Extends the driver to get properties from device tree. Rather than
pass the N & M factors in DT, use the more standard clock-frequency
property. Calculate N & M at run time. In order to do this, we need to
know tclk. So the driver uses clk_get() etc in order to get the clock
and clk_get_rate() to determine the tclk rate. Not all platforms
however have CLK, so some #ifdefery is needed to ensure the driver
still compiles when CLK is not available.
Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
---
- Replaced the timeout property in DT, with a hard coded 1 second.
- Put all the OF code together.
- Split the ARM parts from the driver itself.
- Dropped Sebastian Hesselbarth Acked-by, since the changes are not trivial.
- Change MV64XXX to MV64XYZ in the Subject to try to get it past the list
spam filter.
- return -ENODEV and else if comments from Wolfram.
- Rebased on i2c-embedded/for-next
Documentation/devicetree/bindings/i2c/mrvl-i2c.txt | 19 ++-
drivers/i2c/busses/i2c-mv64xxx.c | 134 +++++++++++++++++++-
2 files changed, 147 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/i2c/mrvl-i2c.txt b/Documentation/devicetree/bindings/i2c/mrvl-i2c.txt
index b891ee2..0f79450 100644
--- a/Documentation/devicetree/bindings/i2c/mrvl-i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/mrvl-i2c.txt
@@ -1,4 +1,4 @@
-* I2C
+* Marvell MMP I2C controller
Required properties :
@@ -32,3 +32,20 @@ Examples:
interrupts = <58>;
};
+* Marvell MV64XXX I2C controller
+
+Required properties :
+
+ - reg : Offset and length of the register set for the device
+ - compatible : Should be "marvell,mv64xxx-i2c"
+ - interrupts : The interrupt number
+ - clock-frequency : Desired I2C bus clock frequency in Hz.
+
+Examples:
+
+ i2c@11000 {
+ compatible = "marvell,mv64xxx-i2c";
+ reg = <0x11000 0x20>;
+ interrupts = <29>;
+ clock-frequency = <100000>;
+ };
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 6e70eea..3d53f4e 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -18,6 +18,11 @@
#include <linux/mv643xx_i2c.h>
#include <linux/platform_device.h>
#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/of_i2c.h>
+#include <linux/clk.h>
+#include <linux/err.h>
/* Register defines */
#define MV64XXX_I2C_REG_SLAVE_ADDR 0x00
@@ -98,6 +103,9 @@ struct mv64xxx_i2c_data {
int rc;
u32 freq_m;
u32 freq_n;
+#if defined(CONFIG_HAVE_CLK)
+ struct clk *clk;
+#endif
wait_queue_head_t waitq;
spinlock_t lock;
struct i2c_msg *msg;
@@ -521,6 +529,83 @@ mv64xxx_i2c_unmap_regs(struct mv64xxx_i2c_data *drv_data)
drv_data->reg_base_p = 0;
}
+#ifdef CONFIG_OF
+static int __devinit
+mv64xxx_calc_freq(const int tclk, const int n, const int m)
+{
+ return tclk / (10 * (m + 1) * (2 << n));
+}
+
+static bool __devinit
+mv64xxx_find_baud_factors(const int req_freq, const int tclk, int *best_n,
+ int *best_m)
+{
+ int freq, delta, best_delta = INT_MAX;
+ int m, n;
+
+ for (n = 0; n <= 7; n++)
+ for (m = 0; m <= 15; m++) {
+ freq = mv64xxx_calc_freq(tclk, n, m);
+ delta = req_freq - freq;
+ if (delta >= 0 && delta < best_delta) {
+ *best_m = m;
+ *best_n = n;
+ best_delta = delta;
+ }
+ if (best_delta == 0)
+ return true;
+ }
+ if (best_delta == INT_MAX)
+ return false;
+ return true;
+}
+
+static int __devinit
+mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
+ struct device_node *np)
+{
+ int bus_freq;
+ int tclk;
+ int rc = 0;
+
+ /* CLK is mandatory when using DT to describe the i2c bus. We
+ * need to know tclk in order to calculate bus clock
+ * factors.
+ */
+#if !defined(CONFIG_HAVE_CLK)
+ /* Have OF but no CLK */
+ return -ENODEV;
+#else
+ if (IS_ERR(drv_data->clk)) {
+ rc = -ENODEV;
+ goto out;
+ }
+ tclk = clk_get_rate(drv_data->clk);
+ of_property_read_u32(np, "clock-frequency", &bus_freq);
+ if (!mv64xxx_find_baud_factors(bus_freq, tclk,
+ &drv_data->freq_n, &drv_data->freq_m)) {
+ rc = -EINVAL;
+ goto out;
+ }
+ drv_data->irq = irq_of_parse_and_map(np, 0);
+
+ /* Its not yet defined how timeouts will be specified in device tree.
