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path: root/drivers/clk/clk-fractional-divider.c (follow)
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2019-02-22clk: fractional-divider: check parent rate only if flag is setKatsuhiro Suzuki1-1/+1
Custom approximation of fractional-divider may not need parent clock rate checking. For example Rockchip SoCs work fine using grand parent clock rate even if target rate is greater than parent. This patch checks parent clock rate only if CLK_SET_RATE_PARENT flag is set. For detailed example, clock tree of Rockchip I2S audio hardware. - Clock rate of CPLL is 1.2GHz, GPLL is 491.52MHz. - i2s1_div is integer divider can divide N (N is 1~128). Input clock is CPLL or GPLL. Initial divider value is N = 1. Ex) PLL = CPLL, N = 10, i2s1_div output rate is CPLL / 10 = 1.2GHz / 10 = 120MHz - i2s1_frac is fractional divider can divide input to x/y, x and y are 16bit integer. CPLL --> | selector | ---> i2s1_div -+--> | selector | --> I2S1 MCLK GPLL --> | | ,--------------' | | `--> i2s1_frac ---> | | Clock mux system try to choose suitable one from i2s1_div and i2s1_frac for master clock (MCLK) of I2S1. Bad scenario as follows: - Try to set MCLK to 8.192MHz (32kHz audio replay) Candidate setting is - i2s1_div: GPLL / 60 = 8.192MHz i2s1_div candidate is exactly same as target clock rate, so mux choose this clock source. i2s1_div output rate is changed 491.52MHz -> 8.192MHz - After that try to set to 11.2896MHz (44.1kHz audio replay) Candidate settings are - i2s1_div : CPLL / 107 = 11.214945MHz - i2s1_frac: i2s1_div = 8.192MHz This is because clk_fd_round_rate() thinks target rate (11.2896MHz) is higher than parent rate (i2s1_div = 8.192MHz) and returns parent clock rate. Above is current upstreamed behavior. Clock mux system choose i2s1_div, but this clock rate is not acceptable for I2S driver, so users cannot replay audio. Expected behavior is: - Try to set master clock to 11.2896MHz (44.1kHz audio replay) Candidate settings are - i2s1_div : CPLL / 107 = 11.214945MHz - i2s1_frac: i2s1_div * 147/6400 = 11.2896MHz Change i2s1_div to GPLL / 1 = 491.52MHz at same time. If apply this commit, clk_fd_round_rate() calls custom approximate function of Rockchip even if target rate is higher than parent. Custom function changes both grand parent (i2s1_div) and parent (i2s_frac) settings at same time. Clock mux system can choose i2s1_frac and audio works fine. Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net> Reviewed-by: Heiko Stuebner <heiko@sntech.de> [sboyd@kernel.org: Make function into a macro instead] Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2018-12-14Merge branches 'clk-imx7ulp', 'clk-imx6-fixes', 'clk-imx-fixes', 'clk-imx8qxp' and 'clk-imx8mq' into clk-nextStephen Boyd1-0/+10
- NXP i.MX7ULP SoC clock support - Support for i.MX8QXP SoC clocks - Support for NXP i.MX8MQ clock controllers * clk-imx7ulp: clk: imx: add imx7ulp clk driver clk: imx: implement new clk_hw based APIs clk: imx: make mux parent strings const dt-bindings: clock: add imx7ulp clock binding doc clk: imx: add imx7ulp composite clk support clk: imx: add pfdv2 support clk: imx: add pllv4 support clk: fractional-divider: add CLK_FRAC_DIVIDER_ZERO_BASED flag support clk: imx: add gatable clock divider support * clk-imx6-fixes: clk: imx6q: handle ENET PLL bypass clk: imx6q: optionally get CCM inputs via standard clock handles clk: imx6q: reset exclusive gates on init * clk-imx-fixes: clk: imx6q: add DCICx clocks gate clk: imx6sl: ensure MMDC CH0 handshake is bypassed clk: imx7d: remove UART1 clock setting * clk-imx8qxp: clk: imx: add imx8qxp lpcg driver clk: imx: add lpcg clock support clk: imx: add imx8qxp clk driver clk: imx: add scu clock common part clk: imx: add configuration option for mmio clks dt-bindings: clock: add imx8qxp lpcg clock binding dt-bindings: clock: imx8qxp: add SCU clock IDs firmware: imx: add pm svc headfile dt-bindings: fsl: scu: update power domain binding firmware: imx: remove resource id enums dt-bindings: imx: add scu resource id headfile * clk-imx8mq: clk: imx: Make the i.MX8MQ CCM clock driver CLK_IMX8MQ dependant clk: imx: remove redundant initialization of ret to zero clk: imx: Add SCCG PLL type clk: imx: Add fractional PLL output clock clk: imx: Add clock driver for i.MX8MQ CCM clk: imx: Add imx composite clock dt-bindings: Add binding for i.MX8MQ CCM
2018-12-11clk: Tag basic clk types with SPDXStephen Boyd1-4/+1
These are all GPL-2.0 files per the existing license text. Replace the boiler plate with the tag. Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2018-12-03clk: fractional-divider: add CLK_FRAC_DIVIDER_ZERO_BASED flag supportA.s. Dong1-0/+10
Adding CLK_FRAC_DIVIDER_ZERO_BASED flag to indicate the numerator and denominator value in register are start from 0. This can be used to support frac dividers like below: Divider output clock = Divider input clock x [(frac +1) / (div +1)] where frac/div in register is: 000b - Divide by 1. 001b - Divide by 2. 010b - Divide by 3. Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Michael Turquette <mturquette@baylibre.com> Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com> Signed-off-by: Stephen Boyd <sboyd@kernel.org>
