* [PATCH 2/2] powerpc: i2c-mpc: make I2C bus speed configurable
2009-03-31 12:43 [PATCH 0/2] test Wolfgang Grandegger
2009-03-31 12:43 ` [PATCH 1/2] powerpc: i2c-mpc: preserve I2C clocking Wolfgang Grandegger
@ 2009-03-31 12:43 ` Wolfgang Grandegger
1 sibling, 0 replies; 6+ messages in thread
From: Wolfgang Grandegger @ 2009-03-31 12:43 UTC (permalink / raw)
To: linuxppc-dev; +Cc: devicetree-discuss
This patch makes the I2C bus speed configurable by using the I2C node
property "clock-frequency". If the property is not defined, the old
fixed clock settings will be used for backward comptibility.
The generic I2C clock properties, especially the CPU-specific source
clock pre-scaler are defined via the OF match table:
static const struct of_device_id mpc_i2c_of_match[] = {
{.compatible = "fsl,mpc5200b-i2c",
.data = (void *)FSL_I2C_DEV_CLOCK_5200, },
{.compatible = "fsl,mpc5200-i2c",
.data = (void *)FSL_I2C_DEV_CLOCK_5200, },
{.compatible = "fsl,mpc8313-i2c",
.data = (void *)FSL_I2C_DEV_SEPARATE_DFSRR, },
{.compatible = "fsl,mpc8543-i2c",
.data = (void *)(FSL_I2C_DEV_SEPARATE_DFSRR |
FSL_I2C_DEV_CLOCK_DIV2), },
{.compatible = "fsl,mpc8544-i2c",
.data = (void *)(FSL_I2C_DEV_SEPARATE_DFSRR |
FSL_I2C_DEV_CLOCK_DIV23), },
/* Backward compatibility */
{.compatible = "fsl-i2c", },
{},
};
The "data" field defines the relevant I2C flags for the comptible CPU.
It used arch-specific tables and functions to determine the proper
Freqency Divider Register (fdr).
Furthermore dev_dbg() and dev_info() are now used to profit from a more
comprehensive output.
Signed-off-by: Wolfgang Grandegger <wg@grandegger•com>
---
arch/powerpc/platforms/52xx/mpc52xx_common.c | 48 ++++++++++++
arch/powerpc/sysdev/fsl_soc.c | 90 +++++++++++++++++++++++
drivers/i2c/busses/i2c-mpc.c | 104 +++++++++++++++++++--------
include/linux/fsl_devices.h | 6 +
4 files changed, 221 insertions(+), 27 deletions(-)
Index: linux-2.6/drivers/i2c/busses/i2c-mpc.c
===================================================================
--- linux-2.6.orig/drivers/i2c/busses/i2c-mpc.c 2009-03-31 13:28:03.000000000 +0200
+++ linux-2.6/drivers/i2c/busses/i2c-mpc.c 2009-03-31 13:38:01.355720989 +0200
@@ -20,12 +20,14 @@
#include <linux/of_platform.h>
#include <linux/of_i2c.h>
-#include <asm/io.h>
+#include <linux/io.h>
#include <linux/fsl_devices.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
+#include <sysdev/fsl_soc.h>
+
#define DRV_NAME "mpc-i2c"
#define MPC_I2C_FDR 0x04
@@ -50,6 +52,7 @@
#define CSR_RXAK 0x01
struct mpc_i2c {
+ struct device *dev;
void __iomem *base;
u32 interrupt;
wait_queue_head_t queue;
@@ -105,7 +108,7 @@
while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
schedule();
