RE: [PATCH V4 3/5] clk: imx: Support building i.MX common clock driver as module

[Anson Huang]

> Subject: Re: [PATCH V4 3/5] clk: imx: Support building i.MX common clock
> driver as module
> 
> On Thu, Jul 2, 2020 at 10:19 AM Anson Huang <Anson.Huang@xxxxxxx>
> wrote:
> >
> > There are more and more requirements of building SoC specific drivers
> > as modules, add support for building i.MX common clock driver as
> > module to meet the requirement.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
> > ---
> > Changes since V3:
> >         - ONLY include __setup_param() build for built-in, module build no
> need
> >           to have it.
> > ---
> >  drivers/clk/imx/Kconfig            |  8 ++++++--
> >  drivers/clk/imx/Makefile           | 40
> +++++++++++++++++++-------------------
> >  drivers/clk/imx/clk-composite-8m.c |  2 ++
> >  drivers/clk/imx/clk-cpu.c          |  2 ++
> >  drivers/clk/imx/clk-frac-pll.c     |  2 ++
> >  drivers/clk/imx/clk-gate2.c        |  2 ++
> >  drivers/clk/imx/clk-pll14xx.c      |  5 +++++
> >  drivers/clk/imx/clk-sscg-pll.c     |  2 ++
> >  drivers/clk/imx/clk.c              | 22 +++++++++++++++------
> >  9 files changed, 57 insertions(+), 28 deletions(-)
> >
> > diff --git a/drivers/clk/imx/Kconfig b/drivers/clk/imx/Kconfig index
> > 09fc8ad..f6ddf76 100644
> > --- a/drivers/clk/imx/Kconfig
> > +++ b/drivers/clk/imx/Kconfig
> > @@ -1,8 +1,8 @@
> >  # SPDX-License-Identifier: GPL-2.0
> >  # common clock support for NXP i.MX SoC family.
> >  config MXC_CLK
> > -       bool
> > -       def_bool ARCH_MXC
> > +       tristate "IMX clock"
> > +       depends on ARCH_MXC
> >
> >  config MXC_CLK_SCU
> >         bool
> > @@ -101,24 +101,28 @@ config CLK_VF610  config CLK_IMX8MM
> >         bool "IMX8MM CCM Clock Driver"
> >         depends on ARCH_MXC
> > +       select MXC_CLK
> >         help
> >             Build the driver for i.MX8MM CCM Clock Driver
> >
> >  config CLK_IMX8MN
> >         bool "IMX8MN CCM Clock Driver"
> >         depends on ARCH_MXC
> > +       select MXC_CLK
> >         help
> >             Build the driver for i.MX8MN CCM Clock Driver
> >
> >  config CLK_IMX8MP
> >         bool "IMX8MP CCM Clock Driver"
> >         depends on ARCH_MXC
> > +       select MXC_CLK
> >         help
> >             Build the driver for i.MX8MP CCM Clock Driver
> >
> >  config CLK_IMX8MQ
> >         bool "IMX8MQ CCM Clock Driver"
> >         depends on ARCH_MXC
> > +       select MXC_CLK
> >         help
> >             Build the driver for i.MX8MQ CCM Clock Driver
> >
> > diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile index
> > 394ade7..17f5d12 100644
> > --- a/drivers/clk/imx/Makefile
> > +++ b/drivers/clk/imx/Makefile
> > @@ -1,25 +1,25 @@
> >  # SPDX-License-Identifier: GPL-2.0
> >
> > -obj-$(CONFIG_MXC_CLK) += \
> > -       clk.o \
> > -       clk-busy.o \
> > -       clk-composite-8m.o \
> > -       clk-cpu.o \
> > -       clk-composite-7ulp.o \
> > -       clk-divider-gate.o \