+ * So hard code the value to 1 second.
+ */
+ drv_data->adapter.timeout = HZ;
+out:
+ return rc;
+#endif
+}
+#else /* CONFIG_OF */
+static int __devinit
+mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
+ struct device_node *np)
+{
+ return -ENODEV;
+}
+#endif /* CONFIG_OF */
+
static int __devinit
mv64xxx_i2c_probe(struct platform_device *pd)
{
@@ -528,7 +613,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
struct mv64xxx_i2c_pdata *pdata = pd->dev.platform_data;
int rc;
- if (!pdata)
+ if ((!pdata && !pd->dev.of_node))
return -ENODEV;
drv_data = kzalloc(sizeof(struct mv64xxx_i2c_data), GFP_KERNEL);
@@ -546,19 +631,35 @@ mv64xxx_i2c_probe(struct platform_device *pd)
init_waitqueue_head(&drv_data->waitq);
spin_lock_init(&drv_data->lock);
- drv_data->freq_m = pdata->freq_m;
- drv_data->freq_n = pdata->freq_n;
- drv_data->irq = platform_get_irq(pd, 0);
+#if defined(CONFIG_HAVE_CLK)
+ /* Not all platforms have a clk */
+ drv_data->clk = clk_get(&pd->dev, NULL);
+ if (!IS_ERR(drv_data->clk)) {
+ clk_prepare(drv_data->clk);
+ clk_enable(drv_data->clk);
+ }
+#endif
+ if (pdata) {
+ drv_data->freq_m = pdata->freq_m;
+ drv_data->freq_n = pdata->freq_n;
+ drv_data->irq = platform_get_irq(pd, 0);
+ drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout);
+ } else if (pd->dev.of_node) {
+ rc = mv64xxx_of_config(drv_data, pd->dev.of_node);
+ if (rc)
+ goto exit_unmap_regs;
+ }
if (drv_data->irq < 0) {
rc = -ENXIO;
goto exit_unmap_regs;
}
+
drv_data->adapter.dev.parent = &pd->dev;
drv_data->adapter.algo = &mv64xxx_i2c_algo;
drv_data->adapter.owner = THIS_MODULE;
drv_data->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
- drv_data->adapter.timeout = msecs_to_jiffies(pdata->timeout);
drv_data->adapter.nr = pd->id;
+ drv_data->adapter.dev.of_node = pd->dev.of_node;
platform_set_drvdata(pd, drv_data);
i2c_set_adapdata(&drv_data->adapter, drv_data);
@@ -577,11 +678,20 @@ mv64xxx_i2c_probe(struct platform_device *pd)
goto exit_free_irq;
}
+ of_i2c_register_devices(&drv_data->adapter);
+
return 0;
exit_free_irq:
free_irq(drv_data->irq, drv_data);
exit_unmap_regs:
+#if defined(CONFIG_HAVE_CLK)
+ /* Not all platforms have a clk */
+ if (!IS_ERR(drv_data->clk)) {
+ clk_disable(drv_data->clk);
+ clk_unprepare(drv_data->clk);
+ }
+#endif
mv64xxx_i2c_unmap_regs(drv_data);
exit_kfree:
kfree(drv_data);
@@ -597,17 +707,31 @@ mv64xxx_i2c_remove(struct platform_device *dev)
rc = i2c_del_adapter(&drv_data->adapter);
free_irq(drv_data->irq, drv_data);
mv64xxx_i2c_unmap_regs(drv_data);
+#if defined(CONFIG_HAVE_CLK)
+ /* Not all platforms have a clk */
+ if (!IS_ERR(drv_data->clk)) {
+ clk_disable(drv_data->clk);
+ clk_unprepare(drv_data->clk);
+ }
+#endif
kfree(drv_data);
return rc;
}
+static const struct of_device_id mv64xxx_i2c_of_match_table[] __devinitdata = {
+ { .compatible = "marvell,mv64xxx-i2c", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, mv64xxx_i2c_of_match_table);
+
static struct platform_driver mv64xxx_i2c_driver = {
.probe = mv64xxx_i2c_probe,
.remove = __devexit_p(mv64xxx_i2c_remove),
.driver = {
.owner = THIS_MODULE,
.name = MV64XXX_I2C_CTLR_NAME,
+ .of_match_table = of_match_ptr(mv64xxx_i2c_of_match_table),
},
};
--
1.7.10.4
--
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