Re: [RFC][PATCH 1/5] ARM: OMAP2+: gpmc: driver conversion

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Hi Afzal,

On 3/26/2012 3:04, Mohammed, Afzal wrote:
Hi Jon,

On Sat, Mar 24, 2012 at 04:51:13, Hunter, Jon wrote:
+struct gpmc_child {
+	char			*name;
+	int			id;
+	struct resource		*res;
+	unsigned		num_res;
+	struct resource		gpmc_res[GPMC_CS_NUM];

Does this imply a gpmc child device can use more than one chip-select? I
am trying to understand the link between number of resources and
GPMC_CS_NUM.

Yes, relevant portion in commit message as follows,

A peripheral connected to GPMC can have multiple
address spaces using different chip select. Hence
GPMC driver has been provided capability to
distinguish this scenario, i.e. create platform
devices only once for each connected peripheral,
and not for each configured chip select. The
peripheral that made it necessary was tusb6010.

Ok, makes sense. I believe that most devices are using a single CS and less common for devices to use more than one. Therefore, I was not sure if it made sense to allocate the gpmc_res struct dynamically as I doubt you will ever have a device using all 8 chip-selects ;-)

Also, I don't see where the gpmc_child->res and gpmc_child->num_res are actually used. Are these needed?

[snip]

Do we need to free irqs here?

Irqs has been conveniently forgotten in this patch, in mainline, I could
not find any platforms using GPMC irq. This can be added later once
driver conversion is done, if required.

I just meant that if we allocate them during the probe maybe we should remove when exiting.

[snip]

+	/* GPMC specific */
+	unsigned		cs;
+	unsigned long		mem_size;
+	unsigned long		mem_start;
+	unsigned long		mem_offset;
+	struct gpmc_config	*config;
+	unsigned		num_config;
+	struct gpmc_timings	*timing;
+};
+
+struct gpmc_pdata {
+	/* GPMC_FCLK rate in picoseconds */
+	unsigned long			fclk_rate;

fclk_period

+	struct gpmc_device_pdata	*device_pdata;
+	unsigned			num_device;
+};

Do you need both gpmc_pdata and gpmc_device_pdata? Would not a single
structure work?

Gpmc_device_data is dedicated to each CS, gpmc_pdata is required
at least to inform driver about clock rate.

Ok, understood! So the struct gpmc_device_pdata only has a single chip-select entry and so looking at the code you will have multiple instances of this structure of a gpmc device that uses more than one chip-select. Any reason you did it this way and not have a single pdata struct for each device defining all chip-selects it uses?

Generally, as the change involved moving a lot of code, seems more reviews
are on those than the actual changes than what I intended to get reviewed,
next patch series will be modified not to move existing code, hence some
of your suggested changes may not be present in it, probably those to be
done as another cleanup patch.

Yes I understand. However, it is a good opportunity to clean some of this up even if it is existing code :-)

Cheers
Jon
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