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Date: Sat, 24 Mar 2018 07:26:26 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Paul Cercueil <paul@...pouillou.net>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Marc Zyngier <marc.zyngier@....com>,
Lee Jones <lee.jones@...aro.org>,
Ralf Baechle <ralf@...ux-mips.org>,
Rob Herring <robh+dt@...nel.org>,
Jonathan Corbet <corbet@....net>,
Mark Rutland <mark.rutland@....com>
Cc: James Hogan <jhogan@...nel.org>,
Maarten ter Huurne <maarten@...ewalker.org>,
linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-mips@...ux-mips.org,
linux-doc@...r.kernel.org
Subject: Re: [PATCH v4 7/8] clocksource: Add a new timer-ingenic driver
On 18/03/2018 00:29, Paul Cercueil wrote:
> This driver will use the TCU (Timer Counter Unit) present on the Ingenic
> JZ47xx SoCs to provide the kernel with a clocksource and timers.
Please provide a more detailed description about the timer.
Where is the clocksource ?
I don't see the point of using channel idx and pwm checking here.
There is one clockevent, why create multiple channels ? Can't you stick
to the usual init routine for a timer.
> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> ---
> drivers/clocksource/Kconfig | 8 ++
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/timer-ingenic.c | 278 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 287 insertions(+)
> create mode 100644 drivers/clocksource/timer-ingenic.c
>
> v2: Use SPDX identifier for the license
> v3: - Move documentation to its own patch
> - Search the devicetree for PWM clients, and use all the TCU
> channels that won't be used for PWM
> v4: - Add documentation about why we search for PWM clients
> - Verify that the PWM clients are for the TCU PWM driver
>
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index d2e5382821a4..481422145fb4 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -592,4 +592,12 @@ config CLKSRC_ST_LPC
> Enable this option to use the Low Power controller timer
> as clocksource.
>
> +config INGENIC_TIMER
> + bool "Clocksource/timer using the TCU in Ingenic JZ SoCs"
> + depends on MACH_INGENIC || COMPILE_TEST
bool "Clocksource/timer using the TCU in Ingenic JZ SoCs" if COMPILE_TEST
Remove the depends MACH_INGENIC.
> + select CLKSRC_OF
> + default y
No default, Kconfig platform selects the timer.
> + help
> + Support for the timer/counter unit of the Ingenic JZ SoCs.
> +
> endmenu
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index d6dec4489d66..98691e8999fe 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -74,5 +74,6 @@ obj-$(CONFIG_ASM9260_TIMER) += asm9260_timer.o
> obj-$(CONFIG_H8300_TMR8) += h8300_timer8.o
> obj-$(CONFIG_H8300_TMR16) += h8300_timer16.o
> obj-$(CONFIG_H8300_TPU) += h8300_tpu.o
> +obj-$(CONFIG_INGENIC_TIMER) += timer-ingenic.o
> obj-$(CONFIG_CLKSRC_ST_LPC) += clksrc_st_lpc.o
> obj-$(CONFIG_X86_NUMACHIP) += numachip.o
> diff --git a/drivers/clocksource/timer-ingenic.c b/drivers/clocksource/timer-ingenic.c
> new file mode 100644
> index 000000000000..8c777c0c0023
> --- /dev/null
> +++ b/drivers/clocksource/timer-ingenic.c
> @@ -0,0 +1,278 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Ingenic JZ47xx SoC TCU clocksource driver
> + * Copyright (C) 2018 Paul Cercueil <paul@...pouillou.net>
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/clk.h>
> +#include <linux/clockchips.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/mfd/syscon/ingenic-tcu.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +#define NUM_CHANNELS 8
> +
> +struct ingenic_tcu;
> +
> +struct ingenic_tcu_channel {
> + unsigned int idx;
> + struct clk *clk;
> +};
> +
> +struct ingenic_tcu {
> + struct ingenic_tcu_channel channels[NUM_CHANNELS];
