Re: [PATCH v2 2/2] clk: keystone: Add new driver to handle syscon based clocks

[Stephen Boyd <sboyd@kernel.org>]

Quoting Vignesh Raghavendra (2020-02-06 20:44:25)
> diff --git a/drivers/clk/keystone/Kconfig b/drivers/clk/keystone/Kconfig
> index 38aeefb1e808..69ca3db1a99e 100644
> --- a/drivers/clk/keystone/Kconfig
> +++ b/drivers/clk/keystone/Kconfig
> @@ -26,3 +26,11 @@ config TI_SCI_CLK_PROBE_FROM_FW
>           This is mostly only useful for debugging purposes, and will
>           increase the boot time of the device. If you want the clocks probed
>           from firmware, say Y. Otherwise, say N.
> +
> +config TI_SYSCON_CLK
> +       tristate "Syscon based clock driver for K2/K3 SoCs"
> +       depends on (ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST) && OF
> +       default (ARCH_KEYSTONE || ARCH_K3)

Drop parenthesis. It's not useful. Also, not sure why OF is a build
dependency. Please drop it.

	depends on ARCH_KEYSTONE || ARCH_K3 || COMPILE_TEST
	default ARCH_KEYSTONE || ARCH_K3

> +       help
> +         This adds clock driver support for syscon based gate
> +         clocks on TI's K2 and K3 SoCs.
> diff --git a/drivers/clk/keystone/Makefile b/drivers/clk/keystone/Makefile
> index d044de6f965c..0e426e648f7c 100644
> --- a/drivers/clk/keystone/Makefile
> +++ b/drivers/clk/keystone/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  obj-$(CONFIG_COMMON_CLK_KEYSTONE)      += pll.o gate.o
>  obj-$(CONFIG_TI_SCI_CLK)               += sci-clk.o
> +obj-$(CONFIG_TI_SYSCON_CLK)            += syscon-clk.o
> diff --git a/drivers/clk/keystone/syscon-clk.c b/drivers/clk/keystone/syscon-clk.c
> new file mode 100644
> index 000000000000..42e7416371ff
> --- /dev/null
> +++ b/drivers/clk/keystone/syscon-clk.c
> @@ -0,0 +1,177 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
> +//

These last three comment lines should be normal kernel style. /* */

> +
> +#include <linux/clk-provider.h>
> +#include <linux/clk.h>

Is this used?

> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>

Hopefully these two includes aren't needed.

> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
[...]
> +
> +static int ti_syscon_gate_clk_probe(struct platform_device *pdev)
> +{
> +       const struct ti_syscon_gate_clk_data *data, *p;
> +       struct clk_hw_onecell_data *hw_data;
> +       struct device *dev = &pdev->dev;
> +       struct regmap *regmap;
> +       int num_clks = 0;

Please don't initialize here.

> +       int i;
> +
> +       data = of_device_get_match_data(dev);

Use device_get_match_data() instead?

> +       if (!data)
> +               return -EINVAL;
> +
> +       regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
> +                                                "ti,tbclk-syscon");
> +       if (IS_ERR(regmap)) {
> +               if (PTR_ERR(regmap) == -EPROBE_DEFER)
> +                       return -EPROBE_DEFER;
> +               dev_err(dev, "failed to find parent regmap\n");
> +               return PTR_ERR(regmap);
> +       }
> +
> +       for (p = data; p->name; p++)

Initialize num_clks here so we know it's a loop that's counting.

> +               num_clks++;
> +
> +       hw_data = devm_kzalloc(dev, struct_size(hw_data, hws, num_clks),
> +                              GFP_KERNEL);
> +       if (!hw_data)
> +               return -ENOMEM;
> +
> +       hw_data->num = num_clks;
> +
> +       for (i = 0; i < num_clks; i++) {
> +               hw_data->hws[i] = ti_syscon_gate_clk_register(dev, regmap,
> +                                                             &data[i]);
> +               if (IS_ERR(hw_data->hws[i]))
> +                       dev_err(dev, "failed to register %s",

Add a newline?

> +                               data[i].name);

And we don't fail? So it really isn't a problem? Maybe dev_warn()
instead?

> +       }
> +
> +       return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
> +                                          hw_data);
> +}
> +
> +#define TI_SYSCON_CLK_GATE(_name, _offset, _bit_idx)   \
> +       {                                               \
> +               .name = _name,                          \
> +               .offset = (_offset),                    \
> +               .bit_idx = (_bit_idx),                  \
> +       }
> +
> +static const struct ti_syscon_gate_clk_data am654_clk_data[] = {
> +       TI_SYSCON_CLK_GATE("ehrpwm_tbclk0", 0x0, 0),
> +       TI_SYSCON_CLK_GATE("ehrpwm_tbclk1", 0x4, 0),
> +       TI_SYSCON_CLK_GATE("ehrpwm_tbclk2", 0x8, 0),
> +       TI_SYSCON_CLK_GATE("ehrpwm_tbclk3", 0xc, 0),
> +       TI_SYSCON_CLK_GATE("ehrpwm_tbclk4", 0x10, 0),
> +       TI_SYSCON_CLK_GATE("ehrpwm_tbclk5", 0x14, 0),
> +       { /* Sentinel */ },
> +};
> +
> +static const struct of_device_id ti_syscon_gate_clk_ids[] = {
> +       {
> +               .compatible = "ti,am654-ehrpwm-tbclk",
> +               .data = &am654_clk_data,
> +       },
> +       { }
> +};
> +MODULE_DEVICE_TABLE(of, ti_syscon_gate_clk_ids);
> +
> +static struct platform_driver ti_syscon_gate_clk_driver = {
> +       .probe = ti_syscon_gate_clk_probe,
> +       .driver = {
> +               .name = "ti-syscon-gate-clk",
> +               .of_match_table = ti_syscon_gate_clk_ids,
> +       },
> +};
> +

Nitpick: Drop the newline.

> +module_platform_driver(ti_syscon_gate_clk_driver);
> +