diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-viai2c-wmt.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-viai2c-wmt.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-viai2c-wmt.c b/drivers/i2c/busses/i2c-viai2c-wmt.c new file mode 100644 index 0000000000..420fd10fe3 --- /dev/null +++ b/drivers/i2c/busses/i2c-viai2c-wmt.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Wondermedia I2C Master Mode Driver + * + * Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz> + * + * Derived from GPLv2+ licensed source: + * - Copyright (C) 2008 WonderMedia Technologies, Inc. + */ + +#include <linux/clk.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include "i2c-viai2c-common.h" + +#define REG_SLAVE_CR 0x10 +#define REG_SLAVE_SR 0x12 +#define REG_SLAVE_ISR 0x14 +#define REG_SLAVE_IMR 0x16 +#define REG_SLAVE_DR 0x18 +#define REG_SLAVE_TR 0x1A + +/* REG_TR */ +#define SCL_TIMEOUT(x) (((x) & 0xFF) << 8) +#define TR_STD 0x0064 +#define TR_HS 0x0019 + +/* REG_MCR */ +#define MCR_APB_96M 7 +#define MCR_APB_166M 12 + +static u32 wmt_i2c_func(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_NOSTART; +} + +static const struct i2c_algorithm wmt_i2c_algo = { + .master_xfer = viai2c_xfer, + .functionality = wmt_i2c_func, +}; + +static int wmt_i2c_reset_hardware(struct viai2c *i2c) +{ + int err; + + err = clk_prepare_enable(i2c->clk); + if (err) { + dev_err(i2c->dev, "failed to enable clock\n"); + return err; + } + + err = clk_set_rate(i2c->clk, 20000000); + if (err) { + dev_err(i2c->dev, "failed to set clock = 20Mhz\n"); + clk_disable_unprepare(i2c->clk); + return err; + } + + writew(0, i2c->base + VIAI2C_REG_CR); + writew(MCR_APB_166M, i2c->base + VIAI2C_REG_MCR); + writew(VIAI2C_ISR_MASK_ALL, i2c->base + VIAI2C_REG_ISR); + writew(VIAI2C_IMR_ENABLE_ALL, i2c->base + VIAI2C_REG_IMR); + writew(VIAI2C_CR_ENABLE, i2c->base + VIAI2C_REG_CR); + readw(i2c->base + VIAI2C_REG_CSR); /* read clear */ + writew(VIAI2C_ISR_MASK_ALL, i2c->base + VIAI2C_REG_ISR); + + if (i2c->tcr == VIAI2C_TCR_FAST) + writew(SCL_TIMEOUT(128) | TR_HS, i2c->base + VIAI2C_REG_TR); + else + writew(SCL_TIMEOUT(128) | TR_STD, i2c->base + VIAI2C_REG_TR); + + return 0; +} + +static irqreturn_t wmt_i2c_isr(int irq, void *data) +{ + struct viai2c *i2c = data; + u8 status; + + /* save the status and write-clear it */ + status = readw(i2c->base + VIAI2C_REG_ISR); + writew(status, i2c->base + VIAI2C_REG_ISR); + + i2c->ret = 0; + if (status & VIAI2C_ISR_NACK_ADDR) + i2c->ret = -EIO; + + if (status & VIAI2C_ISR_SCL_TIMEOUT) + i2c->ret = -ETIMEDOUT; + + if (!i2c->ret) + i2c->ret = viai2c_irq_xfer(i2c); + + /* All the data has been successfully transferred or error occurred */ + if (i2c->ret) + complete(&i2c->complete); + + return IRQ_HANDLED; +} + +static int wmt_i2c_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct viai2c *i2c; + struct i2c_adapter *adap; + int err; + u32 clk_rate; + + err = viai2c_init(pdev, &i2c, VIAI2C_PLAT_WMT); + if (err) + return err; + + i2c->irq = platform_get_irq(pdev, 0); + if (i2c->irq < 0) + return i2c->irq; + + err = devm_request_irq(&pdev->dev, i2c->irq, wmt_i2c_isr, + 0, pdev->name, i2c); + if (err) + return dev_err_probe(&pdev->dev, err, + "failed to request irq %i\n", i2c->irq); + + i2c->clk = of_clk_get(np, 0); + if (IS_ERR(i2c->clk)) { + dev_err(&pdev->dev, "unable to request clock\n"); + return PTR_ERR(i2c->clk); + } + + err = of_property_read_u32(np, "clock-frequency", &clk_rate); + if (!err && clk_rate == I2C_MAX_FAST_MODE_FREQ) + i2c->tcr = VIAI2C_TCR_FAST; + + adap = &i2c->adapter; + i2c_set_adapdata(adap, i2c); + strscpy(adap->name, "WMT I2C adapter", sizeof(adap->name)); + adap->owner = THIS_MODULE; + adap->algo = &wmt_i2c_algo; + adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; + + err = wmt_i2c_reset_hardware(i2c); + if (err) { + dev_err(&pdev->dev, "error initializing hardware\n"); + return err; + } + + err = i2c_add_adapter(adap); + if (err) + /* wmt_i2c_reset_hardware() enables i2c_dev->clk */ + clk_disable_unprepare(i2c->clk); + + return err; +} + +static void wmt_i2c_remove(struct platform_device *pdev) +{ + struct viai2c *i2c = platform_get_drvdata(pdev); + + /* Disable interrupts, clock and delete adapter */ + writew(0, i2c->base + VIAI2C_REG_IMR); + clk_disable_unprepare(i2c->clk); + i2c_del_adapter(&i2c->adapter); +} + +static const struct of_device_id wmt_i2c_dt_ids[] = { + { .compatible = "wm,wm8505-i2c" }, + { /* Sentinel */ }, +}; + +static struct platform_driver wmt_i2c_driver = { + .probe = wmt_i2c_probe, + .remove_new = wmt_i2c_remove, + .driver = { + .name = "wmt-i2c", + .of_match_table = wmt_i2c_dt_ids, + }, +}; + +module_platform_driver(wmt_i2c_driver); + +MODULE_DESCRIPTION("Wondermedia I2C master-mode bus adapter"); +MODULE_AUTHOR("Tony Prisk <linux@prisktech.co.nz>"); +MODULE_LICENSE("GPL"); +MODULE_DEVICE_TABLE(of, wmt_i2c_dt_ids); |