> > -       clk-fixup-div.o \
> > -       clk-fixup-mux.o \
> > -       clk-frac-pll.o \
> > -       clk-gate-exclusive.o \
> > -       clk-gate2.o \
> > -       clk-pfd.o \
> > -       clk-pfdv2.o \
> > -       clk-pllv1.o \
> > -       clk-pllv2.o \
> > -       clk-pllv3.o \
> > -       clk-pllv4.o \
> > -       clk-sscg-pll.o \
> > -       clk-pll14xx.o
> > +mxc-clk-objs += clk.o
> > +mxc-clk-objs += clk-busy.o
> > +mxc-clk-objs += clk-composite-7ulp.o
> > +mxc-clk-objs += clk-composite-8m.o
> > +mxc-clk-objs += clk-cpu.o
> > +mxc-clk-objs += clk-divider-gate.o
> > +mxc-clk-objs += clk-fixup-div.o
> > +mxc-clk-objs += clk-fixup-mux.o
> > +mxc-clk-objs += clk-frac-pll.o
> > +mxc-clk-objs += clk-gate2.o
> > +mxc-clk-objs += clk-gate-exclusive.o
> > +mxc-clk-objs += clk-pfd.o
> > +mxc-clk-objs += clk-pfdv2.o
> > +mxc-clk-objs += clk-pllv1.o
> > +mxc-clk-objs += clk-pllv2.o
> > +mxc-clk-objs += clk-pllv3.o
> > +mxc-clk-objs += clk-pllv4.o
> > +mxc-clk-objs += clk-pll14xx.o
> > +mxc-clk-objs += clk-sscg-pll.o
> > +obj-$(CONFIG_MXC_CLK) += mxc-clk.o
> >
> >  obj-$(CONFIG_MXC_CLK_SCU) += \
> >         clk-scu.o \
> > diff --git a/drivers/clk/imx/clk-composite-8m.c
> > b/drivers/clk/imx/clk-composite-8m.c
> > index d2b5af8..78fb7e5 100644
> > --- a/drivers/clk/imx/clk-composite-8m.c
> > +++ b/drivers/clk/imx/clk-composite-8m.c
> > @@ -5,6 +5,7 @@
> >
> >  #include <linux/clk-provider.h>
> >  #include <linux/errno.h>
> > +#include <linux/export.h>
> >  #include <linux/io.h>
> >  #include <linux/slab.h>
> >
> > @@ -243,3 +244,4 @@ struct clk_hw
> *imx8m_clk_hw_composite_flags(const char *name,
> >         kfree(mux);
> >         return ERR_CAST(hw);
> >  }
> > +EXPORT_SYMBOL_GPL(imx8m_clk_hw_composite_flags);
> > diff --git a/drivers/clk/imx/clk-cpu.c b/drivers/clk/imx/clk-cpu.c
> > index cb182be..cb6ca4c 100644
> > --- a/drivers/clk/imx/clk-cpu.c
> > +++ b/drivers/clk/imx/clk-cpu.c
> > @@ -5,6 +5,7 @@
> >
> >  #include <linux/clk.h>
> >  #include <linux/clk-provider.h>
> > +#include <linux/export.h>
> >  #include <linux/slab.h>
> >  #include "clk.h"
> >
> > @@ -104,3 +105,4 @@ struct clk_hw *imx_clk_hw_cpu(const char *name,
> > const char *parent_name,
> >
> >         return hw;
> >  }
> > +EXPORT_SYMBOL_GPL(imx_clk_hw_cpu);
> > diff --git a/drivers/clk/imx/clk-frac-pll.c
> > b/drivers/clk/imx/clk-frac-pll.c index 101e0a3..c703056 100644
> > --- a/drivers/clk/imx/clk-frac-pll.c
> > +++ b/drivers/clk/imx/clk-frac-pll.c
> > @@ -10,6 +10,7 @@
> >
> >  #include <linux/clk-provider.h>
> >  #include <linux/err.h>
> > +#include <linux/export.h>
> >  #include <linux/io.h>
> >  #include <linux/iopoll.h>
> >  #include <linux/slab.h>
> > @@ -233,3 +234,4 @@ struct clk_hw *imx_clk_hw_frac_pll(const char
> > *name,
> >
> >         return hw;
> >  }
> > +EXPORT_SYMBOL_GPL(imx_clk_hw_frac_pll);
> > diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
> > index b87ab3c..512f675 100644
> > --- a/drivers/clk/imx/clk-gate2.c