2017-08-08clk: fractional-divider: allow overriding of approximationElaine Zhang1-8/+20
Fractional dividers may have special requirements concerning numerator and denominator selection that differ from just getting the best approximation. For example on Rockchip socs the denominator must be at least 20 times larger than the numerator to generate precise clock frequencies. Therefore add the ability to provide custom approximation functions. Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com> Acked-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
2016-04-19clk: fractional-divider: Add hw based registration APIsStephen Boyd1-5/+35
Add registration APIs in the clk fractional divider code to return struct clk_hw pointers instead of struct clk pointers. This way we hide the struct clk pointer from providers unless they need to use consumer facing APIs. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2016-01-29clk: move the common clock's to_clk_*(_hw) macros to clk-provider.hGeliang Tang1-2/+0
to_clk_*(_hw) macros have been repeatedly defined in many places. This patch moves all the to_clk_*(_hw) definitions in the common clock framework to public header clk-provider.h, and drop the local definitions. Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2015-10-02clk: fractional-divider: switch to rational best approximationAndy Shevchenko1-15/+26
This patch converts the code to use rational best approximation algorithm which is much more precise. Suggested-by: Stephen Boyd <sboyd@codeaurora.org> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2015-10-02clk: fractional-divider: keep mwidth and nwidth internallyAndy Shevchenko1-2/+4
The patch adds mwidth and nwidth fields to the struct clk_fractional_divider for further usage. While here, use GENMASK() instead of open coding this functionality. Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2015-10-02clk: fractional-divider: rename prate -> parent_rateAndy Shevchenko1-5/+5
Rename function parameter to be more explicit what it is for. This also makes it in align with struct clk_ops. There is no functional change. Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2015-07-28clk: basic-type: Silence warnings about lock imbalancesStephen Boyd1-0/+8
The basic clock types use conditional locking for the register accessor spinlocks. Add __acquire() and __release() markings in the right locations so that sparse isn't tripped up on the conditional locking. drivers/clk/clk-mux.c:68:12: warning: context imbalance in 'clk_mux_set_parent' - different lock contexts for basic block drivers/clk/clk-divider.c:379:12: warning: context imbalance in 'clk_divider_set_rate' - different lock contexts for basic block drivers/clk/clk-gate.c:71:9: warning: context imbalance in 'clk_gate_endisable' - different lock contexts for basic block drivers/clk/clk-fractional-divider.c:36:9: warning: context imbalance in 'clk_fd_recalc_rate' - different lock contexts for basic block drivers/clk/clk-fractional-divider.c:68:12: warning: context imbalance in 'clk_fd_set_rate' - different lock contexts for basic block Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2015-05-14clk: basic-types: Remove useless allocation failure printksStephen Boyd1-3/+1
Printing an error on kmalloc() failures is unnecessary. Remove the print and use *ptr in sizeof() for future-proof code. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2015-03-12clk: fractional-divider: support for divider bypassingHeikki Krogerus1-0/+3
If the divider or multiplier values are 0 in the register, bypassing the divider and returning the parent clock rate in clk_fd_recalc_rate(). Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Michael Turquette <mturquette@linaro.org> [mturquette@linaro.org: fixed commitlog typo]
2014-09-10clk: fractional-divider: cast parent_rate to u64 before multiplyingHeiko Stübner1-1/+1
On 32bit architectures, like ARM calculating the fractional rate will do the multiplication before converting the value to u64 when it gets assigned to ret, which can produce overflows. The error in question happened with a parent_rate of 386MHz, m = 3000, n = 60000, which resulted in a wrong rate value of 15812Hz. Therefore cast parent_rate to u64 to make sure the multiplication happens in a 64bit space and produces the correct 192MHz in the example. Signed-off-by: Heiko Stuebner <heiko@sntech.de> Signed-off-by: Mike Turquette <mturquette@linaro.org>
2014-05-20clk: new basic clk type for fractional dividerHeikki Krogerus1-0/+135
Fractional divider clocks are fairly common. This adds basic type for them. Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Acked-by: Mike Turquette <mturquette@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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