[PATCHv3] I2C: MV64XXX: Add Device Tree support
Andrew Lunn
andrew at lunn.ch
Mon Jul 16 05:16:45 EDT 2012
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.
Also extend the kirkwood DT support to supply the needed properties. A
default clock-frequency is 400KHz, which some platforms might need to
override to 100KHz if they have devices which do not support fast
mode.
Signed-off-by: Andrew Lunn <andrew at lunn.ch>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth at googlemail.com>
---
v2: Removed duplicate interrupt in DT.
v3: Use clock-frequency property, instead of explicit n & m baud factors.
i2c fix.
---
Documentation/devicetree/bindings/i2c/mrvl-i2c.txt | 21 +++-
arch/arm/boot/dts/kirkwood.dtsi | 11 ++
arch/arm/mach-kirkwood/board-dt.c | 2 +
arch/arm/mach-kirkwood/common.c | 2 +
arch/arm/plat-orion/common.c | 1 +
drivers/i2c/busses/i2c-mv64xxx.c | 107 +++++++++++++++++++-
6 files changed, 138 insertions(+), 6 deletions(-)
diff --git a/Documentation/devicetree/bindings/i2c/mrvl-i2c.txt b/Documentation/devicetree/bindings/i2c/mrvl-i2c.txt
index b891ee2..885f340 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 +32,22 @@ 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 : Te interrupt number
+ - clock-frequency : Desired I2C bus clock frequency in Hz.
+ - timeout-ms : How long to wait for a transaction to complete
+
+Examples:
+
+ i2c at 11000 {
+ compatible = "marvell,mv64xxx-i2c";
+ reg = <0x11000 0x20>;
+ interrupts = <29>;
+ clock-frequency = <100000>;
+ timeout-ms = <1000>;
+ };
diff --git a/arch/arm/boot/dts/kirkwood.dtsi b/arch/arm/boot/dts/kirkwood.dtsi
index a3350fd..bc57d81 100644
--- a/arch/arm/boot/dts/kirkwood.dtsi
+++ b/arch/arm/boot/dts/kirkwood.dtsi
@@ -82,5 +82,16 @@
/* set partition map and/or chip-delay in board dts */
status = "disabled";
};
+
+ i2c at 11000 {
+ compatible = "marvell,mv64xxx-i2c";
+ reg = <0x11000 0x20>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ interrupts = <29>;
+ clock-frequency = <400000>;
+ timeout-ms = <1000>;
+ status = "disable";
+ };
};
};
diff --git a/arch/arm/mach-kirkwood/board-dt.c b/arch/arm/mach-kirkwood/board-dt.c
index 8f8da5d..24c8fdd 100644
--- a/arch/arm/mach-kirkwood/board-dt.c
+++ b/arch/arm/mach-kirkwood/board-dt.c
@@ -28,6 +28,8 @@ static struct of_device_id kirkwood_dt_match_table[] __initdata = {
struct of_dev_auxdata kirkwood_auxdata_lookup[] __initdata = {
OF_DEV_AUXDATA("marvell,orion-spi", 0xf1010600, "orion_spi.0", NULL),
+ OF_DEV_AUXDATA("marvell,mv64xxx-i2c", 0xf1011000, "mv64xxx_i2c.0",
+ NULL),
{},
};
diff --git a/arch/arm/mach-kirkwood/common.c b/arch/arm/mach-kirkwood/common.c
index f261cd2..078d9c6 100644
--- a/arch/arm/mach-kirkwood/common.c
+++ b/arch/arm/mach-kirkwood/common.c
@@ -17,6 +17,7 @@
#include <linux/dma-mapping.h>
#include <linux/clk-provider.h>
#include <linux/spinlock.h>
+#include <linux/mv643xx_i2c.h>
#include <net/dsa.h>
#include <asm/page.h>
#include <asm/timex.h>
@@ -241,6 +242,7 @@ void __init kirkwood_clk_init(void)
orion_clkdev_add("0", "pcie", pex0);
