diff options
Diffstat (limited to 'drivers/w1')
| -rw-r--r-- | drivers/w1/Kconfig | 14 | ||||
| -rw-r--r-- | drivers/w1/Makefile | 1 | ||||
| -rw-r--r-- | drivers/w1/mxc_w1.c | 232 |
3 files changed, 247 insertions, 0 deletions
diff --git a/drivers/w1/Kconfig b/drivers/w1/Kconfig index d6e045739d..031bab25ae 100644 --- a/drivers/w1/Kconfig +++ b/drivers/w1/Kconfig @@ -20,6 +20,20 @@ config W1_GPIO help Emulate a 1-wire bus using a GPIO. +config W1_MXC + bool "Enable 1-wire controller on i.MX processors" + default no + depends on ARCH_MX25 || ARCH_MX31 || ARCH_MX5 + help + Support the one wire controller found in some members of the NXP + i.MX SoC family. + There are currently two silicon variants: + V1: i.MX21, i.MX27, i.MX31, i.MX51 + V2: i.MX25, i.MX35, i.MX50, i.MX53 + Newer i.MX SoCs such as the i.MX6 do not have one wire controllers. + + The driver supports both silicon variants. + endif endmenu diff --git a/drivers/w1/Makefile b/drivers/w1/Makefile index 7fd8697f84..9825187b65 100644 --- a/drivers/w1/Makefile +++ b/drivers/w1/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_W1) += w1-uclass.o obj-$(CONFIG_W1_GPIO) += w1-gpio.o +obj-$(CONFIG_W1_MXC) += mxc_w1.o diff --git a/drivers/w1/mxc_w1.c b/drivers/w1/mxc_w1.c new file mode 100644 index 0000000000..9279ba32b8 --- /dev/null +++ b/drivers/w1/mxc_w1.c @@ -0,0 +1,232 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Driver for one wire controller in some i.MX Socs + * + * There are currently two silicon variants: + * V1: i.MX21, i.MX27, i.MX31, i.MX51 + * V2: i.MX25, i.MX35, i.MX50, i.MX53 + * Newer i.MX SoCs such as the i.MX6 do not have one wire controllers. + * + * The V1 controller only supports single bit operations. + * The V2 controller is backwards compatible on the register level but adds + * byte size operations and a "search ROM accelerator mode" + * + * This driver does not currently support the search ROM accelerator + * + * Copyright (c) 2018 Flowbird + * Martin Fuzzey <martin.fuzzey@flowbird.group> + */ + +#include <asm/arch/clock.h> +#include <common.h> +#include <dm.h> +#include <linux/io.h> +#include <w1.h> + +struct mxc_w1_regs { + u16 control; +#define MXC_W1_CONTROL_RPP BIT(7) +#define MXC_W1_CONTROL_PST BIT(6) +#define MXC_W1_CONTROL_WR(x) BIT(5 - (x)) +#define MXC_W1_CONTROL_RDST BIT(3) + + u16 time_divider; + u16 reset; + + /* Registers below on V2 silicon only */ + u16 command; + u16 tx_rx; + u16 interrupt; +#define MXC_W1_INTERRUPT_TBE BIT(2) +#define MXC_W1_INTERRUPT_TSRE BIT(3) +#define MXC_W1_INTERRUPT_RBF BIT(4) +#define MXC_W1_INTERRUPT_RSRF BIT(5) + + u16 interrupt_en; +}; + +struct mxc_w1_pdata { + struct mxc_w1_regs *regs; +}; + +/* + * this is the low level routine to read/write a bit on the One Wire + * interface on the hardware. It does write 0 if parameter bit is set + * to 0, otherwise a write 1/read. + */ +static u8 mxc_w1_touch_bit(struct mxc_w1_pdata *pdata, u8 bit) +{ + u16 *ctrl_addr = &pdata->regs->control; + u16 mask = MXC_W1_CONTROL_WR(bit); + unsigned int timeout_cnt = 400; /* Takes max. 120us according to + * datasheet. + */ + + writew(mask, ctrl_addr); + + while (timeout_cnt--) { + if (!(readw(ctrl_addr) & mask)) + break; + + udelay(1); + } + + return (readw(ctrl_addr) & MXC_W1_CONTROL_RDST) ? 