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7b0e62920a
linux-next/drivers/i2c/busses
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Shinya Kuribayashi 7b0e62920a i2c: i2c-sh_mobile: calculate clock parameters at driver probing time 
Currently SCL clock parameters (ICCH/ICCL) are calculated in
activate_ch(), which gets called every time sh_mobile_i2c_xfer() is
processed, while each I2C bus speed is system-defined and in general
those parameters do not have to be updated over I2C transactions.

The only reason I could see having it transaction-time is to adjust
ICCH/ICCL values according to the operating frequency of the I2C
hardware block, in the face of DFS (Dynamic Frequency Scaling).

However, this won't be necessary.

The operating frequency of the I2C hardware block can change _even_
in the middle of I2C transactions.  There is no way to prevent it
from happening, and I2C hardware block can work with such dynamic
frequency change, of course.

Another is that ICCH/ICCL clock parameters optimized for the faster
operating frequency, can also be applied to the slower operating
frequency, as long as slave devices work.  However, the converse is
not true.  It would violate SCL timing specs of the I2C standard.

What we can do now is to calculate the ICCH/ICCL clock parameters
according to the fastest operating clock of the I2C hardware block.
And if that's the case, that calculation should be done just once
at driver-module-init time.

This patch moves ICCH/ICCL calculating part from activate_ch() into
sh_mobile_i2c_init(), and call it from sh_mobile_i2c_probe().

Note that sh_mobile_i2c_init() just prepares clock parameters using
the clock rate and platform data provided, but does _not_ make any
hardware I/O accesses.  We don't have to care about run-time PM
maintenance here.

Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
2012-11-16 08:57:16 +01:00
..
i2c-acorn.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
i2c-ali15x3.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-ali1535.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-ali1563.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-amd756-s4882.c i2c: Use snprintf to set adapter names 2009-01-07 14:29:18 +01:00
i2c-amd756.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-amd8111.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-at91.c i2c: at91: fix SMBus quick command 2012-11-14 10:28:28 +01:00
i2c-au1550.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-bfin-twi.c i2c: i2c-bfin-twi: Move blackfin TWI register access Macro to head file. 2012-07-13 08:37:31 +02:00
i2c-cpm.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-davinci.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-designware-core.c i2c-designware: i2c_dw_xfer_msg can be static 2012-10-05 22:23:53 +02:00
i2c-designware-core.h i2c: designware: Add support for 16bit register access 2012-05-12 14:28:11 +02:00
i2c-designware-pcidrv.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-designware-platdrv.c i2c: designware: Add clk_{un}prepare() support 2012-05-12 14:28:15 +02:00
i2c-diolan-u2c.c i2c: diolan-u2c: Fix master_xfer return code 2012-08-18 12:27:27 +02:00
i2c-eg20t.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-elektor.c Fix common misspellings 2011-03-31 11:26:23 -03:00
i2c-gpio.c i2c: i2c-gpio: fix name issue with multiple i2c gpio nodes 2012-11-14 09:56:43 +01:00
i2c-highlander.c Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1 2012-01-14 12:32:16 -08:00
i2c-hydra.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-i801.c i2c-i801: Fix comment 2012-10-28 21:37:01 +01:00
i2c-ibm_iic.c Autogenerated GPG tag for Rusty D1ADB8F1: 15EE 8D6C AB0E 7F0C F999 BFCB D920 0E6C D1AD B8F1 2012-01-14 12:32:16 -08:00
i2c-ibm_iic.h
i2c-imx.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-intel-mid.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-iop3xx.c i2c: iop3xx: use standard gpiolib functions 2012-07-25 09:26:41 -05:00
i2c-iop3xx.h i2c-iop3xx: add iomem annotation 2011-01-04 00:53:37 +00:00
i2c-isch.c i2c-isch: Decrease delay in command completion check loop 2012-03-26 21:47:18 +02:00
i2c-mpc.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-mv64xxx.c I2C: MV64XYZ: Add Device Tree support 2012-07-23 22:04:11 +02:00
i2c-mxs.c i2c: mxs: remove broken PIOQUEUE support 2012-11-02 10:52:32 +01:00
i2c-nforce2-s4985.c i2c: Fix oops on bus multiplexer driver loading 2008-08-10 22:56:15 +02:00
i2c-nforce2.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-nomadik.c i2c: nomadik: Fix the usage of wait_for_completion_timeout 2012-11-12 18:21:55 +01:00
i2c-nuc900.c ARM: w90x900: move platform_data definitions 2012-09-14 11:18:59 +02:00
i2c-ocores.c i2c: ocores: Use devm_request_and_ioremap() 2012-11-13 12:16:24 +01:00
i2c-octeon.c i2c: Convert i2c-octeon.c to use device tree. 2012-07-23 13:54:53 +01:00
i2c-omap.c i2c: omap: don't save a value only needed for read-clearing 2012-11-14 19:52:12 +01:00
i2c-parport-light.c i2c-parport: Various cleanups 2011-05-24 20:58:49 +02:00
i2c-parport.c i2c-parport: i2c_parport_irq can be static 2012-10-05 22:23:53 +02:00
i2c-parport.h i2c-parport: Various cleanups 2011-05-24 20:58:49 +02:00
i2c-pasemi.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-pca-isa.c i2c-pca: Fix waitforcompletion() return value 2010-09-30 14:14:22 +02:00
i2c-pca-platform.c i2c: Dynamically assign adapter id if it wasn't explictly specified 2012-05-12 14:28:11 +02:00
i2c-piix4.c i2c-piix4: Fix build failure 2012-10-05 22:23:55 +02:00
i2c-pmcmsp.c i2c-pmcmsp: remove IRQF_SAMPLE_RANDOM which is now a no-op 2012-07-19 10:38:47 -04:00
i2c-pnx.c i2c: pnx: Fix read transactions of >= 2 bytes 2012-09-12 17:52:44 +02:00
i2c-powermac.c i2c/powermac: Improve detection of devices from device-tree 2012-07-11 18:22:46 +10:00
i2c-puv3.c i2c-puv3: Use struct dev_pm_ops for power management 2012-07-12 12:04:54 +02:00
i2c-pxa-pci.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-pxa.c i2c/i2c-pxa: remove conditional compilation of clk code 2012-07-30 17:25:12 -07:00
i2c-rcar.c i2c: rcar: fix section mismatch 2012-11-13 11:24:15 +01:00
i2c-s3c2410.c Merge branch 'i2c-embedded/for-next' of git://git.pengutronix.de/git/wsa/linux 2012-10-11 10:27:51 +09:00
i2c-s6000.c i2c: Change mail address of Oskar Schirmer 2012-05-17 15:15:56 +02:00
i2c-s6000.h i2c: Change mail address of Oskar Schirmer 2012-05-17 15:15:56 +02:00
i2c-scmi.c i2c-scmi: convert to module_acpi_driver() 2012-09-21 13:39:56 -04:00
i2c-sh7760.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-sh_mobile.c i2c: i2c-sh_mobile: calculate clock parameters at driver probing time 2012-11-16 08:57:16 +01:00
i2c-sibyte.c i2c/mips: Fix error return codes from Sibyte i2c bus driver 2010-07-10 09:42:47 +02:00
i2c-simtec.c i2c/busses: Use module_platform_driver() 2012-01-12 20:32:04 +01:00
i2c-sirf.c i2c: add CSR SiRFprimaII on-chip I2C controllers driver 2012-03-07 19:05:04 +01:00
i2c-sis96x.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-sis630.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-sis5595.c i2c: Convert to DEFINE_PCI_DEVICE_TABLE 2012-01-12 20:32:04 +01:00
i2c-stu300.c i2c: stu300: use devm managed resources 2012-07-16 13:48:51 +02:00
i2c-taos-evm.c i2c-taos-evm: Fix log messages 2011-06-29 11:36:10 +02:00
i2c-tegra.c i2c: tegra: set irq name as device name 2012-11-02 10:52:52 +01:00
i2c-tiny-usb.c i2c-tiny-usb: Add support for the Robofuzz OSIF USB/I2C converter 2012-07-24 14:13:59 +02:00
i2c-versatile.c i2c: Dynamically assign adapter id if it wasn't explictly specified 2012-05-12 14:28:11 +02:00
i2c-via.c i2c/busses: Use module_pci_driver 2012-07-24 14:13:56 +02:00
i2c-viapro.c i2c-viapro: Add VIA VX900 device ID 2012-10-05 22:23:53 +02:00
i2c-xiic.c I2C: xiic: Add OF binding support 2012-05-12 14:28:18 +02:00
i2c-xlr.c i2c: Support for Netlogic XLR/XLS I2C controller. 2012-02-24 22:25:57 +01:00
Kconfig i2c-i801: Simplify dependency towards GPIOLIB 2012-10-28 21:37:01 +01:00
Makefile i2c-stub: Move to drivers/i2c 2012-10-28 21:37:00 +01:00
scx200_acb.c i2c/scx200_*: Replace printks with pr_<level>s 2012-10-05 22:23:52 +02:00
scx200_i2c.c i2c/scx200_*: Replace printks with pr_<level>s 2012-10-05 22:23:52 +02:00