> + unsigned long requested;
> + struct regmap *map;
> +};
> +
> +struct ingenic_clock_event_device {
> + struct clock_event_device cevt;
> + struct ingenic_tcu_channel *channel;
> + char name[32];
> +};
> +
> +#define ingenic_cevt(_evt) \
> + container_of(_evt, struct ingenic_clock_event_device, cevt)
> +
> +static inline struct ingenic_tcu *to_ingenic_tcu(struct ingenic_tcu_channel *ch)
> +{
> + return container_of(ch, struct ingenic_tcu, channels[ch->idx]);
> +}
> +
> +static int ingenic_tcu_cevt_set_state_shutdown(struct clock_event_device *evt)
> +{
> + struct ingenic_clock_event_device *jzcevt = ingenic_cevt(evt);
> + struct ingenic_tcu_channel *channel = jzcevt->channel;
> + struct ingenic_tcu *tcu = to_ingenic_tcu(channel);
> + unsigned int idx = channel->idx;
> +
> + regmap_write(tcu->map, TCU_REG_TECR, BIT(idx));
> + return 0;
> +}
> +
> +static int ingenic_tcu_cevt_set_next(unsigned long next,
> + struct clock_event_device *evt)
> +{
> + struct ingenic_clock_event_device *jzcevt = ingenic_cevt(evt);
> + struct ingenic_tcu_channel *channel = jzcevt->channel;
> + struct ingenic_tcu *tcu = to_ingenic_tcu(channel);
> + unsigned int idx = channel->idx;
> +
> + if (next > 0xffff)
> + return -EINVAL;
> +
> + regmap_write(tcu->map, TCU_REG_TDFRc(idx), (unsigned int) next);
> + regmap_write(tcu->map, TCU_REG_TCNTc(idx), 0);
> + regmap_write(tcu->map, TCU_REG_TESR, BIT(idx));
> +
> + return 0;
> +}
> +
> +static irqreturn_t ingenic_tcu_cevt_cb(int irq, void *dev_id)
> +{
> + struct clock_event_device *cevt = dev_id;
> + struct ingenic_clock_event_device *jzcevt = ingenic_cevt(cevt);
> + struct ingenic_tcu_channel *channel = jzcevt->channel;
> + struct ingenic_tcu *tcu = to_ingenic_tcu(channel);
> + unsigned int idx = channel->idx;
> +
> + regmap_write(tcu->map, TCU_REG_TECR, BIT(idx));
> +
> + if (cevt->event_handler)
> + cevt->event_handler(cevt);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int __init ingenic_tcu_req_channel(struct ingenic_tcu_channel *channel)
> +{
> + struct ingenic_tcu *tcu = to_ingenic_tcu(channel);
> + char buf[16];
> + int err;
> +
> + if (test_and_set_bit(channel->idx, &tcu->requested))
> + return -EBUSY;
> +
> + snprintf(buf, sizeof(buf), "timer%u", channel->idx);
> + channel->clk = clk_get(NULL, buf);
> + if (IS_ERR(channel->clk)) {
> + err = PTR_ERR(channel->clk);
> + goto out_release;
> + }
> +
> + err = clk_prepare_enable(channel->clk);
> + if (err)
> + goto out_clk_put;
> +
> + return 0;
> +
> +out_clk_put:
> + clk_put(channel->clk);
> +out_release:
> + clear_bit(channel->idx, &tcu->requested);
> + return err;
> +}
> +
> +static int __init ingenic_tcu_reset_channel(struct device_node *np,
> + struct ingenic_tcu_channel *channel)
> +{
> + struct ingenic_tcu *tcu = to_ingenic_tcu(channel);
> +
> + return regmap_update_bits(tcu->map, TCU_REG_TCSRc(channel->idx),
> + 0xffff & ~TCU_TCSR_RESERVED_BITS, 0);
> +}
> +
> +static void __init ingenic_tcu_free_channel(struct ingenic_tcu_channel *channel)
> +{
> + struct ingenic_tcu *tcu = to_ingenic_tcu(channel);
> +
> + clk_disable_unprepare(channel->clk);
> + clk_put(channel->clk);
> + clear_bit(channel->idx, &tcu->requested);
> +}
> +
> +static const char * const ingenic_tcu_timer_names[] = {
> + "TCU0", "TCU1", "TCU2", "TCU3", "TCU4", "TCU5", "TCU6", "TCU7",
> +};
> +
> +static int __init ingenic_tcu_setup_cevt(struct device_node *np,
> + struct ingenic_tcu *tcu, unsigned int idx)
> +{
> + struct ingenic_tcu_channel *channel = &tcu->channels[idx];
> + struct ingenic_clock_event_device *jzcevt;
> + unsigned long rate;
> + int err, virq;
> +
> + err = ingenic_tcu_req_channel(channel);
> + if (err)
> + return err;
> +
> + err = ingenic_tcu_reset_channel(np, channel);
