Add a driver for the EMMA mobile I2C block. The driver supports low and high-speed interrupt driven PIO transfers. Signed-off-by: Ian Molton <ian.molton@xxxxxxxxxxxxxxx> --- drivers/i2c/busses/Kconfig | 10 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-em.c | 534 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 545 insertions(+) create mode 100644 drivers/i2c/busses/i2c-em.c diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index dc6dea6..e5cda34 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -777,6 +777,16 @@ config I2C_RCAR This driver can also be built as a module. If so, the module will be called i2c-rcar. +config I2C_EM + tristate "EMMA Mobile series I2C adapter" + depends on I2C && HAVE_CLK + help + If you say yes to this option, support will be included for the + I2C interface on the Renesas Electronics EM/EV of processors. + + This driver can also be built as a module. If so, the module + will be called i2c-em + comment "External I2C/SMBus adapter drivers" config I2C_DIOLAN_U2C diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index d00997f..f7022ab 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -76,6 +76,7 @@ obj-$(CONFIG_I2C_OCTEON) += i2c-octeon.o obj-$(CONFIG_I2C_XILINX) += i2c-xiic.o obj-$(CONFIG_I2C_XLR) += i2c-xlr.o obj-$(CONFIG_I2C_RCAR) += i2c-rcar.o +obj-$(CONFIG_I2C_EM) += i2c-em.o # External I2C/SMBus adapter drivers obj-$(CONFIG_I2C_DIOLAN_U2C) += i2c-diolan-u2c.o diff --git a/drivers/i2c/busses/i2c-em.c b/drivers/i2c/busses/i2c-em.c new file mode 100644 index 0000000..e8fc7aa --- /dev/null +++ b/drivers/i2c/busses/i2c-em.c @@ -0,0 +1,534 @@ +/* + * (c) 2013 Ian Molton <ian.molton@xxxxxxxxxxxxxxx> + * Parts (c) 2010 Renesas Electronics Corporation + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * 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 02110-1335, USA. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/delay.h> +#include <linux/of_i2c.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/sched.h> + +#include <linux/interrupt.h> +#include <linux/device.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> + +/* INT Reg */ +#define EMXX_I2C_INT_RAW (IO_ADDRESS(EMXX_INTA_D_BASE) + 0x014) +#define EMXX_I2C_INT_IIR (IO_ADDRESS(EMXX_INTA_D_BASE) + 0x024) + +/* INT Reg bit */ +#define EMXX_I2C0_INTC_MST (1 << 0) +#define EMXX_I2C1_INTC_MST (1 << 1) +#define EMXX_I2C0_INTC_IIR (1 << 16) +#define EMXX_I2C1_INTC_IIR (1 << 17) + +/* I2C Registers */ + +#define I2C_OFS_IICACT0 0x00 /* start */ +#define I2C_OFS_IIC0 0x04 /* shift */ +#define I2C_OFS_IICC0 0x08 /* control */ +#define I2C_OFS_SVA0 0x0c /* slave address */ +#define I2C_OFS_IICCL0 0x10 /* clock select */ +#define I2C_OFS_IICX0 0x14 /* extention */ +#define I2C_OFS_IICS0 0x18 /* status */ +#define I2C_OFS_IICSE0 0x1c /* status For emulation */ +#define I2C_OFS_IICF0 0x20 /* IIC flag */ + + +/* I2C IICACT0 Masks */ +#define I2C_BIT_IICE0 0x0001 + +/* I2C IICC0 Masks */ +#define I2C_BIT_LREL0 0x0040 +#define I2C_BIT_WREL0 0x0020 +#define I2C_BIT_SPIE0 0x0010 +#define I2C_BIT_WTIM0 0x0008 +#define I2C_BIT_ACKE0 0x0004 +#define I2C_BIT_STT0 0x0002 +#define I2C_BIT_SPT0 0x0001 + +/* I2C IICCL0 Masks */ +#define I2C_BIT_CLD0 0x0020 +#define I2C_BIT_DAD0 0x0010 +#define I2C_BIT_SMC0 0x0008 +#define I2C_BIT_DFC0 0x0004 +#define I2C_BIT_CLO1 0x0002 +#define I2C_BIT_CLO0 0x0001 + +/* I2C IICSE0 Masks */ +#define I2C_BIT_MSTS0 