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@xxxxxxxxxx>
Signed-off-by: Jett.Zhou <jtzhou@xxxxxxxxxxx>
Signed-off-by: Yi Zhang <yizhang@xxxxxxxxxxx>
---
drivers/i2c/busses/i2c-pxa.c | 66 ++++++++++++++++++++++++++++++++++++++++----
1 file changed, 60 insertions(+), 6 deletions(-)
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 8d76197..ee79599 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 +510,33 @@ 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;
+
+ 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 +556,8 @@ 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 +1230,26 @@ 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 +1300,14 @@ 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 +1325,6 @@ 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
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