if (time_after(jiffies, orig_jiffies + timeout)) {
- pr_debug("I2C: timeout\n");
+ dev_dbg(i2c->dev, "timeout\n");
writeccr(i2c, 0);
result = -EIO;
break;
@@ -119,10 +122,10 @@
(i2c->interrupt & CSR_MIF), timeout * HZ);
if (unlikely(result < 0)) {
- pr_debug("I2C: wait interrupted\n");
+ dev_dbg(i2c->dev, "wait interrupted\n");
writeccr(i2c, 0);
} else if (unlikely(!(i2c->interrupt & CSR_MIF))) {
- pr_debug("I2C: wait timeout\n");
+ dev_dbg(i2c->dev, "wait timeout\n");
writeccr(i2c, 0);
result = -ETIMEDOUT;
}
@@ -135,17 +138,17 @@
return result;
if (!(x & CSR_MCF)) {
- pr_debug("I2C: unfinished\n");
+ dev_dbg(i2c->dev, "unfinished\n");
return -EIO;
}
if (x & CSR_MAL) {
- pr_debug("I2C: MAL\n");
+ dev_dbg(i2c->dev, "MAL\n");
return -EIO;
}
if (writing && (x & CSR_RXAK)) {
- pr_debug("I2C: No RXAK\n");
+ dev_dbg(i2c->dev, "No RXAK\n");
/* generate stop */
writeccr(i2c, CCR_MEN);
return -EIO;
@@ -153,17 +156,38 @@
return 0;
}
-static void mpc_i2c_setclock(struct mpc_i2c *i2c)
+static void mpc_i2c_setclock(struct device_node *node,
+ struct mpc_i2c *i2c, u32 clock)
{
- /* Set clock and filters */
- if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
- writeb(0x31, i2c->base + MPC_I2C_FDR);
- writeb(0x10, i2c->base + MPC_I2C_DFSRR);
- } else if (i2c->flags & FSL_I2C_DEV_CLOCK_5200)
- writeb(0x3f, i2c->base + MPC_I2C_FDR);
- else
- writel(0x1031, i2c->base + MPC_I2C_FDR);
-}
+ int fdr;
+
+ fdr = fsl_i2c_get_fdr(node, clock, i2c->flags);
+
+ if (i2c->flags & FSL_I2C_DEV_CLOCK_5200) {
+ pr_debug("I2C: old fdr=%d\n", readb(i2c->base + MPC_I2C_FDR));
+ if (fdr < 0)
+ fdr = 0x3f; /* backward compatibility */
+ writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
+ dev_info("clock %d Hz (fdr=%d)\n", clock, fdr);
+ } else {
+ if (fdr < 0)
+ fdr = 0x1031; /* backward compatibility */
+ if (i2c->flags & FSL_I2C_DEV_SEPARATE_DFSRR) {
+ pr_debug("I2C: old dfsrr=%d fdr=%d\n",
+ readb(i2c->base + MPC_I2C_DFSRR),
+ readb(i2c->base + MPC_I2C_FDR));
+ writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
+ writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);
+ dev_info("clock %d Hz (dfsrr=%d fdr=%d)\n",
+ clock, fdr >> 8, fdr & 0xff);
+ } else {
+ pr_debug("I2C: old fdr=%d\n",
+ readl(i2c->base + MPC_I2C_FDR));
+ writel(fdr & 0xffff, i2c->base + MPC_I2C_FDR);
+ dev_info("clock %d Hz (fdr=%d)\n", clock, fdr);
+ }
+ }
+ }
static void mpc_i2c_start(struct mpc_i2c *i2c)
{
@@ -267,12 +291,12 @@
/* Allow bus up to 1s to become not busy */
while (readb(i2c->base + MPC_I2C_SR) & CSR_MBB) {
if (signal_pending(current)) {
- pr_debug("I2C: Interrupted\n");
+ dev_dbg(i2c->dev, "interrupted\n");
writeccr(i2c, 0);
return -EINTR;
}
