From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David E. Box" Subject: [PATCH V4 1/2] i2c-designware: Add i2c bus locking support Date: Thu, 15 Jan 2015 01:12:16 -0800 Message-ID: <1421313137-1613-2-git-send-email-david.e.box@linux.intel.com> References: <1421313137-1613-1-git-send-email-david.e.box@linux.intel.com> Return-path: In-Reply-To: <1421313137-1613-1-git-send-email-david.e.box@linux.intel.com> In-Reply-To: <1417478973-25522-1-git-send-email-david.e.box@linux.intel.com> References: <1417478973-25522-1-git-send-email-david.e.box@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: wsa@the-dreams.de Cc: jdelvare@suse.de, arnd@arndb.de, maxime.ripard@free-electrons.com, dianders@chromium.org, david.e.box@linux.intel.com, u.kleine-koenig@pengutronix.de, laurent.pinchart+renesas@ideasonboard.com, boris.brezillon@free-electrons.com, maxime.coquelin@st.com, andrew@lunn.ch, sjg@chromium.org, markus.mayer@linaro.org, ch.naveen@samsung.com, jacob.jun.pan@linux.intel.com, max.schwarz@online.de, mika.westerberg@linux.intel.com, skuribay@pobox.com, Romain.Baeriswyl@abilis.com, wenkai.du@intel.com, christian.ruppert@abilis.com, alan@linux.intel.com, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org List-Id: linux-i2c@vger.kernel.org Adds support for acquiring and releasing a hardware bus lock in the i2c designware core transfer function. This is needed for i2c bus controllers that are shared with but not controlled by the kernel. Signed-off-by: David E. Box --- drivers/i2c/busses/i2c-designware-core.c | 26 ++++++++++++++++++++++++++ drivers/i2c/busses/i2c-designware-core.h | 6 ++++++ 2 files changed, 32 insertions(+) diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index 3c20e4b..3d3ac4d 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -289,6 +289,15 @@ int i2c_dw_init(struct dw_i2c_dev *dev) u32 hcnt, lcnt; u32 reg; u32 sda_falling_time, scl_falling_time; + int ret; + + if (dev->acquire_lock) { + ret = dev->acquire_lock(dev); + if (ret) { + dev_err(dev->dev, "couldn't acquire bus ownership\n"); + return ret; + } + } input_clock_khz = dev->get_clk_rate_khz(dev); @@ -302,6 +311,8 @@ int i2c_dw_init(struct dw_i2c_dev *dev) } else if (reg != DW_IC_COMP_TYPE_VALUE) { dev_err(dev->dev, "Unknown Synopsys component type: " "0x%08x\n", reg); + if (dev->release_lock) + dev->release_lock(dev); return -ENODEV; } @@ -368,6 +379,9 @@ int i2c_dw_init(struct dw_i2c_dev *dev) /* configure the i2c master */ dw_writel(dev, dev->master_cfg , DW_IC_CON); + + if (dev->release_lock) + dev->release_lock(dev); return 0; } EXPORT_SYMBOL_GPL(i2c_dw_init); @@ -631,6 +645,14 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) dev->abort_source = 0; dev->rx_outstanding = 0; + if (dev->acquire_lock) { + ret = dev->acquire_lock(dev); + if (ret) { + dev_err(dev->dev, "couldn't acquire bus ownership\n"); + goto done_nolock; + } + } + ret = i2c_dw_wait_bus_not_busy(dev); if (ret < 0) goto done; @@ -676,6 +698,10 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) ret = -EIO; done: + if (dev->release_lock) + dev->release_lock(dev); + +done_nolock: pm_runtime_mark_last_busy(dev->dev); pm_runtime_put_autosuspend(dev->dev); mutex_unlock(&dev->lock); diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index d66b6cb..a472c91 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -65,6 +65,9 @@ * @ss_lcnt: standard speed LCNT value * @fs_hcnt: fast speed HCNT value * @fs_lcnt: fast speed LCNT value + * @acquire_lock: function to acquire a hardware lock on the bus + * @release_lock: function to release a hardware lock on the bus + * @pm_runtime_disabled: true if pm runtime is disabled * * HCNT and LCNT parameters can be used if the platform knows more accurate * values than the one computed based only on the input clock frequency. @@ -105,6 +108,9 @@ struct dw_i2c_dev { u16 ss_lcnt; u16 fs_hcnt; u16 fs_lcnt; + int (*acquire_lock)(struct dw_i2c_dev *dev); + void (*release_lock)(struct dw_i2c_dev *dev); + bool pm_runtime_disabled; }; #define ACCESS_SWAP 0x00000001 -- 1.9.1