From 4596818bca07e0928168970839e08875cf51b4cc Mon Sep 17 00:00:00 2001 From: John Crispin Date: Mon, 29 Apr 2013 14:40:43 +0200 Subject: [PATCH 26/33] i2c: MIPS: adds ralink I2C driver Signed-off-by: John Crispin --- .../devicetree/bindings/i2c/i2c-ralink.txt | 27 ++ drivers/i2c/busses/Kconfig | 4 + drivers/i2c/busses/Makefile | 1 + drivers/i2c/busses/i2c-ralink.c | 274 ++++++++++++++++++++ 4 files changed, 306 insertions(+) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-ralink.txt create mode 100644 drivers/i2c/busses/i2c-ralink.c diff --git a/Documentation/devicetree/bindings/i2c/i2c-ralink.txt b/Documentation/devicetree/bindings/i2c/i2c-ralink.txt new file mode 100644 index 0000000..8fa8ac3 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-ralink.txt @@ -0,0 +1,27 @@ +I2C for Ralink platforms + +Required properties : +- compatible : Must be "link,rt3052-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 = "link,rt3052-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 631736e..e2c2381 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -628,6 +628,10 @@ config I2C_PXA_SLAVE is necessary for systems where the PXA may be a target on the I2C bus. +config I2C_RALINK + tristate "Ralink I2C Controller" + select OF_I2C + config HAVE_S3C2410_I2C bool help diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 8f4fc23..7e39a13 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -62,6 +62,7 @@ obj-$(CONFIG_I2C_PNX) += i2c-pnx.o obj-$(CONFIG_I2C_PUV3) += i2c-puv3.o obj-$(CONFIG_I2C_PXA) += i2c-pxa.o obj-$(CONFIG_I2C_PXA_PCI) += i2c-pxa-pci.o +obj-$(CONFIG_I2C_RALINK) += i2c-ralink.o obj-$(CONFIG_I2C_S3C2410) += i2c-s3c2410.o obj-$(CONFIG_I2C_S6000) += i2c-s6000.o obj-$(CONFIG_I2C_SH7760) += i2c-sh7760.o diff --git a/drivers/i2c/busses/i2c-ralink.c b/drivers/i2c/busses/i2c-ralink.c new file mode 100644 index 0000000..f4dc13d --- /dev/null +++ b/drivers/i2c/busses/i2c-ralink.c @@ -0,0 +1,274 @@ +/* + * drivers/i2c/busses/i2c-ralink.c + * + * Copyright (C) 2013 Steven Liu + * + * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#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 0x400 + +#define CLKDIV_VALUE 200 // clock rate is 40M, 40M / (200*2) = 100k (standard i2c bus rate). +//#define CLKDIV_VALUE 50 // clock rate is 40M, 40M / (50*2) = 400k (fast i2c bus rate). + +#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_wait_rx_done(void) +{ + int retries = I2C_RETRY; + + do { + if (!retries--) + break; + } while(!(rt_i2c_r32(REG_STATUS_REG) & I2C_DATARDY)); + + return (retries < 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); +} + +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; + + if (msg->flags & I2C_M_TEN) { + printk("10 bits addr not supported\n"); + return -EINVAL; + } + + if (msg->flags & I2C_M_RD) { + for (i = 0; i < nblock; i++) { + rt_i2c_wait_idle(); + 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()) + return -1; + msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG); + } + } + + rt_i2c_wait_idle(); + 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()) + return -1; + msg->buf[pos++] = rt_i2c_r32(REG_DATAIN_REG); + } + } else { + rt_i2c_wait_idle(); + 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()) + return -1; + } + } + + return 0; +} + +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()) { + printk("i2c transfer failed\n"); + return 0; + } + + 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) { + printk("i2c transfer failed\n"); + return 0; + } + + 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) { + dev_err(&pdev->dev, "failed to allocate i2c_adapter\n"); + return -ENOMEM; + } + + membase = devm_request_and_ioremap(&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; + + of_i2c_register_devices(adapter); + + 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 "); +MODULE_DESCRIPTION("Ralink I2c host driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:Ralink-I2C"); -- 1.7.10.4