orion_clkdev_add("1", "pcie", pex1);
orion_clkdev_add(NULL, "kirkwood-i2s", audio);
+ orion_clkdev_add(NULL, MV64XXX_I2C_CTLR_NAME ".0", runit);
}
/*****************************************************************************
diff --git a/arch/arm/plat-orion/common.c b/arch/arm/plat-orion/common.c
index c179378..d245a87 100644
--- a/arch/arm/plat-orion/common.c
+++ b/arch/arm/plat-orion/common.c
@@ -47,6 +47,7 @@ void __init orion_clkdev_init(struct clk *tclk)
orion_clkdev_add(NULL, MV643XX_ETH_NAME ".2", tclk);
orion_clkdev_add(NULL, MV643XX_ETH_NAME ".3", tclk);
orion_clkdev_add(NULL, "orion_wdt", tclk);
+ orion_clkdev_add(NULL, MV64XXX_I2C_CTLR_NAME ".0", tclk);
}
/* Fill in the resources structure and link it into the platform
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index 4f44a33..e97246b 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 +103,7 @@ struct mv64xxx_i2c_data {
int rc;
u32 freq_m;
u32 freq_n;
+ struct clk *clk;
wait_queue_head_t waitq;
spinlock_t lock;
struct i2c_msg *msg;
@@ -521,6 +527,36 @@ mv64xxx_i2c_unmap_regs(struct mv64xxx_i2c_data *drv_data)
drv_data->reg_base_p = 0;
}
+#ifdef CONFIG_OF
+static int __devinit
+calc_freq(const int tclk, const int n, const int m)
+{
+ return tclk / (10 * (m + 1) * (2 << n));
+}
+
+static bool __devinit
+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 = 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;
+}
+#endif
static int __devinit
mv64xxx_i2c_probe(struct platform_device *pd)
{
@@ -528,7 +564,7 @@ mv64xxx_i2c_probe(struct platform_device *pd)
struct mv64xxx_i2c_pdata *pdata = pd->dev.platform_data;
int rc;
- if ((pd->id != 0) || !pdata)
+ if ((!pdata && !pd->dev.of_node) || (pdata && (pd->id != 0)))
return -ENODEV;
drv_data = kzalloc(sizeof(struct mv64xxx_i2c_data), GFP_KERNEL);
@@ -546,19 +582,64 @@ 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);
+ }
+#ifdef CONFIG_OF
+ if (pd->dev.of_node) {
+ int bus_freq;
+ int tclk;
+ /* 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)
+ if (IS_ERR(drv_data->clk)) {
+ rc = -ENODEV;
+ goto exit_unmap_regs;
+ }
+ tclk = clk_get_rate(drv_data->clk);
+ of_property_read_u32(pd->dev.of_node, "clock-frequency",
+ &bus_freq);
+ if (!find_baud_factors(bus_freq, tclk,
+ &drv_data->freq_n, &drv_data->freq_m)) {
+ rc = -EINVAL;
+ goto exit_unmap_regs;
+ }
+ drv_data->irq = irq_of_parse_and_map(pd->dev.of_node, 0);
+#else
+ /* Have OF but no CLK */
+ rc = -ENODEV;
+ goto exit_unmap_regs;
+#endif
+ }
+#endif
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);
+ if (pd->dev.of_node)
+ drv_data->adapter.timeout = msecs_to_jiffies(
+ of_property_read_u32(pd->dev.of_node, "timeout-ms",
+ &drv_data->freq_n));
+ else
+ 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);
@@ -577,6 +658,8 @@ mv64xxx_i2c_probe(struct platform_device *pd)
goto exit_free_irq;
}
+ of_i2c_register_devices(&drv_data->adapter);
+
return 0;
exit_free_irq:
@@ -597,17 +680,31 @@ 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
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