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b858bab
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linux
/
drivers
/
gpu
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drm
/
i915
/
intel_i2c.c
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672 lines (558 loc) · 17 KB
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linux
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drivers
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gpu
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drm
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i915
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intel_i2c.c
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/* * Copyright (c) 2006 Dave Airlie <airlied@linux.ie> * Copyright © 2006-2008,2010 Intel Corporation * Jesse Barnes <jesse.barnes@intel.com> * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. * * Authors: * Eric Anholt <eric@anholt.net> * Chris Wilson <chris@chris-wilson.co.uk> */ #include <linux/i2c.h> #include <linux/i2c-algo-bit.h> #include <linux/export.h> #include <drm/drmP.h> #include "intel_drv.h" #include <drm/i915_drm.h> #include "i915_drv.h" struct gmbus_port { const char *name; int reg; }; static const struct gmbus_port gmbus_ports[] = { { "ssc", GPIOB }, { "vga", GPIOA }, { "panel", GPIOC }, { "dpc", GPIOD }, { "dpb", GPIOE }, { "dpd", GPIOF }, }; /* Intel GPIO access functions */ #define I2C_RISEFALL_TIME 10 static inline struct intel_gmbus * to_intel_gmbus(struct i2c_adapter *i2c) { return container_of(i2c, struct intel_gmbus, adapter); } void intel_i2c_reset(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; I915_WRITE(dev_priv->gpio_mmio_base + GMBUS0, 0); I915_WRITE(dev_priv->gpio_mmio_base + GMBUS4, 0); } static void intel_i2c_quirk_set(struct drm_i915_private *dev_priv, bool enable) { u32 val; /* When using bit bashing for I2C, this bit needs to be set to 1 */ if (!IS_PINEVIEW(dev_priv->dev)) return; val = I915_READ(DSPCLK_GATE_D); if (enable) val |= DPCUNIT_CLOCK_GATE_DISABLE; else val &= ~DPCUNIT_CLOCK_GATE_DISABLE; I915_WRITE(DSPCLK_GATE_D, val); } static u32 get_reserved(struct intel_gmbus *bus) { struct drm_i915_private *dev_priv = bus->dev_priv; struct drm_device *dev = dev_priv->dev; u32 reserved = 0; /* On most chips, these bits must be preserved in software. */ if (!IS_I830(dev) && !IS_845G(dev)) reserved = I915_READ_NOTRACE(bus->gpio_reg) & (GPIO_DATA_PULLUP_DISABLE | GPIO_CLOCK_PULLUP_DISABLE); return reserved; } static int get_clock(void *data) { struct intel_gmbus *bus = data; struct drm_i915_private *dev_priv = bus->dev_priv; u32 reserved = get_reserved(bus); I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_CLOCK_DIR_MASK); I915_WRITE_NOTRACE(bus->gpio_reg, reserved); return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_CLOCK_VAL_IN) != 0; } static int get_data(void *data) { struct intel_gmbus *bus = data; struct drm_i915_private *dev_priv = bus->dev_priv; u32 reserved = get_reserved(bus); I915_WRITE_NOTRACE(bus->gpio_reg, reserved | GPIO_DATA_DIR_MASK); I915_WRITE_NOTRACE(bus->gpio_reg, reserved); return (I915_READ_NOTRACE(bus->gpio_reg) & GPIO_DATA_VAL_IN) != 0; } static void set_clock(void *data, int state_high) { struct intel_gmbus *bus = data; struct drm_i915_private *dev_priv = bus->dev_priv; u32 reserved = get_reserved(bus); u32 clock_bits; if (state_high) clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK; else clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK | GPIO_CLOCK_VAL_MASK; I915_WRITE_NOTRACE(bus->gpio_reg, reserved | clock_bits); POSTING_READ(bus->gpio_reg); } static void set_data(void *data, int state_high) { struct intel_gmbus *bus = data; struct drm_i915_private *dev_priv = bus->dev_priv; u32 reserved = get_reserved(bus); u32 data_bits; if (state_high) data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK; else data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK | GPIO_DATA_VAL_MASK; I915_WRITE_NOTRACE(bus->gpio_reg, reserved | data_bits); POSTING_READ(bus->gpio_reg); } static int intel_gpio_pre_xfer(struct i2c_adapter *adapter) { struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus, adapter); struct drm_i915_private *dev_priv = bus->dev_priv; intel_i2c_reset(dev_priv->dev); intel_i2c_quirk_set(dev_priv, true); set_data(bus, 1); set_clock(bus, 1); udelay(I2C_RISEFALL_TIME); return 0; } static void intel_gpio_post_xfer(struct i2c_adapter *adapter) { struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus, adapter); struct drm_i915_private *dev_priv = bus->dev_priv; set_data(bus, 1); set_clock(bus, 1); intel_i2c_quirk_set(dev_priv, false); } static void intel_gpio_setup(struct intel_gmbus *bus, u32 pin) { struct drm_i915_private *dev_priv = bus->dev_priv; struct i2c_algo_bit_data *algo; algo = &bus->bit_algo; /* -1 to map pin pair to gmbus index */ bus->gpio_reg = dev_priv->gpio_mmio_base + gmbus_ports[pin - 1].reg; bus->adapter.algo_data = algo; algo->setsda = set_data; algo->setscl = set_clock; algo->getsda = get_data; algo->getscl = get_clock; algo->pre_xfer = intel_gpio_pre_xfer; algo->post_xfer = intel_gpio_post_xfer; algo->udelay = I2C_RISEFALL_TIME; algo->timeout = usecs_to_jiffies(2200); algo->data = bus; } static int gmbus_wait_hw_status(struct drm_i915_private *dev_priv, u32 gmbus2_status, u32 gmbus4_irq_en) { int i; int reg_offset = dev_priv->gpio_mmio_base; u32 gmbus2 = 0; DEFINE_WAIT(wait); if (!HAS_GMBUS_IRQ(dev_priv->dev)) gmbus4_irq_en = 0; /* Important: The hw handles only the first bit, so set only one! Since * we also need to check for NAKs besides the hw ready/idle signal, we * need to wake up periodically and check that ourselves. */ I915_WRITE(GMBUS4 + reg_offset, gmbus4_irq_en); for (i = 0; i < msecs_to_jiffies_timeout(50); i++) { prepare_to_wait(&dev_priv->gmbus_wait_queue, &wait, TASK_UNINTERRUPTIBLE); gmbus2 = I915_READ_NOTRACE(GMBUS2 + reg_offset); if (gmbus2 & (GMBUS_SATOER | gmbus2_status)) break; schedule_timeout(1); } finish_wait(&dev_priv->gmbus_wait_queue, &wait); I915_WRITE(GMBUS4 + reg_offset, 0); if (gmbus2 & GMBUS_SATOER) return -ENXIO; if (gmbus2 & gmbus2_status) return 0; return -ETIMEDOUT; } static int gmbus_wait_idle(struct drm_i915_private *dev_priv) { int ret; int reg_offset = dev_priv->gpio_mmio_base; #define C ((I915_READ_NOTRACE(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0) if (!HAS_GMBUS_IRQ(dev_priv->dev)) return wait_for(C, 10); /* Important: The hw handles only the first bit, so set only one! */ I915_WRITE(GMBUS4 + reg_offset, GMBUS_IDLE_EN); ret = wait_event_timeout(dev_priv->gmbus_wait_queue, C, msecs_to_jiffies_timeout(10)); I915_WRITE(GMBUS4 + reg_offset, 0); if (ret) return 0; else return -ETIMEDOUT; #undef C } static int gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv, unsigned short addr, u8 *buf, unsigned int len, u32 gmbus1_index) { int reg_offset = dev_priv->gpio_mmio_base; I915_WRITE(GMBUS1 + reg_offset, gmbus1_index | GMBUS_CYCLE_WAIT | (len << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_READ | GMBUS_SW_RDY); while (len) { int ret; u32 val, loop = 0; ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN); if (ret) return ret; val = I915_READ(GMBUS3 + reg_offset); do { *buf++ = val & 0xff; val >>= 8; } while (--len && ++loop < 4); } return 0; } static int gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, u32 gmbus1_index) { u8 *buf = msg->buf; unsigned int rx_size = msg->len; unsigned int len; int ret; do { len = min(rx_size, GMBUS_BYTE_COUNT_MAX); ret = gmbus_xfer_read_chunk(dev_priv, msg->addr, buf, len, gmbus1_index); if (ret) return ret; rx_size -= len; buf += len; } while (rx_size != 0); return 0; } static int gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, unsigned short addr, u8 *buf, unsigned int len) { int reg_offset = dev_priv->gpio_mmio_base; unsigned int chunk_size = len; u32 val, loop; val = loop = 0; while (len && loop < 4) { val |= *buf++ << (8 * loop++); len -= 1; } I915_WRITE(GMBUS3 + reg_offset, val); I915_WRITE(GMBUS1 + reg_offset, GMBUS_CYCLE_WAIT | (chunk_size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_WRITE | GMBUS_SW_RDY); while (len) { int ret; val = loop = 0; do { val |= *buf++ << (8 * loop); } while (--len && ++loop < 4); I915_WRITE(GMBUS3 + reg_offset, val); ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN); if (ret) return ret; } return 0; } static int gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) { u8 *buf = msg->buf; unsigned int tx_size = msg->len; unsigned int len; int ret; do { len = min(tx_size, GMBUS_BYTE_COUNT_MAX); ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len); if (ret) return ret; buf += len; tx_size -= len; } while (tx_size != 0); return 0; } /* * The gmbus controller can combine a 1 or 2 byte write with a read that * immediately follows it by using an "INDEX" cycle. */ static bool gmbus_is_index_read(struct i2c_msg *msgs, int i, int num) { return (i + 1 < num && msgs[i].addr == msgs[i + 1].addr && !(msgs[i].flags & I2C_M_RD) && msgs[i].len <= 2 && (msgs[i + 1].flags & I2C_M_RD)); } static int gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs) { int reg_offset = dev_priv->gpio_mmio_base; u32 gmbus1_index = 0; u32 gmbus5 = 0; int ret; if (msgs[0].len == 2) gmbus5 = GMBUS_2BYTE_INDEX_EN | msgs[0].buf[1] | (msgs[0].buf[0] << 8); if (msgs[0].len == 1) gmbus1_index = GMBUS_CYCLE_INDEX | (msgs[0].buf[0] << GMBUS_SLAVE_INDEX_SHIFT); /* GMBUS5 holds 16-bit index */ if (gmbus5) I915_WRITE(GMBUS5 + reg_offset, gmbus5); ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus1_index); /* Clear GMBUS5 after each index transfer */ if (gmbus5) I915_WRITE(GMBUS5 + reg_offset, 0); return ret; } static int gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus, adapter); struct drm_i915_private *dev_priv = bus->dev_priv; int i = 0, inc, try = 0, reg_offset; int ret = 0; intel_aux_display_runtime_get(dev_priv); mutex_lock(&dev_priv->gmbus_mutex); if (bus->force_bit) { ret = i2c_bit_algo.master_xfer(adapter, msgs, num); goto out; } reg_offset = dev_priv->gpio_mmio_base; retry: I915_WRITE(GMBUS0 + reg_offset, bus->reg0); for (; i < num; i += inc) { inc = 1; if (gmbus_is_index_read(msgs, i, num)) { ret = gmbus_xfer_index_read(dev_priv, &msgs[i]); inc = 2; /* an index read is two msgs */ } else if (msgs[i].flags & I2C_M_RD) { ret = gmbus_xfer_read(dev_priv, &msgs[i], 0); } else { ret = gmbus_xfer_write(dev_priv, &msgs[i]); } if (ret == -ETIMEDOUT) goto timeout; if (ret == -ENXIO) goto clear_err; ret = gmbus_wait_hw_status(dev_priv, GMBUS_HW_WAIT_PHASE, GMBUS_HW_WAIT_EN); if (ret == -ENXIO) goto clear_err; if (ret) goto timeout; } /* Generate a STOP condition on the bus. Note that gmbus can't generata * a STOP on the very first cycle. To simplify the code we * unconditionally generate the STOP condition with an additional gmbus * cycle. */ I915_WRITE(GMBUS1 + reg_offset, GMBUS_CYCLE_STOP | GMBUS_SW_RDY); /* Mark the GMBUS interface as disabled after waiting for idle. * We will re-enable it at the start of the next xfer, * till then let it sleep. */ if (gmbus_wait_idle(dev_priv)) { DRM_DEBUG_KMS("GMBUS [%s] timed out waiting for idle\n", adapter->name); ret = -ETIMEDOUT; } I915_WRITE(GMBUS0 + reg_offset, 0); ret = ret ?: i; goto out; clear_err: /* * Wait for bus to IDLE before clearing NAK. * If we clear the NAK while bus is still active, then it will stay * active and the next transaction may fail. * * If no ACK is received during the address phase of a transaction, the * adapter must report -ENXIO. It is not clear what to return if no ACK * is received at other times. But we have to be careful to not return * spurious -ENXIO because that will prevent i2c and drm edid functions * from retrying. So return -ENXIO only when gmbus properly quiescents - * timing out seems to happen when there _is_ a ddc chip present, but * it's slow responding and only answers on the 2nd retry. */ ret = -ENXIO; if (gmbus_wait_idle(dev_priv)) { DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n", adapter->name); ret = -ETIMEDOUT; } /* Toggle the Software Clear Interrupt bit. This has the effect * of resetting the GMBUS controller and so clearing the * BUS_ERROR raised by the slave's NAK. */ I915_WRITE(GMBUS1 + reg_offset, GMBUS_SW_CLR_INT); I915_WRITE(GMBUS1 + reg_offset, 0); I915_WRITE(GMBUS0 + reg_offset, 0); DRM_DEBUG_KMS("GMBUS [%s] NAK for addr: %04x %c(%d)\n", adapter->name, msgs[i].addr, (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len); /* * Passive adapters sometimes NAK the first probe. Retry the first * message once on -ENXIO for GMBUS transfers; the bit banging algorithm * has retries internally. See also the retry loop in * drm_do_probe_ddc_edid, which bails out on the first -ENXIO. */ if (ret == -ENXIO && i == 0 && try++ == 0) { DRM_DEBUG_KMS("GMBUS [%s] NAK on first message, retry\n", adapter->name); goto retry; } goto out; timeout: DRM_INFO("GMBUS [%s] timed out, falling back to bit banging on pin %d\n", bus->adapter.name, bus->reg0 & 0xff); I915_WRITE(GMBUS0 + reg_offset, 0); /* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */ bus->force_bit = 1; ret = i2c_bit_algo.master_xfer(adapter, msgs, num); out: mutex_unlock(&dev_priv->gmbus_mutex); intel_aux_display_runtime_put(dev_priv); return ret; } static u32 gmbus_func(struct i2c_adapter *adapter) { return i2c_bit_algo.functionality(adapter) & (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | /* I2C_FUNC_10BIT_ADDR | */ I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL); } static const struct i2c_algorithm gmbus_algorithm = { .master_xfer = gmbus_xfer, .functionality = gmbus_func }; /** * intel_gmbus_setup - instantiate all Intel i2c GMBuses * @dev: DRM device */ int intel_setup_gmbus(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; int ret, i; if (HAS_PCH_NOP(dev)) return 0; else if (HAS_PCH_SPLIT(dev)) dev_priv->gpio_mmio_base = PCH_GPIOA - GPIOA; else if (IS_VALLEYVIEW(dev)) dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE; else dev_priv->gpio_mmio_base = 0; mutex_init(&dev_priv->gmbus_mutex); init_waitqueue_head(&dev_priv->gmbus_wait_queue); for (i = 0; i < GMBUS_NUM_PORTS; i++) { struct intel_gmbus *bus = &dev_priv->gmbus[i]; u32 port = i + 1; /* +1 to map gmbus index to pin pair */ bus->adapter.owner = THIS_MODULE; bus->adapter.class = I2C_CLASS_DDC; snprintf(bus->adapter.name, sizeof(bus->adapter.name), "i915 gmbus %s", gmbus_ports[i].name); bus->adapter.dev.parent = &dev->pdev->dev; bus->dev_priv = dev_priv; bus->adapter.algo = &gmbus_algorithm; /* By default use a conservative clock rate */ bus->reg0 = port | GMBUS_RATE_100KHZ; /* gmbus seems to be broken on i830 */ if (IS_I830(dev)) bus->force_bit = 1; intel_gpio_setup(bus, port); ret = i2c_add_adapter(&bus->adapter); if (ret) goto err; } intel_i2c_reset(dev_priv->dev); return 0; err: while (--i) { struct intel_gmbus *bus = &dev_priv->gmbus[i]; i2c_del_adapter(&bus->adapter); } return ret; } struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv, unsigned port) { WARN_ON(!intel_gmbus_is_port_valid(port)); /* -1 to map pin pair to gmbus index */ return (intel_gmbus_is_port_valid(port)) ? &dev_priv->gmbus[port - 1].adapter : NULL; } void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed) { struct intel_gmbus *bus = to_intel_gmbus(adapter); bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed; } void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit) { struct intel_gmbus *bus = to_intel_gmbus(adapter); bus->force_bit += force_bit ? 1 : -1; DRM_DEBUG_KMS("%sabling bit-banging on %s. force bit now %d\n", force_bit ? "en" : "dis", adapter->name, bus->force_bit); } void intel_teardown_gmbus(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; int i; for (i = 0; i < GMBUS_NUM_PORTS; i++) { struct intel_gmbus *bus = &dev_priv->gmbus[i]; i2c_del_adapter(&bus->adapter); } }
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