i2c: i2c-mpc: make I2C bus speed configurable
authorWolfgang Grandegger <wg@grandegger.com>
Tue, 7 Apr 2009 08:20:55 +0000 (10:20 +0200)
committerBen Dooks <ben-linux@fluff.org>
Tue, 7 Apr 2009 09:18:47 +0000 (10:18 +0100)
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,mpc8543-i2c",
 .data = &(struct fsl_i2c_match_data) {
.setclock = mpc_i2c_setclock_8xxx,
.prescaler = 2,
},
},

The "data" field defines the relevant I2C setclock function and the
relevant pre-scaler for the I2C source clock frequency.

It uses arch-specific tables and functions to determine resonable
Freqency Divider Register (fdr) values for MPC83xx, MPC85xx, MPC86xx,
MPC5200 and MPC5200B.

The i2c->flags field and the corresponding FSL_I2C_DEV_* definitions
have been removed as they are obsolete.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
drivers/i2c/busses/i2c-mpc.c

index 9b38c92364640656d30e20c5887f0c43e56b48aa..4af5c09f0e8fe3def51810746652f6d70da52717 100644 (file)
@@ -26,6 +26,9 @@
 #include <linux/interrupt.h>
 #include <linux/delay.h>
 
+#include <asm/mpc52xx.h>
+#include <sysdev/fsl_soc.h>
+
 #define DRV_NAME "mpc-i2c"
 
 #define MPC_I2C_FDR   0x04
@@ -56,7 +59,18 @@ struct mpc_i2c {
        wait_queue_head_t queue;
        struct i2c_adapter adap;
        int irq;
-       u32 flags;
+};
+
+struct mpc_i2c_divider {
+       u16 divider;
+       u16 fdr;        /* including dfsrr */
+};
+
+struct mpc_i2c_match_data {
+       void (*setclock)(struct device_node *node,
+                        struct mpc_i2c *i2c,
+                        u32 clock, u32 prescaler);
+       u32 prescaler;
 };
 
 static inline void writeccr(struct mpc_i2c *i2c, u32 x)
@@ -150,17 +164,180 @@ static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
        return 0;
 }
 
-static void mpc_i2c_setclock(struct mpc_i2c *i2c)
+#ifdef CONFIG_PPC_52xx
+static const struct mpc_i2c_divider mpc_i2c_dividers_52xx[] = {
+       {20, 0x20}, {22, 0x21}, {24, 0x22}, {26, 0x23},
+       {28, 0x24}, {30, 0x01}, {32, 0x25}, {34, 0x02},
+       {36, 0x26}, {40, 0x27}, {44, 0x04}, {48, 0x28},
+       {52, 0x63}, {56, 0x29}, {60, 0x41}, {64, 0x2a},
+       {68, 0x07}, {72, 0x2b}, {80, 0x2c}, {88, 0x09},
+       {96, 0x2d}, {104, 0x0a}, {112, 0x2e}, {120, 0x81},
+       {128, 0x2f}, {136, 0x47}, {144, 0x0c}, {160, 0x30},
+       {176, 0x49}, {192, 0x31}, {208, 0x4a}, {224, 0x32},
+       {240, 0x0f}, {256, 0x33}, {272, 0x87}, {288, 0x10},
+       {320, 0x34}, {352, 0x89}, {384, 0x35}, {416, 0x8a},
+       {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}, {3584, 0x7e}, {3840, 0x1f},
+       {4096, 0x7f}, {4608, 0x5c}, {5120, 0x5d}, {6144, 0x5e},
+       {7168, 0xbe}, {7680, 0x5f}, {8192, 0xbf}, {9216, 0x9c},
+       {10240, 0x9d}, {12288, 0x9e}, {15360, 0x9f}
+};
+
+int mpc_i2c_get_fdr_52xx(struct device_node *node, u32 clock, int prescaler)
+{
+       const struct mpc52xx_i2c_divider *div = NULL;
+       unsigned int pvr = mfspr(SPRN_PVR);
+       u32 divider;
+       int i;
+
+       if (!clock)
+               return -EINVAL;
+
+       /* Determine divider value */
+       divider = mpc52xx_find_ipb_freq(node) / 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(mpc52xx_i2c_dividers); i++) {
+               div = &mpc_i2c_dividers_52xx[i];
+               /* Old MPC5200 rev A CPUs do not support the high bits */
+               if (div->fdr & 0xc0 && pvr == 0x80822011)
+                       continue;
+               if (div->divider >= divider)
+                       break;
+       }
+
+       return div ? (int)div->fdr : -EINVAL;
+}
+
+static void mpc_i2c_setclock_52xx(struct device_node *node,
+                                 struct mpc_i2c *i2c,
+                                 u32 clock, u32 prescaler)
+{
+       int fdr = mpc52xx_i2c_get_fdr(node, clock, prescaler);
+
+       if (fdr < 0)
+               fdr = 0x3f; /* backward compatibility */
+       writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
+       dev_info(i2c->dev, "clock %d Hz (fdr=%d)\n", clock, fdr);
+}
+#else /* !CONFIG_PPC_52xx */
+static void mpc_i2c_setclock_52xx(struct device_node *node,
+                                 struct mpc_i2c *i2c,
+                                 u32 clock, u32 prescaler)
+{
+}
+#endif /* CONFIG_PPC_52xx*/
+
+#ifdef CONFIG_FSL_SOC
+static const struct mpc_i2c_divider mpc_i2c_dividers_8xxx[] = {
+       {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 mpc_i2c_get_sec_cfg_8xxx(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) & 0x00000080; /* sec-cfg */
+                       iounmap(reg);
+               }
+       }
+       if (node)
+               of_node_put(node);
+
+       return val;
+}
+
+int mpc_i2c_get_fdr_8xxx(struct device_node *node, u32 clock, u32 prescaler)
+{
+       const struct mpc_i2c_divider *div = NULL;
+       u32 divider;
+       int i;
+
+       if (!clock)
+               return -EINVAL;
+
+       /* Determine proper divider value */
+       if (of_device_is_compatible(node, "fsl,mpc8544-i2c"))
+               prescaler = mpc_i2c_get_sec_cfg_8xxx() ? 3 : 2;
+       if (!prescaler)
+               prescaler = 1;
+
+       divider = fsl_get_sys_freq() / clock / prescaler;
+
+       pr_debug("I2C: src_clock=%d clock=%d divider=%d\n",
+                fsl_get_sys_freq(), clock, 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(mpc_i2c_dividers_8xxx); i++) {
+               div = &mpc_i2c_dividers_8xxx[i];
+               if (div->divider >= divider)
+                       break;
+       }
+
+       return div ? (int)div->fdr : -EINVAL;
+}
+
+static void mpc_i2c_setclock_8xxx(struct device_node *node,
+                                 struct mpc_i2c *i2c,
+                                 u32 clock, u32 prescaler)
+{
+       int fdr = mpc_i2c_get_fdr_8xxx(node, clock, prescaler);
+
+       if (fdr < 0)
+               fdr = 0x1031; /* backward compatibility */
+       writeb(fdr & 0xff, i2c->base + MPC_I2C_FDR);
+       writeb((fdr >> 8) & 0xff, i2c->base + MPC_I2C_DFSRR);
+       dev_info(i2c->dev, "clock %d Hz (dfsrr=%d fdr=%d)\n",
+                clock, fdr >> 8, fdr & 0xff);
+}
+
+#else /* !CONFIG_FSL_SOC */
+static void mpc_i2c_setclock_8xxx(struct device_node *node,
+                                 struct mpc_i2c *i2c,
+                                 u32 clock, u32 prescaler)
 {
-       /* 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);
 }
+#endif /* CONFIG_FSL_SOC */
 
