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From: Florian Fainelli <f.fainelli@gmail.com>
To: Matthias Brugger <matthias.bgg@gmail.com>,
	Stefan Wahren <wahrenst@gmx.net>, Eric Anholt <eric@anholt.net>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Ray Jui <rjui@broadcom.com>,
	Scott Branden <sbranden@broadcom.com>,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Linus Walleij <linus.walleij@linaro.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Mark Brown <broonie@kernel.org>
Cc: bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH RFC 07/18] clk: bcm2835: Add BCM2838_CLOCK_EMMC2 support
Date: Thu, 18 Jul 2019 09:51:43 -0700
Message-ID: <3b691366-81b1-efe3-8b7e-a81f0fc9c2fb@gmail.com> (raw)
In-Reply-To: <f6d8fecd-94d3-a5a8-2d4c-c1ae2b6a0919@gmail.com>



On 7/18/2019 1:47 AM, Matthias Brugger wrote:
> 
> 
> On 17/07/2019 21:50, Stefan Wahren wrote:
>> The new BCM2838 supports an additional clock for the emmc2 block.
>> So add a new compatible to register this clock only for BCM2838.
>>
>> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
>> ---
>>  drivers/clk/bcm/clk-bcm2835.c | 33 +++++++++++++++++++++++++++++++--
>>  1 file changed, 31 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
>> index 867ae3c..5fe4695 100644
>> --- a/drivers/clk/bcm/clk-bcm2835.c
>> +++ b/drivers/clk/bcm/clk-bcm2835.c
>> @@ -31,7 +31,8 @@
>>  #include <linux/delay.h>
>>  #include <linux/io.h>
>>  #include <linux/module.h>
>> -#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +
>>  #include <linux/platform_device.h>
>>  #include <linux/slab.h>
>>  #include <dt-bindings/clock/bcm2835.h>
>> @@ -114,6 +115,8 @@
>>  #define CM_AVEODIV		0x1bc
>>  #define CM_EMMCCTL		0x1c0
>>  #define CM_EMMCDIV		0x1c4
>> +#define CM_EMMC2CTL		0x1d0
>> +#define CM_EMMC2DIV		0x1d4
>>
>>  /* General bits for the CM_*CTL regs */
>>  # define CM_ENABLE			BIT(4)
>> @@ -1950,6 +1953,15 @@ static const struct bcm2835_clk_desc clk_desc_array[] = {
>>  		.frac_bits = 8,
>>  		.tcnt_mux = 39),
>>
>> +	/* EMMC2 clock (only available for BCM2838) */
>> +	[BCM2838_CLOCK_EMMC2]	= REGISTER_PER_CLK(
>> +		.name = "emmc2",
>> +		.ctl_reg = CM_EMMC2CTL,
>> +		.div_reg = CM_EMMC2DIV,
>> +		.int_bits = 4,
>> +		.frac_bits = 8,
>> +		.tcnt_mux = 42),
>> +
>>  	/* General purpose (GPIO) clocks */
>>  	[BCM2835_CLOCK_GP0]	= REGISTER_PER_CLK(
>>  		.name = "gp0",
>> @@ -2101,6 +2113,14 @@ static int bcm2835_mark_sdc_parent_critical(struct clk *sdc)
>>  	return clk_prepare_enable(parent);
>>  }
>>
>> +bool bcm2835_has_clk(size_t index) {
>> +	return index != BCM2838_CLOCK_EMMC2;
>> +}
>> +
>> +bool bcm2838_has_clk(size_t index) {
>> +	return true;
>> +}
>> +
>>  static int bcm2835_clk_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> @@ -2109,9 +2129,14 @@ static int bcm2835_clk_probe(struct platform_device *pdev)
>>  	struct resource *res;
>>  	const struct bcm2835_clk_desc *desc;
>>  	const size_t asize = ARRAY_SIZE(clk_desc_array);
>> +	bool (*has_clk_func)(size_t);
>>  	size_t i;
>>  	int ret;
>>
>> +	has_clk_func = of_device_get_match_data(&pdev->dev);
>> +	if (!has_clk_func)
>> +		return -ENODEV;
>> +
>>  	cprman = devm_kzalloc(dev,
>>  			      struct_size(cprman, onecell.hws, asize),
>>  			      GFP_KERNEL);
>> @@ -2146,6 +2171,9 @@ static int bcm2835_clk_probe(struct platform_device *pdev)
>>  	hws = cprman->onecell.hws;
>>
>>  	for (i = 0; i < asize; i++) {
>> +		if (!has_clk_func(i))
>> +			continue;
>> +
> 
> I think that's very hacky. Can't we just create a per SoC list which get's
> passed via .data and in probe we iterate through that list and enable the
> clocks? That would make clear which clocks are just for bcm2838, basically emmc2.