0x0080 +#define I2C_BIT_ALD0 0x0040 +#define I2C_BIT_EXC0 0x0020 +#define I2C_BIT_COI0 0x0010 +#define I2C_BIT_TRC0 0x0008 +#define I2C_BIT_ACKD0 0x0004 +#define I2C_BIT_STD0 0x0002 +#define I2C_BIT_SPD0 0x0001 + +/* I2C IICF0 Masks */ +#define I2C_BIT_STCF 0x0080 +#define I2C_BIT_IICBSY 0x0040 +#define I2C_BIT_STCEN 0x0002 +#define I2C_BIT_IICRSV 0x0001 + +/* For setting of sending and receiving */ +#define I2C_DIR_R 0x01 + +static int em_i2c_xfer(struct i2c_adapter *, struct i2c_msg[], int); + +struct em_i2c_device { + struct i2c_adapter adap; + wait_queue_head_t i2c_wait; + void __iomem *membase; + struct clk *clk; + struct clk *sclk; + int irq; + int flags; + int pending; + spinlock_t irq_lock; +}; + +static u32 em_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm em_i2c_algo = { + .master_xfer = em_i2c_xfer, + .smbus_xfer = NULL, + .functionality = em_i2c_func, +}; + +static void em_i2c_enable_clock(struct em_i2c_device *i2c_dev) +{ + clk_enable(i2c_dev->clk); + clk_enable(i2c_dev->sclk); +} + +static void em_i2c_disable_clock(struct em_i2c_device *i2c_dev) +{ + clk_disable(i2c_dev->sclk); + clk_disable(i2c_dev->clk); +} + +static int em_i2c_wait_for_event(struct em_i2c_device *i2c_dev, u16 *status) +{ + int interrupted; + + do { + interrupted = wait_event_interruptible_timeout( + i2c_dev->i2c_wait, i2c_dev->pending, + i2c_dev->adap.timeout); + + if (i2c_dev->pending) { + spin_lock_irq(&i2c_dev->irq_lock); + i2c_dev->pending = 0; + spin_unlock_irq(&i2c_dev->irq_lock); + *status = readl(i2c_dev->membase + I2C_OFS_IICSE0); + return 0; + } + + } while (interrupted); + + *status = 0; + + return -ETIMEDOUT; +} + +static int em_i2c_stop(struct em_i2c_device *i2c_dev) +{ + u16 status; + + /* Send Stop condition */ + writel((readl(i2c_dev->membase + I2C_OFS_IICC0) | I2C_BIT_SPT0 | + I2C_BIT_SPIE0), i2c_dev->membase + I2C_OFS_IICC0); + + /* Wait for stop condition */ + em_i2c_wait_for_event(i2c_dev, &status); + /* FIXME - check status? */ + + if ((readl(i2c_dev->membase + I2C_OFS_IICSE0) & I2C_BIT_SPD0) != 0) + return 0; + + return -EBUSY; +} + +static int em_i2c_start(struct em_i2c_device *i2c_dev) +{ + /* Send start condition */ + writel((readl(i2c_dev->membase + I2C_OFS_IICC0)) | I2C_BIT_ACKE0 | + I2C_BIT_WTIM0, i2c_dev->membase + I2C_OFS_IICC0); + + writel((readl(i2c_dev->membase + I2C_OFS_IICC0) | I2C_BIT_STT0), + i2c_dev->membase + I2C_OFS_IICC0); + + return -EBUSY; +} + +static void em_i2c_reset(struct i2c_adapter *adap) +{ + struct em_i2c_device *i2c_dev = + (struct em_i2c_device *)(i2c_get_adapdata(adap)); + + /* If I2C active */ + if (readl(i2c_dev->membase + I2C_OFS_IICACT0) & I2C_BIT_IICE0) { + + /* Disable I2C operation */ + writel(0, i2c_dev->membase + I2C_OFS_IICACT0); + + while (readl(i2c_dev->membase + I2C_OFS_IICACT0) == 1) + ; + } + + /* Transfer mode set */ + writel(i2c_dev->flags, i2c_dev->membase + I2C_OFS_IICCL0); + + /* Can Issue start without detecting a stop, Reservation disabled. */ + writel(I2C_BIT_STCEN | I2C_BIT_IICRSV, + i2c_dev->membase + I2C_OFS_IICF0); + + /* I2C enable, 9 bit interrupt mode */ + writel(I2C_BIT_WTIM0, i2c_dev->membase + I2C_OFS_IICC0); + + /* Enable I2C operation */ + writel(I2C_BIT_IICE0, i2c_dev->membase + I2C_OFS_IICACT0); + + while (readl(i2c_dev->membase + I2C_OFS_IICACT0) == 0) + ; +} + +static int __em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, + int stop) +{ + struct em_i2c_device *i2c_dev = + (struct em_i2c_device *)i2c_get_adapdata(adap); + int count = 0; + u16 status; + + /* Start transfer */ + em_i2c_start(i2c_dev); + + /* Send slave address and R/W type */ + writel((msg->addr << 1) | ((msg->flags & I2C_M_RD) ? 