 static void mpc_i2c_start(struct mpc_i2c *i2c)
 {
@@ -315,8 +492,11 @@ static struct i2c_adapter mpc_ops = {
 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 result = 0;
+       int plen;
 
        i2c = kzalloc(sizeof(*i2c), GFP_KERNEL);
        if (!i2c)
@@ -324,13 +504,6 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
 
        i2c->dev = &op->dev; /* for debug and error output */
 
-       if (of_get_property(op->node, "dfsrr", NULL))
-               i2c->flags |= FSL_I2C_DEV_SEPARATE_DFSRR;
-
-       if (of_device_is_compatible(op->node, "fsl,mpc5200-i2c") ||
-                       of_device_is_compatible(op->node, "mpc5200-i2c"))
-               i2c->flags |= FSL_I2C_DEV_CLOCK_5200;
-
        init_waitqueue_head(&i2c->queue);
 
        i2c->base = of_iomap(op->node, 0);
@@ -350,7 +523,22 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
                }
        }
 
-       mpc_i2c_setclock(i2c);
+       if (!of_get_property(op->node, "fsl,preserve-clocking", NULL)) {
+               prop = of_get_property(op->node, "clock-frequency", &plen);
+               if (prop && plen == sizeof(u32))
+                       clock = *prop;
+
+               if (match->data) {
+                       struct mpc_i2c_match_data *data =
+                               (struct mpc_i2c_match_data *)match->data;
+                       data->setclock(op->node, i2c, clock, data->prescaler);
+               } else {
+                       /* Backwards compatibility */
+                       if (of_get_property(op->node, "dfsrr", NULL))
+                               mpc_i2c_setclock_8xxx(op->node, i2c,
+                                                     clock, 0);
+               }
+       }
 
        dev_set_drvdata(&op->dev, i2c);
 
@@ -395,9 +583,43 @@ static int __devexit fsl_i2c_remove(struct of_device *op)
 };
 
 static const struct of_device_id mpc_i2c_of_match[] = {
-       {.compatible = "fsl-i2c",},
+       {.compatible = "mpc5200-i2c",
+        .data = &(struct mpc_i2c_match_data) {
+                       .setclock = mpc_i2c_setclock_52xx,
+               },
+       },
+       {.compatible = "fsl,mpc5200b-i2c",
+        .data = &(struct mpc_i2c_match_data) {
+                       .setclock = mpc_i2c_setclock_52xx,
+               },
+       },
+       {.compatible = "fsl,mpc5200-i2c",
+        .data = &(struct mpc_i2c_match_data) {
+                       .setclock = mpc_i2c_setclock_52xx,
+               },
+       },
+       {.compatible = "fsl,mpc8313-i2c",
+        .data = &(struct mpc_i2c_match_data) {
+                       .setclock = mpc_i2c_setclock_8xxx,
+               },
+       },
+       {.compatible = "fsl,mpc8543-i2c",
+        .data = &(struct mpc_i2c_match_data) {
+                       .setclock = mpc_i2c_setclock_8xxx,
+                       .prescaler = 2,
+               },
+       },
+       {.compatible = "fsl,mpc8544-i2c",
+        .data = &(struct mpc_i2c_match_data) {
+                       .setclock = mpc_i2c_setclock_8xxx,
+                       .prescaler = 3,
+               },
+       /* Backward compatibility */
+       },
+       {.compatible = "fsl-i2c", },
        {},
 };
+
 MODULE_DEVICE_TABLE(of, mpc_i2c_of_match);