> > +++ b/drivers/clk/imx/clk-gate2.c
> > @@ -7,6 +7,7 @@
> >   */
> >
> >  #include <linux/clk-provider.h>
> > +#include <linux/export.h>
> >  #include <linux/module.h>
> >  #include <linux/slab.h>
> >  #include <linux/io.h>
> > @@ -177,3 +178,4 @@ struct clk_hw *clk_hw_register_gate2(struct device
> > *dev, const char *name,
> >
> >         return hw;
> >  }
> > +EXPORT_SYMBOL_GPL(clk_hw_register_gate2);
> > diff --git a/drivers/clk/imx/clk-pll14xx.c
> > b/drivers/clk/imx/clk-pll14xx.c index f9eb189..f5c3e7e 100644
> > --- a/drivers/clk/imx/clk-pll14xx.c
> > +++ b/drivers/clk/imx/clk-pll14xx.c
> > @@ -6,6 +6,7 @@
> >  #include <linux/bitops.h>
> >  #include <linux/clk-provider.h>
> >  #include <linux/err.h>
> > +#include <linux/export.h>
> >  #include <linux/io.h>
> >  #include <linux/iopoll.h>
> >  #include <linux/slab.h>
> > @@ -68,6 +69,7 @@ struct imx_pll14xx_clk imx_1443x_pll = {
> >         .rate_table = imx_pll1443x_tbl,
> >         .rate_count = ARRAY_SIZE(imx_pll1443x_tbl),  };
> > +EXPORT_SYMBOL_GPL(imx_1443x_pll);
> >
> >  struct imx_pll14xx_clk imx_1443x_dram_pll = {
> >         .type = PLL_1443X,
> > @@ -75,12 +77,14 @@ struct imx_pll14xx_clk imx_1443x_dram_pll = {
> >         .rate_count = ARRAY_SIZE(imx_pll1443x_tbl),
> >         .flags = CLK_GET_RATE_NOCACHE,
> >  };
> > +EXPORT_SYMBOL_GPL(imx_1443x_dram_pll);
> >
> >  struct imx_pll14xx_clk imx_1416x_pll = {
> >         .type = PLL_1416X,
> >         .rate_table = imx_pll1416x_tbl,
> >         .rate_count = ARRAY_SIZE(imx_pll1416x_tbl),
> >  };
> > +EXPORT_SYMBOL_GPL(imx_1416x_pll);
> >
> >  static const struct imx_pll14xx_rate_table *imx_get_pll_settings(
> >                 struct clk_pll14xx *pll, unsigned long rate)
> > @@ -436,3 +440,4 @@ struct clk_hw *imx_dev_clk_hw_pll14xx(struct
> device *dev, const char *name,
> >
> >         return hw;
> >  }
> > +EXPORT_SYMBOL_GPL(imx_dev_clk_hw_pll14xx);
> > diff --git a/drivers/clk/imx/clk-sscg-pll.c b/drivers/clk/imx/clk-sscg-pll.c
> > index 773d8a5..9d6cdff 100644
> > --- a/drivers/clk/imx/clk-sscg-pll.c
> > +++ b/drivers/clk/imx/clk-sscg-pll.c
> > @@ -10,6 +10,7 @@
> >
> >  #include <linux/clk-provider.h>
> >  #include <linux/err.h>
> > +#include <linux/export.h>
> >  #include <linux/io.h>
> >  #include <linux/iopoll.h>
> >  #include <linux/slab.h>
> > @@ -537,3 +538,4 @@ struct clk_hw *imx_clk_hw_sscg_pll(const char
> *name,
> >
> >         return hw;
> >  }
> > +EXPORT_SYMBOL_GPL(imx_clk_hw_sscg_pll);
> > diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c
> > index 87ab8db..6f2a94d 100644
> > --- a/drivers/clk/imx/clk.c
> > +++ b/drivers/clk/imx/clk.c
> > @@ -3,6 +3,7 @@
> >  #include <linux/clk-provider.h>
> >  #include <linux/err.h>
> >  #include <linux/io.h>
> > +#include <linux/module.h>
> >  #include <linux/of.h>
> >  #include <linux/slab.h>
> >  #include <linux/spinlock.h>
> > @@ -13,6 +14,7 @@
> >  #define CCDR_MMDC_CH1_MASK             BIT(16)
> >
> >  DEFINE_SPINLOCK(imx_ccm_lock);
> > +EXPORT_SYMBOL_GPL(imx_ccm_lock);
