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Commit f2bd5efe authored by Wolfgang Grandegger's avatar Wolfgang Grandegger Committed by Ben Dooks
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i2c: i2c-mpc: make I2C bus speed configurable 



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: default avatarWolfgang Grandegger <wg@grandegger.com>
Signed-off-by: default avatarBen Dooks <ben-linux@fluff.org>
parent 54377cd0

drivers/i2c/busses/i2c-mpc.c

+242 −20
Original line number Diff line number Diff line
@@ -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)

{

	/* 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);

	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

		writel(0x1031, i2c->base + MPC_I2C_FDR);

				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)

{

}

#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 = "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);