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authorPaul Walmsley <paul@pwsan.com>2010-01-08 17:23:15 -0500
committerPaul Walmsley <paul@pwsan.com>2010-01-08 17:23:15 -0500
commitca6eccb31ef63722b35ea695f75089adeec319d7 (patch)
treec88b9a6500b855343fa9b62429e1182c311d3fd7 /arch/arm/mach-omap2/opp2420_data.c
parent19fe458310915a216bbba32a210b6f29ac7c929f (diff)
OMAP2xxx OPP: clean up comments in OPP data
Revise some of the comments in the OMAP2xxx OPP data for clarity. Signed-off-by: Paul Walmsley <paul@pwsan.com> Cc: Richard Woodruff <r-woodruff2@ti.com>
Diffstat (limited to 'arch/arm/mach-omap2/opp2420_data.c')
-rw-r--r--arch/arm/mach-omap2/opp2420_data.c38
1 files changed, 20 insertions, 18 deletions
diff --git a/arch/arm/mach-omap2/opp2420_data.c b/arch/arm/mach-omap2/opp2420_data.c
index 126a9396b3a8..e6dda694fd5c 100644
--- a/arch/arm/mach-omap2/opp2420_data.c
+++ b/arch/arm/mach-omap2/opp2420_data.c
@@ -9,45 +9,47 @@
9 * The OMAP2 processor can be run at several discrete 'PRCM configurations'. 9 * The OMAP2 processor can be run at several discrete 'PRCM configurations'.
10 * These configurations are characterized by voltage and speed for clocks. 10 * These configurations are characterized by voltage and speed for clocks.
11 * The device is only validated for certain combinations. One way to express 11 * The device is only validated for certain combinations. One way to express
12 * these combinations is via the 'ratio's' which the clocks operate with 12 * these combinations is via the 'ratios' which the clocks operate with
13 * respect to each other. These ratio sets are for a given voltage/DPLL 13 * respect to each other. These ratio sets are for a given voltage/DPLL
14 * setting. All configurations can be described by a DPLL setting and a ratio 14 * setting. All configurations can be described by a DPLL setting and a ratio.
15 * There are 3 ratio sets for the 2430 and X ratio sets for 2420.
16 *
17 * 2430 differs from 2420 in that there are no more phase synchronizers used.
18 * They both have a slightly different clock domain setup. 2420(iva1,dsp) vs
19 * 2430 (iva2.1, NOdsp, mdm)
20 * 15 *
21 * XXX Missing voltage data. 16 * XXX Missing voltage data.
17 * XXX Missing 19.2MHz sys_clk rate sets (needed for N800/N810)
22 * 18 *
23 * THe format described in this file is deprecated. Once a reasonable 19 * THe format described in this file is deprecated. Once a reasonable
24 * OPP API exists, the data in this file should be converted to use it. 20 * OPP API exists, the data in this file should be converted to use it.
25 * 21 *
26 * This is technically part of the OMAP2xxx clock code. 22 * This is technically part of the OMAP2xxx clock code.
23 *
24 * Considerable work is still needed to fully support dynamic frequency
25 * changes on OMAP2xxx-series chips. Readers interested in such a
26 * project are encouraged to review the Maemo Diablo RX-34 and RX-44
27 * kernel source at:
28 * http://repository.maemo.org/pool/diablo/free/k/kernel-source-diablo/
27 */ 29 */
28 30
29#include "opp2xxx.h" 31#include "opp2xxx.h"
30#include "sdrc.h" 32#include "sdrc.h"
31#include "clock.h" 33#include "clock.h"
32 34
33/*------------------------------------------------------------------------- 35/*
34 * Key dividers which make up a PRCM set. Ratio's for a PRCM are mandated. 36 * Key dividers which make up a PRCM set. Ratios for a PRCM are mandated.
35 * xtal_speed, dpll_speed, mpu_speed, CM_CLKSEL_MPU, 37 * xtal_speed, dpll_speed, mpu_speed, CM_CLKSEL_MPU,
36 * CM_CLKSEL_DSP, CM_CLKSEL_GFX, CM_CLKSEL1_CORE, CM_CLKSEL1_PLL, 38 * CM_CLKSEL_DSP, CM_CLKSEL_GFX, CM_CLKSEL1_CORE, CM_CLKSEL1_PLL,
37 * CM_CLKSEL2_PLL, CM_CLKSEL_MDM 39 * CM_CLKSEL2_PLL, CM_CLKSEL_MDM
38 * 40 *
39 * Filling in table based on H4 boards and 2430-SDPs variants available. 41 * Filling in table based on H4 boards available. There are quite a
40 * There are quite a few more rates combinations which could be defined. 42 * few more rate combinations which could be defined.
41 * 43 *
42 * When multiple values are defined the start up will try and choose the 44 * When multiple values are defined the start up will try and choose
43 * fastest one. If a 'fast' value is defined, then automatically, the /2 45 * the fastest one. If a 'fast' value is defined, then automatically,
44 * one should be included as it can be used. Generally having more that 46 * the /2 one should be included as it can be used. Generally having
45 * one fast set does not make sense, as static timings need to be changed 47 * more than one fast set does not make sense, as static timings need
46 * to change the set. The exception is the bypass setting which is 48 * to be changed to change the set. The exception is the bypass
47 * availble for low power bypass. 49 * setting which is available for low power bypass.
48 * 50 *
49 * Note: This table needs to be sorted, fastest to slowest. 51 * Note: This table needs to be sorted, fastest to slowest.
50 *-------------------------------------------------------------------------*/ 52 **/
51const struct prcm_config omap2420_rate_table[] = { 53const struct prcm_config omap2420_rate_table[] = {
52 /* PRCM I - FAST */ 54 /* PRCM I - FAST */
53 {S12M, S660M, S330M, RI_CM_CLKSEL_MPU_VAL, /* 330MHz ARM */ 55 {S12M, S660M, S330M, RI_CM_CLKSEL_MPU_VAL, /* 330MHz ARM */