if (time_after(jiffies, orig_jiffies + HZ)) {
- pr_debug("I2C: timeout\n");
+ dev_dbg(i2c->dev, "timeout\n");
if (readb(i2c->base + MPC_I2C_SR) ==
(CSR_MCF | CSR_MBB | CSR_RXAK))
mpc_i2c_fixup(i2c);
@@ -283,9 +307,10 @@
for (i = 0; ret >= 0 && i < num; i++) {
pmsg = &msgs[i];
- pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n",
- pmsg->flags & I2C_M_RD ? "read" : "write",
- pmsg->len, pmsg->addr, i + 1, num);
+ dev_dbg(i2c->dev,
+ "doing %s %d bytes to 0x%02x - %d of %d messages\n",
+ pmsg->flags & I2C_M_RD ? "read" : "write",
+ pmsg->len, pmsg->addr, i + 1, num);
if (pmsg->flags & I2C_M_RD)
ret =
mpc_read(i2c, pmsg->addr, pmsg->buf, pmsg->len, i);
@@ -316,9 +341,12 @@
static int __devinit fsl_i2c_probe(struct of_device *op, const struct of_device_id *match)
{
- int result = 0;
struct mpc_i2c *i2c;
+ const u32 *prop;
+ u32 clock = 0;
int set_clock;
+ int result = 0;
+ int plen;
i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
if (!i2c)
@@ -328,7 +356,11 @@
set_clock = 0;
} else {
set_clock = 1;
+ prop = of_get_property(op->node, "clock-frequency", &plen);
+ if (prop && plen == sizeof(u32))
+ clock = *prop;
+ /* Backwards compatibility */
if (of_get_property(op->node, "dfsrr", NULL))
i2c->flags |= FSL_I2C_DEV_SEPARATE_DFSRR;
@@ -356,11 +388,15 @@
}
}
- if (set_clock)
- mpc_i2c_setclock(i2c);
+ if (set_clock) {
+ if (match->data)
+ i2c->flags = (u32)match->data;
+ mpc_i2c_setclock(op->node, i2c, clock);
+ }
dev_set_drvdata(&op->dev, i2c);
+ i2c->dev = &op->dev;
i2c->adap = mpc_ops;
i2c_set_adapdata(&i2c->adap, i2c);
i2c->adap.dev.parent = &op->dev;
@@ -402,9 +438,23 @@
};
static const struct of_device_id mpc_i2c_of_match[] = {
- {.compatible = "fsl-i2c",},
+ {.compatible = "fsl,mpc5200b-i2c",
+ .data = (void *)FSL_I2C_DEV_CLOCK_5200, },
+ {.compatible = "fsl,mpc5200-i2c",
+ .data = (void *)FSL_I2C_DEV_CLOCK_5200, },
+ {.compatible = "fsl,mpc8313-i2c",
+ .data = (void *)FSL_I2C_DEV_SEPARATE_DFSRR, },
+ {.compatible = "fsl,mpc8543-i2c",
+ .data = (void *)(FSL_I2C_DEV_SEPARATE_DFSRR |
+ FSL_I2C_DEV_CLOCK_DIV2), },
+ {.compatible = "fsl,mpc8544-i2c",
+ .data = (void *)(FSL_I2C_DEV_SEPARATE_DFSRR |
+ FSL_I2C_DEV_CLOCK_DIV23), },
+ /* Backward compatibility */
+ {.compatible = "fsl-i2c", },
{},
};
+
MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);
@@ -425,7 +475,7 @@
rv = of_register_platform_driver(&mpc_i2c_driver);
if (rv)
- printk(KERN_ERR DRV_NAME
+ printk(KERN_ERR DRV_NAME
" of_register_platform_driver failed (%i)\n", rv);
return rv;
}
Index: linux-2.6/arch/powerpc/sysdev/fsl_soc.c
===================================================================
--- linux-2.6.orig/arch/powerpc/sysdev/fsl_soc.c 2009-03-31 13:25:08.000000000 +0200