1 : 0), + i2c_dev->membase + I2C_OFS_IIC0); + + /* Wait for transaction */ + if (em_i2c_wait_for_event(i2c_dev, &status)) + goto out_reset; + + /* Arbitration, Extension mode or Slave mode are all errors */ + if (status & (I2C_BIT_EXC0 | I2C_BIT_COI0 | I2C_BIT_ALD0) + || !(status & I2C_BIT_MSTS0)) + goto out_reset; + + /* Extra setup for read transactions */ + if (!(status & I2C_BIT_TRC0)) { + + /* msg->flags is Write type */ + if (!(msg->flags & I2C_M_RD)) + goto out_reset; + + /* Recieved No ACK (result of setting slave address and R/W) */ + if (!(status & I2C_BIT_ACKD0)) { + em_i2c_stop(i2c_dev); + goto out; + } + + /* 8 bit interrupt mode */ + writel((readl(i2c_dev->membase + I2C_OFS_IICC0) + & ~I2C_BIT_WTIM0) | I2C_BIT_ACKE0, + i2c_dev->membase + I2C_OFS_IICC0); + writel((readl(i2c_dev->membase + I2C_OFS_IICC0) + & ~I2C_BIT_WTIM0) | I2C_BIT_WREL0, + i2c_dev->membase + I2C_OFS_IICC0); + + /* Wait for transaction */ + if (em_i2c_wait_for_event(i2c_dev, &status)) + goto out_reset; + } + + /* Send / receive data */ + do { + /* Arbitration, Extension mode or Slave mode are errors*/ + if (status & (I2C_BIT_EXC0 | I2C_BIT_COI0 | I2C_BIT_ALD0) + || !(status & I2C_BIT_MSTS0)) + goto out_reset; + + if (!(status & I2C_BIT_TRC0)) { /* Read transaction */ + + /* msg->flags is Write type */ + if (!(msg->flags & I2C_M_RD)) + goto out_reset; + + if (count == msg->len) + break; + + msg->buf[count++] = + readl(i2c_dev->membase + I2C_OFS_IIC0); + + + writel((readl(i2c_dev->membase + I2C_OFS_IICC0) + | I2C_BIT_WREL0), + i2c_dev->membase + I2C_OFS_IICC0); + + } else { /* Write transaction */ + + /* msg->flags is Read type */ + if ((msg->flags & I2C_M_RD)) + goto out_reset; + + /* Recieved No ACK */ + if (!(status & I2C_BIT_ACKD0)) { + em_i2c_stop(i2c_dev); + goto out; + } + + if (count == msg->len) + break; + + /* Write data */ + writel(msg->buf[count++], i2c_dev->membase + + I2C_OFS_IIC0); + } + + /* Wait for R/W transaction */ + if (em_i2c_wait_for_event(i2c_dev, &status)) + goto out_reset; + + } while (1); + + if (stop) + em_i2c_stop(i2c_dev); + + return count; + +out_reset: + em_i2c_reset(adap); +out: + return -EREMOTEIO; +} + +static int em_i2c_wait_free(struct i2c_adapter *adap) +{ + struct em_i2c_device *i2c_dev; + int status; + int timeout = adap->timeout; + + i2c_dev = (struct em_i2c_device *)(i2c_get_adapdata(adap)); + + /* wait until I2C bus free */ + while ((readl(i2c_dev->membase + I2C_OFS_IICF0) & I2C_BIT_IICBSY) + && timeout--) { + schedule_timeout_uninterruptible(1); + } + + status = (timeout <= 0); + + if (status) + dev_info(&adap->dev, "I2C bus is busy\n"); + + return status; +} + +static int em_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, + int num) +{ + struct em_i2c_device *i2c_dev = + (struct em_i2c_device *)(i2c_get_adapdata(adap)); + int ret = 0; + int i; + + if (msgs == NULL) + return -EINVAL; + + for (i = 0; i < num; i++) + if (msgs[i].buf == NULL) + return -EINVAL; + + em_i2c_enable_clock(i2c_dev); + em_i2c_reset(adap); + + /* Attempt to gain control of the adapter */ + i = 0; + while (em_i2c_wait_free(adap)) { + switch (i) { + case 0: + if (!