> >
> >  void imx_unregister_clocks(struct clk *clks[], unsigned int count)
> >  {
> > @@ -29,8 +31,9 @@ void imx_unregister_hw_clocks(struct clk_hw *hws[],
> unsigned int count)
> >         for (i = 0; i < count; i++)
> >                 clk_hw_unregister(hws[i]);
> >  }
> > +EXPORT_SYMBOL_GPL(imx_unregister_hw_clocks);
> >
> > -void __init imx_mmdc_mask_handshake(void __iomem *ccm_base,
> > +void imx_mmdc_mask_handshake(void __iomem *ccm_base,
> >                                     unsigned int chn)
> >  {
> >         unsigned int reg;
> > @@ -59,8 +62,9 @@ void imx_check_clk_hws(struct clk_hw *clks[],
> unsigned int count)
> >                         pr_err("i.MX clk %u: register failed with %ld\n",
> >                                i, PTR_ERR(clks[i]));
> >  }
> > +EXPORT_SYMBOL_GPL(imx_check_clk_hws);
> >
> > -static struct clk * __init imx_obtain_fixed_clock_from_dt(const char *name)
> > +static struct clk *imx_obtain_fixed_clock_from_dt(const char *name)
> >  {
> >         struct of_phandle_args phandle;
> >         struct clk *clk = ERR_PTR(-ENODEV);
> > @@ -80,7 +84,7 @@ static struct clk * __init
> imx_obtain_fixed_clock_from_dt(const char *name)
> >         return clk;
> >  }
> >
> > -struct clk * __init imx_obtain_fixed_clock(
> > +struct clk *imx_obtain_fixed_clock(
> >                         const char *name, unsigned long rate)
> >  {
> >         struct clk *clk;
> > @@ -91,7 +95,7 @@ struct clk * __init imx_obtain_fixed_clock(
> >         return clk;
> >  }
> >
> > -struct clk_hw * __init imx_obtain_fixed_clock_hw(
> > +struct clk_hw *imx_obtain_fixed_clock_hw(
> >                         const char *name, unsigned long rate)
> >  {
> >         struct clk *clk;
> > @@ -113,6 +117,7 @@ struct clk_hw * imx_obtain_fixed_clk_hw(struct
> device_node *np,
> >
> >         return __clk_get_hw(clk);
> >  }
> > +EXPORT_SYMBOL_GPL(imx_obtain_fixed_clk_hw);
> >
> >  /*
> >   * This fixups the register CCM_CSCMR1 write value.
> > @@ -143,16 +148,18 @@ void imx_cscmr1_fixup(u32 *val)
> >  static int imx_keep_uart_clocks;
> >  static struct clk ** const *imx_uart_clocks;
> >
> > -static int __init imx_keep_uart_clocks_param(char *str)
> > +static int __maybe_unused imx_keep_uart_clocks_param(char *str)
> >  {
> >         imx_keep_uart_clocks = 1;
> >
> >         return 0;
> >  }
> > +#ifndef MODULE
> >  __setup_param("earlycon", imx_keep_uart_earlycon,
> >               imx_keep_uart_clocks_param, 0);
> >  __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
> >               imx_keep_uart_clocks_param, 0);
> 
> I feel not only the __setup_param, the whole logic of keep_uart_clocks
> are not needed for Module case. Is it true?

Yes, but the 'keep_uart_clocks' is false by default and the function imx_keep_uart_clocks_param()
already has '__maybe_unused', it does NOT impact anything if it is for module build, so I did NOT
add the #ifndef check for them, just to keep code easy and clean.

Thanks,
Anson