From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Thu, 17 Jul 2014 11:08:45 +0200 Subject: [PATCH 05/14] clk: Add a function to retrieve phase In-Reply-To: <1405588134-2396-1-git-send-email-maxime.ripard@free-electrons.com> References: <1405588134-2396-1-git-send-email-maxime.ripard@free-electrons.com> Message-ID: <1405588134-2396-6-git-send-email-maxime.ripard@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The current phase API doesn't look into the actual hardware to get the phase value, but will rather get it from a variable only set by the set_phase function. This will cause issue when the client driver will never call the set_phase function, where we can end up having a reported phase that will not match what the hardware has been programmed to by the bootloader or what phase is programmed out of reset. Add a new get_phase function for the drivers to implement so that we can get this value. Signed-off-by: Maxime Ripard --- drivers/clk/clk.c | 17 ++++++++++++++--- include/linux/clk-provider.h | 5 +++++ 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 3eae203cda47..a6471df0a3f5 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1825,8 +1825,8 @@ out: * clk_get_phase - return the phase shift of a clock signal * @clk: clock signal source * - * Returns the phase shift of a clock node in degrees, otherwise returns - * -EERROR. + * Returns the phase shift of a clock node in degrees. Any negative + * values are errors. */ int clk_get_phase(struct clk *clk) { @@ -1836,7 +1836,18 @@ int clk_get_phase(struct clk *clk) goto out; clk_prepare_lock(); - ret = clk->phase; + + if (clk->phase) { + ret = clk->phase; + goto out_unlock; + } + + if (!clk->ops->get_phase) + goto out_unlock; + + ret = clk->ops->get_phase(clk->hw); + +out_unlock: clk_prepare_unlock(); out: diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 3a35a0647118..fa53f90456a9 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -129,6 +129,10 @@ struct dentry; * set then clock accuracy will be initialized to parent accuracy * or 0 (perfect clock) if clock has no parent. * + * @get_phase: Queries the hardware to get the current phase of a clock. + * Returned values are 0-359 degrees on success, negative + * error codes on failure. + * * @set_phase: Shift the phase this clock signal in degrees specified * by the second argument. Valid values for degrees are * 0-359. Return 0 on success, otherwise -EERROR. @@ -181,6 +185,7 @@ struct clk_ops { unsigned long parent_rate, u8 index); unsigned long (*recalc_accuracy)(struct clk_hw *hw, unsigned long parent_accuracy); + int (*get_phase)(struct clk_hw *hw); int (*set_phase)(struct clk_hw *hw, int degrees); void (*init)(struct clk_hw *hw); int (*debug_init)(struct clk_hw *hw, struct dentry *dentry); -- 2.0.1