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i2c: ocores: fix clock-frequency binding usage

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clock-frequency property is meant to control the bus frequency for i2c bus
drivers, but it was incorrectly used to specify i2c controller input clock
frequency.
Introduce new attribute, opencores,ip-clock-frequency, that specifies i2c
controller clock frequency and make clock-frequency attribute compatible
with other i2c drivers. Maintain backwards compatibility in case
opencores,ip-clock-frequency attribute is missing.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Max Filippov
2015-02-02 18:28:12 +03:00
committed by Wolfram Sang
parent 8c340f6090
commit 3a33a85401
2 changed files with 58 additions and 15 deletions
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55
drivers/i2c/busses/i2c-ocores.c
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@@ -35,7 +35,8 @@ struct ocores_i2c {
int pos;
int nmsgs;
int state; /* see STATE_ */
int clock_khz;
int ip_clock_khz;
int bus_clock_khz;
void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);
u8 (*getreg)(struct ocores_i2c *i2c, int reg);
};
@@ -215,21 +216,34 @@ static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
return -ETIMEDOUT;
}
static void ocores_init(struct ocores_i2c *i2c)
static int ocores_init(struct device *dev, struct ocores_i2c *i2c)
{
int prescale;
int diff;
u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
/* make sure the device is disabled */
oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
prescale = (i2c->clock_khz / (5*100)) - 1;
prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
prescale = clamp(prescale, 0, 0xffff);
diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
if (abs(diff) > i2c->bus_clock_khz / 10) {
dev_err(dev,
"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
i2c->ip_clock_khz, i2c->bus_clock_khz);
return -EINVAL;
}
oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
/* Init the device */
oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
return 0;
}
@@ -304,6 +318,8 @@ static int ocores_i2c_of_probe(struct platform_device *pdev,
struct device_node *np = pdev->dev.of_node;
const struct of_device_id *match;
u32 val;
u32 clock_frequency;
bool clock_frequency_present;
if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
/* no 'reg-shift', check for deprecated 'regstep' */
@@ -319,12 +335,24 @@ static int ocores_i2c_of_probe(struct platform_device *pdev,
}
}
if (of_property_read_u32(np, "clock-frequency", &val)) {
dev_err(&pdev->dev,
"Missing required parameter 'clock-frequency'\n");
return -ENODEV;
clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
&clock_frequency);
i2c->bus_clock_khz = 100;
if (of_property_read_u32(np, "opencores,ip-clock-frequency", &val)) {
if (!clock_frequency_present) {
dev_err(&pdev->dev,
"Missing required parameter 'opencores,ip-clock-frequency'\n");
return -ENODEV;
}
i2c->ip_clock_khz = clock_frequency / 1000;
dev_warn(&pdev->dev,
"Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
} else {
i2c->ip_clock_khz = val / 1000;
if (clock_frequency_present)
i2c->bus_clock_khz = clock_frequency / 1000;
}
i2c->clock_khz = val / 1000;
of_property_read_u32(pdev->dev.of_node, "reg-io-width",
&i2c->reg_io_width);
@@ -368,7 +396,8 @@ static int ocores_i2c_probe(struct platform_device *pdev)
if (pdata) {
i2c->reg_shift = pdata->reg_shift;
i2c->reg_io_width = pdata->reg_io_width;
i2c->clock_khz = pdata->clock_khz;
i2c->ip_clock_khz = pdata->clock_khz;
i2c->bus_clock_khz = 100;
} else {
ret = ocores_i2c_of_probe(pdev, i2c);
if (ret)
@@ -402,7 +431,9 @@ static int ocores_i2c_probe(struct platform_device *pdev)
}
}
ocores_init(i2c);
ret = ocores_init(&pdev->dev, i2c);
if (ret)
return ret;
init_waitqueue_head(&i2c->wait);
ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
@@ -465,9 +496,7 @@ static int ocores_i2c_resume(struct device *dev)
{
struct ocores_i2c *i2c = dev_get_drvdata(dev);
ocores_init(i2c);
return 0;
return ocores_init(dev, i2c);
}
static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);