--- /dev/null
+/*
+ * Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+
+#include <asm/mach-types.h>
+#include <mach/hardware.h>
+#include <mach/i2c.h>
+
+/** Defines ********************************************************************
+*******************************************************************************/
+
+
+/* IMX I2C registers */
+#define IMX_I2C_IADR 0x00 /* i2c slave address */
+#define IMX_I2C_IFDR 0x04 /* i2c frequency divider */
+#define IMX_I2C_I2CR 0x08 /* i2c control */
+#define IMX_I2C_I2SR 0x0C /* i2c status */
+#define IMX_I2C_I2DR 0x10 /* i2c transfer data */
+
+/* Bits of IMX I2C registers */
+#define I2SR_RXAK 0x01
+#define I2SR_IIF 0x02
+#define I2SR_SRW 0x04
+#define I2SR_IAL 0x10
+#define I2SR_IBB 0x20
+#define I2SR_IAAS 0x40
+#define I2SR_ICF 0x80
+#define I2CR_RSTA 0x04
+#define I2CR_TXAK 0x08
+#define I2CR_MTX 0x10
+#define I2CR_MSTA 0x20
+#define I2CR_IIEN 0x40
+#define I2CR_IEN 0x80
+
+static void __iomem *base;
+static int stopped;
+
+/** Functions for IMX I2C adapter driver ***************************************
+*******************************************************************************/
+
+static int pm_i2c_imx_bus_busy(int for_busy)
+{
+ unsigned int temp;
+
+ while (1) {
+ temp = readb(base + IMX_I2C_I2SR);
+ if (for_busy && (temp & I2SR_IBB))
+ break;
+ if (!for_busy && !(temp & I2SR_IBB))
+ break;
+ pr_debug("waiting bus busy=%d\n", for_busy);
+ }
+
+ return 0;
+}
+
+static int pm_i2c_imx_trx_complete(void)
+{
+ unsigned int temp;
+ while (!((temp = readb(base + IMX_I2C_I2SR)) & I2SR_IIF))
+ pr_debug("waiting or I2SR_IIF\n");
+ temp &= ~I2SR_IIF;
+ writeb(temp, base + IMX_I2C_I2SR);
+
+ return 0;
+}
+
+static int pm_i2c_imx_acked(void)
+{
+ if (readb(base + IMX_I2C_I2SR) & I2SR_RXAK) {
+ pr_info("<%s> No ACK\n", __func__);
+ return -EIO; /* No ACK */
+ }
+ return 0;
+}
+
+static int pm_i2c_imx_start(void)
+{
+ unsigned int temp = 0;
+ int result;
+
+ /* Enable I2C controller */
+ writeb(0, base + IMX_I2C_I2SR);
+ writeb(I2CR_IEN, base + IMX_I2C_I2CR);
+
+ /* Wait controller to be stable */
+ udelay(50);
+
+ /* Start I2C transaction */
+ temp = readb(base + IMX_I2C_I2CR);
+ temp |= I2CR_MSTA;
+ writeb(temp, base + IMX_I2C_I2CR);
+ result = pm_i2c_imx_bus_busy(1);
+
+ temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
+ writeb(temp, base + IMX_I2C_I2CR);
+ return result;
+}
+
+static void pm_i2c_imx_stop(void)
+{
+ unsigned int temp = 0;
+
+ /* Stop I2C transaction */
+ temp = readb(base + IMX_I2C_I2CR);
+ temp &= ~(I2CR_MSTA | I2CR_MTX);
+ writeb(temp, base + IMX_I2C_I2CR);
+
+ pm_i2c_imx_bus_busy(0);
+
+ /* Disable I2C controller */
+ writeb(0, base + IMX_I2C_I2CR);
+}
+
+static int pm_i2c_imx_write(struct i2c_msg *msgs)
+{
+ int i, result;
+
+ /* write slave address */
+ writeb(msgs->addr << 1, base + IMX_I2C_I2DR);
+ result = pm_i2c_imx_trx_complete();
+ if (result)
+ return result;
+ result = pm_i2c_imx_acked();
+ if (result)
+ return result;
+
+ /* write data */
+ for (i = 0; i < msgs->len; i++) {
+ writeb(msgs->buf[i], base + IMX_I2C_I2DR);
+ result = pm_i2c_imx_trx_complete();
+ if (result)
+ return result;
+ result = pm_i2c_imx_acked();
+ if (result)
+ return result;
+ }
+ return 0;
+}
+
+static int pm_i2c_imx_read(struct i2c_msg *msgs)
+{
+ int i, result;
+ unsigned int temp;
+
+ /* write slave address */
+ writeb((msgs->addr << 1) | 0x01, base + IMX_I2C_I2DR);
+ result = pm_i2c_imx_trx_complete();
+ if (result)
+ return result;
+ result = pm_i2c_imx_acked();
+ if (result)
+ return result;
+
+ /* setup bus to read data */
+ temp = readb(base + IMX_I2C_I2CR);
+ temp &= ~I2CR_MTX;
+ if (msgs->len - 1)
+ temp &= ~I2CR_TXAK;
+ writeb(temp, base + IMX_I2C_I2CR);
+ readb(base + IMX_I2C_I2DR); /* dummy read */
+
+ /* read data */
+ for (i = 0; i < msgs->len; i++) {
+ result = pm_i2c_imx_trx_complete();
+ if (result)
+ return result;
+ if (i == (msgs->len - 1)) {
+ /* It must generate STOP before read I2DR to prevent
+ controller from generating another clock cycle */
+ temp = readb(base + IMX_I2C_I2CR);
+ temp &= ~(I2CR_MSTA | I2CR_MTX);
+ writeb(temp, base + IMX_I2C_I2CR);
+ pm_i2c_imx_bus_busy(0);
+ stopped = 1;
+ } else if (i == (msgs->len - 2)) {
+ temp = readb(base + IMX_I2C_I2CR);
+ temp |= I2CR_TXAK;
+ writeb(temp, base + IMX_I2C_I2CR);
+ }
+ msgs->buf[i] = readb(base + IMX_I2C_I2DR);
+ }
+ return 0;
+}
+
+int pm_i2c_imx_xfer(struct i2c_msg *msgs, int num)
+{
+ unsigned int i, temp;
+ int result;
+
+ /* Start I2C transfer */
+ result = pm_i2c_imx_start();
+ if (result)
+ goto fail0;
+
+ /* read/write data */
+ for (i = 0; i < num; i++) {
+ if (i) {
+ temp = readb(base + IMX_I2C_I2CR);
+ temp |= I2CR_RSTA;
+ writeb(temp, base + IMX_I2C_I2CR);
+ result = pm_i2c_imx_bus_busy(1);
+ if (result)
+ goto fail0;
+ }
+ /* write/read data */
+ if (msgs[i].flags & I2C_M_RD)
+ result = pm_i2c_imx_read(&msgs[i]);
+ else
+ result = pm_i2c_imx_write(&msgs[i]);
+ if (result)
+ goto fail0;
+ }
+
+fail0:
+ /* Stop I2C transfer */
+ pm_i2c_imx_stop();
+
+ return (result < 0) ? result : num;
+}
+
+void pm_i2c_init(u32 base_addr)
+{
+ base = ioremap(base_addr, SZ_4K);
+}
+
+void pm_i2c_deinit(void)
+{
+ iounmap(base);
+}
projects / linux-imx.git / blobdiff