[PATCH 4/5] i2c: adapt the i2c-imx driver to mpc85xx machines.
Renaud Barbier
renaud.barbier at ge.com
Thu Aug 30 10:00:16 EDT 2012
A function to calculate the frequency divider and digital filter sampling rate
for the 85xx processors is added to the i2c-imx driver. Hence, this driver is
used on IMX and 85xx machines.
Signed-off-by: Renaud Barbier <renaud.barbier at ge.com>
---
arch/ppc/mach-mpc85xx/include/mach/immap_85xx.h | 3 +
drivers/i2c/busses/Kconfig | 4 +-
drivers/i2c/busses/i2c-imx.c | 87 ++++++++++++++++++++++-
3 files changed, 90 insertions(+), 4 deletions(-)
diff --git a/arch/ppc/mach-mpc85xx/include/mach/immap_85xx.h b/arch/ppc/mach-mpc85xx/include/mach/immap_85xx.h
index bf0f7f5..d2f8bbe 100644
--- a/arch/ppc/mach-mpc85xx/include/mach/immap_85xx.h
+++ b/arch/ppc/mach-mpc85xx/include/mach/immap_85xx.h
@@ -136,4 +136,7 @@
#define GFAR_BASE_ADDR (CFG_IMMR + TSEC1_OFFSET)
#define MDIO_BASE_ADDR (CFG_IMMR + 0x24000)
+
+#define I2C1_BASE_ADDR (CFG_IMMR + 0x3000)
+#define I2C2_BASE_ADDR (CFG_IMMR + 0x3100)
#endif /*__IMMAP_85xx__*/
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 1ce5c00..3f998ea 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -5,8 +5,8 @@
menu "I2C Hardware Bus support"
config I2C_IMX
- bool "i.MX I2C Master driver"
- depends on ARCH_IMX && !ARCH_IMX1
+ bool "MPC85xx/i.MX I2C Master driver"
+ depends on (ARCH_IMX && !ARCH_IMX1) || ARCH_MPC85XX
config I2C_OMAP
bool "OMAP I2C Master driver"
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index da6218f..2dfa4f1 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1,4 +1,5 @@
/*
+ * Copyright 2012 GE Intelligent Platforms, Inc.
* Copyright (C) 2002 Motorola GSG-China
* 2009 Marc Kleine-Budde, Pengutronix
*
@@ -22,7 +23,8 @@
*
* Desc.:
* Implementation of I2C Adapter/Algorithm Driver
- * for I2C Bus integrated in Freescale i.MX/MXC processors
+ * for I2C Bus integrated in Freescale i.MX/MXC processors and
+ * 85xx processors.
*
* Derived from Motorola GSG China I2C example driver
*
@@ -36,7 +38,6 @@
#include <clock.h>
#include <common.h>
#include <driver.h>
-#include <gpio.h>
#include <init.h>
#include <malloc.h>
#include <types.h>
@@ -50,7 +51,11 @@
#include <mach/clock.h>
/* This will be the driver name */
+#ifdef CONFIG_PPC
+#define DRIVER_NAME "i2c-mpc"
+#else
#define DRIVER_NAME "i2c-imx"
+#endif
/* Default value */
#define IMX_I2C_BIT_RATE 100000 /* 100kHz */
@@ -61,6 +66,7 @@
#define IMX_I2C_I2CR 0x08 /* i2c control */
#define IMX_I2C_I2SR 0x0C /* i2c status */
#define IMX_I2C_I2DR 0x10 /* i2c transfer data */
+#define IMX_I2C_DFSRR 0x14 /* i2c digital filter smapling rate */
/* Bits of IMX I2C registers */
#define I2SR_RXAK 0x01
@@ -85,6 +91,7 @@
*
* Duplicated divider values removed from list
*/
+#ifndef CONFIG_PPC
static u16 i2c_clk_div[50][2] = {
{ 22, 0x20 }, { 24, 0x21 }, { 26, 0x22 }, { 28, 0x23 },
{ 30, 0x00 }, { 32, 0x24 }, { 36, 0x25 }, { 40, 0x26 },
@@ -100,6 +107,7 @@ static u16 i2c_clk_div[50][2] = {
{ 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
{ 3072, 0x1E }, { 3840, 0x1F }
};
+#endif
struct imx_i2c_struct {
void __iomem *base;
@@ -107,6 +115,7 @@ struct imx_i2c_struct {
unsigned int disable_delay;
int stopped;
unsigned int ifdr; /* IMX_I2C_IFDR */
+ unsigned int dfsrr; /* IMX_I2C_DFSRR */
};
#define to_imx_i2c_struct(a) container_of(a, struct imx_i2c_struct, adapter)
@@ -215,6 +224,8 @@ static int i2c_imx_start(struct i2c_adapter *adapter)
int result;
writeb(i2c_imx->ifdr, base + IMX_I2C_IFDR);
+ if (i2c_imx->dfsrr != -1)
+ writeb(i2c_imx->dfsrr, base + IMX_I2C_DFSRR);
/* Enable I2C controller */
writeb(0, base + IMX_I2C_I2SR);
writeb(I2CR_IEN, base + IMX_I2C_I2CR);
@@ -271,6 +282,76 @@ static void i2c_imx_stop(struct i2c_adapter *adapter)
writeb(0, base + IMX_I2C_I2CR);
}
+#ifdef CONFIG_PPC
+static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
+ unsigned int rate)
+{
+ void __iomem *base;
+ unsigned int i2c_clk;
+ unsigned short divider;
+ /*
+ * We want to choose an FDR/DFSR that generates an I2C bus speed that
+ * is equal to or lower than the requested speed. That means that we
+ * want the first divider that is equal to or greater than the
+ * calculated divider.
