diff options
Diffstat (limited to 'drivers/w1')
| -rw-r--r-- | drivers/w1/masters/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/w1/masters/Makefile | 1 | ||||
| -rw-r--r-- | drivers/w1/masters/sgi_w1.c | 130 |
3 files changed, 140 insertions, 0 deletions
diff --git a/drivers/w1/masters/Kconfig b/drivers/w1/masters/Kconfig index 7ae260577901..24b9a8e05f64 100644 --- a/drivers/w1/masters/Kconfig +++ b/drivers/w1/masters/Kconfig @@ -65,5 +65,14 @@ config HDQ_MASTER_OMAP Say Y here if you want support for the 1-wire or HDQ Interface on an OMAP processor. +config W1_MASTER_SGI + tristate "SGI ASIC driver" + help + Say Y here if you want support for your 1-wire devices using + SGI ASIC 1-Wire interface + + This support is also available as a module. If so, the module + will be called sgi_w1. + endmenu diff --git a/drivers/w1/masters/Makefile b/drivers/w1/masters/Makefile index 18954cae4256..dae629b7ab49 100644 --- a/drivers/w1/masters/Makefile +++ b/drivers/w1/masters/Makefile @@ -11,3 +11,4 @@ obj-$(CONFIG_W1_MASTER_MXC) += mxc_w1.o obj-$(CONFIG_W1_MASTER_DS1WM) += ds1wm.o obj-$(CONFIG_W1_MASTER_GPIO) += w1-gpio.o obj-$(CONFIG_HDQ_MASTER_OMAP) += omap_hdq.o +obj-$(CONFIG_W1_MASTER_SGI) += sgi_w1.o diff --git a/drivers/w1/masters/sgi_w1.c b/drivers/w1/masters/sgi_w1.c new file mode 100644 index 000000000000..1b2d96b945be --- /dev/null +++ b/drivers/w1/masters/sgi_w1.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * sgi_w1.c - w1 master driver for one wire support in SGI ASICs + */ + +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/jiffies.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/platform_data/sgi-w1.h> + +#include <linux/w1.h> + +#define MCR_RD_DATA BIT(0) +#define MCR_DONE BIT(1) + +#define MCR_PACK(pulse, sample) (((pulse) << 10) | ((sample) << 2)) + +struct sgi_w1_device { + u32 __iomem *mcr; + struct w1_bus_master bus_master; + char dev_id[64]; +}; + +static u8 sgi_w1_wait(u32 __iomem *mcr) +{ + u32 mcr_val; + + do { + mcr_val = readl(mcr); + } while (!(mcr_val & MCR_DONE)); + + return (mcr_val & MCR_RD_DATA) ? 1 : 0; +} + +/* + * this is the low level routine to + * reset the device on the One Wire interface + * on the hardware + */ +static u8 sgi_w1_reset_bus(void *data) +{ + struct sgi_w1_device *dev = data; + u8 ret; + + writel(MCR_PACK(520, 65), dev->mcr); + ret = sgi_w1_wait(dev->mcr); + udelay(500); /* recovery time */ + return ret; +} + +/* + * 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 sgi_w1_touch_bit(void *data, u8 bit) +{ + struct sgi_w1_device *dev = data; + u8 ret; + + if (bit) + writel(MCR_PACK(6, 13), dev->mcr); + else + writel(MCR_PACK(80, 30), dev->mcr); + + ret = sgi_w1_wait(dev->mcr); + if (bit) + udelay(100); /* recovery */ + return ret; +} + +static int sgi_w1_probe(struct platform_device *pdev) +{ + struct sgi_w1_device *sdev; + struct sgi_w1_platform_data *pdata; + struct resource *res; + + sdev = devm_kzalloc(&pdev->dev, sizeof(struct sgi_w1_device), + GFP_KERNEL); + if (!sdev) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + sdev->mcr = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(sdev->mcr)) + return PTR_ERR(sdev->mcr); + + sdev->bus_master.data = sdev; + sdev->bus_master.reset_bus = sgi_w1_reset_bus; + sdev->bus_master.touch_bit = sgi_w1_touch_bit; + + pdata = dev_get_platdata(&pdev->dev); + if (pdata) { + strlcpy(sdev->dev_id, pdata->dev_id, sizeof(sdev->dev_id)); + sdev->bus_master.dev_id = sdev->dev_id; + } + + platform_set_drvdata(pdev, sdev); + + return w1_add_master_device(&sdev->bus_master); +} + +/* + * disassociate the w1 device from the driver + */ +static int sgi_w1_remove(struct platform_device *pdev) +{ + struct sgi_w1_device *sdev = platform_get_drvdata(pdev); + + w1_remove_master_device(&sdev->bus_master); + + return 0; +} + +static struct platform_driver sgi_w1_driver = { + .driver = { + .name = "sgi_w1", + }, + .probe = sgi_w1_probe, + .remove = sgi_w1_remove, +}; +module_platform_driver(sgi_w1_driver); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Thomas Bogendoerfer"); +MODULE_DESCRIPTION("Driver for One-Wire IP in SGI ASICs"); |