diff options
| -rw-r--r-- | Documentation/devicetree/bindings/i2c/i2c-digicolor.txt | 25 | ||||
| -rw-r--r-- | drivers/i2c/busses/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/i2c/busses/Makefile | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-digicolor.c | 385 |
4 files changed, 420 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c-digicolor.txt b/Documentation/devicetree/bindings/i2c/i2c-digicolor.txt new file mode 100644 index 0000000..457a098 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-digicolor.txt @@ -0,0 +1,25 @@ +Conexant Digicolor I2C controller + +Required properties: + - compatible: must be "cnxt,cx92755-i2c" + - reg: physical address and length of the device registers + - interrupts: a single interrupt specifier + - clocks: clock for the device + - #address-cells: should be <1> + - #size-cells: should be <0> + +Optional properties: +- clock-frequency: the desired I2C bus clock frequency in Hz; in + absence of this property the default value is used (100 kHz). + +Example: + + i2c: i2c@f0000120 { + compatible = "cnxt,cx92755-i2c"; + reg = <0xf0000120 0x10>; + interrupts = <28>; + clocks = <&main_clk>; + clock-frequency = <100000>; + #address-cells = <1>; + #size-cells = <0>; + }; diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 22da9c2..db09881 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -485,6 +485,15 @@ config I2C_DESIGNWARE_BAYTRAIL the platform firmware controlling it. You should say Y if running on a BayTrail system using the AXP288. +config I2C_DIGICOLOR + tristate "Conexant Digicolor I2C driver" + depends on ARCH_DIGICOLOR + help + Support for Conexant Digicolor SoCs (CX92755) I2C controller driver. + + This driver can also be built as a module. If so, the module + will be called i2c-digicolor. + config I2C_EFM32 tristate "EFM32 I2C controller" depends on ARCH_EFM32 || COMPILE_TEST diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 3638feb..4413f09 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -45,6 +45,7 @@ i2c-designware-platform-objs := i2c-designware-platdrv.o i2c-designware-platform-$(CONFIG_I2C_DESIGNWARE_BAYTRAIL) += i2c-designware-baytrail.o obj-$(CONFIG_I2C_DESIGNWARE_PCI) += i2c-designware-pci.o i2c-designware-pci-objs := i2c-designware-pcidrv.o +obj-$(CONFIG_I2C_DIGICOLOR) += i2c-digicolor.o obj-$(CONFIG_I2C_EFM32) += i2c-efm32.o obj-$(CONFIG_I2C_EG20T) += i2c-eg20t.o obj-$(CONFIG_I2C_EXYNOS5) += i2c-exynos5.o diff --git a/drivers/i2c/busses/i2c-digicolor.c b/drivers/i2c/busses/i2c-digicolor.c new file mode 100644 index 0000000..03f1e55 --- /dev/null +++ b/drivers/i2c/busses/i2c-digicolor.c @@ -0,0 +1,385 @@ +/* + * I2C bus driver for Conexant Digicolor SoCs + * + * Author: Baruch Siach <baruch@tkos.co.il> + * + * Copyright (C) 2015 Paradox Innovation Ltd. + * + * 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. + */ + +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> + +#define DEFAULT_FREQ 100000 +#define TIMEOUT_MS 100 + +#define II_CONTROL 0x0 +#define II_CONTROL_LOCAL_RESET BIT(0) + +#define II_CLOCKTIME 0x1 + +#define II_COMMAND 0x2 +#define II_CMD_START 1 +#define II_CMD_RESTART 2 +#define II_CMD_SEND_ACK 3 +#define II_CMD_GET_ACK 6 +#define II_CMD_GET_NOACK 7 +#define II_CMD_STOP 10 +#define II_COMMAND_GO BIT(7) +#define II_COMMAND_COMPLETION_STATUS(r) (((r) >> 5) & 3) +#define II_CMD_STATUS_NORMAL 0 +#define II_CMD_STATUS_ACK_GOOD 1 +#define II_CMD_STATUS_ACK_BAD 2 +#define II_CMD_STATUS_ABORT 3 + +#define II_DATA 0x3 +#define II_INTFLAG_CLEAR 0x8 +#define II_INTENABLE 0xa + +struct dc_i2c { + struct i2c_adapter adap; + struct