 July 2015 06:11 PM, Vaibhav Hiremath wrote:
> 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 <vaibhav.hiremath@linaro.org>
> Signed-off-by: Jett.Zhou <jtzhou@marvell.com>
> Signed-off-by: Yi Zhang <yizhang@marvell.com>
> ---
>   drivers/i2c/busses/i2c-pxa.c | 69 ++++++++++++++++++++++++++++++++++++++++----
>   1 file changed, 63 insertions(+), 6 deletions(-)
>

Robert,

It would be helpful if you can test this patch-series and confirm that
it now fixes the NULL pointer deference issue.

Thanks,
Vaibhav
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Robert Jarzmik Aug. 5, 2015, 7:11 p.m. UTC | #2 
Vaibhav Hiremath <vaibhav.hiremath@linaro.org> writes:

> Robert,
>
> It would be helpful if you can test this patch-series and confirm that
> it now fixes the NULL pointer deference issue.
>
> Thanks,
> Vaibhav
Hi Vaibhav,

My next slot is probably this comming Sunday. I'll do the test and report.

Cheers.
Vaibhav Hiremath Aug. 6, 2015, 5:45 a.m. UTC | #3 
On Thursday 06 August 2015 12:41 AM, Robert Jarzmik wrote:
> My next slot is probably this comming Sunday. I'll do the test and report

Thanks a lot.

Thanks,
Vaibhav
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Robert Jarzmik Aug. 9, 2015, 12:18 p.m. UTC | #4 
Vaibhav Hiremath <vaibhav.hiremath@linaro.org> writes:

> Robert,
>
> It would be helpful if you can test this patch-series and confirm that
> it now fixes the NULL pointer deference issue.
Tested, it works on pxa27x in master mode, in non-DT mode.

For all non-DT patches, you can add my :
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>

Cheers.
Vaibhav Hiremath Aug. 9, 2015, 4:53 p.m. UTC | #5 
On Sunday 09 August 2015 05:48 PM, Robert Jarzmik wrote:
> Vaibhav Hiremath <vaibhav.hiremath@linaro.org> writes:
>
>> Robert,
>>
>> It would be helpful if you can test this patch-series and confirm that
>> it now fixes the NULL pointer deference issue.
> Tested, it works on pxa27x in master mode, in non-DT mode.
>
> For all non-DT patches, you can add my :
> Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
>

Thanks Robert,

Wolfram,
Request you to please take a look at this series.
We can have discussion on DT properties as well.

Thanks,
Vaibhav
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diff mbox

Patch

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;