+ */
+ u8 dfsr, fdr;
+ /* a, b and dfsr matches identifiers A,B and C respectively in AN2919 */
+ unsigned short a, b, ga, gb;
+ unsigned long c_div, est_div;
+
+ fdr = 0x31; /* Default if no FDR found */
+ base = i2c_imx->base;
+ i2c_clk = fsl_get_i2c_freq();
+ divider = min((unsigned short)(i2c_clk / rate), (unsigned short) -1);
+
+ /*
+ * Condition 1: dfsr <= 50ns/T (T=period of I2C source clock in ns).
+ * or (dfsr * T) <= 50ns.
+ * Translate to dfsr = 5 * Frequency / 100,000,000
+ */
+ dfsr = (5 * (i2c_clk / 1000)) / 100000;
+ dev_dbg(i2c_imx->adapter.dev,
+ "<%s> requested speed:%d, i2c_clk:%d\n", __func__,
+ rate, i2c_clk);
+ if (!dfsr)
+ dfsr = 1;
+
+ est_div = ~0;
+ for (ga = 0x4, a = 10; a <= 30; ga++, a += 2) {
+ for (gb = 0; gb < 8; gb++) {
+ b = 16 << gb;
+ c_div = b * (a + ((3*dfsr)/b)*2);
+ if ((c_div > divider) && (c_div < est_div)) {
+ unsigned short bin_gb, bin_ga;
+
+ est_div = c_div;
+ bin_gb = gb << 2;
+ bin_ga = (ga & 0x3) | ((ga & 0x4) << 3);
+ fdr = bin_gb | bin_ga;
+ rate = i2c_clk / est_div;
+ dev_dbg(i2c_imx->adapter.dev,
+ "FDR:0x%.2x, div:%ld, ga:0x%x, gb:0x%x,"
+ " a:%d, b:%d, speed:%d\n", fdr, est_div,
+ ga, gb, a, b, rate);
+ /* Condition 2 not accounted for */
+ dev_dbg(i2c_imx->adapter.dev,
+ "Tr <= %d ns\n", (b - 3 * dfsr) *
+ 1000000 / (i2c_clk / 1000));
+ }
+ }
+ if (a == 20)
+ a += 2;
+ if (a == 24)
+ a += 4;
+ }
+ dev_dbg(i2c_imx->adapter.dev,
+ "divider:%d, est_div:%ld, DFSR:%d\n", divider, est_div, dfsr);
+ dev_dbg(i2c_imx->adapter.dev, "FDR:0x%.2x, speed:%d\n", fdr, rate);
+ i2c_imx->ifdr = fdr;
+ i2c_imx->dfsrr = dfsr;
+}
+#else
static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
unsigned int rate)
{
@@ -307,6 +388,7 @@ static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
dev_dbg(i2c_imx->adapter.dev, "<%s> IFDR[IC]=0x%x, REAL DIV=%d\n",
__func__, i2c_clk_div[i][1], i2c_clk_div[i][0]);
}
+#endif
static int i2c_imx_write(struct i2c_adapter *adapter, struct i2c_msg *msgs)
{
@@ -474,6 +556,7 @@ static int __init i2c_imx_probe(struct device_d *pdev)
i2c_imx->adapter.nr = pdev->id;
i2c_imx->adapter.dev = pdev;
i2c_imx->base = dev_request_mem_region(pdev, 0);
+ i2c_imx->dfsrr = -1;
/* Set up clock divider */
if (pdata && pdata->bitrate)
--
1.7.1
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