Add a driver for the i2c core found on various mediatek/ralink SoCs. This driver is based on the code found inside the SDK.
Signed-off-by: Michele Mogioni <[email protected]> Signed-off-by: John Crispin <[email protected]> --- .../devicetree/bindings/i2c/i2c-rt2880.txt | 27 ++ drivers/i2c/busses/Kconfig | 10 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-rt2880.c | 300 ++++++++++++++++++++ 4 files changed, 338 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-rt2880.txt create mode 100644 drivers/i2c/busses/i2c-rt2880.c diff --git a/Documentation/devicetree/bindings/i2c/i2c-rt2880.txt b/Documentation/devicetree/bindings/i2c/i2c-rt2880.txt new file mode 100644 index 0000000..fa4588b --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-rt2880.txt @@ -0,0 +1,27 @@ +I2C for Ralink platforms + +Required properties : +- compatible : Must be "ralink,rt2880-i2c" +- reg: physical base address of the controller and length of memory mapped + region. +- #address-cells = <1>; +- #size-cells = <0>; + +Optional properties: +- Child nodes conforming to i2c bus binding + +Example : + +palmbus@10000000 { + i2c@900 { + compatible = "ralink,rt2880-i2c"; + reg = <0x900 0x100>; + #address-cells = <1>; + #size-cells = <0>; + + hwmon@4b { + compatible = "national,lm92"; + reg = <0x4b>; + }; + }; +}; diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 2ac87fa..2e4b4d5 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -687,6 +687,16 @@ config I2C_RK3X This driver can also be built as a module. If so, the module will be called i2c-rk3x. +config I2C_RT2880 + tristate "Ralink RT2880 I2C Controller" + depends on MIPS && RALINK + help + Say Y here to include support for the I2C adapter in Ralink RT2880 + SoCs. + + This driver can also be built as a module. If so, the module will + be called i2c-rt2880. + config HAVE_S3C2410_I2C bool help diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 49bf07e..967e9f5 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -67,6 +67,7 @@ obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o obj-$(CONFIG_I2C_QUP) += i2c-qup.o obj-$(CONFIG_I2C_RIIC) += i2c-riic.o obj-$(CONFIG_I2C_RK3X) += i2c-rk3x.o +obj-$(CONFIG_I2C_RT2880) += i2c-rt2880.o obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o obj-$(CONFIG_I2C_SH_MOBILE) += i2c-sh_mobile.o diff --git a/drivers/i2c/busses/i2c-rt2880.c b/drivers/i2c/busses/i2c-rt2880.c new file mode 100644 index 0000000..b4803e6 --- /dev/null +++ b/drivers/i2c/busses/i2c-rt2880.c @@ -0,0 +1,300 @@ +/* + * drivers/i2c/busses/i2c-ralink.c + * + * Copyright (C) 2013 Steven Liu <[email protected]> + * + * Improve driver for i2cdetect from i2c-tools to detect i2c devices on the bus. + * (C) 2014 Sittisak <[email protected]> + * (C) 2014 Michele Mogioni <[email protected]> + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * 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. + * + */ + +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/reset.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/errno.h> +#include <linux/platform_device.h> +#include <linux/i2c.h> +#include <linux/io.h> +#include <linux/err.h> + +#include <asm/mach-ralink/ralink_regs.h> + +#define REG_CONFIG_REG 0x00 +#define REG_CLKDIV_REG 0x04 +#define REG_DEVADDR_REG 0x08 +#define REG_ADDR_REG 0x0C +#define REG_DATAOUT_REG 0x10 +#define REG_DATAIN_REG 0x14 +#define REG_STATUS_REG 0x18 +#define REG_STARTXFR_REG 0x1C +#define REG_BYTECNT_REG 0x20 + +#define I2C_STARTERR BIT(4) +#define I2C_ACKERR BIT(3) +#define I2C_DATARDY BIT(2) +#define I2C_SDOEMPTY BIT(1) +#define I2C_BUSY BIT(0) + +#define I2C_DEVADLEN_7 (6 << 2) +#define I2C_ADDRDIS BIT(1) + +#define I2C_RETRY 0x1000 + +/* clock rate is 40M, 40M / (200*2) = 100k (standard i2c bus rate). */ +#define CLKDIV_VALUE 200 +/* clock rate is 40M, 40M / (50*2) = 400k (fast i2c bus rate). */ +/* #define CLKDIV_VALUE 50 */ + +#define READ_CMD 0x01 +#define WRITE_CMD 0x00 +#define READ_BLOCK 64 + +static void __iomem *membase; +static struct i2c_adapter *adapter; + +static void rt_i2c_w32(u32 val, unsigned reg) +{ + iowrite32(val, membase + reg); +} + +static u32 rt_i2c_r32(unsigned reg) +{ + return ioread32(membase + reg); +} + +static inline int rt_i2c_get_ack(void) +{ + return (rt_i2c_r32(REG_STATUS_REG) & I2C_ACKERR) ? -EIO : 0; +} + +static inline int rt_i2c_wait_rx_done(void) +{ + int retries = I2C_RETRY; + + do { + if (!retries--) + break; + } while (!