Re: [PATCH v1 08/12] clk: imx: Add initial support for i.MXRT1170 clock driver

[Jesse Taube <mr.bossman075@xxxxxxxxx>]

On 4/22/22 23:03, Stephen Boyd wrote:
> Quoting Jesse Taube (2022-03-26 07:43:09)
> > diff --git a/drivers/clk/imx/clk-imxrt1170.c b/drivers/clk/imx/clk-imxrt1170.c
> > new file mode 100644
> > index 000000000000..041aea3d4b02
> > --- /dev/null
> > +++ b/drivers/clk/imx/clk-imxrt1170.c
> > @@ -0,0 +1,391 @@
> > +// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
> > +/*
> > + * Copyright (C) 2022
> > + * Author(s):
> > + * Jesse Taube <Mr.Bossman075@xxxxxxxxx>
> > + */
> > +#include <linux/clk.h>
> > +#include <linux/of_address.h>
>
> Is this include used?
Yes `of_iomap`
> > +#include <linux/of_irq.h>
>
> Is this include used?
No, but includes
#include <linux/slab.h>
for `kzalloc`
> > +#include <linux/platform_device.h>
>
> Need to include clk-provider.h
>
> > +#include <dt-bindings/clock/imxrt1170-clock.h>
> > +
> > +#include "clk.h"
> > +
> > +#define CLOCK_MUX_DEFAULT "rcosc48M_div2", "osc", "rcosc400M", "rcosc16M"
> > +
> > +#define LPCG_GATE(gate) (0x6000 + (gate * 0x20))
> > +
> > +#define DEF_CLOCK(flags, macro, name) \
> > +do { \
> > +       hws[macro##_SEL] = imx_clk_hw_mux(#name"_sel", ccm_base + (name * 0x80), \
> > +               8, 3, root_clocks[name], 8); \
> > +       hws[macro##_GATE] = imx_clk_hw_gate_dis_flags(#name"_gate", #name"_sel", \
> > +               ccm_base + (name * 0x80), 24, flags); \
> > +       hws[macro] = imx_clk_hw_divider(#name, #name"_gate", ccm_base + (name * 0x80), 0, 8); \
> > +} while (0)
> > +
> > +enum root_clock_names {
> > +       m7,             /* root clock m7. */
>
> Is the comment adding any value? It has the enum name after "root clock"
> and the enum is "root_clock_names" so it looks very obvious.
>
> > +       m4,             /* root clock m4. */
> > +       bus,            /* root clock bus. */
> > +       bus_lpsr,       /* root clock bus lpsr. */
> [...]
> > +       end,            /* root clock end. */
> > +};
> > +
> > +static const char * const root_clocks[79][8] = {
> > +       {CLOCK_MUX_DEFAULT, "pll_arm", "pll1_sys", "pll3_sys", "pll_video"},
>
> Space after { and before }
>
> > +       {CLOCK_MUX_DEFAULT, "pll3_pfd3", "pll3_sys", "pll2_sys", "pll1_div5"},
> > +       {CLOCK_MUX_DEFAULT, "pll3_sys", "pll1_div5", "pll2_sys", "pll2_pfd3"},
> [...]
> > +       {CLOCK_MUX_DEFAULT, "pll2_pfd3", "rcosc48M", "pll3_pfd1", "pll_audio"}
> > +};
> > +
> > +static const char * const pll_arm_mux[] = {"pll_arm_pre", "osc"};
> > +static const char * const pll3_mux[] = {"pll3_pre", "osc"};
> > +static const char * const pll2_mux[] = {"pll2_pre", "osc"};
> > +
> > +static const struct clk_div_table post_div_table[] = {
> > +       { .val = 3, .div = 1, },
> > +       { .val = 2, .div = 8, },
> > +       { .val = 1, .div = 4, },
> > +       { .val = 0, .div = 2, },
> > +       { }
> > +};
> > +
> > +static struct clk_hw **hws;
> > +static struct clk_hw_onecell_data *clk_hw_data;
>
> Do either of these need to be static global variables? They could be
> local function pointers allocated on the heap (like they already are).
>
> > +
> > +static int imxrt1170_clocks_probe(struct platform_device *pdev)
> > +{
> [...]
> > +       hws[IMXRT1170_CLK_PLL2_PFD3] = imx_clk_hw_pfd("pll2_pfd3", "pll2_sys", pll_base + 0x270, 3);
> > +
> > +       /* CCM clocks */
> > +       ccm_base = devm_platform_ioremap_resource(pdev, 0);
> > +       if (WARN_ON(IS_ERR(ccm_base)))
> > +               return PTR_ERR(ccm_base);
> > +
> > +       DEF_CLOCK(CLK_IS_CRITICAL, IMXRT1170_CLK_M7, m7);
>
> Don't have macros do things to variables that are in global scope. It
> makes things very non-obvious. Instead, pass hw to the macro, or better
> yet make a static inline function and let the compiler decide to inline
> it or not.
>
> > +       DEF_CLOCK(CLK_IS_CRITICAL, IMXRT1170_CLK_M4, m4);
> [...]
> > +       DEF_CLOCK(0, IMXRT1170_CLK_CSI2_UI, csi2_ui);
> > +       DEF_CLOCK(0, IMXRT1170_CLK_CSI, csi);
> > +       DEF_CLOCK(0, IMXRT1170_CLK_CKO1, cko1);
> > +       DEF_CLOCK(0, IMXRT1170_CLK_CKO2, cko2);
> > +
> > +       hws[IMXRT1170_CLK_USB] = imx_clk_hw_gate("usb", "bus", ccm_base + LPCG_GATE(115), 0);
> > +
> > +       clk_set_rate(hws[IMXRT1170_CLK_PLL_ARM]->clk, 90000000);
>
> Use assigned-clock-rates?
>
> > +
> > +       imx_check_clk_hws(hws, IMXRT1170_CLK_END);