(readl(i2c_dev->membase + I2C_OFS_IICSE0) + & I2C_BIT_MSTS0)) { + /* Slave mode -> Error */ + ret = -EBUSY; + goto out; + } + + em_i2c_stop(i2c_dev); + break; + case 1: + em_i2c_reset(adap); + break; + case 2: + ret = -EREMOTEIO; + goto out; + } + i++; + } + + /* Send messages */ + for (i = 0; i < num; i++) { + ret = __em_i2c_xfer(adap, &msgs[i], (i == (num - 1))); + if (ret < 0) + goto out; + } + + /* I2C transfer completed */ + ret = i; + +out: + em_i2c_disable_clock(i2c_dev); + + return ret; +} + +static irqreturn_t em_i2c_irq_handler(int this_irq, void *dev_id) +{ + struct em_i2c_device *i2c_dev = dev_id; + + i2c_dev->pending = 1; + + wake_up_interruptible(&i2c_dev->i2c_wait); + + return IRQ_HANDLED; +} + +static int em_i2c_probe(struct platform_device *pdev) +{ + struct em_i2c_device *i2c_dev; + struct resource *r; + int ret; + + i2c_dev = devm_kzalloc(&pdev->dev, sizeof(struct em_i2c_device), + GFP_KERNEL); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + i2c_dev->membase = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(i2c_dev->membase)) + return PTR_ERR(i2c_dev->membase); + + strlcpy(i2c_dev->adap.name, "em_i2c", sizeof(i2c_dev->adap.name)); + + i2c_dev->clk = devm_clk_get(&pdev->dev, NULL); + if (!IS_ERR(i2c_dev->clk)) + clk_prepare(i2c_dev->clk); + + i2c_dev->sclk = devm_clk_get(&pdev->dev, "sclk"); + if (!IS_ERR(i2c_dev->sclk)) + clk_prepare(i2c_dev->sclk); + + i2c_dev->irq = platform_get_irq(pdev, 0); + i2c_dev->adap.timeout = msecs_to_jiffies(100); + i2c_dev->adap.dev.parent = &pdev->dev; + i2c_dev->adap.algo = &em_i2c_algo; + i2c_dev->adap.owner = THIS_MODULE; + i2c_dev->adap.nr = pdev->id; + i2c_dev->adap.dev.of_node = pdev->dev.of_node; + + init_waitqueue_head(&i2c_dev->i2c_wait); + + spin_lock_init(&i2c_dev->irq_lock); + + i2c_dev->flags = I2C_BIT_DFC0; + + if (of_find_property(pdev->dev.of_node, "high-speed", NULL)) + i2c_dev->flags |= I2C_BIT_SMC0; + + platform_set_drvdata(pdev, i2c_dev); + i2c_set_adapdata(&i2c_dev->adap, i2c_dev); + + em_i2c_enable_clock(i2c_dev); + em_i2c_reset(&i2c_dev->adap); + em_i2c_disable_clock(i2c_dev); + + ret = devm_request_irq(&pdev->dev, i2c_dev->irq, em_i2c_irq_handler, 0, + "em_i2c", i2c_dev); + + if (ret) + goto exit_clk; + + ret = i2c_add_numbered_adapter(&i2c_dev->adap); + + if (ret != 0) + goto exit_clk; + + of_i2c_register_devices(&i2c_dev->adap); + + dev_info(&pdev->dev, "Added i2c controller %d irq %d @ 0x%p\n", + i2c_dev->adap.nr, i2c_dev->irq, i2c_dev->membase); + + return 0; + +exit_clk: + clk_disable(i2c_dev->clk); + clk_unprepare(i2c_dev->clk); + return ret; +} + +static int em_i2c_remove(struct platform_device *dev) +{ + struct em_i2c_device *i2c_dev = platform_get_drvdata(dev); + + i2c_del_adapter(&i2c_dev->adap); + + clk_disable(i2c_dev->clk); + clk_unprepare(i2c_dev->clk); + + return 0; +} + +static struct of_device_id em_i2c_ids[] = { + { .compatible = "renesas,em-i2c", }, + { } +}; + +static struct platform_driver em_i2c_driver = { + .probe = em_i2c_probe, + .remove = em_i2c_remove, + .driver = { + .name = "em-i2c", + .owner = THIS_MODULE, + .of_match_table = em_i2c_ids, + } +}; + + +static int __init em_i2c_init(void) +{ + return platform_driver_register(&em_i2c_driver); +} + +static void __exit em_i2c_exit(void) +{ + platform_driver_unregister(&em_i2c_driver); +} + +MODULE_LICENSE("GPLv2"); + +module_init(em_i2c_init); +module_exit(em_i2c_exit); + -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html