Or within the structure, add a flag that indicates whether the clock is
available or not for a given chip? That would avoid having to introduce
bcm283x_has_clk() functions that needs to maintain a possibly growing
list of clocks. You would still have to check the flag though.

The trade-off here is a large table (larger than necessary) versus more
run time checks.

We could consider having a base table that gets copied into a bcm2838
specific table, and overlay that base structure with what's specific
with bcm2838, is that you have in mind?
-- 
Florian

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  reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-17 19:50 [PATCH RFC 00/18] ARM: Add minimal Raspberry Pi 4 support Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 01/18] ARM: bcm283x: Reduce register ranges for UART, SPI and I2C Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 02/18] ARM: bcm2835: DMA can only address 1GB Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 03/18] ARM: dts: bcm283x: Move BCM2835/6/7 specific to bcm2835-common.dtsi Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 04/18] ARM: dts: bcm283x: Define MMC interfaces at board level Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 05/18] ARM: dts: bcm283x: Define memory " Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 06/18] dt-bindings: bcm2835-cprman: Add bcm2838 support Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 07/18] clk: bcm2835: Add BCM2838_CLOCK_EMMC2 support Stefan Wahren
2019-07-18  8:47   ` Matthias Brugger
2019-07-18 16:51     ` Florian Fainelli [this message]
2019-07-18 18:37       ` Eric Anholt
2019-07-19 16:40         ` Stefan Wahren
2019-07-19 19:49           ` Eric Anholt
2019-07-17 19:50 ` [PATCH RFC 08/18] dt-bindings: sdhci-iproc: Add brcm,bcm2838-emmc2 Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 09/18] mmc: sdhci-iproc: Add support for emmc2 of the BCM2838 Stefan Wahren
2019-07-18  8:34   ` Matthias Brugger
2019-07-18 16:40     ` Florian Fainelli
2019-07-18 16:48       ` Matthias Brugger
2019-07-18 16:52         ` Florian Fainelli
2019-07-18 17:46         ` Stefan Wahren
2019-07-18 18:09         ` Stefan Wahren
2019-07-18 18:19           ` Andrei Gherzan
2019-07-17 19:50 ` [PATCH RFC 10/18] pinctrl: bcm2835: bcm7211: Add support for 7211 pull-up functionality Stefan Wahren
2019-08-02 22:05   ` Linus Walleij
2019-07-17 19:50 ` [PATCH RFC 11/18] pinctrl: bcm2835: Fix BCM7211 pinconf handling Stefan Wahren
2019-08-02 22:06   ` Linus Walleij
2019-07-17 19:50 ` [PATCH RFC 12/18] dt-bindings: pinctrl: bcm2835: Add brcm, bcm2838 compatible Stefan Wahren
2019-07-17 19:50 ` [PATCH RFC 13/18] pinctrl: bcm2835: Add BCM2838 support Stefan Wahren
2019-08-02 22:08   ` Linus Walleij
2019-07-18 18:45 ` [PATCH RFC 00/18] ARM: Add minimal Raspberry Pi 4 support Eric Anholt
2019-07-18 18:58   ` Florian Fainelli
2019-07-19 13:18   ` Nicolas Saenz Julienne

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