> + if (err)
> + goto err_out_free_channel;
> +
> + rate = clk_get_rate(channel->clk);
> + if (!rate) {
> + err = -EINVAL;
> + goto err_out_free_channel;
> + }
> +
> + jzcevt = kzalloc(sizeof(*jzcevt), GFP_KERNEL);
> + if (!jzcevt) {
> + err = -ENOMEM;
> + goto err_out_free_channel;
> + }
> +
> + virq = irq_of_parse_and_map(np, idx);
> + if (!virq) {
> + err = -EINVAL;
> + goto err_out_kfree_jzcevt;
> + }
> +
> + err = request_irq(virq, ingenic_tcu_cevt_cb, IRQF_TIMER,
> + ingenic_tcu_timer_names[idx], &jzcevt->cevt);
> + if (err)
> + goto err_out_irq_dispose_mapping;
> +
> + jzcevt->channel = channel;
> + snprintf(jzcevt->name, sizeof(jzcevt->name), "ingenic-tcu-chan%u",
> + channel->idx);
> +
> + jzcevt->cevt.cpumask = cpumask_of(smp_processor_id());
> + jzcevt->cevt.features = CLOCK_EVT_FEAT_ONESHOT;
> + jzcevt->cevt.name = jzcevt->name;
> + jzcevt->cevt.rating = 200;
> + jzcevt->cevt.set_state_shutdown = ingenic_tcu_cevt_set_state_shutdown;
> + jzcevt->cevt.set_next_event = ingenic_tcu_cevt_set_next;
> +
> + clockevents_config_and_register(&jzcevt->cevt, rate, 10, (1 << 16) - 1);
> +
> + return 0;
> +
> +err_out_irq_dispose_mapping:
> + irq_dispose_mapping(virq);
> +err_out_kfree_jzcevt:
> + kfree(jzcevt);
> +err_out_free_channel:
> + ingenic_tcu_free_channel(channel);
> + return err;
> +}
> +
> +static int __init ingenic_tcu_init(struct device_node *np)
> +{
> + unsigned long available_channels = GENMASK(NUM_CHANNELS - 1, 0);
> + struct device_node *node, *pwm_driver_node;
> + struct ingenic_tcu *tcu;
> + unsigned int i, channel;
> + int err;
> + u32 val;
> +
> + /* Parse the devicetree for clients of the TCU PWM driver;
> + * every TCU channel not requested for PWM will be used as
> + * a timer.
> + */
> + for_each_node_with_property(node, "pwms") {
> + /* Get the PWM channel ID (field 1 of the "pwms" node) */
> + err = of_property_read_u32_index(node, "pwms", 1, &val);
> + if (!err && val >= NUM_CHANNELS)
> + err = -EINVAL;
> + if (err) {
> + pr_err("timer-ingenic: Unable to parse PWM nodes!");
> + break;
> + }
> +
> + /* Get the PWM driver node (field 0 of the "pwms" node) */
> + pwm_driver_node = of_parse_phandle(node, "pwms", 0);
> + if (!pwm_driver_node) {
> + pr_err("timer-ingenic: Unable to find PWM driver node");
> + break;
> + }
> +
> + /* Verify that the node we found is for the TCU PWM driver,
> + * by checking that this driver and the PWM driver passed
> + * as phandle share the same parent (the "ingenic,tcu"
> + * compatible MFD/syscon node).
> + */
> + if (pwm_driver_node->parent != np->parent)
> + continue;
> +
> + pr_info("timer-ingenic: Reserving channel %u for PWM", val);
> + available_channels &= ~BIT(val);
> + }
> +
> + tcu = kzalloc(sizeof(*tcu), GFP_KERNEL);
> + if (!tcu)
> + return -ENOMEM;
> +
> + tcu->map = syscon_node_to_regmap(np->parent);
> + if (IS_ERR(tcu->map)) {
> + err = PTR_ERR(tcu->map);
> + kfree(tcu);
> + return err;
> + }
> +
> + for (i = 0; i < NUM_CHANNELS; i++)
> + tcu->channels[i].idx = i;
I'm pretty sure you can do better thaningenic_tcu_setup that :)
> + for_each_set_bit(channel, &available_channels, NUM_CHANNELS) {
> + err = _cevt(np, tcu, channel);
> + if (err) {
> + pr_warn("timer-ingenic: Unable to init TCU channel %u: %i",
> + channel, err);
> + continue;
> + }
> + }
> +
> + return 0;
> +}
> +
> +/* We only probe via devicetree, no need for a platform driver */
> +CLOCKSOURCE_OF_DECLARE(jz4740_tcu, "ingenic,jz4740-tcu", ingenic_tcu_init);
> +CLOCKSOURCE_OF_DECLARE(jz4770_tcu, "ingenic,jz4770-tcu", ingenic_tcu_init);
> +CLOCKSOURCE_OF_DECLARE(jz4780_tcu, "ingenic,jz4780-tcu", ingenic_tcu_init);
s/CLOCKSOURCE_OF_DECLARE/TIMER_OF_DECLARE/
>
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