(rt_i2c_r32(REG_STATUS_REG) & I2C_DATARDY)); + + return (retries < 0) ? -ETIMEDOUT : 0; +} + +static inline int rt_i2c_wait_idle(void) +{ + int retries = I2C_RETRY; + + do { + if (!retries--) + break; + } while (rt_i2c_r32(REG_STATUS_REG) & I2C_BUSY); + + return (retries < 0); +} + +static inline int rt_i2c_wait_tx_done(void) +{ + int retries = I2C_RETRY; + + do { + if (!retries--) + break; + } while (!(rt_i2c_r32(REG_STATUS_REG) & I2C_SDOEMPTY)); + + return (retries < 0) ? -ETIMEDOUT : 0; +} + +static int rt_i2c_handle_msg(struct i2c_adapter *a, struct i2c_msg *msg) +{ + int i = 0, j = 0, pos = 0; + int nblock = msg->len / READ_BLOCK; + int rem = msg->len % READ_BLOCK; + int ret = 0; + + if (msg->flags & I2C_M_TEN) { + dev_err(a->dev.parent, "10 bits addr not supported\n"); + return -EINVAL; + } + + if (msg->flags & I2C_M_RD) { + for (i = 0; i < nblock; i++) { + if (rt_i2c_wait_idle()) { + dev_err(a->dev.parent, "i2c-read line busy\n"); + return -ETIMEDOUT; + } + rt_i2c_w32(READ_BLOCK - 1, REG_BYTECNT_REG); + rt_i2c_w32(READ_CMD, REG_STARTXFR_REG); + for (j = 0; j < READ_BLOCK; j++) { + if (rt_i2c_wait_rx_done() < 0) + ret = rt_i2c_wait_rx_done(); + if (rt_i2c_get_ack() < 0) + ret = rt_i2c_get_ack(); + msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG); + } + } + + if (rt_i2c_wait_idle()) { + dev_err(a->dev.parent, "i2c-read line busy\n"); + return -ETIMEDOUT; + } + if (rem) { + rt_i2c_w32(rem - 1, REG_BYTECNT_REG); + rt_i2c_w32(READ_CMD, REG_STARTXFR_REG); + } + for (i = 0; i < rem; i++) { + if (rt_i2c_wait_rx_done() < 0) + ret = rt_i2c_wait_rx_done(); + if (rt_i2c_get_ack() < 0) + ret = rt_i2c_get_ack(); + + msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG); + } + } else { + if (rt_i2c_wait_idle()) { + dev_err(a->dev.parent, "i2c-write line busy\n"); + return -ETIMEDOUT; + } + rt_i2c_w32(msg->len - 1, REG_BYTECNT_REG); + for (i = 0; i < msg->len; i++) { + rt_i2c_w32(msg->buf[i], REG_DATAOUT_REG); + rt_i2c_w32(WRITE_CMD, REG_STARTXFR_REG); + + if (rt_i2c_wait_tx_done() < 0) + ret = rt_i2c_wait_tx_done(); + if (rt_i2c_get_ack() < 0) + ret = rt_i2c_get_ack(); + } + } + + return ret; +} + +static int rt_i2c_master_xfer(struct i2c_adapter *a, struct i2c_msg *m, int n) +{ + int i = 0; + int ret = 0; + + if (rt_i2c_wait_idle()) { + dev_err(a->dev.parent, "i2c-master_xfer line busy\n"); + return -ETIMEDOUT; + } + + device_reset(a->dev.parent); + + rt_i2c_w32(m->addr, REG_DEVADDR_REG); + rt_i2c_w32(I2C_DEVADLEN_7 | I2C_ADDRDIS, REG_CONFIG_REG); + rt_i2c_w32(CLKDIV_VALUE, REG_CLKDIV_REG); + + for (i = 0; i < n && !ret; i++) { + ret = rt_i2c_handle_msg(a, &m[i]); + + if (ret < 0) + return ret; + } + + return n; +} + +static u32 rt_i2c_func(struct i2c_adapter *a) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm rt_i2c_algo = { + .master_xfer = rt_i2c_master_xfer, + .functionality = rt_i2c_func, +}; + +static int rt_i2c_probe(struct platform_device *pdev) +{ + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + int ret; + + if (!res) { + dev_err(&pdev->dev, "no memory resource found\n"); + return -ENODEV; + } + + adapter = devm_kzalloc(&pdev->dev, sizeof(struct i2c_adapter), + GFP_KERNEL); + if (!adapter) + return -ENOMEM; + + membase = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(membase)) + return PTR_ERR(membase); + + strlcpy(adapter->name, dev_name(&pdev->dev), sizeof(adapter->name)); + adapter->owner = THIS_MODULE; + adapter->nr = pdev->id; + adapter->timeout = HZ; + adapter->algo = &rt_i2c_algo; + adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; + adapter->dev.parent = &pdev->dev; + adapter->dev.of_node = pdev->dev.of_node; + + ret = i2c_add_numbered_adapter(adapter); + if (ret) + return ret; + + platform_set_drvdata(pdev, adapter); + + dev_info(&pdev->dev, "loaded\n"); + + return 0; +} + +static int rt_i2c_remove(struct platform_device *pdev) +{ + platform_set_drvdata(pdev, NULL); + + return 0; +} + +static const struct of_device_id i2c_rt_dt_ids[] = { + { .compatible = "ralink,rt2880-i2c", }, + { /* sentinel */ } +}; + +MODULE_DEVICE_TABLE(of, i2c_rt_dt_ids); + +static struct platform_driver rt_i2c_driver = { + .probe = rt_i2c_probe, + .remove = rt_i2c_remove, + .driver = { + .owner = THIS_MODULE, + .name = "i2c-ralink", + .of_match_table = i2c_rt_dt_ids, + }, +}; + +static int __init i2c_rt_init(void) +{ + return platform_driver_register(&rt_i2c_driver); +} +subsys_initcall(i2c_rt_init); + +static void __exit i2c_rt_exit(void) +{ + platform_driver_unregister(&rt_i2c_driver); +} + +module_exit(i2c_rt_exit); + +MODULE_AUTHOR("Steven Liu <[email protected]>"); +MODULE_DESCRIPTION("Ralink I2c host driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:Ralink-I2C"); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