1 : 0; +} + +static u8 mxc_w1_read_byte(struct udevice *dev) +{ + struct mxc_w1_pdata *pdata = dev_get_platdata(dev); + struct mxc_w1_regs *regs = pdata->regs; + u16 status; + + if (dev_get_driver_data(dev) < 2) { + int i; + u8 ret = 0; + + for (i = 0; i < 8; i++) + ret |= (mxc_w1_touch_bit(pdata, 1) << i); + + return ret; + } + + readw(®s->tx_rx); + writew(0xFF, ®s->tx_rx); + + do { + udelay(1); /* Without this bytes are sometimes duplicated... */ + status = readw(®s->interrupt); + } while (!(status & MXC_W1_INTERRUPT_RBF)); + + return (u8)readw(®s->tx_rx); +} + +static void mxc_w1_write_byte(struct udevice *dev, u8 byte) +{ + struct mxc_w1_pdata *pdata = dev_get_platdata(dev); + struct mxc_w1_regs *regs = pdata->regs; + u16 status; + + if (dev_get_driver_data(dev) < 2) { + int i; + + for (i = 0; i < 8; i++) + mxc_w1_touch_bit(pdata, (byte >> i) & 0x1); + + return; + } + + readw(®s->tx_rx); + writew(byte, ®s->tx_rx); + + do { + udelay(1); + status = readw(®s->interrupt); + } while (!(status & MXC_W1_INTERRUPT_TSRE)); +} + +static bool mxc_w1_reset(struct udevice *dev) +{ + struct mxc_w1_pdata *pdata = dev_get_platdata(dev); + u16 reg_val; + + writew(MXC_W1_CONTROL_RPP, &pdata->regs->control); + + do { + reg_val = readw(&pdata->regs->control); + } while (reg_val & MXC_W1_CONTROL_RPP); + + return !(reg_val & MXC_W1_CONTROL_PST); +} + +static u8 mxc_w1_triplet(struct udevice *dev, bool bdir) +{ + struct mxc_w1_pdata *pdata = dev_get_platdata(dev); + u8 id_bit = mxc_w1_touch_bit(pdata, 1); + u8 comp_bit = mxc_w1_touch_bit(pdata, 1); + u8 retval; + + if (id_bit && comp_bit) + return 0x03; /* error */ + + if (!id_bit && !comp_bit) { + /* Both bits are valid, take the direction given */ + retval = bdir ? 0x04 : 0; + } else { + /* Only one bit is valid, take that direction */ + bdir = id_bit; + retval = id_bit ? 0x05 : 0x02; + } + + mxc_w1_touch_bit(pdata, bdir); + + return retval; +} + +static int mxc_w1_ofdata_to_platdata(struct udevice *dev) +{ + struct mxc_w1_pdata *pdata = dev_get_platdata(dev); + fdt_addr_t addr; + + addr = devfdt_get_addr(dev); + if (addr == FDT_ADDR_T_NONE) + return -EINVAL; + + pdata->regs = (struct mxc_w1_regs *)addr; + + return 0; +}; + +static int mxc_w1_probe(struct udevice *dev) +{ + struct mxc_w1_pdata *pdata = dev_get_platdata(dev); + unsigned int clkrate = mxc_get_clock(MXC_IPG_PERCLK); + unsigned int clkdiv; + + if (clkrate < 10000000) { + dev_err(dev, "input clock frequency (%u Hz) too low\n", + clkrate); + return -EINVAL; + } + + clkdiv = clkrate / 1000000; + clkrate /= clkdiv; + if (clkrate < 980000 || clkrate > 1020000) { + dev_err(dev, "Incorrect time base frequency %u Hz\n", clkrate); + return -EINVAL; + } + + writew(clkdiv - 1, &pdata->regs->time_divider); + + return 0; +} + +static const struct w1_ops mxc_w1_ops = { + .read_byte = mxc_w1_read_byte, + .reset = mxc_w1_reset, + .triplet = mxc_w1_triplet, + .write_byte = mxc_w1_write_byte, +}; + +static const struct udevice_id mxc_w1_id[] = { + { .compatible = "fsl,imx21-owire", .data = 1 }, + { .compatible = "fsl,imx27-owire", .data = 1 }, + { .compatible = "fsl,imx31-owire", .data = 1 }, + { .compatible = "fsl,imx51-owire", .data = 1 }, + + { .compatible = "fsl,imx25-owire", .data = 2 }, + { .compatible = "fsl,imx35-owire", .data = 2 }, + { .compatible = "fsl,imx50-owire", .data = 2 }, + { .compatible = "fsl,imx53-owire", .data = 2 }, + { }, +}; + +U_BOOT_DRIVER(mxc_w1_drv) = { + .id = UCLASS_W1, + .name = "mxc_w1_drv", + .of_match = mxc_w1_id, + .ofdata_to_platdata = mxc_w1_ofdata_to_platdata, + .ops = &mxc_w1_ops, + .platdata_auto_alloc_size = sizeof(struct mxc_w1_pdata), + .probe = mxc_w1_probe, +}; |