+++ linux-2.6/arch/powerpc/sysdev/fsl_soc.c 2009-03-31 13:34:40.531721011 +0200
@@ -102,6 +102,96 @@
}
EXPORT_SYMBOL(fsl_get_sys_freq);
+#ifdef CONFIG_I2C_MPC
+static const struct fsl_i2c_divider {
+ u16 divider;
+ u16 fdr; /* including dfsrr */
+} fsl_i2c_8xxx_dividers[] = {
+ {160, 0x0120}, {192, 0x0121}, {224, 0x0122}, {256, 0x0123},
+ {288, 0x0100}, {320, 0x0101}, {352, 0x0601}, {384, 0x0102},
+ {416, 0x0602}, {448, 0x0126}, {480, 0x0103}, {512, 0x0127},
+ {544, 0x0b03}, {576, 0x0104}, {608, 0x1603}, {640, 0x0105},
+ {672, 0x2003}, {704, 0x0b05}, {736, 0x2b03}, {768, 0x0106},
+ {800, 0x3603}, {832, 0x0b06}, {896, 0x012a}, {960, 0x0107},
+ {1024, 0x012b}, {1088, 0x1607}, {1152, 0x0108}, {1216, 0x2b07},
+ {1280, 0x0109}, {1408, 0x1609}, {1536, 0x010a}, {1664, 0x160a},
+ {1792, 0x012e}, {1920, 0x010b}, {2048, 0x012f}, {2176, 0x2b0b},
+ {2304, 0x010c}, {2560, 0x010d}, {2816, 0x2b0d}, {3072, 0x010e},
+ {3328, 0x2b0e}, {3584, 0x0132}, {3840, 0x010f}, {4096, 0x0133},
+ {4608, 0x0110}, {5120, 0x0111}, {6144, 0x0112}, {7168, 0x0136},
+ {7680, 0x0113}, {8192, 0x0137}, {9216, 0x0114}, {10240, 0x0115},
+ {12288, 0x0116}, {14336, 0x013a}, {15360, 0x0117}, {16384, 0x013b},
+ {18432, 0x0118}, {20480, 0x0119}, {24576, 0x011a}, {28672, 0x013e},
+ {30720, 0x011b}, {32768, 0x013f}, {36864, 0x011c}, {40960, 0x011d},
+ {49152, 0x011e}, {61440, 0x011f}
+};
+
+u32 fsl_i2c_get_sec_cfg(void)
+{
+ struct device_node *node = NULL;
+ u32 __iomem *reg;
+ u32 val = 0;
+
+ node = of_find_node_by_name(NULL, "global-utilities");
+ if (node) {
+ const u32 *prop = of_get_property(node, "reg", NULL);
+ if (prop) {
+ /*
+ * Map and check POR Device Status Register 2
+ * (PORDEVSR2) at 0xE0014
+ */
+ reg = ioremap(get_immrbase() + *prop + 0x14, 0x4);
+ if (!reg)
+ printk(KERN_ERR
+ "Error: couldn't map PORDEVSR2\n");
+ else
+ val = in_be32(reg);
+ iounmap(reg);
+ }
+ }
+ if (node)
+ of_node_put(node);
+
+ return val;
+}
+
+int fsl_i2c_get_fdr(struct device_node *node, u32 i2c_clock, u32 i2c_flags)
+{
+ const struct fsl_i2c_divider *div = NULL;
+ u32 src_clock, divider;
+ int i;
+
+ if (!i2c_clock)
+ return -EINVAL;
+
+ /* Determine divider value */
+ src_clock = fsl_get_sys_freq();
+ divider = src_clock / i2c_clock;
+ if (i2c_flags & FSL_I2C_DEV_CLOCK_DIV2)
+ divider /= 2;
+ else if (i2c_flags & FSL_I2C_DEV_CLOCK_DIV3)
+ divider /= 3;
+ else if (i2c_flags & FSL_I2C_DEV_CLOCK_DIV23)
+ divider /= fsl_i2c_get_sec_cfg() ? 3 : 2;
+
+ pr_debug("I2C: src_clock=%d clock=%d flags=%#x divider=%d\n",
+ src_clock, i2c_clock, i2c_flags, divider);
+
+ /*
+ * We want to choose an FDR/DFSR that generates an I2C bus speed that
+ * is equal to or lower than the requested speed.
