forked from Minki/linux
I2C: MV64XYZ: Add Device Tree support
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@lunn.ch> [wsa: converted some ints to u32 to match signedness] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
This commit is contained in:
Andrew Lunn
Wolfram Sang
parent
6f535b9426
commit
b61d157589
@ -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>;
|
||||
};
|
||||
|
||||
@ -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 +529,82 @@ 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 u32 req_freq, const u32 tclk, u32 *best_n,
|
||||
u32 *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)
|
||||
{
|
||||
u32 bus_freq, 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 +612,7 @@ 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 +630,35 @@ 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 +677,20 @@ 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 +706,31 @@ 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),
|
||||
},
|
||||
};
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user