device *dev; + void __iomem *regs; + struct clk *clk; + unsigned int frequency; + + struct i2c_msg *msg; + unsigned int msgbuf_ptr; + int last; + spinlock_t lock; + struct completion done; + int state; + int error; +}; + +enum { + STATE_IDLE, + STATE_START, + STATE_ADDR, + STATE_WRITE, + STATE_READ, + STATE_STOP, +}; + +static void dc_i2c_cmd(struct dc_i2c *i2c, u8 cmd) +{ + writeb_relaxed(cmd | II_COMMAND_GO, i2c->regs + II_COMMAND); +} + +static u8 dc_i2c_addr_cmd(struct i2c_msg *msg) +{ + u8 addr = (msg->addr & 0x7f) << 1; + + if (msg->flags & I2C_M_RD) + addr |= 1; + + return addr; +} + +static void dc_i2c_data(struct dc_i2c *i2c, u8 data) +{ + writeb_relaxed(data, i2c->regs + II_DATA); +} + +static void dc_i2c_write_byte(struct dc_i2c *i2c, u8 byte) +{ + dc_i2c_data(i2c, byte); + dc_i2c_cmd(i2c, II_CMD_SEND_ACK); +} + +static void dc_i2c_write_buf(struct dc_i2c *i2c) +{ + dc_i2c_write_byte(i2c, i2c->msg->buf[i2c->msgbuf_ptr++]); +} + +static void dc_i2c_next_read(struct dc_i2c *i2c) +{ + bool last = (i2c->msgbuf_ptr + 1 == i2c->msg->len); + + dc_i2c_cmd(i2c, last ? II_CMD_GET_NOACK : II_CMD_GET_ACK); +} + +static void dc_i2c_stop(struct dc_i2c *i2c) +{ + i2c->state = STATE_STOP; + if (i2c->last) + dc_i2c_cmd(i2c, II_CMD_STOP); + else + complete(&i2c->done); +} + +static u8 dc_i2c_read_byte(struct dc_i2c *i2c) +{ + return readb_relaxed(i2c->regs + II_DATA); +} + +static void dc_i2c_read_buf(struct dc_i2c *i2c) +{ + i2c->msg->buf[i2c->msgbuf_ptr++] = dc_i2c_read_byte(i2c); + dc_i2c_next_read(i2c); +} + +static void dc_i2c_set_irq(struct dc_i2c *i2c, int enable) +{ + if (enable) + writeb_relaxed(1, i2c->regs + II_INTFLAG_CLEAR); + writeb_relaxed(!!enable, i2c->regs + II_INTENABLE); +} + +static int dc_i2c_cmd_status(struct dc_i2c *i2c) +{ + u8 cmd = readb_relaxed(i2c->regs + II_COMMAND); + + return II_COMMAND_COMPLETION_STATUS(cmd); +} + +static void dc_i2c_start_msg(struct dc_i2c *i2c, int first) +{ + struct i2c_msg *msg = i2c->msg; + + if (!(msg->flags & I2C_M_NOSTART)) { + i2c->state = STATE_START; + dc_i2c_cmd(i2c, first ? II_CMD_START : II_CMD_RESTART); + } else if (msg->flags & I2C_M_RD) { + i2c->state = STATE_READ; + dc_i2c_next_read(i2c); + } else { + i2c->state = STATE_WRITE; + dc_i2c_write_buf(i2c); + } +} + +static irqreturn_t dc_i2c_irq(int irq, void *dev_id) +{ + struct dc_i2c *i2c = dev_id; + int cmd_status = dc_i2c_cmd_status(i2c); + unsigned long flags; + u8 addr_cmd; + + writeb_relaxed(1, i2c->regs + II_INTFLAG_CLEAR); + + spin_lock_irqsave(&i2c->lock, flags); + + if (cmd_status == II_CMD_STATUS_ACK_BAD + || cmd_status == II_CMD_STATUS_ABORT) { + i2c->error = -EIO; + complete(&i2c->done); + goto out; + } + + switch (i2c->state) { + case STATE_START: + addr_cmd = dc_i2c_addr_cmd(i2c->msg); + dc_i2c_write_byte(i2c, addr_cmd); + i2c->state = STATE_ADDR; + break; + case STATE_ADDR: + if (i2c->msg->flags & I2C_M_RD) { + dc_i2c_next_read(i2c); + i2c->state = STATE_READ; + break; + } + i2c->state = STATE_WRITE; + /* fall through */ + case STATE_WRITE: + if (i2c->msgbuf_ptr < i2c->msg->len) + dc_i2c_write_buf(i2c); + else + dc_i2c_stop(i2c); + break; + case STATE_READ: + if (i2c->msgbuf_ptr < i2c->msg->len) + dc_i2c_read_buf(i2c); + else + dc_i2c_stop(i2c); + break; + case STATE_STOP: + i2c->state = STATE_IDLE; + complete(&i2c->done); + break; + } + +out: + spin_unlock_irqrestore(&i2c->lock, flags); + return IRQ_HANDLED; +} + +static int dc_i2c_xfer_msg(struct dc_i2c *i2c, struct i2c_msg *msg, int first, + int last) +{ + unsigned long timeout = msecs_to_jiffies(TIMEOUT_MS); + unsigned long flags; + + spin_lock_irqsave(&i2c->lock, flags); + i2c->msg = msg; + i2c->msgbuf_ptr = 0; + i2c->last = last; + i2c->error = 0; + + reinit_completion(&i2c->done); + dc_i2c_set_irq(i2c, 1); + dc_i2c_start_msg(i2c, first); + spin_unlock_irqrestore(&i2c->lock, flags); + + timeout = wait_for_completion_timeout(&i2c->done, timeout); + dc_i2c_set_irq(i2c, 0); + if (timeout == 0) { + i2c->state = STATE_IDLE; + return -ETIMEDOUT; + } + + if (i2c->error) + return i2c->error; + + return 0; +} + +static int dc_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) +{ + struct dc_i2c *i2c = adap->algo_data; + int i, ret; + + for (i = 0; i < num; i++) { + ret = dc_i2c_xfer_msg(i2c, &msgs[i], i == 0, i == num - 1); + if (ret) + return ret; + } + + return num; +} + +static int dc_i2c_init_hw(struct dc_i2c *i2c) +{ + unsigned long clk_rate = clk_get_rate(i2c->clk); + unsigned int clocktime; + + writeb_relaxed(II_CONTROL_LOCAL_RESET, i2c->regs + II_CONTROL); + udelay(100); + writeb_relaxed(0, i2c->regs + II_CONTROL); + udelay(100); + + clocktime = DIV_ROUND_UP(clk_rate, 64 * i2c->frequency); + if (clocktime < 1 || clocktime > 0xff) { + dev_err(i2c->dev, "can't set bus speed of %u Hz\n", + i2c->frequency); + return -EINVAL; + } + writeb_relaxed(clocktime - 1, i2c->regs + II_CLOCKTIME); + + return 0; +} + +static u32 dc_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART; +} + +static const struct i2c_algorithm dc_i2c_algorithm = { + .master_xfer = dc_i2c_xfer, + .functionality = dc_i2c_func, +}; + +static int dc_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct dc_i2c *i2c; + struct resource *r; + int ret = 0, irq; + + i2c = devm_kzalloc(&pdev->dev, sizeof(struct dc_i2c), GFP_KERNEL); + if (!i2c) + return -ENOMEM; + + if (of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &i2c->frequency)) + i2c->frequency = DEFAULT_FREQ; + + i2c->dev = &pdev->dev; + platform_set_drvdata(pdev, i2c); + + spin_lock_init(&i2c->lock); + init_completion(&i2c->done); + + i2c->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(i2c->clk)) + return PTR_ERR(i2c->clk); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + i2c->regs = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(i2c->regs)) + return PTR_ERR(i2c->regs); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + ret = devm_request_irq(&pdev->dev, irq, dc_i2c_irq, 0, + dev_name(&pdev->dev), i2c); + if (ret < 0) + return ret; + + strlcpy(i2c->adap.name, "Conexant Digicolor I2C adapter", + sizeof(i2c->adap.name)); + i2c->adap.owner = THIS_MODULE; + i2c->adap.algo = &dc_i2c_algorithm; + i2c->adap.dev.parent = &pdev->dev; + i2c->adap.dev.of_node = np; + i2c->adap.algo_data = i2c; + + ret = dc_i2c_init_hw(i2c); + if (ret) + return ret; + + ret = clk_prepare_enable(i2c->clk); + if (ret < 0) + return ret; + + ret = i2c_add_adapter(&i2c->adap); + if (ret < 0) { + clk_unprepare(i2c->clk); + return ret; + } + + return 0; +} + +static int dc_i2c_remove(struct platform_device *pdev) +{ + struct dc_i2c *i2c = platform_get_drvdata(pdev); + + i2c_del_adapter(&i2c->adap); + clk_disable_unprepare(i2c->clk); + + return 0; +} + +static const struct of_device_id dc_i2c_match[] = { + { .compatible = "cnxt,cx92755-i2c" }, + { }, +}; + +static struct platform_driver dc_i2c_driver = { + .probe = dc_i2c_probe, + .remove = dc_i2c_remove, + .driver = { + .name = "digicolor-i2c", + .of_match_table = dc_i2c_match, + }, +}; +module_platform_driver(dc_i2c_driver); + +MODULE_AUTHOR("Baruch Siach <baruch@tkos.co.il>"); +MODULE_DESCRIPTION("Conexant Digicolor I2C master driver"); +MODULE_LICENSE("GPL v2"); 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