diff options
Diffstat (limited to 'arch/arm/plat-spear/padmux.c')
| -rw-r--r-- | arch/arm/plat-spear/padmux.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/arch/arm/plat-spear/padmux.c b/arch/arm/plat-spear/padmux.c new file mode 100644 index 000000000000..d2aab3adcdeb --- /dev/null +++ b/arch/arm/plat-spear/padmux.c @@ -0,0 +1,164 @@ +/* + * arch/arm/plat-spear/include/plat/padmux.c + * + * SPEAr platform specific gpio pads muxing source file + * + * Copyright (C) 2009 ST Microelectronics + * Viresh Kumar<viresh.kumar@st.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/err.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <plat/padmux.h> + +/* + * struct pmx: pmx definition structure + * + * base: base address of configuration registers + * mode_reg: mode configurations + * mux_reg: muxing configurations + * active_mode: pointer to current active mode + */ +struct pmx { + u32 base; + struct pmx_reg mode_reg; + struct pmx_reg mux_reg; + struct pmx_mode *active_mode; +}; + +static struct pmx *pmx; + +/** + * pmx_mode_set - Enables an multiplexing mode + * @mode - pointer to pmx mode + * + * It will set mode of operation in hardware. + * Returns -ve on Err otherwise 0 + */ +static int pmx_mode_set(struct pmx_mode *mode) +{ + u32 val; + + if (!mode->name) + return -EFAULT; + + pmx->active_mode = mode; + + val = readl(pmx->base + pmx->mode_reg.offset); + val &= ~pmx->mode_reg.mask; + val |= mode->mask & pmx->mode_reg.mask; + writel(val, pmx->base + pmx->mode_reg.offset); + + return 0; +} + +/** + * pmx_devs_enable - Enables list of devices + * @devs - pointer to pmx device array + * @count - number of devices to enable + * + * It will enable pads for all required peripherals once and only once. + * If peripheral is not supported by current mode then request is rejected. + * Conflicts between peripherals are not handled and peripherals will be + * enabled in the order they are present in pmx_dev array. + * In case of conflicts last peripheral enalbed will be present. + * Returns -ve on Err otherwise 0 + */ +static int pmx_devs_enable(struct pmx_dev **devs, u8 count) +{ + u32 val, i, mask; + + if (!count) + return -EINVAL; + + val = readl(pmx->base + pmx->mux_reg.offset); + for (i = 0; i < count; i++) { + u8 j = 0; + + if (!devs[i]->name || !devs[i]->modes) { + printk(KERN_ERR "padmux: dev name or modes is null\n"); + continue; + } + /* check if peripheral exists in active mode */ + if (pmx->active_mode) { + bool found = false; + for (j = 0; j < devs[i]->mode_count; j++) { + if (devs[i]->modes[j].ids & + pmx->active_mode->id) { + found = true; + break; + } + } + if (found == false) { + printk(KERN_ERR "%s device not available in %s"\ + "mode\n", devs[i]->name, + pmx->active_mode->name); + continue; + } + } + + /* enable peripheral */ + mask = devs[i]->modes[j].mask & pmx->mux_reg.mask; + if (devs[i]->enb_on_reset) + val &= ~mask; + else + val |= mask; + + devs[i]->is_active = true; + } + writel(val, pmx->base + pmx->mux_reg.offset); + kfree(pmx); + + /* this will ensure that multiplexing can't be changed now */ + pmx = (struct pmx *)-1; + + return 0; +} + +/** + * pmx_register - registers a platform requesting pad mux feature + * @driver - pointer to driver structure containing driver specific parameters + * + * Also this must be called only once. This will allocate memory for pmx + * structure, will call pmx_mode_set, will call pmx_devs_enable. + * Returns -ve on Err otherwise 0 + */ +int pmx_register(struct pmx_driver *driver) +{ + int ret = 0; + + if (pmx) + return -EPERM; + if (!driver->base || !driver->devs) + return -EFAULT; + + pmx = kzalloc(sizeof(*pmx), GFP_KERNEL); + if (!pmx) + return -ENOMEM; + + pmx->base = (u32)driver->base; + pmx->mode_reg.offset = driver->mode_reg.offset; + pmx->mode_reg.mask = driver->mode_reg.mask; + pmx->mux_reg.offset = driver->mux_reg.offset; + pmx->mux_reg.mask = driver->mux_reg.mask; + + /* choose mode to enable */ + if (driver->mode) { + ret = pmx_mode_set(driver->mode); + if (ret) + goto pmx_fail; + } + ret = pmx_devs_enable(driver->devs, driver->devs_count); + if (ret) + goto pmx_fail; + + return 0; + +pmx_fail: + return ret; +} |