+ */
+ for (i = 0; i < ARRAY_SIZE(fsl_i2c_8xxx_dividers); i++) {
+ div = &fsl_i2c_8xxx_dividers[i];
+ if (div->divider >= divider)
+ break;
+ }
+
+ return div ? (int)div->fdr : -EINVAL;
+}
+EXPORT_SYMBOL(fsl_i2c_get_fdr);
+#endif /* CONFIG_I2C_MPC */
+
#if defined(CONFIG_CPM2) || defined(CONFIG_QUICC_ENGINE) || defined(CONFIG_8xx)
static u32 brgfreq = -1;
Index: linux-2.6/include/linux/fsl_devices.h
===================================================================
--- linux-2.6.orig/include/linux/fsl_devices.h 2009-03-31 13:25:08.000000000 +0200
+++ linux-2.6/include/linux/fsl_devices.h 2009-03-31 13:28:54.305720748 +0200
@@ -68,6 +68,12 @@
/* Flags related to I2C device features */
#define FSL_I2C_DEV_SEPARATE_DFSRR 0x00000001
#define FSL_I2C_DEV_CLOCK_5200 0x00000002
+#define FSL_I2C_DEV_CLOCK_DIV2 0x00000004
+#define FSL_I2C_DEV_CLOCK_DIV3 0x00000008
+#define FSL_I2C_DEV_CLOCK_DIV23 0x00000010
+
+extern int fsl_i2c_get_fdr(struct device_node *node,
+ u32 i2c_clock, u32 i2c_flags);
enum fsl_usb2_operating_modes {
FSL_USB2_MPH_HOST,
Index: linux-2.6/arch/powerpc/platforms/52xx/mpc52xx_common.c
===================================================================
--- linux-2.6.orig/arch/powerpc/platforms/52xx/mpc52xx_common.c 2009-03-31 13:25:08.000000000 +0200
+++ linux-2.6/arch/powerpc/platforms/52xx/mpc52xx_common.c 2009-03-31 13:28:54.309718526 +0200
@@ -225,3 +225,51 @@
while (1);
}
+
+/**
+ * fsl_i2c_get_fdr: get calculate and return I2 frequency divider register
+ */
+static const struct mpc52xx_i2c_divider {
+ u16 divider;
+ u16 fdr; /* including dfsrr */
+} mpc52xx_i2_dividers[] = {
+ {20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
+ {28, 0x24}, {30, 0x01}, {32, 0x25}, {34, 0x02},
+ {36, 0x26}, {40, 0x27}, {44, 0x04}, {48, 0x28},
+ {56, 0x29}, {64, 0x2a}, {68, 0x07}, {72, 0x2b},
+ {80, 0x2c}, {88, 0x09}, {96, 0x2d}, {104, 0x0a},
+ {112, 0x2e}, {128, 0x2f}, {144, 0x0c}, {160, 0x30},
+ {192, 0x31}, {224, 0x32}, {240, 0x0f}, {256, 0x33},
+ {288, 0x10}, {320, 0x34}, {384, 0x35}, {448, 0x36},
+ {480, 0x13}, {512, 0x37}, {576, 0x14}, {640, 0x38},
+ {768, 0x39}, {896, 0x3a}, {960, 0x17}, {1024, 0x3b},
+ {1152, 0x18}, {1280, 0x3c}, {1536, 0x3d}, {1792, 0x3e},
+ {1920, 0x1b}, {2048, 0x3f}, {2304, 0x1c}, {2560, 0x1d},
+ {3072, 0x1e}, {3840, 0x1f}
+};
+
+int fsl_i2c_get_fdr(struct device_node *node, u32 i2c_clock, u32 i2c_flags)
+{
+ const struct fsl_i2c_divider *div = NULL;
+ u32 divider;
+ int i;
+
+ if (!i2c_clock)
+ return -EINVAL;
+
+ /* Determine divider value */
+ divider = mpc52xx_find_ipb_freq(node) / i2c_clock;
+
+ /*
+ * We want to choose an FDR/DFSR that generates an I2C bus speed that
+ * is equal to or lower than the requested speed.
+ */
+ for (i = 0; i < ARRAY_SIZE(fsl_i2c_8xxx_dividers); i++) {
+ div = &fsl_i2c_8xxx_dividers[i];
+ if (div->divider >= divider)
+ break;
+ }
+
+ return div ? (int)div->fdr : -EINVAL;
+}
+EXPORT_SYMBOL(fsl_i2c_get_fdr);
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