--- /dev/null +++ b/drivers/i2c/busses/i2c-bcm2708.c @@ -0,0 +1,408 @@ +/* + * Driver for Broadcom BCM2708 BSC Controllers + * + * Copyright (C) 2012 Chris Boot & Frank Buss + * + * This driver is inspired by: + * i2c-ocores.c, by Peter Korsgaard + * + * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* BSC register offsets */ +#define BSC_C 0x00 +#define BSC_S 0x04 +#define BSC_DLEN 0x08 +#define BSC_A 0x0c +#define BSC_FIFO 0x10 +#define BSC_DIV 0x14 +#define BSC_DEL 0x18 +#define BSC_CLKT 0x1c + +/* Bitfields in BSC_C */ +#define BSC_C_I2CEN 0x00008000 +#define BSC_C_INTR 0x00000400 +#define BSC_C_INTT 0x00000200 +#define BSC_C_INTD 0x00000100 +#define BSC_C_ST 0x00000080 +#define BSC_C_CLEAR_1 0x00000020 +#define BSC_C_CLEAR_2 0x00000010 +#define BSC_C_READ 0x00000001 + +/* Bitfields in BSC_S */ +#define BSC_S_CLKT 0x00000200 +#define BSC_S_ERR 0x00000100 +#define BSC_S_RXF 0x00000080 +#define BSC_S_TXE 0x00000040 +#define BSC_S_RXD 0x00000020 +#define BSC_S_TXD 0x00000010 +#define BSC_S_RXR 0x00000008 +#define BSC_S_TXW 0x00000004 +#define BSC_S_DONE 0x00000002 +#define BSC_S_TA 0x00000001 + +#define I2C_TIMEOUT_MS 150 + +#define DRV_NAME "bcm2708_i2c" + +static unsigned int baudrate = CONFIG_I2C_BCM2708_BAUDRATE; +module_param(baudrate, uint, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP); +MODULE_PARM_DESC(baudrate, "The I2C baudrate"); + + +struct bcm2708_i2c { + struct i2c_adapter adapter; + + spinlock_t lock; + void __iomem *base; + int irq; + struct clk *clk; + + struct completion done; + + struct i2c_msg *msg; + int pos; + int nmsgs; + bool error; +}; + +/* + * This function sets the ALT mode on the I2C pins so that we can use them with + * the BSC hardware. + * + * FIXME: This is a hack. Use pinmux / pinctrl. + */ +static void bcm2708_i2c_init_pinmode(int id) +{ +#define INP_GPIO(g) *(gpio+((g)/10)) &= ~(7<<(((g)%10)*3)) +#define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3)) + + int pin; + u32 *gpio = ioremap(0x20200000, SZ_16K); + + BUG_ON(id != 0 && id != 1); + /* BSC0 is on GPIO 0 & 1, BSC1 is on GPIO 2 & 3 */ + for (pin = id*2+0; pin <= id*2+1; pin++) { +printk("bcm2708_i2c_init_pinmode(%d,%d)\n", id, pin); + INP_GPIO(pin); /* set mode to GPIO input first */ + SET_GPIO_ALT(pin, 0); /* set mode to ALT 0 */ + } + + iounmap(gpio); + +#undef INP_GPIO +#undef SET_GPIO_ALT +} + +static inline u32 bcm2708_rd(struct bcm2708_i2c *bi, unsigned reg) +{ + return readl(bi->base + reg); +} + +static inline void bcm2708_wr(struct bcm2708_i2c *bi, unsigned reg, u32 val) +{ + writel(val, bi->base + reg); +} + +static inline void bcm2708_bsc_reset(struct bcm2708_i2c *bi) +{ + bcm2708_wr(bi, BSC_C, 0); + bcm2708_wr(bi, BSC_S, BSC_S_CLKT | BSC_S_ERR | BSC_S_DONE); +} + +static inline void bcm2708_bsc_fifo_drain(struct bcm2708_i2c *bi) +{ + while ((bcm2708_rd(bi, BSC_S) & BSC_S_RXD) && (bi->pos < bi->msg->len)) + bi->msg->buf[bi->pos++] = bcm2708_rd(bi, BSC_FIFO); +} + +static inline void bcm2708_bsc_fifo_fill(struct bcm2708_i2c *bi) +{ + while ((bcm2708_rd(bi, BSC_S) & BSC_S_TXD) && (bi->pos < bi->msg->len)) + bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]); +} + +static inline void bcm2708_bsc_setup(struct bcm2708_i2c *bi) +{ + unsigned long bus_hz; + u32 cdiv; + u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1; + + bus_hz = clk_get_rate(bi->clk); + cdiv = bus_hz / baudrate; + + if (bi->msg->flags & I2C_M_RD) + c |= BSC_C_INTR | BSC_C_READ; + else + c |= BSC_C_INTT; + + bcm2708_wr(bi, BSC_DIV, cdiv); + bcm2708_wr(bi, BSC_A, bi->msg->addr); + bcm2708_wr(bi, BSC_DLEN, bi->msg->len); + bcm2708_wr(bi, BSC_C, c); +} + +static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id) +{ + struct bcm2708_i2c *bi = dev_id; + bool handled = true; + u32 s; + + spin_lock(&bi->lock); + + /* we may see camera interrupts on the "other" I2C channel + Just return if we've not sent anything */ + if (!bi->nmsgs || !bi->msg ) + goto early_exit; + + s = bcm2708_rd(bi, BSC_S); + + if (s & (BSC_S_CLKT | BSC_S_ERR)) { + bcm2708_bsc_reset(bi); + bi->error = true; + + /* wake up our bh */ + complete(&bi->done); + } else if (s & BSC_S_DONE) { + bi->nmsgs--; + + if (bi->msg->flags & I2C_M_RD) + bcm2708_bsc_fifo_drain(bi); + + bcm2708_bsc_reset(bi); + + if (bi->nmsgs) { + /* advance to next message */ + bi->msg++; + bi->pos = 0; + bcm2708_bsc_setup(bi); + } else { + /* wake up our bh */ + complete(&bi->done); + } + } else if (s & BSC_S_TXW) { + bcm2708_bsc_fifo_fill(bi); + } else if (s & BSC_S_RXR) { + bcm2708_bsc_fifo_drain(bi); + } else { + handled = false; + } + +early_exit: + spin_unlock(&bi->lock); + + return handled ? IRQ_HANDLED : IRQ_NONE; +} + +static int bcm2708_i2c_master_xfer(struct i2c_adapter *adap, + struct i2c_msg *msgs, int num) +{ + struct bcm2708_i2c *bi = adap->algo_data; + unsigned long flags; + int ret; + + spin_lock_irqsave(&bi->lock, flags); + + INIT_COMPLETION(bi->done); + bi->msg = msgs; + bi->pos = 0; + bi->nmsgs = num; + bi->error = false; + + spin_unlock_irqrestore(&bi->lock, flags); + + bcm2708_bsc_setup(bi); + + ret = wait_for_completion_timeout(&bi->done, + msecs_to_jiffies(I2C_TIMEOUT_MS)); + if (ret == 0) { + dev_err(&adap->dev, "transfer timed out\n"); + spin_lock_irqsave(&bi->lock, flags); + bcm2708_bsc_reset(bi); + spin_unlock_irqrestore(&bi->lock, flags); + return -ETIMEDOUT; + } + + return bi->error ? -EIO : num; +} + +static u32 bcm2708_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | /*I2C_FUNC_10BIT_ADDR |*/ I2C_FUNC_SMBUS_EMUL; +} + +static struct i2c_algorithm bcm2708_i2c_algorithm = { + .master_xfer = bcm2708_i2c_master_xfer, + .functionality = bcm2708_i2c_functionality, +}; + +static int bcm2708_i2c_probe(struct platform_device *pdev) +{ + struct resource *regs; + int irq, err = -ENOMEM; + struct clk *clk; + struct bcm2708_i2c *bi; + struct i2c_adapter *adap; + + regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!regs) { + dev_err(&pdev->dev, "could not get IO memory\n"); + return -ENXIO; + } + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(&pdev->dev, "could not get IRQ\n"); + return irq; + } + + clk = clk_get(&pdev->dev, NULL); + if (IS_ERR(clk)) { + dev_err(&pdev->dev, "could not find clk: %ld\n", PTR_ERR(clk)); + return PTR_ERR(clk); + } + + bcm2708_i2c_init_pinmode(pdev->id); + + bi = kzalloc(sizeof(*bi), GFP_KERNEL); + if (!bi) + goto out_clk_put; + + platform_set_drvdata(pdev, bi); + + adap = &bi->adapter; + adap->class = I2C_CLASS_HWMON | I2C_CLASS_DDC; + adap->algo = &bcm2708_i2c_algorithm; + adap->algo_data = bi; + adap->dev.parent = &pdev->dev; + adap->nr = pdev->id; + strlcpy(adap->name, dev_name(&pdev->dev), sizeof(adap->name)); + + switch (pdev->id) { + case 0: + adap->class = I2C_CLASS_HWMON; + break; + case 1: + adap->class = I2C_CLASS_DDC; + break; + default: + dev_err(&pdev->dev, "can only bind to BSC 0 or 1\n"); + err = -ENXIO; + goto out_free_bi; + } + + spin_lock_init(&bi->lock); + init_completion(&bi->done); + + bi->base = ioremap(regs->start, resource_size(regs)); + if (!bi->base) { + dev_err(&pdev->dev, "could not remap memory\n"); + goto out_free_bi; + } + + bi->irq = irq; + bi->clk = clk; + + err = request_irq(irq, bcm2708_i2c_interrupt, IRQF_SHARED, + dev_name(&pdev->dev), bi); + if (err) { + dev_err(&pdev->dev, "could not request IRQ: %d\n", err); + goto out_iounmap; + } + + bcm2708_bsc_reset(bi); + + err = i2c_add_numbered_adapter(adap); + if (err < 0) { + dev_err(&pdev->dev, "could not add I2C adapter: %d\n", err); + goto out_free_irq; + } + + dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %dk)\n", + pdev->id, (unsigned long)regs->start, irq, baudrate/1000); + + return 0; + +out_free_irq: + free_irq(bi->irq, bi); +out_iounmap: + iounmap(bi->base); +out_free_bi: + kfree(bi); +out_clk_put: + clk_put(clk); + return err; +} + +static int bcm2708_i2c_remove(struct platform_device *pdev) +{ + struct bcm2708_i2c *bi = platform_get_drvdata(pdev); + + platform_set_drvdata(pdev, NULL); + + i2c_del_adapter(&bi->adapter); + free_irq(bi->irq, bi); + iounmap(bi->base); + clk_disable(bi->clk); + clk_put(bi->clk); + kfree(bi); + + return 0; +} + +static struct platform_driver bcm2708_i2c_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, + .probe = bcm2708_i2c_probe, + .remove = bcm2708_i2c_remove, +}; + +// module_platform_driver(bcm2708_i2c_driver); + + +static int __init bcm2708_i2c_init(void) +{ + return platform_driver_register(&bcm2708_i2c_driver); +} + +static void __exit bcm2708_i2c_exit(void) +{ + platform_driver_unregister(&bcm2708_i2c_driver); +} + +module_init(bcm2708_i2c_init); +module_exit(bcm2708_i2c_exit); + + + +MODULE_DESCRIPTION("BSC controller driver for Broadcom BCM2708"); +MODULE_AUTHOR("Chris Boot "); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" DRV_NAME); --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -344,6 +344,25 @@ config I2C_BCM2835 This support is also available as a module. If so, the module will be called i2c-bcm2835. +config I2C_BCM2708 + tristate "BCM2708 BSC" + depends on MACH_BCM2708 + help + Enabling this option will add BSC (Broadcom Serial Controller) + support for the BCM2708. BSC is a Broadcom proprietary bus compatible + with I2C/TWI/SMBus. + +config I2C_BCM2708_BAUDRATE + prompt "BCM2708 I2C baudrate" + depends on I2C_BCM2708 + int + default 100000 + help + Set the I2C baudrate. This will alter the default value. A + different baudrate can be set by using a module parameter as well. If + no parameter is provided when loading, this is the value that will be + used. + config I2C_BLACKFIN_TWI tristate "Blackfin TWI I2C support" depends on BLACKFIN --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_I2C_POWERMAC) += i2c-powerm obj-$(CONFIG_I2C_AT91) += i2c-at91.o obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o +obj-$(CONFIG_I2C_BCM2708) += i2c-bcm2708.o obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o obj-$(CONFIG_I2C_CBUS_GPIO) += i2c-cbus-gpio.o obj-$(CONFIG_I2C_CPM) += i2c-cpm.o